4 * Copyright (C) 2005 David Brownell
5 * Copyright (C) 2008 Secret Lab Technologies Ltd.
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License as published by
9 * the Free Software Foundation; either version 2 of the License, or
10 * (at your option) any later version.
12 * This program is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 * GNU General Public License for more details.
17 * You should have received a copy of the GNU General Public License
18 * along with this program; if not, write to the Free Software
19 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
22 #include <linux/kernel.h>
23 #include <linux/kmod.h>
24 #include <linux/device.h>
25 #include <linux/init.h>
26 #include <linux/cache.h>
27 #include <linux/dma-mapping.h>
28 #include <linux/dmaengine.h>
29 #include <linux/mutex.h>
30 #include <linux/of_device.h>
31 #include <linux/of_irq.h>
32 #include <linux/clk/clk-conf.h>
33 #include <linux/slab.h>
34 #include <linux/mod_devicetable.h>
35 #include <linux/spi/spi.h>
36 #include <linux/of_gpio.h>
37 #include <linux/pm_runtime.h>
38 #include <linux/pm_domain.h>
39 #include <linux/export.h>
40 #include <linux/sched/rt.h>
41 #include <linux/delay.h>
42 #include <linux/kthread.h>
43 #include <linux/ioport.h>
44 #include <linux/acpi.h>
46 #define CREATE_TRACE_POINTS
47 #include <trace/events/spi.h>
49 static void spidev_release(struct device
*dev
)
51 struct spi_device
*spi
= to_spi_device(dev
);
53 /* spi masters may cleanup for released devices */
54 if (spi
->master
->cleanup
)
55 spi
->master
->cleanup(spi
);
57 spi_master_put(spi
->master
);
62 modalias_show(struct device
*dev
, struct device_attribute
*a
, char *buf
)
64 const struct spi_device
*spi
= to_spi_device(dev
);
67 len
= acpi_device_modalias(dev
, buf
, PAGE_SIZE
- 1);
71 return sprintf(buf
, "%s%s\n", SPI_MODULE_PREFIX
, spi
->modalias
);
73 static DEVICE_ATTR_RO(modalias
);
75 static struct attribute
*spi_dev_attrs
[] = {
76 &dev_attr_modalias
.attr
,
79 ATTRIBUTE_GROUPS(spi_dev
);
81 /* modalias support makes "modprobe $MODALIAS" new-style hotplug work,
82 * and the sysfs version makes coldplug work too.
85 static const struct spi_device_id
*spi_match_id(const struct spi_device_id
*id
,
86 const struct spi_device
*sdev
)
89 if (!strcmp(sdev
->modalias
, id
->name
))
96 const struct spi_device_id
*spi_get_device_id(const struct spi_device
*sdev
)
98 const struct spi_driver
*sdrv
= to_spi_driver(sdev
->dev
.driver
);
100 return spi_match_id(sdrv
->id_table
, sdev
);
102 EXPORT_SYMBOL_GPL(spi_get_device_id
);
104 static int spi_match_device(struct device
*dev
, struct device_driver
*drv
)
106 const struct spi_device
*spi
= to_spi_device(dev
);
107 const struct spi_driver
*sdrv
= to_spi_driver(drv
);
109 /* Attempt an OF style match */
110 if (of_driver_match_device(dev
, drv
))
114 if (acpi_driver_match_device(dev
, drv
))
118 return !!spi_match_id(sdrv
->id_table
, spi
);
120 return strcmp(spi
->modalias
, drv
->name
) == 0;
123 static int spi_uevent(struct device
*dev
, struct kobj_uevent_env
*env
)
125 const struct spi_device
*spi
= to_spi_device(dev
);
128 rc
= acpi_device_uevent_modalias(dev
, env
);
132 add_uevent_var(env
, "MODALIAS=%s%s", SPI_MODULE_PREFIX
, spi
->modalias
);
136 #ifdef CONFIG_PM_SLEEP
137 static int spi_legacy_suspend(struct device
*dev
, pm_message_t message
)
140 struct spi_driver
*drv
= to_spi_driver(dev
->driver
);
142 /* suspend will stop irqs and dma; no more i/o */
145 value
= drv
->suspend(to_spi_device(dev
), message
);
147 dev_dbg(dev
, "... can't suspend\n");
152 static int spi_legacy_resume(struct device
*dev
)
155 struct spi_driver
*drv
= to_spi_driver(dev
->driver
);
157 /* resume may restart the i/o queue */
160 value
= drv
->resume(to_spi_device(dev
));
162 dev_dbg(dev
, "... can't resume\n");
167 static int spi_pm_suspend(struct device
*dev
)
169 const struct dev_pm_ops
*pm
= dev
->driver
? dev
->driver
->pm
: NULL
;
172 return pm_generic_suspend(dev
);
174 return spi_legacy_suspend(dev
, PMSG_SUSPEND
);
177 static int spi_pm_resume(struct device
*dev
)
179 const struct dev_pm_ops
*pm
= dev
->driver
? dev
->driver
->pm
: NULL
;
182 return pm_generic_resume(dev
);
184 return spi_legacy_resume(dev
);
187 static int spi_pm_freeze(struct device
*dev
)
189 const struct dev_pm_ops
*pm
= dev
->driver
? dev
->driver
->pm
: NULL
;
192 return pm_generic_freeze(dev
);
194 return spi_legacy_suspend(dev
, PMSG_FREEZE
);
197 static int spi_pm_thaw(struct device
*dev
)
199 const struct dev_pm_ops
*pm
= dev
->driver
? dev
->driver
->pm
: NULL
;
202 return pm_generic_thaw(dev
);
204 return spi_legacy_resume(dev
);
207 static int spi_pm_poweroff(struct device
*dev
)
209 const struct dev_pm_ops
*pm
= dev
->driver
? dev
->driver
->pm
: NULL
;
212 return pm_generic_poweroff(dev
);
214 return spi_legacy_suspend(dev
, PMSG_HIBERNATE
);
217 static int spi_pm_restore(struct device
*dev
)
219 const struct dev_pm_ops
*pm
= dev
->driver
? dev
->driver
->pm
: NULL
;
222 return pm_generic_restore(dev
);
224 return spi_legacy_resume(dev
);
227 #define spi_pm_suspend NULL
228 #define spi_pm_resume NULL
229 #define spi_pm_freeze NULL
230 #define spi_pm_thaw NULL
231 #define spi_pm_poweroff NULL
232 #define spi_pm_restore NULL
235 static const struct dev_pm_ops spi_pm
= {
236 .suspend
= spi_pm_suspend
,
237 .resume
= spi_pm_resume
,
238 .freeze
= spi_pm_freeze
,
240 .poweroff
= spi_pm_poweroff
,
241 .restore
= spi_pm_restore
,
243 pm_generic_runtime_suspend
,
244 pm_generic_runtime_resume
,
249 struct bus_type spi_bus_type
= {
251 .dev_groups
= spi_dev_groups
,
252 .match
= spi_match_device
,
253 .uevent
= spi_uevent
,
256 EXPORT_SYMBOL_GPL(spi_bus_type
);
259 static int spi_drv_probe(struct device
*dev
)
261 const struct spi_driver
*sdrv
= to_spi_driver(dev
->driver
);
264 ret
= of_clk_set_defaults(dev
->of_node
, false);
268 ret
= dev_pm_domain_attach(dev
, true);
269 if (ret
!= -EPROBE_DEFER
) {
270 ret
= sdrv
->probe(to_spi_device(dev
));
272 dev_pm_domain_detach(dev
, true);
278 static int spi_drv_remove(struct device
*dev
)
280 const struct spi_driver
*sdrv
= to_spi_driver(dev
->driver
);
283 ret
= sdrv
->remove(to_spi_device(dev
));
284 dev_pm_domain_detach(dev
, true);
289 static void spi_drv_shutdown(struct device
*dev
)
291 const struct spi_driver
*sdrv
= to_spi_driver(dev
->driver
);
293 sdrv
->shutdown(to_spi_device(dev
));
297 * spi_register_driver - register a SPI driver
298 * @sdrv: the driver to register
301 int spi_register_driver(struct spi_driver
*sdrv
)
303 sdrv
->driver
.bus
= &spi_bus_type
;
305 sdrv
->driver
.probe
= spi_drv_probe
;
307 sdrv
->driver
.remove
= spi_drv_remove
;
309 sdrv
->driver
.shutdown
= spi_drv_shutdown
;
310 return driver_register(&sdrv
->driver
);
312 EXPORT_SYMBOL_GPL(spi_register_driver
);
314 /*-------------------------------------------------------------------------*/
316 /* SPI devices should normally not be created by SPI device drivers; that
317 * would make them board-specific. Similarly with SPI master drivers.
