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8ae12a0d DB |
1 | /* |
2 | * Copyright (C) 2005 David Brownell | |
3 | * | |
4 | * This program is free software; you can redistribute it and/or modify | |
5 | * it under the terms of the GNU General Public License as published by | |
6 | * the Free Software Foundation; either version 2 of the License, or | |
7 | * (at your option) any later version. | |
8 | * | |
9 | * This program is distributed in the hope that it will be useful, | |
10 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
11 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
12 | * GNU General Public License for more details. | |
13 | * | |
14 | * You should have received a copy of the GNU General Public License | |
15 | * along with this program; if not, write to the Free Software | |
16 | * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. | |
17 | */ | |
18 | ||
19 | #ifndef __LINUX_SPI_H | |
20 | #define __LINUX_SPI_H | |
21 | ||
22 | /* | |
b885244e | 23 | * INTERFACES between SPI master-side drivers and SPI infrastructure. |
8ae12a0d | 24 | * (There's no SPI slave support for Linux yet...) |
8ae12a0d DB |
25 | */ |
26 | extern struct bus_type spi_bus_type; | |
27 | ||
28 | /** | |
29 | * struct spi_device - Master side proxy for an SPI slave device | |
30 | * @dev: Driver model representation of the device. | |
31 | * @master: SPI controller used with the device. | |
32 | * @max_speed_hz: Maximum clock rate to be used with this chip | |
33 | * (on this board); may be changed by the device's driver. | |
4cff33f9 | 34 | * The spi_transfer.speed_hz can override this for each transfer. |
33e34dc6 | 35 | * @chip_select: Chipselect, distinguishing chips handled by @master. |
8ae12a0d DB |
36 | * @mode: The spi mode defines how data is clocked out and in. |
37 | * This may be changed by the device's driver. | |
33e34dc6 DB |
38 | * The "active low" default for chipselect mode can be overridden |
39 | * (by specifying SPI_CS_HIGH) as can the "MSB first" default for | |
40 | * each word in a transfer (by specifying SPI_LSB_FIRST). | |
8ae12a0d | 41 | * @bits_per_word: Data transfers involve one or more words; word sizes |
747d844e | 42 | * like eight or 12 bits are common. In-memory wordsizes are |
8ae12a0d | 43 | * powers of two bytes (e.g. 20 bit samples use 32 bits). |
ccf77cc4 DB |
44 | * This may be changed by the device's driver, or left at the |
45 | * default (0) indicating protocol words are eight bit bytes. | |
4cff33f9 | 46 | * The spi_transfer.bits_per_word can override this for each transfer. |
8ae12a0d | 47 | * @irq: Negative, or the number passed to request_irq() to receive |
747d844e | 48 | * interrupts from this device. |
8ae12a0d | 49 | * @controller_state: Controller's runtime state |
b885244e | 50 | * @controller_data: Board-specific definitions for controller, such as |
747d844e | 51 | * FIFO initialization parameters; from board_info.controller_data |
33e34dc6 DB |
52 | * @modalias: Name of the driver to use with this device, or an alias |
53 | * for that name. This appears in the sysfs "modalias" attribute | |
54 | * for driver coldplugging, and in uevents used for hotplugging | |
8ae12a0d | 55 | * |
33e34dc6 | 56 | * A @spi_device is used to interchange data between an SPI slave |
8ae12a0d DB |
57 | * (usually a discrete chip) and CPU memory. |
58 | * | |
33e34dc6 | 59 | * In @dev, the platform_data is used to hold information about this |
8ae12a0d DB |
60 | * device that's meaningful to the device's protocol driver, but not |
61 | * to its controller. One example might be an identifier for a chip | |
33e34dc6 DB |
62 | * variant with slightly different functionality; another might be |
63 | * information about how this particular board wires the chip's pins. | |
8ae12a0d DB |
64 | */ |
65 | struct spi_device { | |
66 | struct device dev; | |
67 | struct spi_master *master; | |
68 | u32 max_speed_hz; | |
69 | u8 chip_select; | |
70 | u8 mode; | |
b885244e DB |
71 | #define SPI_CPHA 0x01 /* clock phase */ |
72 | #define SPI_CPOL 0x02 /* clock polarity */ | |
0c868461 DB |
73 | #define SPI_MODE_0 (0|0) /* (original MicroWire) */ |
74 | #define SPI_MODE_1 (0|SPI_CPHA) | |
8ae12a0d DB |
