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[mirror_ubuntu-jammy-kernel.git] / drivers / spi / spi-mpc512x-psc.c
1 /*
2 * MPC512x PSC in SPI mode driver.
3 *
4 * Copyright (C) 2007,2008 Freescale Semiconductor Inc.
5 * Original port from 52xx driver:
6 * Hongjun Chen <hong-jun.chen@freescale.com>
7 *
8 * Fork of mpc52xx_psc_spi.c:
9 * Copyright (C) 2006 TOPTICA Photonics AG., Dragos Carp
10 *
11 * This program is free software; you can redistribute it and/or modify it
12 * under the terms of the GNU General Public License as published by the
13 * Free Software Foundation; either version 2 of the License, or (at your
14 * option) any later version.
15 */
16
17 #include <linux/module.h>
18 #include <linux/kernel.h>
19 #include <linux/init.h>
20 #include <linux/errno.h>
21 #include <linux/interrupt.h>
22 #include <linux/of_address.h>
23 #include <linux/of_irq.h>
24 #include <linux/of_platform.h>
25 #include <linux/completion.h>
26 #include <linux/io.h>
27 #include <linux/delay.h>
28 #include <linux/clk.h>
29 #include <linux/spi/spi.h>
30 #include <linux/fsl_devices.h>
31 #include <linux/gpio.h>
32 #include <asm/mpc52xx_psc.h>
33
34 struct mpc512x_psc_spi {
35 void (*cs_control)(struct spi_device *spi, bool on);
36
37 /* driver internal data */
38 struct mpc52xx_psc __iomem *psc;
39 struct mpc512x_psc_fifo __iomem *fifo;
40 unsigned int irq;
41 u8 bits_per_word;
42 struct clk *clk_mclk;
43 u32 mclk_rate;
44
45 struct completion txisrdone;
46 };
47
48 /* controller state */
49 struct mpc512x_psc_spi_cs {
50 int bits_per_word;
51 int speed_hz;
52 };
53
54 /* set clock freq, clock ramp, bits per work
55 * if t is NULL then reset the values to the default values
56 */
57 static int mpc512x_psc_spi_transfer_setup(struct spi_device *spi,
58 struct spi_transfer *t)
59 {
60 struct mpc512x_psc_spi_cs *cs = spi->controller_state;
61
62 cs->speed_hz = (t && t->speed_hz)
63 ? t->speed_hz : spi->max_speed_hz;
64 cs->bits_per_word = (t && t->bits_per_word)
65 ? t->bits_per_word : spi->bits_per_word;
66 cs->bits_per_word = ((cs->bits_per_word + 7) / 8) * 8;
67 return 0;
68 }
69
70 static void mpc512x_psc_spi_activate_cs(struct spi_device *spi)
71 {
72 struct mpc512x_psc_spi_cs *cs = spi->controller_state;
73 struct mpc512x_psc_spi *mps = spi_master_get_devdata(spi->master);
74 struct mpc52xx_psc __iomem *psc = mps->psc;
75 u32 sicr;
76 u32 ccr;
77 int speed;
78 u16 bclkdiv;
79
80 sicr = in_be32(&psc->sicr);
81
82 /* Set clock phase and polarity */
83 if (spi->mode & SPI_CPHA)
84 sicr |= 0x00001000;
85 else
86 sicr &= ~0x00001000;
87
88 if (spi->mode & SPI_CPOL)
89 sicr |= 0x00002000;
90 else
91 sicr &= ~0x00002000;
92
93 if (spi->mode & SPI_LSB_FIRST)
94 sicr |= 0x10000000;
95 else
96 sicr &= ~0x10000000;
97 out_be32(&psc->sicr, sicr);
98
99 ccr = in_be32(&psc->ccr);
100 ccr &= 0xFF000000;
101 speed = cs->speed_hz;
102 if (!speed)
103 speed = 1000000; /* default 1MHz */
104 bclkdiv = (mps->mclk_rate / speed) - 1;
105
106 ccr |= (((bclkdiv & 0xff) << 16) | (((bclkdiv >> 8) & 0xff) << 8));
107 out_be32(&psc->ccr, ccr);
108 mps->bits_per_word = cs->bits_per_word;
109
110 if (mps->cs_control && gpio_is_valid(spi->cs_gpio))
111 mps->cs_control(spi, (spi->mode & SPI_CS_HIGH) ? 1 : 0);
112 }
113
114 static void mpc512x_psc_spi_deactivate_cs(struct spi_device *spi)
115 {
116 struct mpc512x_psc_spi *mps = spi_master_get_devdata(spi->master);
117
118 if (mps->cs_control && gpio_is_valid(spi->cs_gpio))
119 mps->cs_control(spi, (spi->mode & SPI_CS_HIGH) ? 0 : 1);
120
121 }
122
123 /* extract and scale size field in txsz or rxsz */
124 #define MPC512x_PSC_FIFO_SZ(sz) ((sz & 0x7ff) << 2);
125
126 #define EOFBYTE 1
127
128 static int mpc512x_psc_spi_transfer_rxtx(struct spi_device *spi,