318 * Device registration normally goes into like arch/.../mach.../board-YYY.c
319 * with other readonly (flashable) information about mainboard devices.
323 struct list_head list
;
324 struct spi_board_info board_info
;
327 static LIST_HEAD(board_list
);
328 static LIST_HEAD(spi_master_list
);
331 * Used to protect add/del opertion for board_info list and
332 * spi_master list, and their matching process
334 static DEFINE_MUTEX(board_lock
);
337 * spi_alloc_device - Allocate a new SPI device
338 * @master: Controller to which device is connected
341 * Allows a driver to allocate and initialize a spi_device without
342 * registering it immediately. This allows a driver to directly
343 * fill the spi_device with device parameters before calling
344 * spi_add_device() on it.
346 * Caller is responsible to call spi_add_device() on the returned
347 * spi_device structure to add it to the SPI master. If the caller
348 * needs to discard the spi_device without adding it, then it should
349 * call spi_dev_put() on it.
351 * Returns a pointer to the new device, or NULL.
353 struct spi_device
*spi_alloc_device(struct spi_master
*master
)
355 struct spi_device
*spi
;
357 if (!spi_master_get(master
))
360 spi
= kzalloc(sizeof(*spi
), GFP_KERNEL
);
362 spi_master_put(master
);
366 spi
->master
= master
;
367 spi
->dev
.parent
= &master
->dev
;
368 spi
->dev
.bus
= &spi_bus_type
;
369 spi
->dev
.release
= spidev_release
;
370 spi
->cs_gpio
= -ENOENT
;
371 device_initialize(&spi
->dev
);
374 EXPORT_SYMBOL_GPL(spi_alloc_device
);
376 static void spi_dev_set_name(struct spi_device
*spi
)
378 struct acpi_device
*adev
= ACPI_COMPANION(&spi
->dev
);
381 dev_set_name(&spi
->dev
, "spi-%s", acpi_dev_name(adev
));
385 dev_set_name(&spi
->dev
, "%s.%u", dev_name(&spi
->master
->dev
),
389 static int spi_dev_check(struct device
*dev
, void *data
)
391 struct spi_device
*spi
= to_spi_device(dev
);
392 struct spi_device
*new_spi
= data
;
394 if (spi
->master
== new_spi
->master
&&
395 spi
->chip_select
== new_spi
->chip_select
)
401 * spi_add_device - Add spi_device allocated with spi_alloc_device
402 * @spi: spi_device to register
404 * Companion function to spi_alloc_device. Devices allocated with
405 * spi_alloc_device can be added onto the spi bus with this function.
407 * Returns 0 on success; negative errno on failure
409 int spi_add_device(struct spi_device
*spi
)
411 static DEFINE_MUTEX(spi_add_lock
);
412 struct spi_master
*master
= spi
->master
;
413 struct device
*dev
= master
->dev
.parent
;
416 /* Chipselects are numbered 0..max; validate. */
417 if (spi
->chip_select
>= master
->num_chipselect
) {
418 dev_err(dev
, "cs%d >= max %d\n",
420 master
->num_chipselect
);
424 /* Set the bus ID string */
425 spi_dev_set_name(spi
);
427 /* We need to make sure there's no other device with this
428 * chipselect **BEFORE** we call setup(), else we'll trash
429 * its configuration. Lock against concurrent add() calls.
431 mutex_lock(&spi_add_lock
);
433 status
= bus_for_each_dev(&spi_bus_type
, NULL
, spi
, spi_dev_check
);
435 dev_err(dev
, "chipselect %d already in use\n",
440 if (master
->cs_gpios
)
441 spi
->cs_gpio
= master
->cs_gpios
[spi
->chip_select
];
443 /* Drivers may modify this initial i/o setup, but will
444 * normally rely on the device being setup. Devices
445 * using SPI_CS_HIGH can't coexist well otherwise...
447 status
= spi_setup(spi
);
449 dev_err(dev
, "can't setup %s, status %d\n",
450 dev_name(&spi
->dev
), status
);
454 /* Device may be bound to an active driver when this returns */
455 status
= device_add(&spi
->dev
);
457 dev_err(dev
, "can't add %s, status %d\n",
458 dev_name(&spi
->dev
), status
);
460 dev_dbg(dev
, "registered child %s\n", dev_name(&spi
->dev
));
463 mutex_unlock(&spi_add_lock
);
466 EXPORT_SYMBOL_GPL(spi_add_device
);
469 * spi_new_device - instantiate one new SPI device
470 * @master: Controller to which device is connected
471 * @chip: Describes the SPI device
474 * On typical mainboards, this is purely internal; and it's not needed
475 * after board init creates the hard-wired devices. Some development
476 * platforms may not be able to use spi_register_board_info though, and
477 * this is exported so that for example a USB or parport based adapter
478 * driver could add devices (which it would learn about out-of-band).
480 * Returns the new device, or NULL.
482 struct spi_device
*spi_new_device(struct spi_master
*master
,
483 struct spi_board_info
*chip
)
485 struct spi_device
*proxy
;
488 /* NOTE: caller did any chip->bus_num checks necessary.
490 * Also, unless we change the return value convention to use
491 * error-or-pointer (not NULL-or-pointer), troubleshootability
492 * suggests syslogged diagnostics are best here (ugh).
495 proxy
= spi_alloc_device(master
);
499 WARN_ON(strlen(chip
->modalias
) >= sizeof(proxy
->modalias
));
501 proxy
->chip_select
= chip
->chip_select
;
502 proxy
->max_speed_hz
= chip
->max_speed_hz
;
503 proxy
->mode
= chip
->mode
;
504 proxy
->irq
= chip
->irq
;
505 strlcpy(proxy
->modalias
, chip
->modalias
, sizeof(proxy
->modalias
));
506 proxy
->dev
.platform_data
= (void *) chip
->platform_data
;
507 proxy
->controller_data
= chip
->controller_data
;
508 proxy
->controller_state
= NULL
;
510 status
= spi_add_device(proxy
);
518 EXPORT_SYMBOL_GPL(spi_new_device
);
520 static void spi_match_master_to_boardinfo(struct spi_master
*master
,
521 struct spi_board_info
*bi
)
523 struct spi_device
*dev
;
525 if (master
->bus_num
!= bi
->bus_num
)
528 dev
= spi_new_device(master
, bi
);
530 dev_err(master
->dev
.parent
, "can't create new device for %s\n",
535 * spi_register_board_info - register SPI devices for a given board
536 * @info: array of chip descriptors
537 * @n: how many descriptors are provided
540 * Board-specific early init code calls this (probably during arch_initcall)
541 * with segments of the SPI device table. Any device nodes are created later,
542 * after the relevant parent SPI controller (bus_num) is defined. We keep
543 * this table of devices forever, so that reloading a controller driver will
544 * not make Linux forget about these hard-wired devices.
546 * Other code can also call this, e.g. a particular add-on board might provide
547 * SPI devices through its expansion connector, so code initializing that board
548 * would naturally declare its SPI devices.
550 * The board info passed can safely be __initdata ... but be careful of
551 * any embedded pointers (platform_data, etc), they're copied as-is.