75 | #define SPI_MODE_2 (SPI_CPOL|0) |
76 | #define SPI_MODE_3 (SPI_CPOL|SPI_CPHA) | |
b885244e | 77 | #define SPI_CS_HIGH 0x04 /* chipselect active high? */ |
ccf77cc4 | 78 | #define SPI_LSB_FIRST 0x08 /* per-word bits-on-wire */ |
8ae12a0d DB |
79 | u8 bits_per_word; |
80 | int irq; | |
81 | void *controller_state; | |
b885244e | 82 | void *controller_data; |
8ae12a0d DB |
83 | const char *modalias; |
84 | ||
33e34dc6 DB |
85 | /* |
86 | * likely need more hooks for more protocol options affecting how | |
87 | * the controller talks to each chip, like: | |
88 | * - memory packing (12 bit samples into low bits, others zeroed) | |
89 | * - priority | |
90 | * - drop chipselect after each word | |
91 | * - chipselect delays | |
92 | * - ... | |
93 | */ | |
8ae12a0d DB |
94 | }; |
95 | ||
96 | static inline struct spi_device *to_spi_device(struct device *dev) | |
97 | { | |
b885244e | 98 | return dev ? container_of(dev, struct spi_device, dev) : NULL; |
8ae12a0d DB |
99 | } |
100 | ||
101 | /* most drivers won't need to care about device refcounting */ | |
102 | static inline struct spi_device *spi_dev_get(struct spi_device *spi) | |
103 | { | |
104 | return (spi && get_device(&spi->dev)) ? spi : NULL; | |
105 | } | |
106 | ||
107 | static inline void spi_dev_put(struct spi_device *spi) | |
108 | { | |
109 | if (spi) | |
110 | put_device(&spi->dev); | |
111 | } | |
112 | ||
113 | /* ctldata is for the bus_master driver's runtime state */ | |
114 | static inline void *spi_get_ctldata(struct spi_device *spi) | |
115 | { | |
116 | return spi->controller_state; | |
117 | } | |
118 | ||
119 | static inline void spi_set_ctldata(struct spi_device *spi, void *state) | |
120 | { | |
121 | spi->controller_state = state; | |
122 | } | |
123 | ||
9b40ff4d BD |
124 | /* device driver data */ |
125 | ||
126 | static inline void spi_set_drvdata(struct spi_device *spi, void *data) | |
127 | { | |
128 | dev_set_drvdata(&spi->dev, data); | |
129 | } | |
130 | ||
131 | static inline void *spi_get_drvdata(struct spi_device *spi) | |
132 | { | |
133 | return dev_get_drvdata(&spi->dev); | |
134 | } | |
8ae12a0d DB |
135 | |
136 | struct spi_message; | |
137 | ||
138 | ||
b885244e DB |
139 | |
140 | struct spi_driver { | |
141 | int (*probe)(struct spi_device *spi); | |
142 | int (*remove)(struct spi_device *spi); | |
143 | void (*shutdown)(struct spi_device *spi); | |
144 | int (*suspend)(struct spi_device *spi, pm_message_t mesg); | |
145 | int (*resume)(struct spi_device *spi); | |
146 | struct device_driver driver; | |
147 | }; | |
148 | ||
149 | static inline struct spi_driver *to_spi_driver(struct device_driver *drv) | |
150 | { | |
151 | return drv ? container_of(drv, struct spi_driver, driver) : NULL; | |
152 | } | |
153 | ||
154 | extern int spi_register_driver(struct spi_driver *sdrv); | |
155 | ||
33e34dc6 DB |
156 | /** |
157 | * spi_unregister_driver - reverse effect of spi_register_driver | |
158 | * @sdrv: the driver to unregister | |
159 | * Context: can sleep | |
160 | */ | |
b885244e DB |
161 | static inline void spi_unregister_driver(struct spi_driver *sdrv) |
162 | { | |
ddc1e975 BD |
163 | if (sdrv) |
164 | driver_unregister(&sdrv->driver); | |
b885244e DB |
165 | } |
166 | ||
167 | ||
8ae12a0d DB |
168 | /** |
169 | * struct spi_master - interface to SPI master controller | |
170 | * @cdev: class interface to this driver | |
171 | * @bus_num: board-specific (and often SOC-specific) identifier for a | |
747d844e | 172 | * given SPI controller. |
b885244e | 173 | * @num_chipselect: chipselects are used to distinguish individual |
747d844e DB |
174 | * SPI slaves, and are numbered from zero to num_chipselects. |
175 | * each slave has a chipselect signal, but it's common that not | |
176 | * every chipselect is connected to a slave. | |
8ae12a0d | 177 | * @setup: updates the device mode and clocking records used by a |
80224561 DB |
178 | * device's SPI controller; protocol code may call this. This |
179 | * must fail if an unrecognized or unsupported mode is requested. | |
33e34dc6 DB |
180 | * It's always safe to call this unless transfers are pending on |
181 | * the device whose settings are being modified. | |
8ae12a0d DB |