129 struct spi_transfer *t)
130 {
131 struct mpc512x_psc_spi *mps = spi_master_get_devdata(spi->master);
132 struct mpc512x_psc_fifo __iomem *fifo = mps->fifo;
133 size_t tx_len = t->len;
134 size_t rx_len = t->len;
135 u8 *tx_buf = (u8 *)t->tx_buf;
136 u8 *rx_buf = (u8 *)t->rx_buf;
137
138 if (!tx_buf && !rx_buf && t->len)
139 return -EINVAL;
140
141 while (rx_len || tx_len) {
142 size_t txcount;
143 u8 data;
144 size_t fifosz;
145 size_t rxcount;
146 int rxtries;
147
148 /*
149 * send the TX bytes in as large a chunk as possible
150 * but neither exceed the TX nor the RX FIFOs
151 */
152 fifosz = MPC512x_PSC_FIFO_SZ(in_be32(&fifo->txsz));
153 txcount = min(fifosz, tx_len);
154 fifosz = MPC512x_PSC_FIFO_SZ(in_be32(&fifo->rxsz));
155 fifosz -= in_be32(&fifo->rxcnt) + 1;
156 txcount = min(fifosz, txcount);
157 if (txcount) {
158
159 /* fill the TX FIFO */
160 while (txcount-- > 0) {
161 data = tx_buf ? *tx_buf++ : 0;
162 if (tx_len == EOFBYTE && t->cs_change)
163 setbits32(&fifo->txcmd,
164 MPC512x_PSC_FIFO_EOF);
165 out_8(&fifo->txdata_8, data);
166 tx_len--;
167 }
168
169 /* have the ISR trigger when the TX FIFO is empty */
170 reinit_completion(&mps->txisrdone);
171 out_be32(&fifo->txisr, MPC512x_PSC_FIFO_EMPTY);
172 out_be32(&fifo->tximr, MPC512x_PSC_FIFO_EMPTY);
173 wait_for_completion(&mps->txisrdone);
174 }
175
176 /*
177 * consume as much RX data as the FIFO holds, while we
178 * iterate over the transfer's TX data length
179 *
180 * only insist in draining all the remaining RX bytes
181 * when the TX bytes were exhausted (that's at the very
182 * end of this transfer, not when still iterating over
183 * the transfer's chunks)
184 */
185 rxtries = 50;
186 do {
187
188 /*
189 * grab whatever was in the FIFO when we started
190 * looking, don't bother fetching what was added to
191 * the FIFO while we read from it -- we'll return
192 * here eventually and prefer sending out remaining
193 * TX data
194 */
195 fifosz = in_be32(&fifo->rxcnt);
196 rxcount = min(fifosz, rx_len);
197 while (rxcount-- > 0) {
198 data = in_8(&fifo->rxdata_8);
199 if (rx_buf)
200 *rx_buf++ = data;
201 rx_len--;
202 }
203
204 /*
205 * come back later if there still is TX data to send,
206 * bail out of the RX drain loop if all of the TX data
207 * was sent and all of the RX data was received (i.e.
208 * when the transmission has completed)
209 */
210 if (tx_len)
211 break;
212 if (!rx_len)
213 break;
214
215 /*
216 * TX data transmission has completed while RX data
217 * is still pending -- that's a transient situation
218 * which depends on wire speed and specific
219 * hardware implementation details (buffering) yet
220 * should resolve very quickly
221 *
222 * just yield for a moment to not hog the CPU for
223 * too long when running SPI at low speed
224 *
225 * the timeout range is rather arbitrary and tries
226 * to balance throughput against system load; the
227 * chosen values result in a minimal timeout of 50
228 * times 10us and thus work at speeds as low as
229 * some 20kbps, while the maximum timeout at the
230 * transfer's end could be 5ms _if_ nothing else
231 * ticks in the system _and_ RX data still wasn't
232 * received, which only occurs in situations that
233 * are exceptional; removing the unpredictability
234 * of the timeout either decreases throughput
235 * (longer timeouts), or puts more load on the
236 * system (fixed short timeouts) or requires the
237 * use of a timeout API instead of a counter and an
238 * unknown inner delay
239 */
240 usleep_range(10, 100);
241
242 } while (--rxtries > 0);
243 if (!tx_len && rx_len && !rxtries) {
244 /*
245 * not enough RX bytes even after several retries
246 * and the resulting rather long timeout?