553 int spi_register_board_info(struct spi_board_info
const *info
, unsigned n
)
555 struct boardinfo
*bi
;
561 bi
= kzalloc(n
* sizeof(*bi
), GFP_KERNEL
);
565 for (i
= 0; i
< n
; i
++, bi
++, info
++) {
566 struct spi_master
*master
;
568 memcpy(&bi
->board_info
, info
, sizeof(*info
));
569 mutex_lock(&board_lock
);
570 list_add_tail(&bi
->list
, &board_list
);
571 list_for_each_entry(master
, &spi_master_list
, list
)
572 spi_match_master_to_boardinfo(master
, &bi
->board_info
);
573 mutex_unlock(&board_lock
);
579 /*-------------------------------------------------------------------------*/
581 static void spi_set_cs(struct spi_device
*spi
, bool enable
)
583 if (spi
->mode
& SPI_CS_HIGH
)
586 if (spi
->cs_gpio
>= 0)
587 gpio_set_value(spi
->cs_gpio
, !enable
);
588 else if (spi
->master
->set_cs
)
589 spi
->master
->set_cs(spi
, !enable
);
592 #ifdef CONFIG_HAS_DMA
593 static int spi_map_buf(struct spi_master
*master
, struct device
*dev
,
594 struct sg_table
*sgt
, void *buf
, size_t len
,
595 enum dma_data_direction dir
)
597 const bool vmalloced_buf
= is_vmalloc_addr(buf
);
598 const int desc_len
= vmalloced_buf
? PAGE_SIZE
: master
->max_dma_len
;
599 const int sgs
= DIV_ROUND_UP(len
, desc_len
);
600 struct page
*vm_page
;
605 ret
= sg_alloc_table(sgt
, sgs
, GFP_KERNEL
);
609 for (i
= 0; i
< sgs
; i
++) {
610 min
= min_t(size_t, len
, desc_len
);
613 vm_page
= vmalloc_to_page(buf
);
618 sg_buf
= page_address(vm_page
) +
619 ((size_t)buf
& ~PAGE_MASK
);
624 sg_set_buf(&sgt
->sgl
[i
], sg_buf
, min
);
630 ret
= dma_map_sg(dev
, sgt
->sgl
, sgt
->nents
, dir
);
643 static void spi_unmap_buf(struct spi_master
*master
, struct device
*dev
,
644 struct sg_table
*sgt
, enum dma_data_direction dir
)
646 if (sgt
->orig_nents
) {
647 dma_unmap_sg(dev
, sgt
->sgl
, sgt
->orig_nents
, dir
);
652 static int __spi_map_msg(struct spi_master
*master
, struct spi_message
*msg
)
654 struct device
*tx_dev
, *rx_dev
;
655 struct spi_transfer
*xfer
;
658 if (!master
->can_dma
)
661 tx_dev
= master
->dma_tx
->device
->dev
;
662 rx_dev
= master
->dma_rx
->device
->dev
;
664 list_for_each_entry(xfer
, &msg
->transfers
, transfer_list
) {
665 if (!master
->can_dma(master
, msg
->spi
, xfer
))
668 if (xfer
->tx_buf
!= NULL
) {
669 ret
= spi_map_buf(master
, tx_dev
, &xfer
->tx_sg
,
670 (void *)xfer
->tx_buf
, xfer
->len
,
676 if (xfer
->rx_buf
!= NULL
) {
677 ret
= spi_map_buf(master
, rx_dev
, &xfer
->rx_sg
,
678 xfer
->rx_buf
, xfer
->len
,
681 spi_unmap_buf(master
, tx_dev
, &xfer
->tx_sg
,
688 master
->cur_msg_mapped
= true;
693 static int spi_unmap_msg(struct spi_master
*master
, struct spi_message
*msg
)
695 struct spi_transfer
*xfer
;
696 struct device
*tx_dev
, *rx_dev
;
698 if (!master
->cur_msg_mapped
|| !master
->can_dma
)
701 tx_dev
= master
->dma_tx
->device
->dev
;
702 rx_dev
= master
->dma_rx
->device
->dev
;
704 list_for_each_entry(xfer
, &msg
->transfers
, transfer_list
) {
705 if (!master
->can_dma(master
, msg
->spi
, xfer
))
708 spi_unmap_buf(master
, rx_dev
, &xfer
->rx_sg
, DMA_FROM_DEVICE
);
709 spi_unmap_buf(master
, tx_dev
, &xfer
->tx_sg
, DMA_TO_DEVICE
);
714 #else /* !CONFIG_HAS_DMA */
715 static inline int __spi_map_msg(struct spi_master
*master
,
716 struct spi_message
*msg
)
721 static inline int spi_unmap_msg(struct spi_master
*master
,
722 struct spi_message
*msg
)
726 #endif /* !CONFIG_HAS_DMA */
728 static int spi_map_msg(struct spi_master
*master
, struct spi_message
*msg
)
730 struct spi_transfer
*xfer
;
732 unsigned int max_tx
, max_rx
;
734 if (master
->flags
& (SPI_MASTER_MUST_RX
| SPI_MASTER_MUST_TX
)) {
738 list_for_each_entry(xfer
, &msg
->transfers
, transfer_list
) {
739 if ((master
->flags
& SPI_MASTER_MUST_TX
) &&
741 max_tx
= max(xfer
->len
, max_tx
);
742 if ((master
->flags
& SPI_MASTER_MUST_RX
) &&
744 max_rx
= max(xfer
->len
, max_rx
);
748 tmp
= krealloc(master
->dummy_tx
, max_tx
,
749 GFP_KERNEL
| GFP_DMA
);
752 master
->dummy_tx
= tmp
;
753 memset(tmp
, 0, max_tx
);
757 tmp
= krealloc(master
->dummy_rx
, max_rx
,
758 GFP_KERNEL
| GFP_DMA
);
761 master
->dummy_rx
= tmp
;
764 if (max_tx
|| max_rx
) {
765 list_for_each_entry(xfer
, &msg
->transfers
,
768 xfer
->tx_buf
= master
->dummy_tx
;
770 xfer
->rx_buf
= master
->dummy_rx
;
775 return __spi_map_msg(master
, msg
);
779 * spi_transfer_one_message - Default implementation of transfer_one_message()
781 * This is a standard implementation of transfer_one_message() for
782 * drivers which impelment a transfer_one() operation. It provides
783 * standard handling of delays and chip select management.
785 static int spi_transfer_one_message(struct spi_master
*master
,
786 struct spi_message
*msg
)
788 struct spi_transfer
*xfer
;
789 bool keep_cs
= false;
793 spi_set_cs(msg
->spi
, true);
795 list_for_each_entry(xfer
, &msg
->transfers
, transfer_list
) {
796 trace_spi_transfer_start(msg
, xfer
);
798 if (xfer
->tx_buf
|| xfer
->rx_buf
) {
799 reinit_completion(&master
->xfer_completion
);
801 ret
= master
->transfer_one(master
, msg
->spi
, xfer
);
803 dev_err(&msg
->spi
->dev
,
804 "SPI transfer failed: %d\n", ret
);
810 ms
= xfer
->len
* 8 * 1000 / xfer
->speed_hz
;
811 ms
+= ms
+ 100; /* some tolerance */
813 ms
= wait_for_completion_timeout(&master
->xfer_completion
,
814 msecs_to_jiffies(ms
));
818 dev_err(&msg
->spi
->dev
,
819 "SPI transfer timed out\n");
820 msg
->status
= -ETIMEDOUT
;
824 dev_err(&msg
->spi
->dev
,
825 "Bufferless transfer has length %u\n",
829 trace_spi_transfer_stop(msg
, xfer
);
831 if (msg
->status
!= -EINPROGRESS
)
834 if (xfer
->delay_usecs
)
835 udelay(xfer
->delay_usecs
);
837 if (xfer
->cs_change
) {
838 if (list_is_last(&xfer
->transfer_list
,
842 spi_set_cs(msg
->spi
, false);
844 spi_set_cs(msg
->spi
, true);
848 msg
->actual_length
+= xfer
->len
;
852 if (ret
!= 0 || !keep_cs
)
853 spi_set_cs(msg
->spi
, false);
855 if (msg
->status
== -EINPROGRESS
)
858 spi_finalize_current_message(master
);
864 * spi_finalize_current_transfer - report completion of a transfer
865 * @master: the master reporting completion
867 * Called by SPI drivers using the core transfer_one_message()
868 * implementation to notify it that the current interrupt driven
869 * transfer has finished and the next one may be scheduled.
871 void spi_finalize_current_transfer(struct spi_master
*master
)
873 complete(&master
->xfer_completion
);
875 EXPORT_SYMBOL_GPL(spi_finalize_current_transfer
);
878 * spi_pump_messages - kthread work function which processes spi message queue
879 * @work: pointer to kthread work struct contained in the master struct
881 * This function checks if there is any spi message in the queue that
882 * needs processing and if so call out to the driver to initialize hardware
883 * and transfer each message.