182 | * @transfer: adds a message to the controller's transfer queue. |
183 | * @cleanup: frees controller-specific state | |
184 | * | |
33e34dc6 | 185 | * Each SPI master controller can communicate with one or more @spi_device |
8ae12a0d DB |
186 | * children. These make a small bus, sharing MOSI, MISO and SCK signals |
187 | * but not chip select signals. Each device may be configured to use a | |
188 | * different clock rate, since those shared signals are ignored unless | |
189 | * the chip is selected. | |
190 | * | |
191 | * The driver for an SPI controller manages access to those devices through | |
33e34dc6 DB |
192 | * a queue of spi_message transactions, copying data between CPU memory and |
193 | * an SPI slave device. For each such message it queues, it calls the | |
8ae12a0d DB |
194 | * message's completion function when the transaction completes. |
195 | */ | |
196 | struct spi_master { | |
07b24630 | 197 | struct class_device cdev; |
8ae12a0d | 198 | |
a020ed75 | 199 | /* other than negative (== assign one dynamically), bus_num is fully |
8ae12a0d | 200 | * board-specific. usually that simplifies to being SOC-specific. |
a020ed75 | 201 | * example: one SOC has three SPI controllers, numbered 0..2, |
8ae12a0d DB |
202 | * and one board's schematics might show it using SPI-2. software |
203 | * would normally use bus_num=2 for that controller. | |
204 | */ | |
a020ed75 | 205 | s16 bus_num; |
8ae12a0d DB |
206 | |
207 | /* chipselects will be integral to many controllers; some others | |
208 | * might use board-specific GPIOs. | |
209 | */ | |
210 | u16 num_chipselect; | |
211 | ||
212 | /* setup mode and clock, etc (spi driver may call many times) */ | |
213 | int (*setup)(struct spi_device *spi); | |
214 | ||
215 | /* bidirectional bulk transfers | |
216 | * | |
217 | * + The transfer() method may not sleep; its main role is | |
218 | * just to add the message to the queue. | |
219 | * + For now there's no remove-from-queue operation, or | |
220 | * any other request management | |
221 | * + To a given spi_device, message queueing is pure fifo | |
222 | * | |
223 | * + The master's main job is to process its message queue, | |
224 | * selecting a chip then transferring data | |
225 | * + If there are multiple spi_device children, the i/o queue | |
226 | * arbitration algorithm is unspecified (round robin, fifo, | |
227 | * priority, reservations, preemption, etc) | |
228 | * | |
229 | * + Chipselect stays active during the entire message | |
230 | * (unless modified by spi_transfer.cs_change != 0). | |
231 | * + The message transfers use clock and SPI mode parameters | |
232 | * previously established by setup() for this device | |
233 | */ | |
234 | int (*transfer)(struct spi_device *spi, | |
235 | struct spi_message *mesg); | |
236 | ||
237 | /* called on release() to free memory provided by spi_master */ | |
0ffa0285 | 238 | void (*cleanup)(struct spi_device *spi); |
8ae12a0d DB |
239 | }; |
240 | ||
0c868461 DB |
241 | static inline void *spi_master_get_devdata(struct spi_master *master) |
242 | { | |
07b24630 | 243 | return class_get_devdata(&master->cdev); |
0c868461 DB |
244 | } |
245 | ||
246 | static inline void spi_master_set_devdata(struct spi_master *master, void *data) | |
247 | { | |
07b24630 | 248 | class_set_devdata(&master->cdev, data); |
0c868461 DB |
249 | } |
250 | ||
251 | static inline struct spi_master *spi_master_get(struct spi_master *master) | |
252 | { | |
07b24630 | 253 | if (!master || !class_device_get(&master->cdev)) |
0c868461 DB |
254 | return NULL; |
255 | return master; | |
256 | } | |
257 | ||
258 | static inline void spi_master_put(struct spi_master *master) | |
259 | { | |
260 | if (master) | |
07b24630 | 261 | class_device_put(&master->cdev); |
0c868461 DB |
262 | } |
263 | ||
264 | ||
8ae12a0d DB |
265 | /* the spi driver core manages memory for the spi_master classdev */ |
266 | extern struct spi_master * | |
267 | spi_alloc_master(struct device *host, unsigned size); | |
268 | ||
269 | extern int spi_register_master(struct spi_master *master); | |
270 | extern void spi_unregister_master(struct spi_master *master); | |
271 | ||
272 | extern struct spi_master *spi_busnum_to_master(u16 busnum); | |
273 | ||