247 */
248 rxcount = in_be32(&fifo->rxcnt);
249 dev_warn(&spi->dev,
250 "short xfer, missing %zd RX bytes, FIFO level %zd\n",
251 rx_len, rxcount);
252 }
253
254 /*
255 * drain and drop RX data which "should not be there" in
256 * the first place, for undisturbed transmission this turns
257 * into a NOP (except for the FIFO level fetch)
258 */
259 if (!tx_len && !rx_len) {
260 while (in_be32(&fifo->rxcnt))
261 in_8(&fifo->rxdata_8);
262 }
263
264 }
265 return 0;
266 }
267
268 static int mpc512x_psc_spi_msg_xfer(struct spi_master *master,
269 struct spi_message *m)
270 {
271 struct spi_device *spi;
272 unsigned cs_change;
273 int status;
274 struct spi_transfer *t;
275
276 spi = m->spi;
277 cs_change = 1;
278 status = 0;
279 list_for_each_entry(t, &m->transfers, transfer_list) {
280 if (t->bits_per_word || t->speed_hz) {
281 status = mpc512x_psc_spi_transfer_setup(spi, t);
282 if (status < 0)
283 break;
284 }
285
286 if (cs_change)
287 mpc512x_psc_spi_activate_cs(spi);
288 cs_change = t->cs_change;
289
290 status = mpc512x_psc_spi_transfer_rxtx(spi, t);
291 if (status)
292 break;
293 m->actual_length += t->len;
294
295 if (t->delay_usecs)
296 udelay(t->delay_usecs);
297
298 if (cs_change)
299 mpc512x_psc_spi_deactivate_cs(spi);
300 }
301
302 m->status = status;
303 m->complete(m->context);
304
305 if (status || !cs_change)
306 mpc512x_psc_spi_deactivate_cs(spi);
307
308 mpc512x_psc_spi_transfer_setup(spi, NULL);
309
310 spi_finalize_current_message(master);
311 return status;
312 }
313
314 static int mpc512x_psc_spi_prep_xfer_hw(struct spi_master *master)
315 {
316 struct mpc512x_psc_spi *mps = spi_master_get_devdata(master);
317 struct mpc52xx_psc __iomem *psc = mps->psc;
318
319 dev_dbg(&master->dev, "%s()\n", __func__);
320
321 /* Zero MR2 */
322 in_8(&psc->mode);
323 out_8(&psc->mode, 0x0);
324
325 /* enable transmitter/receiver */
326 out_8(&psc->command, MPC52xx_PSC_TX_ENABLE | MPC52xx_PSC_RX_ENABLE);
327
328 return 0;
329 }
330
331 static int mpc512x_psc_spi_unprep_xfer_hw(struct spi_master *master)
332 {
333 struct mpc512x_psc_spi *mps = spi_master_get_devdata(master);
334 struct mpc52xx_psc __iomem *psc = mps->psc;
335 struct mpc512x_psc_fifo __iomem *fifo = mps->fifo;
336
337 dev_dbg(&master->dev, "%s()\n", __func__);
338
339 /* disable transmitter/receiver and fifo interrupt */
340 out_8(&psc->command, MPC52xx_PSC_TX_DISABLE | MPC52xx_PSC_RX_DISABLE);
341 out_be32(&fifo->tximr, 0);
342
343 return 0;
344 }
345
346 static int mpc512x_psc_spi_setup(struct spi_device *spi)
347 {
348 struct mpc512x_psc_spi_cs *cs = spi->controller_state;
349 int ret;
350
351 if (spi->bits_per_word % 8)
352 return -EINVAL;
353
354 if (!cs) {
355 cs = kzalloc(sizeof *cs, GFP_KERNEL);
356 if (!cs)
357 return -ENOMEM;
358
359 if (gpio_is_valid(spi->cs_gpio)) {
360 ret = gpio_request(spi->cs_gpio, dev_name(&spi->dev));
361 if (ret) {
362 dev_err(&spi->dev, "can't get CS gpio: %d\n",
363 ret);
364 kfree(cs);
365 return ret;
366 }
367 gpio_direction_output(spi->cs_gpio,
368 spi->mode & SPI_CS_HIGH ? 0 : 1);
369 }
370
371 spi->controller_state = cs;
372 }
373
374 cs->bits_per_word = spi->bits_per_word;
375 cs->speed_hz = spi->max_speed_hz;
376