886 static void spi_pump_messages(struct kthread_work
*work
)
888 struct spi_master
*master
=
889 container_of(work
, struct spi_master
, pump_messages
);
891 bool was_busy
= false;
894 /* Lock queue and check for queue work */
895 spin_lock_irqsave(&master
->queue_lock
, flags
);
896 if (list_empty(&master
->queue
) || !master
->running
) {
898 spin_unlock_irqrestore(&master
->queue_lock
, flags
);
901 master
->busy
= false;
902 spin_unlock_irqrestore(&master
->queue_lock
, flags
);
903 kfree(master
->dummy_rx
);
904 master
->dummy_rx
= NULL
;
905 kfree(master
->dummy_tx
);
906 master
->dummy_tx
= NULL
;
907 if (master
->unprepare_transfer_hardware
&&
908 master
->unprepare_transfer_hardware(master
))
909 dev_err(&master
->dev
,
910 "failed to unprepare transfer hardware\n");
911 if (master
->auto_runtime_pm
) {
912 pm_runtime_mark_last_busy(master
->dev
.parent
);
913 pm_runtime_put_autosuspend(master
->dev
.parent
);
915 trace_spi_master_idle(master
);
919 /* Make sure we are not already running a message */
920 if (master
->cur_msg
) {
921 spin_unlock_irqrestore(&master
->queue_lock
, flags
);
924 /* Extract head of queue */
926 list_first_entry(&master
->queue
, struct spi_message
, queue
);
928 list_del_init(&master
->cur_msg
->queue
);
933 spin_unlock_irqrestore(&master
->queue_lock
, flags
);
935 if (!was_busy
&& master
->auto_runtime_pm
) {
936 ret
= pm_runtime_get_sync(master
->dev
.parent
);
938 dev_err(&master
->dev
, "Failed to power device: %d\n",
945 trace_spi_master_busy(master
);
947 if (!was_busy
&& master
->prepare_transfer_hardware
) {
948 ret
= master
->prepare_transfer_hardware(master
);
950 dev_err(&master
->dev
,
951 "failed to prepare transfer hardware\n");
953 if (master
->auto_runtime_pm
)
954 pm_runtime_put(master
->dev
.parent
);
959 trace_spi_message_start(master
->cur_msg
);
961 if (master
->prepare_message
) {
962 ret
= master
->prepare_message(master
, master
->cur_msg
);
964 dev_err(&master
->dev
,
965 "failed to prepare message: %d\n", ret
);
966 master
->cur_msg
->status
= ret
;
967 spi_finalize_current_message(master
);
970 master
->cur_msg_prepared
= true;
973 ret
= spi_map_msg(master
, master
->cur_msg
);
975 master
->cur_msg
->status
= ret
;
976 spi_finalize_current_message(master
);
980 ret
= master
->transfer_one_message(master
, master
->cur_msg
);
982 dev_err(&master
->dev
,
983 "failed to transfer one message from queue\n");
988 static int spi_init_queue(struct spi_master
*master
)
990 struct sched_param param
= { .sched_priority
= MAX_RT_PRIO
- 1 };
992 INIT_LIST_HEAD(&master
->queue
);
993 spin_lock_init(&master
->queue_lock
);
995 master
->running
= false;
996 master
->busy
= false;
998 init_kthread_worker(&master
->kworker
);
999 master
->kworker_task
= kthread_run(kthread_worker_fn
,
1000 &master
->kworker
, "%s",
1001 dev_name(&master
->dev
));
1002 if (IS_ERR(master
->kworker_task
)) {
1003 dev_err(&master
->dev
, "failed to create message pump task\n");
1006 init_kthread_work(&master
->pump_messages
, spi_pump_messages
);
1009 * Master config will indicate if this controller should run the
1010 * message pump with high (realtime) priority to reduce the transfer
1011 * latency on the bus by minimising the delay between a transfer
1012 * request and the scheduling of the message pump thread. Without this
1013 * setting the message pump thread will remain at default priority.
1016 dev_info(&master
->dev
,
1017 "will run message pump with realtime priority\n");
1018 sched_setscheduler(master
->kworker_task
, SCHED_FIFO
, ¶m
);
1025 * spi_get_next_queued_message() - called by driver to check for queued
1027 * @master: the master to check for queued messages
1029 * If there are more messages in the queue, the next message is returned from
1032 struct spi_message
*spi_get_next_queued_message(struct spi_master
*master
)
1034 struct spi_message
*next
;
1035 unsigned long flags
;
1037 /* get a pointer to the next message, if any */
1038 spin_lock_irqsave(&master
->queue_lock
, flags
);
1039 next
= list_first_entry_or_null(&master
->queue
, struct spi_message
,
1041 spin_unlock_irqrestore(&master
->queue_lock
, flags
);
1045 EXPORT_SYMBOL_GPL(spi_get_next_queued_message
);
1048 * spi_finalize_current_message() - the current message is complete
1049 * @master: the master to return the message to
1051 * Called by the driver to notify the core that the message in the front of the
1052 * queue is complete and can be removed from the queue.
1054 void spi_finalize_current_message(struct spi_master
*master
)
1056 struct spi_message
*mesg
;
1057 unsigned long flags
;
1060 spin_lock_irqsave(&master
->queue_lock
, flags
);
1061 mesg
= master
->cur_msg
;
1062 master
->cur_msg
= NULL
;
1064 queue_kthread_work(&master
->kworker
, &master
->pump_messages
);
1065 spin_unlock_irqrestore(&master
->queue_lock
, flags
);
1067 spi_unmap_msg(master
, mesg
);
1069 if (master
->cur_msg_prepared
&& master
->unprepare_message
) {
1070 ret
= master
->unprepare_message(master
, mesg
);
1072 dev_err(&master
->dev
,
1073 "failed to unprepare message: %d\n", ret
);
1076 master
->cur_msg_prepared
= false;
1080 mesg
->complete(mesg
->context
);
1082 trace_spi_message_done(mesg
);
1084 EXPORT_SYMBOL_GPL(spi_finalize_current_message
);
1086 static int spi_start_queue(struct spi_master
*master
)
1088 unsigned long flags
;
1090 spin_lock_irqsave(&master
->queue_lock
, flags
);
1092 if (master
->running
|| master
->busy
) {
1093 spin_unlock_irqrestore(&master
->queue_lock
, flags
);
1097 master
->running
= true;
1098 master
->cur_msg
= NULL
;
1099 spin_unlock_irqrestore(&master
->queue_lock
, flags
);
1101 queue_kthread_work(&master
->kworker
, &master
->pump_messages
);
1106 static int spi_stop_queue(struct spi_master
*master
)
1108 unsigned long flags
;
1109 unsigned limit
= 500;
1112 spin_lock_irqsave(&master
->queue_lock
, flags
);
1115 * This is a bit lame, but is optimized for the common execution path.
1116 * A wait_queue on the master->busy could be used, but then the common
1117 * execution path (pump_messages) would be required to call wake_up or
1118 * friends on every SPI message. Do this instead.
1120 while ((!list_empty(&master
->queue
) || master
->busy
) && limit
--) {
1121 spin_unlock_irqrestore(&master
->queue_lock
, flags
);
1122 usleep_range(10000, 11000);
1123 spin_lock_irqsave(&master
->queue_lock
, flags
);
1126 if (!list_empty(&master
->queue
) || master
->busy
)
1129 master
->running
= false;
1131 spin_unlock_irqrestore(&master
->queue_lock
, flags
);
1134 dev_warn(&master
->dev
,
1135 "could not stop message queue\n");
1141 static int spi_destroy_queue(struct spi_master
*master
)
1145 ret
= spi_stop_queue(master
);
1148 * flush_kthread_worker will block until all work is done.