274 | /*---------------------------------------------------------------------------*/ | |
275 | ||
276 | /* | |
277 | * I/O INTERFACE between SPI controller and protocol drivers | |
278 | * | |
279 | * Protocol drivers use a queue of spi_messages, each transferring data | |
280 | * between the controller and memory buffers. | |
281 | * | |
282 | * The spi_messages themselves consist of a series of read+write transfer | |
283 | * segments. Those segments always read the same number of bits as they | |
284 | * write; but one or the other is easily ignored by passing a null buffer | |
285 | * pointer. (This is unlike most types of I/O API, because SPI hardware | |
286 | * is full duplex.) | |
287 | * | |
288 | * NOTE: Allocation of spi_transfer and spi_message memory is entirely | |
289 | * up to the protocol driver, which guarantees the integrity of both (as | |
290 | * well as the data buffers) for as long as the message is queued. | |
291 | */ | |
292 | ||
293 | /** | |
294 | * struct spi_transfer - a read/write buffer pair | |
8275c642 VW |
295 | * @tx_buf: data to be written (dma-safe memory), or NULL |
296 | * @rx_buf: data to be read (dma-safe memory), or NULL | |
33e34dc6 DB |
297 | * @tx_dma: DMA address of tx_buf, if @spi_message.is_dma_mapped |
298 | * @rx_dma: DMA address of rx_buf, if @spi_message.is_dma_mapped | |
8ae12a0d | 299 | * @len: size of rx and tx buffers (in bytes) |
4cff33f9 | 300 | * @speed_hz: Select a speed other then the device default for this |
33e34dc6 | 301 | * transfer. If 0 the default (from @spi_device) is used. |
4cff33f9 | 302 | * @bits_per_word: select a bits_per_word other then the device default |
33e34dc6 | 303 | * for this transfer. If 0 the default (from @spi_device) is used. |
8ae12a0d DB |
304 | * @cs_change: affects chipselect after this transfer completes |
305 | * @delay_usecs: microseconds to delay after this transfer before | |
747d844e | 306 | * (optionally) changing the chipselect status, then starting |
33e34dc6 DB |
307 | * the next transfer or completing this @spi_message. |
308 | * @transfer_list: transfers are sequenced through @spi_message.transfers | |
8ae12a0d DB |
309 | * |
310 | * SPI transfers always write the same number of bytes as they read. | |
33e34dc6 | 311 | * Protocol drivers should always provide @rx_buf and/or @tx_buf. |
8ae12a0d DB |
312 | * In some cases, they may also want to provide DMA addresses for |
313 | * the data being transferred; that may reduce overhead, when the | |
314 | * underlying driver uses dma. | |
315 | * | |
4b1badf5 | 316 | * If the transmit buffer is null, zeroes will be shifted out |
33e34dc6 | 317 | * while filling @rx_buf. If the receive buffer is null, the data |
8275c642 VW |
318 | * shifted in will be discarded. Only "len" bytes shift out (or in). |
319 | * It's an error to try to shift out a partial word. (For example, by | |
320 | * shifting out three bytes with word size of sixteen or twenty bits; | |
321 | * the former uses two bytes per word, the latter uses four bytes.) | |
322 | * | |
80224561 DB |
323 | * In-memory data values are always in native CPU byte order, translated |
324 | * from the wire byte order (big-endian except with SPI_LSB_FIRST). So | |
325 | * for example when bits_per_word is sixteen, buffers are 2N bytes long | |
33e34dc6 | 326 | * (@len = 2N) and hold N sixteen bit words in CPU byte order. |
80224561 DB |
327 | * |
328 | * When the word size of the SPI transfer is not a power-of-two multiple | |
329 | * of eight bits, those in-memory words include extra bits. In-memory | |
330 | * words are always seen by protocol drivers as right-justified, so the | |
331 | * undefined (rx) or unused (tx) bits are always the most significant bits. | |
332 | * | |
8275c642 VW |
333 | * All SPI transfers start with the relevant chipselect active. Normally |
334 | * it stays selected until after the last transfer in a message. Drivers | |
33e34dc6 | 335 | * can affect the chipselect signal using cs_change. |
8ae12a0d DB |
336 | * |
337 | * (i) If the transfer isn't the last one in the message, this flag is | |
338 | * used to make the chipselect briefly go inactive in the middle of the | |
339 | * message. Toggling chipselect in this way may be needed to terminate | |