377 return 0;
378 }
379
380 static void mpc512x_psc_spi_cleanup(struct spi_device *spi)
381 {
382 if (gpio_is_valid(spi->cs_gpio))
383 gpio_free(spi->cs_gpio);
384 kfree(spi->controller_state);
385 }
386
387 static int mpc512x_psc_spi_port_config(struct spi_master *master,
388 struct mpc512x_psc_spi *mps)
389 {
390 struct mpc52xx_psc __iomem *psc = mps->psc;
391 struct mpc512x_psc_fifo __iomem *fifo = mps->fifo;
392 u32 sicr;
393 u32 ccr;
394 int speed;
395 u16 bclkdiv;
396
397 /* Reset the PSC into a known state */
398 out_8(&psc->command, MPC52xx_PSC_RST_RX);
399 out_8(&psc->command, MPC52xx_PSC_RST_TX);
400 out_8(&psc->command, MPC52xx_PSC_TX_DISABLE | MPC52xx_PSC_RX_DISABLE);
401
402 /* Disable psc interrupts all useful interrupts are in fifo */
403 out_be16(&psc->isr_imr.imr, 0);
404
405 /* Disable fifo interrupts, will be enabled later */
406 out_be32(&fifo->tximr, 0);
407 out_be32(&fifo->rximr, 0);
408
409 /* Setup fifo slice address and size */
410 /*out_be32(&fifo->txsz, 0x0fe00004);*/
411 /*out_be32(&fifo->rxsz, 0x0ff00004);*/
412
413 sicr = 0x01000000 | /* SIM = 0001 -- 8 bit */
414 0x00800000 | /* GenClk = 1 -- internal clk */
415 0x00008000 | /* SPI = 1 */
416 0x00004000 | /* MSTR = 1 -- SPI master */
417 0x00000800; /* UseEOF = 1 -- SS low until EOF */
418
419 out_be32(&psc->sicr, sicr);
420
421 ccr = in_be32(&psc->ccr);
422 ccr &= 0xFF000000;
423 speed = 1000000; /* default 1MHz */
424 bclkdiv = (mps->mclk_rate / speed) - 1;
425 ccr |= (((bclkdiv & 0xff) << 16) | (((bclkdiv >> 8) & 0xff) << 8));
426 out_be32(&psc->ccr, ccr);
427
428 /* Set 2ms DTL delay */
429 out_8(&psc->ctur, 0x00);
430 out_8(&psc->ctlr, 0x82);
431
432 /* we don't use the alarms */
433 out_be32(&fifo->rxalarm, 0xfff);
434 out_be32(&fifo->txalarm, 0);
435
436 /* Enable FIFO slices for Rx/Tx */
437 out_be32(&fifo->rxcmd,
438 MPC512x_PSC_FIFO_ENABLE_SLICE | MPC512x_PSC_FIFO_ENABLE_DMA);
439 out_be32(&fifo->txcmd,
440 MPC512x_PSC_FIFO_ENABLE_SLICE | MPC512x_PSC_FIFO_ENABLE_DMA);
441
442 mps->bits_per_word = 8;
443
444 return 0;
445 }
446
447 static irqreturn_t mpc512x_psc_spi_isr(int irq, void *dev_id)
448 {
449 struct mpc512x_psc_spi *mps = (struct mpc512x_psc_spi *)dev_id;
450 struct mpc512x_psc_fifo __iomem *fifo = mps->fifo;
451
452 /* clear interrupt and wake up the rx/tx routine */
453 if (in_be32(&fifo->txisr) &
454 in_be32(&fifo->tximr) & MPC512x_PSC_FIFO_EMPTY) {
455 out_be32(&fifo->txisr, MPC512x_PSC_FIFO_EMPTY);
456 out_be32(&fifo->tximr, 0);
457 complete(&mps->txisrdone);
458 return IRQ_HANDLED;
459 }
460 return IRQ_NONE;
461 }
462
463 static void mpc512x_spi_cs_control(struct spi_device *spi, bool onoff)
464 {
465 gpio_set_value(spi->cs_gpio, onoff);
466 }
467
468 /* bus_num is used only for the case dev->platform_data == NULL */
469 static int mpc512x_psc_spi_do_probe(struct device *dev, u32 regaddr,
470 u32 size, unsigned int irq,
471 s16 bus_num)
472 {
473 struct fsl_spi_platform_data *pdata = dev_get_platdata(dev);
474 struct mpc512x_psc_spi *mps;
475 struct spi_master *master;
476 int ret;
477 void *tempp;
478 int psc_num;
479 char clk_name[16];
480 struct clk *clk;
481
482 master = spi_alloc_master(dev, sizeof *mps);