1149 * If the reason that stop_queue timed out is that the work will never
1150 * finish, then it does no good to call flush/stop thread, so
1154 dev_err(&master
->dev
, "problem destroying queue\n");
1158 flush_kthread_worker(&master
->kworker
);
1159 kthread_stop(master
->kworker_task
);
1165 * spi_queued_transfer - transfer function for queued transfers
1166 * @spi: spi device which is requesting transfer
1167 * @msg: spi message which is to handled is queued to driver queue
1169 static int spi_queued_transfer(struct spi_device
*spi
, struct spi_message
*msg
)
1171 struct spi_master
*master
= spi
->master
;
1172 unsigned long flags
;
1174 spin_lock_irqsave(&master
->queue_lock
, flags
);
1176 if (!master
->running
) {
1177 spin_unlock_irqrestore(&master
->queue_lock
, flags
);
1180 msg
->actual_length
= 0;
1181 msg
->status
= -EINPROGRESS
;
1183 list_add_tail(&msg
->queue
, &master
->queue
);
1185 queue_kthread_work(&master
->kworker
, &master
->pump_messages
);
1187 spin_unlock_irqrestore(&master
->queue_lock
, flags
);
1191 static int spi_master_initialize_queue(struct spi_master
*master
)
1195 master
->transfer
= spi_queued_transfer
;
1196 if (!master
->transfer_one_message
)
1197 master
->transfer_one_message
= spi_transfer_one_message
;
1199 /* Initialize and start queue */
1200 ret
= spi_init_queue(master
);
1202 dev_err(&master
->dev
, "problem initializing queue\n");
1203 goto err_init_queue
;
1205 master
->queued
= true;
1206 ret
= spi_start_queue(master
);
1208 dev_err(&master
->dev
, "problem starting queue\n");
1209 goto err_start_queue
;
1215 spi_destroy_queue(master
);
1220 /*-------------------------------------------------------------------------*/
1222 #if defined(CONFIG_OF)
1224 * of_register_spi_devices() - Register child devices onto the SPI bus
1225 * @master: Pointer to spi_master device
1227 * Registers an spi_device for each child node of master node which has a 'reg'
1230 static void of_register_spi_devices(struct spi_master
*master
)
1232 struct spi_device
*spi
;
1233 struct device_node
*nc
;
1237 if (!master
->dev
.of_node
)
1240 for_each_available_child_of_node(master
->dev
.of_node
, nc
) {
1241 /* Alloc an spi_device */
1242 spi
= spi_alloc_device(master
);
1244 dev_err(&master
->dev
, "spi_device alloc error for %s\n",
1250 /* Select device driver */
1251 if (of_modalias_node(nc
, spi
->modalias
,
1252 sizeof(spi
->modalias
)) < 0) {
1253 dev_err(&master
->dev
, "cannot find modalias for %s\n",
1259 /* Device address */
1260 rc
= of_property_read_u32(nc
, "reg", &value
);
1262 dev_err(&master
->dev
, "%s has no valid 'reg' property (%d)\n",
1267 spi
->chip_select
= value
;
1269 /* Mode (clock phase/polarity/etc.) */
1270 if (of_find_property(nc
, "spi-cpha", NULL
))
1271 spi
->mode
|= SPI_CPHA
;
1272 if (of_find_property(nc
, "spi-cpol", NULL
))
1273 spi
->mode
|= SPI_CPOL
;
1274 if (of_find_property(nc
, "spi-cs-high", NULL
))
1275 spi
->mode
|= SPI_CS_HIGH
;
1276 if (of_find_property(nc
, "spi-3wire", NULL
))
1277 spi
->mode
|= SPI_3WIRE
;
1278 if (of_find_property(nc
, "spi-lsb-first", NULL
))
1279 spi
->mode
|= SPI_LSB_FIRST
;
1281 /* Device DUAL/QUAD mode */
1282 if (!of_property_read_u32(nc
, "spi-tx-bus-width", &value
)) {
1287 spi
->mode
|= SPI_TX_DUAL
;
1290 spi
->mode
|= SPI_TX_QUAD
;
1293 dev_warn(&master
->dev
,
1294 "spi-tx-bus-width %d not supported\n",
1300 if (!of_property_read_u32(nc
, "spi-rx-bus-width", &value
)) {
1305 spi
->mode
|= SPI_RX_DUAL
;
1308 spi
->mode
|= SPI_RX_QUAD
;
1311 dev_warn(&master
->dev
,
1312 "spi-rx-bus-width %d not supported\n",
1319 rc
= of_property_read_u32(nc
, "spi-max-frequency", &value
);
1321 dev_err(&master
->dev
, "%s has no valid 'spi-max-frequency' property (%d)\n",
1326 spi
->max_speed_hz
= value
;
1329 spi
->irq
= irq_of_parse_and_map(nc
, 0);
1331 /* Store a pointer to the node in the device structure */
1333 spi
->dev
.of_node
= nc
;
1335 /* Register the new device */
1336 request_module("%s%s", SPI_MODULE_PREFIX
, spi
->modalias
);
1337 rc
= spi_add_device(spi
);
1339 dev_err(&master
->dev
, "spi_device register error %s\n",
1347 static void of_register_spi_devices(struct spi_master
*master
) { }
1351 static int acpi_spi_add_resource(struct acpi_resource
*ares
, void *data
)
1353 struct spi_device
*spi
= data
;
1355 if (ares
->type
== ACPI_RESOURCE_TYPE_SERIAL_BUS
) {
1356 struct acpi_resource_spi_serialbus
*sb
;
1358 sb
= &ares
->data
.spi_serial_bus
;
1359 if (sb
->type
== ACPI_RESOURCE_SERIAL_TYPE_SPI
) {
1360 spi
->chip_select
= sb
->device_selection
;
1361 spi
->max_speed_hz
= sb
->connection_speed
;
1363 if (sb
->clock_phase
== ACPI_SPI_SECOND_PHASE
)
1364 spi
->mode
|= SPI_CPHA
;
1365 if (sb
->clock_polarity
== ACPI_SPI_START_HIGH
)
1366 spi
->mode
|= SPI_CPOL
;
1367 if (sb
->device_polarity
== ACPI_SPI_ACTIVE_HIGH
)
1368 spi
->mode
|= SPI_CS_HIGH
;
1370 } else if (spi
->irq
< 0) {
1373 if (acpi_dev_resource_interrupt(ares
, 0, &r
))
1377 /* Always tell the ACPI core to skip this resource */
1381 static acpi_status
acpi_spi_add_device(acpi_handle handle
, u32 level
,
1382 void *data
, void **return_value
)
1384 struct spi_master
*master
= data
;
1385 struct list_head resource_list
;
1386 struct acpi_device
*adev
;
1387 struct spi_device
*spi
;
1390 if (acpi_bus_get_device(handle
, &adev
))
1392 if (acpi_bus_get_status(adev
) || !adev
->status
.present
)
1395 spi
= spi_alloc_device(master
);
1397 dev_err(&master
->dev
, "failed to allocate SPI device for %s\n",
1398 dev_name(&adev
->dev
));
1399 return AE_NO_MEMORY
;
1402 ACPI_COMPANION_SET(&spi
->dev
, adev
);
1405 INIT_LIST_HEAD(&resource_list
);
1406 ret
= acpi_dev_get_resources(adev
, &resource_list
,
1407 acpi_spi_add_resource
, spi
);
1408 acpi_dev_free_resource_list(&resource_list
);
1410 if (ret
< 0 || !spi
->max_speed_hz
) {
1415 adev
->power
.flags
.ignore_parent
= true;
1416 strlcpy(spi
->modalias
, acpi_device_hid(adev
), sizeof(spi
->modalias
));
1417 if (spi_add_device(spi
)) {
1418 adev
->power
.flags
.ignore_parent
= false;
1419 dev_err(&master
->dev
, "failed to add SPI device %s from ACPI\n",
1420 dev_name(&adev
->dev
));
1427 static void acpi_register_spi_devices(struct spi_master
*master
)
1432 handle
= ACPI_HANDLE(master
->dev
.parent
);
1436 status
= acpi_walk_namespace(ACPI_TYPE_DEVICE
, handle
, 1,
1437 acpi_spi_add_device
, NULL
,
1439 if (ACPI_FAILURE(status
))
1440 dev_warn(&master
->dev
, "failed to enumerate SPI slaves\n");
1443 static inline void acpi_register_spi_devices(struct spi_master
*master
) {}
1444 #endif /* CONFIG_ACPI */
1446 static void spi_master_release(struct device
*dev
)
1448 struct spi_master
*master
;
1450 master
= container_of(dev
, struct spi_master
, dev
);
1454 static struct class spi_master_class
= {
1455 .name
= "spi_master",
1456 .owner
= THIS_MODULE
,
1457 .dev_release
= spi_master_release
,
1463 * spi_alloc_master - allocate SPI master controller
1464 * @dev: the controller, possibly using the platform_bus
1465 * @size: how much zeroed driver-private data to allocate; the pointer to this
1466 * memory is in the driver_data field of the returned device,
1467 * accessible with spi_master_get_devdata().
1468 * Context: can sleep
1470 * This call is used only by SPI master controller drivers, which are the
1471 * only ones directly touching chip registers. It's how they allocate
1472 * an spi_master structure, prior to calling spi_register_master().
1474 * This must be called from context that can sleep. It returns the SPI
1475 * master structure on success, else NULL.
1477 * The caller is responsible for assigning the bus number and initializing
1478 * the master's methods before calling spi_register_master(); and (after errors
1479 * adding the device) calling spi_master_put() and kfree() to prevent a memory
1482 struct spi_master
*spi_alloc_master(struct device
*dev
, unsigned size
)
1484 struct spi_master
*master
;
1489 master
= kzalloc(size
+ sizeof(*master
), GFP_KERNEL
);
1493 device_initialize(&master
->dev
);
1494 master
->bus_num
= -1;
1495 master
->num_chipselect
= 1;
1496 master
->dev
.class = &spi_master_class
;
1497 master
->dev
.parent
= get_device(dev
);
1498 spi_master_set_devdata(master
, &master
[1]);
1502 EXPORT_SYMBOL_GPL(spi_alloc_master
);
1505 static int of_spi_register_master(struct spi_master
*master
)
1508 struct device_node
*np
= master
->dev
.of_node
;
1513 nb
= of_gpio_named_count(np
, "cs-gpios");
1514 master
->num_chipselect
= max_t(int, nb
, master
->num_chipselect
);
1516 /* Return error only for an incorrectly formed cs-gpios property */
1517 if (nb
== 0 || nb
== -ENOENT
)
1522 cs
= devm_kzalloc(&master
->dev
,
1523 sizeof(int) * master
->num_chipselect
,
1525 master
->cs_gpios
= cs
;
1527 if (!master
->cs_gpios
)
1530 for (i
= 0; i
< master
->num_chipselect
; i
++)
1533 for (i
= 0; i
< nb
; i
++)
1534 cs
[i
] = of_get_named_gpio(np
, "cs-gpios", i
);
1539 static int of_spi_register_master(struct spi_master
*master
)
1546 * spi_register_master - register SPI master controller
1547 * @master: initialized master, originally from spi_alloc_master()
1548 * Context: can sleep
1550 * SPI master controllers connect to their drivers using some non-SPI bus,
1551 * such as the platform bus. The final stage of probe() in that code
1552 * includes calling spi_register_master() to hook up to this SPI bus glue.