340 | * a chip command, letting a single spi_message perform all of group of | |
341 | * chip transactions together. | |
342 | * | |
343 | * (ii) When the transfer is the last one in the message, the chip may | |
344 | * stay selected until the next transfer. This is purely a performance | |
345 | * hint; the controller driver may need to select a different device | |
346 | * for the next message. | |
0c868461 DB |
347 | * |
348 | * The code that submits an spi_message (and its spi_transfers) | |
349 | * to the lower layers is responsible for managing its memory. | |
350 | * Zero-initialize every field you don't set up explicitly, to | |
8275c642 VW |
351 | * insulate against future API updates. After you submit a message |
352 | * and its transfers, ignore them until its completion callback. | |
8ae12a0d DB |
353 | */ |
354 | struct spi_transfer { | |
355 | /* it's ok if tx_buf == rx_buf (right?) | |
356 | * for MicroWire, one buffer must be null | |
0c868461 DB |
357 | * buffers must work with dma_*map_single() calls, unless |
358 | * spi_message.is_dma_mapped reports a pre-existing mapping | |
8ae12a0d DB |
359 | */ |
360 | const void *tx_buf; | |
361 | void *rx_buf; | |
362 | unsigned len; | |
363 | ||
364 | dma_addr_t tx_dma; | |
365 | dma_addr_t rx_dma; | |
366 | ||
367 | unsigned cs_change:1; | |
4cff33f9 | 368 | u8 bits_per_word; |
8ae12a0d | 369 | u16 delay_usecs; |
4cff33f9 | 370 | u32 speed_hz; |
8275c642 VW |
371 | |
372 | struct list_head transfer_list; | |
8ae12a0d DB |
373 | }; |
374 | ||
375 | /** | |
376 | * struct spi_message - one multi-segment SPI transaction | |
8275c642 | 377 | * @transfers: list of transfer segments in this transaction |
8ae12a0d DB |
378 | * @spi: SPI device to which the transaction is queued |
379 | * @is_dma_mapped: if true, the caller provided both dma and cpu virtual | |
380 | * addresses for each transfer buffer | |
381 | * @complete: called to report transaction completions | |
382 | * @context: the argument to complete() when it's called | |
b885244e DB |
383 | * @actual_length: the total number of bytes that were transferred in all |
384 | * successful segments | |
8ae12a0d DB |
385 | * @status: zero for success, else negative errno |
386 | * @queue: for use by whichever driver currently owns the message | |
387 | * @state: for use by whichever driver currently owns the message | |
0c868461 | 388 | * |
33e34dc6 | 389 | * A @spi_message is used to execute an atomic sequence of data transfers, |
8275c642 VW |
390 | * each represented by a struct spi_transfer. The sequence is "atomic" |
391 | * in the sense that no other spi_message may use that SPI bus until that | |
392 | * sequence completes. On some systems, many such sequences can execute as | |
393 | * as single programmed DMA transfer. On all systems, these messages are | |
394 | * queued, and might complete after transactions to other devices. Messages | |
395 | * sent to a given spi_device are alway executed in FIFO order. | |
396 | * | |
0c868461 DB |
397 | * The code that submits an spi_message (and its spi_transfers) |
398 | * to the lower layers is responsible for managing its memory. | |
399 | * Zero-initialize every field you don't set up explicitly, to | |
8275c642 VW |
400 | * insulate against future API updates. After you submit a message |
401 | * and its transfers, ignore them until its completion callback. | |
8ae12a0d DB |
402 | */ |
403 | struct spi_message { | |
747d844e | 404 | struct list_head transfers; |
8ae12a0d DB |
405 | |
406 | struct spi_device *spi; | |
407 | ||
408 | unsigned is_dma_mapped:1; | |
409 | ||
410 | /* REVISIT: we might want a flag affecting the behavior of the | |
411 | * last transfer ... allowing things like "read 16 bit length L" | |
412 | * immediately followed by "read L bytes". Basically imposing | |
413 | * a specific message scheduling algorithm. | |
414 | * | |
415 | * Some controller drivers (message-at-a-time queue processing) | |
416 | * could provide that as their default scheduling algorithm. But | |
b885244e | 417 | * others (with multi-message pipelines) could need a flag to |
8ae12a0d DB |
418 | * tell them about such special cases. |
419 | */ | |
420 | ||
421 | /* completion is reported through a callback */ | |
747d844e | 422 | void (*complete)(void *context); |
8ae12a0d DB |
423 | void *context; |
424 | unsigned actual_length; | |
425 | int status; | |
426 | ||
427 | /* for optional use by whatever driver currently owns the | |
428 | * spi_message ... between calls to spi_async and then later | |
429 | * complete(), that's the spi_master controller driver. | |
430 | */ | |
431 | struct list_head queue; | |
432 | void *state; | |
433 | }; | |
434 | ||
8275c642 VW |
435 | static inline void spi_message_init(struct spi_message *m) |
436 | { | |
437 | memset(m, 0, sizeof *m); | |
438 | INIT_LIST_HEAD(&m->transfers); | |
439 | } | |
440 | ||
441 | static inline void | |
442 | spi_message_add_tail(struct spi_transfer *t, struct spi_message *m) | |
443 | { | |
444 | list_add_tail(&t->transfer_list, &m->transfers); | |
445 | } | |
446 | ||
447 | static inline void | |
448 | spi_transfer_del(struct spi_transfer *t) | |
449 | { | |
450 | list_del(&t->transfer_list); | |
451 | } | |
452 | ||
0c868461 DB |
453 | /* It's fine to embed message and transaction structures in other data |
454 | * structures so long as you don't free them while they're in use. | |
455 | */ | |
456 | ||
457 | static inline struct spi_message *spi_message_alloc(unsigned ntrans, gfp_t flags) | |
458 | { | |
459 | struct spi_message *m; | |
460 | ||
461 | m = kzalloc(sizeof(struct spi_message) | |
462 | + ntrans * sizeof(struct spi_transfer), | |
463 | flags); | |
464 | if (m) { | |
8275c642 VW |
465 | int i; |
466 | struct spi_transfer *t = (struct spi_transfer *)(m + 1); | |
467 | ||
468 | INIT_LIST_HEAD(&m->transfers); | |
469 | for (i = 0; i < ntrans; i++, t++) | |
470 | spi_message_add_tail(t, m); | |
0c868461 DB |
471 | } |
472 | return m; | |
473 | } | |
474 | ||
475 | static inline void spi_message_free(struct spi_message *m) | |
476 | { | |
477 | kfree(m); | |
478 | } | |
479 | ||
8ae12a0d | 480 | /** |
33e34dc6 | 481 | * spi_setup - setup SPI mode and clock rate |
8ae12a0d | 482 | * @spi: the device whose settings are being modified |
33e34dc6 | 483 | * Context: can sleep |
8ae12a0d DB |
484 | * |
485 | * SPI protocol drivers may need to update the transfer mode if the | |
486 | * device doesn't work with the mode 0 default. They may likewise need | |
487 | * to update clock rates or word sizes from initial values. This function | |
488 | * changes those settings, and must be called from a context that can sleep. | |
8275c642 VW |
489 | * The changes take effect the next time the device is selected and data |
490 | * is transferred to or from it. | |
80224561 | 491 | * |
33e34dc6 | 492 | * Note that this call will fail if the protocol driver specifies an option |
80224561 DB |
493 | * that the underlying controller or its driver does not support. For |
494 | * example, not all hardware supports wire transfers using nine bit words, | |
495 | * LSB-first wire encoding, or active-high chipselects. | |
8ae12a0d DB |
496 | */ |
497 | static inline int | |
498 | spi_setup(struct spi_device *spi) | |
499 | { | |
500 | return spi->master->setup(spi); | |
501 | } | |
502 | ||
503 | ||
504 | /** | |
33e34dc6 | 505 | * spi_async - asynchronous SPI transfer |
8ae12a0d DB |
506 | * @spi: device with which data will be exchanged |
507 | * @message: describes the data transfers, including completion callback | |
33e34dc6 | 508 | * Context: any (irqs may be blocked, etc) |
8ae12a0d DB |
509 | * |
510 | * This call may be used in_irq and other contexts which can't sleep, | |
511 | * as well as from task contexts which can sleep. | |
512 | * | |
513 | * The completion callback is invoked in a context which can't sleep. | |
514 | * Before that invocation, the value of message->status is undefined. | |
515 | * When the callback is issued, message->status holds either zero (to | |
0c868461 DB |
516 | * indicate complete success) or a negative error code. After that |
517 | * callback returns, the driver which issued the transfer request may | |
518 | * deallocate the associated memory; it's no longer in use by any SPI | |
519 | * core or controller driver code. | |
8ae12a0d DB |
520 | * |
521 | * Note that although all messages to a spi_device are handled in | |