1554 * SPI controllers use board specific (often SOC specific) bus numbers,
1555 * and board-specific addressing for SPI devices combines those numbers
1556 * with chip select numbers. Since SPI does not directly support dynamic
1557 * device identification, boards need configuration tables telling which
1558 * chip is at which address.
1560 * This must be called from context that can sleep. It returns zero on
1561 * success, else a negative error code (dropping the master's refcount).
1562 * After a successful return, the caller is responsible for calling
1563 * spi_unregister_master().
1565 int spi_register_master(struct spi_master
*master
)
1567 static atomic_t dyn_bus_id
= ATOMIC_INIT((1<<15) - 1);
1568 struct device
*dev
= master
->dev
.parent
;
1569 struct boardinfo
*bi
;
1570 int status
= -ENODEV
;
1576 status
= of_spi_register_master(master
);
1580 /* even if it's just one always-selected device, there must
1581 * be at least one chipselect
1583 if (master
->num_chipselect
== 0)
1586 if ((master
->bus_num
< 0) && master
->dev
.of_node
)
1587 master
->bus_num
= of_alias_get_id(master
->dev
.of_node
, "spi");
1589 /* convention: dynamically assigned bus IDs count down from the max */
1590 if (master
->bus_num
< 0) {
1591 /* FIXME switch to an IDR based scheme, something like
1592 * I2C now uses, so we can't run out of "dynamic" IDs
1594 master
->bus_num
= atomic_dec_return(&dyn_bus_id
);
1598 spin_lock_init(&master
->bus_lock_spinlock
);
1599 mutex_init(&master
->bus_lock_mutex
);
1600 master
->bus_lock_flag
= 0;
1601 init_completion(&master
->xfer_completion
);
1602 if (!master
->max_dma_len
)
1603 master
->max_dma_len
= INT_MAX
;
1605 /* register the device, then userspace will see it.
1606 * registration fails if the bus ID is in use.
1608 dev_set_name(&master
->dev
, "spi%u", master
->bus_num
);
1609 status
= device_add(&master
->dev
);
1612 dev_dbg(dev
, "registered master %s%s\n", dev_name(&master
->dev
),
1613 dynamic
? " (dynamic)" : "");
1615 /* If we're using a queued driver, start the queue */
1616 if (master
->transfer
)
1617 dev_info(dev
, "master is unqueued, this is deprecated\n");
1619 status
= spi_master_initialize_queue(master
);
1621 device_del(&master
->dev
);
1626 mutex_lock(&board_lock
);
1627 list_add_tail(&master
->list
, &spi_master_list
);
1628 list_for_each_entry(bi
, &board_list
, list
)
1629 spi_match_master_to_boardinfo(master
, &bi
->board_info
);
1630 mutex_unlock(&board_lock
);
1632 /* Register devices from the device tree and ACPI */
1633 of_register_spi_devices(master
);
1634 acpi_register_spi_devices(master
);
1638 EXPORT_SYMBOL_GPL(spi_register_master
);
1640 static void devm_spi_unregister(struct device
*dev
, void *res
)
1642 spi_unregister_master(*(struct spi_master
**)res
);
1646 * dev_spi_register_master - register managed SPI master controller
1647 * @dev: device managing SPI master
1648 * @master: initialized master, originally from spi_alloc_master()
1649 * Context: can sleep
1651 * Register a SPI device as with spi_register_master() which will
1652 * automatically be unregister
1654 int devm_spi_register_master(struct device
*dev
, struct spi_master
*master
)
1656 struct spi_master
**ptr
;
1659 ptr
= devres_alloc(devm_spi_unregister
, sizeof(*ptr
), GFP_KERNEL
);
1663 ret
= spi_register_master(master
);
1666 devres_add(dev
, ptr
);
1673 EXPORT_SYMBOL_GPL(devm_spi_register_master
);
1675 static int __unregister(struct device
*dev
, void *null
)
1677 spi_unregister_device(to_spi_device(dev
));
1682 * spi_unregister_master - unregister SPI master controller
1683 * @master: the master being unregistered
1684 * Context: can sleep
1686 * This call is used only by SPI master controller drivers, which are the
1687 * only ones directly touching chip registers.
1689 * This must be called from context that can sleep.
1691 void spi_unregister_master(struct spi_master
*master
)
1695 if (master
->queued
) {
1696 if (spi_destroy_queue(master
))
1697 dev_err(&master
->dev
, "queue remove failed\n");
1700 mutex_lock(&board_lock
);
1701 list_del(&master
->list
);
1702 mutex_unlock(&board_lock
);
1704 dummy
= device_for_each_child(&master
->dev
, NULL
, __unregister
);
1705 device_unregister(&master
->dev
);
1707 EXPORT_SYMBOL_GPL(spi_unregister_master
);
1709 int spi_master_suspend(struct spi_master
*master
)
1713 /* Basically no-ops for non-queued masters */
1714 if (!master
->queued
)
1717 ret
= spi_stop_queue(master
);
1719 dev_err(&master
->dev
, "queue stop failed\n");
1723 EXPORT_SYMBOL_GPL(spi_master_suspend
);
1725 int spi_master_resume(struct spi_master
*master
)
1729 if (!master
->queued
)
1732 ret
= spi_start_queue(master
);
1734 dev_err(&master
->dev
, "queue restart failed\n");
1738 EXPORT_SYMBOL_GPL(spi_master_resume
);
1740 static int __spi_master_match(struct device
*dev
, const void *data
)
1742 struct spi_master
*m
;
1743 const u16
*bus_num
= data
;
1745 m
= container_of(dev
, struct spi_master
, dev
);
1746 return m
->bus_num
== *bus_num
;
1750 * spi_busnum_to_master - look up master associated with bus_num
1751 * @bus_num: the master's bus number
1752 * Context: can sleep
1754 * This call may be used with devices that are registered after
1755 * arch init time. It returns a refcounted pointer to the relevant
1756 * spi_master (which the caller must release), or NULL if there is
1757 * no such master registered.
1759 struct spi_master
*spi_busnum_to_master(u16 bus_num
)
1762 struct spi_master
*master
= NULL
;
1764 dev
= class_find_device(&spi_master_class
, NULL
, &bus_num
,
1765 __spi_master_match
);
1767 master
= container_of(dev
, struct spi_master
, dev
);
1768 /* reference got in class_find_device */
1771 EXPORT_SYMBOL_GPL(spi_busnum_to_master
);
1774 /*-------------------------------------------------------------------------*/
1776 /* Core methods for SPI master protocol drivers. Some of the
1777 * other core methods are currently defined as inline functions.
1781 * spi_setup - setup SPI mode and clock rate
1782 * @spi: the device whose settings are being modified
1783 * Context: can sleep, and no requests are queued to the device
1785 * SPI protocol drivers may need to update the transfer mode if the
1786 * device doesn't work with its default. They may likewise need
1787 * to update clock rates or word sizes from initial values. This function
1788 * changes those settings, and must be called from a context that can sleep.
1789 * Except for SPI_CS_HIGH, which takes effect immediately, the changes take
1790 * effect the next time the device is selected and data is transferred to
1791 * or from it. When this function returns, the spi device is deselected.
1793 * Note that this call will fail if the protocol driver specifies an option
1794 * that the underlying controller or its driver does not support. For
1795 * example, not all hardware supports wire transfers using nine bit words,
1796 * LSB-first wire encoding, or active-high chipselects.