522 | * FIFO order, messages may go to different devices in other orders. | |
523 | * Some device might be higher priority, or have various "hard" access | |
524 | * time requirements, for example. | |
b885244e DB |
525 | * |
526 | * On detection of any fault during the transfer, processing of | |
527 | * the entire message is aborted, and the device is deselected. | |
528 | * Until returning from the associated message completion callback, | |
529 | * no other spi_message queued to that device will be processed. | |
530 | * (This rule applies equally to all the synchronous transfer calls, | |
531 | * which are wrappers around this core asynchronous primitive.) | |
8ae12a0d DB |
532 | */ |
533 | static inline int | |
534 | spi_async(struct spi_device *spi, struct spi_message *message) | |
535 | { | |
536 | message->spi = spi; | |
537 | return spi->master->transfer(spi, message); | |
538 | } | |
539 | ||
540 | /*---------------------------------------------------------------------------*/ | |
541 | ||
542 | /* All these synchronous SPI transfer routines are utilities layered | |
543 | * over the core async transfer primitive. Here, "synchronous" means | |
544 | * they will sleep uninterruptibly until the async transfer completes. | |
545 | */ | |
546 | ||
547 | extern int spi_sync(struct spi_device *spi, struct spi_message *message); | |
548 | ||
549 | /** | |
550 | * spi_write - SPI synchronous write | |
551 | * @spi: device to which data will be written | |
552 | * @buf: data buffer | |
553 | * @len: data buffer size | |
33e34dc6 | 554 | * Context: can sleep |
8ae12a0d DB |
555 | * |
556 | * This writes the buffer and returns zero or a negative error code. | |
557 | * Callable only from contexts that can sleep. | |
558 | */ | |
559 | static inline int | |
560 | spi_write(struct spi_device *spi, const u8 *buf, size_t len) | |
561 | { | |
562 | struct spi_transfer t = { | |
563 | .tx_buf = buf, | |
8ae12a0d | 564 | .len = len, |
8ae12a0d | 565 | }; |
8275c642 | 566 | struct spi_message m; |
8ae12a0d | 567 | |
8275c642 VW |
568 | spi_message_init(&m); |
569 | spi_message_add_tail(&t, &m); | |
8ae12a0d DB |
570 | return spi_sync(spi, &m); |
571 | } | |
572 | ||
573 | /** | |
574 | * spi_read - SPI synchronous read | |
575 | * @spi: device from which data will be read | |
576 | * @buf: data buffer | |
577 | * @len: data buffer size | |
33e34dc6 | 578 | * Context: can sleep |
8ae12a0d | 579 | * |
33e34dc6 | 580 | * This reads the buffer and returns zero or a negative error code. |
8ae12a0d DB |
581 | * Callable only from contexts that can sleep. |
582 | */ | |
583 | static inline int | |
584 | spi_read(struct spi_device *spi, u8 *buf, size_t len) | |
585 | { | |
586 | struct spi_transfer t = { | |
8ae12a0d DB |
587 | .rx_buf = buf, |
588 | .len = len, | |
8ae12a0d | 589 | }; |
8275c642 | 590 | struct spi_message m; |
8ae12a0d | 591 | |
8275c642 VW |
592 | spi_message_init(&m); |
593 | spi_message_add_tail(&t, &m); | |
8ae12a0d DB |
594 | return spi_sync(spi, &m); |
595 | } | |
596 | ||
0c868461 | 597 | /* this copies txbuf and rxbuf data; for small transfers only! */ |
8ae12a0d DB |
598 | extern int spi_write_then_read(struct spi_device *spi, |
599 | const u8 *txbuf, unsigned n_tx, | |
600 | u8 *rxbuf, unsigned n_rx); | |
601 | ||
602 | /** | |
603 | * spi_w8r8 - SPI synchronous 8 bit write followed by 8 bit read | |
604 | * @spi: device with which data will be exchanged | |
605 | * @cmd: command to be written before data is read back | |
33e34dc6 | 606 | * Context: can sleep |
8ae12a0d DB |
607 | * |
608 | * This returns the (unsigned) eight bit number returned by the | |
609 | * device, or else a negative error code. Callable only from | |
610 | * contexts that can sleep. | |
611 | */ | |
612 | static inline ssize_t spi_w8r8(struct spi_device *spi, u8 cmd) | |
613 | { | |
614 | ssize_t status; | |
615 | u8 result; | |
616 | ||
617 | status = spi_write_then_read(spi, &cmd, 1, &result, 1); | |
618 | ||
619 | /* return negative errno or unsigned value */ | |
620 | return (status < 0) ? status : result; | |
621 | } | |
622 | ||
623 | /** | |
624 | * spi_w8r16 - SPI synchronous 8 bit write followed by 16 bit read | |
625 | * @spi: device with which data will be exchanged | |
626 | * @cmd: command to be written before data is read back | |
33e34dc6 | 627 | * Context: can sleep |
8ae12a0d DB |
628 | * |
629 | * This returns the (unsigned) sixteen bit number returned by the | |
630 | * device, or else a negative error code. Callable only from | |
631 | * contexts that can sleep. | |
632 | * | |
633 | * The number is returned in wire-order, which is at least sometimes | |
634 | * big-endian. | |
635 | */ | |
636 | static inline ssize_t spi_w8r16(struct spi_device *spi, u8 cmd) | |
637 | { | |
638 | ssize_t status; | |
639 | u16 result; | |
640 | ||
641 | status = spi_write_then_read(spi, &cmd, 1, (u8 *) &result, 2); | |
642 | ||
643 | /* return negative errno or unsigned value */ | |
644 | return (status < 0) ? status : result; | |
645 | } | |
646 | ||
647 | /*---------------------------------------------------------------------------*/ | |
648 | ||
649 | /* | |
650 | * INTERFACE between board init code and SPI infrastructure. | |
651 | * | |
652 | * No SPI driver ever sees these SPI device table segments, but | |
653 | * it's how the SPI core (or adapters that get hotplugged) grows | |
654 | * the driver model tree. | |
655 | * | |
656 | * As a rule, SPI devices can't be probed. Instead, board init code | |
657 | * provides a table listing the devices which are present, with enough | |
658 | * information to bind and set up the device's driver. There's basic | |
659 | * support for nonstatic configurations too; enough to handle adding | |
660 | * parport adapters, or microcontrollers acting as USB-to-SPI bridges. | |
661 | */ | |
662 | ||
663 | /* board-specific information about each SPI device */ | |
664 | struct spi_board_info { | |
665 | /* the device name and module name are coupled, like platform_bus; | |
666 | * "modalias" is normally the driver name. | |
667 | * | |
668 | * platform_data goes to spi_device.dev.platform_data, | |
b885244e | 669 | * controller_data goes to spi_device.controller_data, |
8ae12a0d DB |
670 | * irq is copied too |
671 | */ | |
672 | char modalias[KOBJ_NAME_LEN]; | |
673 | const void *platform_data; | |
b885244e | 674 | void *controller_data; |
8ae12a0d DB |
675 | int irq; |
676 | ||
677 | /* slower signaling on noisy or low voltage boards */ | |
678 | u32 max_speed_hz; | |
679 | ||
680 | ||
681 | /* bus_num is board specific and matches the bus_num of some | |
682 | * spi_master that will probably be registered later. | |
683 | * | |
684 | * chip_select reflects how this chip is wired to that master; | |
685 | * it's less than num_chipselect. | |
686 | */ | |
687 | u16 bus_num; | |
688 | u16 chip_select; | |
689 | ||
980a01c9 DB |
690 | /* mode becomes spi_device.mode, and is essential for chips |
691 | * where the default of SPI_CS_HIGH = 0 is wrong. | |
692 | */ | |
693 | u8 mode; | |
694 | ||
8ae12a0d DB |
695 | /* ... may need additional spi_device chip config data here. |
696 | * avoid stuff protocol drivers can set; but include stuff | |
697 | * needed to behave without being bound to a driver: | |
8ae12a0d DB |
698 | * - quirks like clock rate mattering when not selected |
699 | */ | |
700 | }; | |
701 | ||
702 | #ifdef CONFIG_SPI | |
703 | extern int | |
704 | spi_register_board_info(struct spi_board_info const *info, unsigned n); | |
705 | #else | |
706 | /* board init code may ignore whether SPI is configured or not */ | |
707 | static inline int | |
708 | spi_register_board_info(struct spi_board_info const *info, unsigned n) | |
709 | { return 0; } | |
710 | #endif | |
711 | ||
712 | ||
713 | /* If you're hotplugging an adapter with devices (parport, usb, etc) | |
0c868461 DB |
714 | * use spi_new_device() to describe each device. You can also call |
715 | * spi_unregister_device() to start making that device vanish, but | |
716 | * normally that would be handled by spi_unregister_master(). | |
8ae12a0d DB |
717 | */ |
718 | extern struct spi_device * | |
719 | spi_new_device(struct spi_master *, struct spi_board_info *); | |
720 | ||
721 | static inline void | |
722 | spi_unregister_device(struct spi_device *spi) | |
723 | { | |
724 | if (spi) | |
725 | device_unregister(&spi->dev); | |
726 | } | |
727 | ||
728 | #endif /* __LINUX_SPI_H */ |