1798 int spi_setup(struct spi_device
*spi
)
1800 unsigned bad_bits
, ugly_bits
;
1803 /* check mode to prevent that DUAL and QUAD set at the same time
1805 if (((spi
->mode
& SPI_TX_DUAL
) && (spi
->mode
& SPI_TX_QUAD
)) ||
1806 ((spi
->mode
& SPI_RX_DUAL
) && (spi
->mode
& SPI_RX_QUAD
))) {
1808 "setup: can not select dual and quad at the same time\n");
1811 /* if it is SPI_3WIRE mode, DUAL and QUAD should be forbidden
1813 if ((spi
->mode
& SPI_3WIRE
) && (spi
->mode
&
1814 (SPI_TX_DUAL
| SPI_TX_QUAD
| SPI_RX_DUAL
| SPI_RX_QUAD
)))
1816 /* help drivers fail *cleanly* when they need options
1817 * that aren't supported with their current master
1819 bad_bits
= spi
->mode
& ~spi
->master
->mode_bits
;
1820 ugly_bits
= bad_bits
&
1821 (SPI_TX_DUAL
| SPI_TX_QUAD
| SPI_RX_DUAL
| SPI_RX_QUAD
);
1824 "setup: ignoring unsupported mode bits %x\n",
1826 spi
->mode
&= ~ugly_bits
;
1827 bad_bits
&= ~ugly_bits
;
1830 dev_err(&spi
->dev
, "setup: unsupported mode bits %x\n",
1835 if (!spi
->bits_per_word
)
1836 spi
->bits_per_word
= 8;
1838 if (!spi
->max_speed_hz
)
1839 spi
->max_speed_hz
= spi
->master
->max_speed_hz
;
1841 if (spi
->master
->setup
)
1842 status
= spi
->master
->setup(spi
);
1844 dev_dbg(&spi
->dev
, "setup mode %d, %s%s%s%s%u bits/w, %u Hz max --> %d\n",
1845 (int) (spi
->mode
& (SPI_CPOL
| SPI_CPHA
)),
1846 (spi
->mode
& SPI_CS_HIGH
) ? "cs_high, " : "",
1847 (spi
->mode
& SPI_LSB_FIRST
) ? "lsb, " : "",
1848 (spi
->mode
& SPI_3WIRE
) ? "3wire, " : "",
1849 (spi
->mode
& SPI_LOOP
) ? "loopback, " : "",
1850 spi
->bits_per_word
, spi
->max_speed_hz
,
1855 EXPORT_SYMBOL_GPL(spi_setup
);
1857 static int __spi_validate(struct spi_device
*spi
, struct spi_message
*message
)
1859 struct spi_master
*master
= spi
->master
;
1860 struct spi_transfer
*xfer
;
1863 if (list_empty(&message
->transfers
))
1866 /* Half-duplex links include original MicroWire, and ones with
1867 * only one data pin like SPI_3WIRE (switches direction) or where
1868 * either MOSI or MISO is missing. They can also be caused by
1869 * software limitations.
1871 if ((master
->flags
& SPI_MASTER_HALF_DUPLEX
)
1872 || (spi
->mode
& SPI_3WIRE
)) {
1873 unsigned flags
= master
->flags
;
1875 list_for_each_entry(xfer
, &message
->transfers
, transfer_list
) {
1876 if (xfer
->rx_buf
&& xfer
->tx_buf
)
1878 if ((flags
& SPI_MASTER_NO_TX
) && xfer
->tx_buf
)
1880 if ((flags
& SPI_MASTER_NO_RX
) && xfer
->rx_buf
)
1886 * Set transfer bits_per_word and max speed as spi device default if
1887 * it is not set for this transfer.
1888 * Set transfer tx_nbits and rx_nbits as single transfer default
1889 * (SPI_NBITS_SINGLE) if it is not set for this transfer.
1891 list_for_each_entry(xfer
, &message
->transfers
, transfer_list
) {
1892 message
->frame_length
+= xfer
->len
;
1893 if (!xfer
->bits_per_word
)
1894 xfer
->bits_per_word
= spi
->bits_per_word
;
1896 if (!xfer
->speed_hz
)
1897 xfer
->speed_hz
= spi
->max_speed_hz
;
1899 if (master
->max_speed_hz
&&
1900 xfer
->speed_hz
> master
->max_speed_hz
)
1901 xfer
->speed_hz
= master
->max_speed_hz
;
1903 if (master
->bits_per_word_mask
) {
1904 /* Only 32 bits fit in the mask */
1905 if (xfer
->bits_per_word
> 32)
1907 if (!(master
->bits_per_word_mask
&
1908 BIT(xfer
->bits_per_word
- 1)))
1913 * SPI transfer length should be multiple of SPI word size
1914 * where SPI word size should be power-of-two multiple
1916 if (xfer
->bits_per_word
<= 8)
1918 else if (xfer
->bits_per_word
<= 16)
1923 /* No partial transfers accepted */
1924 if (xfer
->len
% w_size
)
1927 if (xfer
->speed_hz
&& master
->min_speed_hz
&&
1928 xfer
->speed_hz
< master
->min_speed_hz
)
1931 if (xfer
->tx_buf
&& !xfer
->tx_nbits
)
1932 xfer
->tx_nbits
= SPI_NBITS_SINGLE
;
1933 if (xfer
->rx_buf
&& !xfer
->rx_nbits
)
1934 xfer
->rx_nbits
= SPI_NBITS_SINGLE
;
1935 /* check transfer tx/rx_nbits:
1936 * 1. check the value matches one of single, dual and quad
1937 * 2. check tx/rx_nbits match the mode in spi_device
1940 if (xfer
->tx_nbits
!= SPI_NBITS_SINGLE
&&
1941 xfer
->tx_nbits
!= SPI_NBITS_DUAL
&&
1942 xfer
->tx_nbits
!= SPI_NBITS_QUAD
)
1944 if ((xfer
->tx_nbits
== SPI_NBITS_DUAL
) &&
1945 !(spi
->mode
& (SPI_TX_DUAL
| SPI_TX_QUAD
)))
1947 if ((xfer
->tx_nbits
== SPI_NBITS_QUAD
) &&
1948 !(spi
->mode
& SPI_TX_QUAD
))
1951 /* check transfer rx_nbits */
1953 if (xfer
->rx_nbits
!= SPI_NBITS_SINGLE
&&
1954 xfer
->rx_nbits
!= SPI_NBITS_DUAL
&&
1955 xfer
->rx_nbits
!= SPI_NBITS_QUAD
)
1957 if ((xfer
->rx_nbits
== SPI_NBITS_DUAL
) &&
1958 !(spi
->mode
& (SPI_RX_DUAL
| SPI_RX_QUAD
)))
1960 if ((xfer
->rx_nbits
== SPI_NBITS_QUAD
) &&
1961 !(spi
->mode
& SPI_RX_QUAD
))
1966 message
->status
= -EINPROGRESS
;
1971 static int __spi_async(struct spi_device
*spi
, struct spi_message
*message
)
1973 struct spi_master
*master
= spi
->master
;
1977 trace_spi_message_submit(message
);
1979 return master
->transfer(spi
, message
);
1983 * spi_async - asynchronous SPI transfer
1984 * @spi: device with which data will be exchanged
1985 * @message: describes the data transfers, including completion callback
1986 * Context: any (irqs may be blocked, etc)
1988 * This call may be used in_irq and other contexts which can't sleep,
1989 * as well as from task contexts which can sleep.
1991 * The completion callback is invoked in a context which can't sleep.
1992 * Before that invocation, the value of message->status is undefined.
1993 * When the callback is issued, message->status holds either zero (to
1994 * indicate complete success) or a negative error code. After that
1995 * callback returns, the driver which issued the transfer request may
1996 * deallocate the associated memory; it's no longer in use by any SPI
1997 * core or controller driver code.
1999 * Note that although all messages to a spi_device are handled in
2000 * FIFO order, messages may go to different devices in other orders.
2001 * Some device might be higher priority, or have various "hard" access
2002 * time requirements, for example.
2004 * On detection of any fault during the transfer, processing of
2005 * the entire message is aborted, and the device is deselected.
2006 * Until returning from the associated message completion callback,
2007 * no other spi_message queued to that device will be processed.
2008 * (This rule applies equally to all the synchronous transfer calls,
2009 * which are wrappers around this core asynchronous primitive.)
2011 int spi_async(struct spi_device
*spi
, struct spi_message
*message
)
2013 struct spi_master
*master
= spi
->master
;
2015 unsigned long flags
;
2017 ret
= __spi_validate(spi
, message
);
2021 spin_lock_irqsave(&master
->bus_lock_spinlock
, flags
);
2023 if (master
->bus_lock_flag
)
2026 ret
= __spi_async(spi
, message
);
2028 spin_unlock_irqrestore(&master
->bus_lock_spinlock
, flags
);
2032 EXPORT_SYMBOL_GPL(spi_async
);
2035 * spi_async_locked - version of spi_async with exclusive bus usage
2036 * @spi: device with which data will be exchanged
2037 * @message: describes the data transfers, including completion callback
2038 * Context: any (irqs may be blocked, etc)
2040 * This call may be used in_irq and other contexts which can't sleep,
2041 * as well as from task contexts which can sleep.
2043 * The completion callback is invoked in a context which can't sleep.
2044 * Before that invocation, the value of message->status is undefined.
2045 * When the callback is issued, message->status holds either zero (to
2046 * indicate complete success) or a negative error code. After that
2047 * callback returns, the driver which issued the transfer request may
2048 * deallocate the associated memory; it's no longer in use by any SPI
2049 * core or controller driver code.
2051 * Note that although all messages to a spi_device are handled in
2052 * FIFO order, messages may go to different devices in other orders.
2053 * Some device might be higher priority, or have various "hard" access
2054 * time requirements, for example.
2056 * On detection of any fault during the transfer, processing of
2057 * the entire message is aborted, and the device is deselected.
2058 * Until returning from the associated message completion callback,
2059 * no other spi_message queued to that device will be processed.
2060 * (This rule applies equally to all the synchronous transfer calls,
2061 * which are wrappers around this core asynchronous primitive.)
2063 int spi_async_locked(struct spi_device
*spi
, struct spi_message
*message
)
2065 struct spi_master
*master
= spi
->master
;
2067 unsigned long flags
;
2069 ret
= __spi_validate(spi
, message
);
2073 spin_lock_irqsave(&master
->bus_lock_spinlock
, flags
);
2075 ret
= __spi_async(spi
, message
);
2077 spin_unlock_irqrestore(&master
->bus_lock_spinlock
, flags
);
2082 EXPORT_SYMBOL_GPL(spi_async_locked
);
2085 /*-------------------------------------------------------------------------*/
2087 /* Utility methods for SPI master protocol drivers, layered on
2088 * top of the core. Some other utility methods are defined as
2092 static void spi_complete(void *arg
)
2097 static int __spi_sync(struct spi_device
*spi
, struct spi_message
*message
,
2100 DECLARE_COMPLETION_ONSTACK(done
);
2102 struct spi_master
*master
= spi
->master
;
2104 message
->complete
= spi_complete
;
2105 message
->context
= &done
;
2108 mutex_lock(&master
->bus_lock_mutex
);
2110 status
= spi_async_locked(spi
, message
);
2113 mutex_unlock(&master
->bus_lock_mutex
);
2116 wait_for_completion(&done
);
2117 status
= message
->status
;
2119 message
->context
= NULL
;
2124 * spi_sync - blocking/synchronous SPI data transfers
2125 * @spi: device with which data will be exchanged
2126 * @message: describes the data transfers
2127 * Context: can sleep
2129 * This call may only be used from a context that may sleep. The sleep
2130 * is non-interruptible, and has no timeout. Low-overhead controller
2131 * drivers may DMA directly into and out of the message buffers.
2133 * Note that the SPI device's chip select is active during the message,
2134 * and then is normally disabled between messages. Drivers for some
2135 * frequently-used devices may want to minimize costs of selecting a chip,
2136 * by leaving it selected in anticipation that the next message will go
2137 * to the same chip. (That may increase power usage.)
2139 * Also, the caller is guaranteeing that the memory associated with the
2140 * message will not be freed before this call returns.
2142 * It returns zero on success, else a negative error code.
2144 int spi_sync(struct spi_device
*spi
, struct spi_message
*message
)
2146 return __spi_sync(spi
, message
, 0);
2148 EXPORT_SYMBOL_GPL(spi_sync
);
2151 * spi_sync_locked - version of spi_sync with exclusive bus usage
2152 * @spi: device with which data will be exchanged
2153 * @message: describes the data transfers
2154 * Context: can sleep
2156 * This call may only be used from a context that may sleep. The sleep
2157 * is non-interruptible, and has no timeout. Low-overhead controller
2158 * drivers may DMA directly into and out of the message buffers.
2160 * This call should be used by drivers that require exclusive access to the
2161 * SPI bus. It has to be preceded by a spi_bus_lock call. The SPI bus must
2162 * be released by a spi_bus_unlock call when the exclusive access is over.
2164 * It returns zero on success, else a negative error code.
2166 int spi_sync_locked(struct spi_device
*spi
, struct spi_message
*message
)
2168 return __spi_sync(spi
, message
, 1);
2170 EXPORT_SYMBOL_GPL(spi_sync_locked
);
2173 * spi_bus_lock - obtain a lock for exclusive SPI bus usage
2174 * @master: SPI bus master that should be locked for exclusive bus access
2175 * Context: can sleep
2177 * This call may only be used from a context that may sleep. The sleep
2178 * is non-interruptible, and has no timeout.
2180 * This call should be used by drivers that require exclusive access to the
2181 * SPI bus. The SPI bus must be released by a spi_bus_unlock call when the
2182 * exclusive access is over. Data transfer must be done by spi_sync_locked
2183 * and spi_async_locked calls when the SPI bus lock is held.
2185 * It returns zero on success, else a negative error code.
2187 int spi_bus_lock(struct spi_master
*master
)
2189 unsigned long flags
;
2191 mutex_lock(&master
->bus_lock_mutex
);
2193 spin_lock_irqsave(&master
->bus_lock_spinlock
, flags
);
2194 master
->bus_lock_flag
= 1;
2195 spin_unlock_irqrestore(&master
->bus_lock_spinlock
, flags
);
2197 /* mutex remains locked until spi_bus_unlock is called */
2201 EXPORT_SYMBOL_GPL(spi_bus_lock
);
2204 * spi_bus_unlock - release the lock for exclusive SPI bus usage
2205 * @master: SPI bus master that was locked for exclusive bus access
2206 * Context: can sleep
2208 * This call may only be used from a context that may sleep. The sleep
2209 * is non-interruptible, and has no timeout.
2211 * This call releases an SPI bus lock previously obtained by an spi_bus_lock
2214 * It returns zero on success, else a negative error code.
2216 int spi_bus_unlock(struct spi_master
*master
)
2218 master
->bus_lock_flag
= 0;
2220 mutex_unlock(&master
->bus_lock_mutex
);
2224 EXPORT_SYMBOL_GPL(spi_bus_unlock
);
2226 /* portable code must never pass more than 32 bytes */
2227 #define SPI_BUFSIZ max(32, SMP_CACHE_BYTES)
2232 * spi_write_then_read - SPI synchronous write followed by read
2233 * @spi: device with which data will be exchanged
2234 * @txbuf: data to be written (need not be dma-safe)
2235 * @n_tx: size of txbuf, in bytes
2236 * @rxbuf: buffer into which data will be read (need not be dma-safe)
2237 * @n_rx: size of rxbuf, in bytes
2238 * Context: can sleep
2240 * This performs a half duplex MicroWire style transaction with the
2241 * device, sending txbuf and then reading rxbuf. The return value
2242 * is zero for success, else a negative errno status code.
2243 * This call may only be used from a context that may sleep.
2245 * Parameters to this routine are always copied using a small buffer;
2246 * portable code should never use this for more than 32 bytes.
2247 * Performance-sensitive or bulk transfer code should instead use
2248 * spi_{async,sync}() calls with dma-safe buffers.
2250 int spi_write_then_read(struct spi_device
*spi
,
2251 const void *txbuf
, unsigned n_tx
,
2252 void *rxbuf
, unsigned n_rx
)
2254 static DEFINE_MUTEX(lock
);
2257 struct spi_message message
;
2258 struct spi_transfer x
[2];
2261 /* Use preallocated DMA-safe buffer if we can. We can't avoid
2262 * copying here, (as a pure convenience thing), but we can
2263 * keep heap costs out of the hot path unless someone else is
2264 * using the pre-allocated buffer or the transfer is too large.
2266 if ((n_tx
+ n_rx
) > SPI_BUFSIZ
|| !mutex_trylock(&lock
)) {
2267 local_buf
= kmalloc(max((unsigned)SPI_BUFSIZ
, n_tx
+ n_rx
),
2268 GFP_KERNEL
| GFP_DMA
);
2275 spi_message_init(&message
);
2276 memset(x
, 0, sizeof(x
));
2279 spi_message_add_tail(&x
[0], &message
);
2283 spi_message_add_tail(&x
[1], &message
);
2286 memcpy(local_buf
, txbuf
, n_tx
);
2287 x
[0].tx_buf
= local_buf
;
2288 x
[1].rx_buf
= local_buf
+ n_tx
;
2291 status
= spi_sync(spi
, &message
);
2293 memcpy(rxbuf
, x
[1].rx_buf
, n_rx
);
2295 if (x
[0].tx_buf
== buf
)
2296 mutex_unlock(&lock
);
2302 EXPORT_SYMBOL_GPL(spi_write_then_read
);
2304 /*-------------------------------------------------------------------------*/
2306 static int __init
spi_init(void)
2310 buf
= kmalloc(SPI_BUFSIZ
, GFP_KERNEL
);
2316 status
= bus_register(&spi_bus_type
);
2320 status
= class_register(&spi_master_class
);
2326 bus_unregister(&spi_bus_type
);
2334 /* board_info is normally registered in arch_initcall(),
2335 * but even essential drivers wait till later
2337 * REVISIT only boardinfo really needs static linking. the rest (device and
2338 * driver registration) _could_ be dynamically linked (modular) ... costs
2339 * include needing to have boardinfo data structures be much more public.
2341 postcore_initcall(spi_init
);