483 if (master == NULL)
484 return -ENOMEM;
485
486 dev_set_drvdata(dev, master);
487 mps = spi_master_get_devdata(master);
488 mps->irq = irq;
489
490 if (pdata == NULL) {
491 mps->cs_control = mpc512x_spi_cs_control;
492 master->bus_num = bus_num;
493 } else {
494 mps->cs_control = pdata->cs_control;
495 master->bus_num = pdata->bus_num;
496 master->num_chipselect = pdata->max_chipselect;
497 }
498
499 master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_CS_HIGH | SPI_LSB_FIRST;
500 master->setup = mpc512x_psc_spi_setup;
501 master->prepare_transfer_hardware = mpc512x_psc_spi_prep_xfer_hw;
502 master->transfer_one_message = mpc512x_psc_spi_msg_xfer;
503 master->unprepare_transfer_hardware = mpc512x_psc_spi_unprep_xfer_hw;
504 master->cleanup = mpc512x_psc_spi_cleanup;
505 master->dev.of_node = dev->of_node;
506
507 tempp = ioremap(regaddr, size);
508 if (!tempp) {
509 dev_err(dev, "could not ioremap I/O port range\n");
510 ret = -EFAULT;
511 goto free_master;
512 }
513 mps->psc = tempp;
514 mps->fifo =
515 (struct mpc512x_psc_fifo *)(tempp + sizeof(struct mpc52xx_psc));
516
517 ret = request_irq(mps->irq, mpc512x_psc_spi_isr, IRQF_SHARED,
518 "mpc512x-psc-spi", mps);
519 if (ret)
520 goto free_master;
521 init_completion(&mps->txisrdone);
522
523 psc_num = master->bus_num;
524 snprintf(clk_name, sizeof(clk_name), "psc%d_mclk", psc_num);
525 clk = devm_clk_get(dev, clk_name);
526 if (IS_ERR(clk)) {
527 ret = PTR_ERR(clk);
528 goto free_irq;
529 }
530 ret = clk_prepare_enable(clk);
531 if (ret)
532 goto free_irq;
533 mps->clk_mclk = clk;
534 mps->mclk_rate = clk_get_rate(clk);
535
536 ret = mpc512x_psc_spi_port_config(master, mps);
537 if (ret < 0)
538 goto free_clock;
539
540 ret = devm_spi_register_master(dev, master);
541 if (ret < 0)
542 goto free_clock;
543
544 return ret;
545
546 free_clock:
547 clk_disable_unprepare(mps->clk_mclk);
548 free_irq:
549 free_irq(mps->irq, mps);
550 free_master:
551 if (mps->psc)
552 iounmap(mps->psc);
553 spi_master_put(master);
554
555 return ret;
556 }
557
558 static int mpc512x_psc_spi_do_remove(struct device *dev)
559 {
560 struct spi_master *master = dev_get_drvdata(dev);
561 struct mpc512x_psc_spi *mps = spi_master_get_devdata(master);
562
563 clk_disable_unprepare(mps->clk_mclk);
564 free_irq(mps->irq, mps);
565 if (mps->psc)
566 iounmap(mps->psc);
567
568 return 0;
569 }
570
571 static int mpc512x_psc_spi_of_probe(struct platform_device *op)
572 {
573 const u32 *regaddr_p;
574 u64 regaddr64, size64;
575 s16 id = -1;
576
577 regaddr_p = of_get_address(op->dev.of_node, 0, &size64, NULL);
578 if (!regaddr_p) {
579 dev_err(&op->dev, "Invalid PSC address\n");
580 return -EINVAL;
581 }
582 regaddr64 = of_translate_address(op->dev.of_node, regaddr_p);
583
584 /* get PSC id (0..11, used by port_config) */
585 id = of_alias_get_id(op->dev.of_node, "spi");
586 if (id < 0) {
587 dev_err(&op->dev, "no alias id for %s\n",
588 op->dev.of_node->full_name);
589 return id;
590 }
591
592 return mpc512x_psc_spi_do_probe(&op->dev, (u32) regaddr64, (u32) size64,
593 irq_of_parse_and_map(op->dev.of_node, 0), id);
594 }
595
596 static int mpc512x_psc_spi_of_remove(struct platform_device *op)
597 {
598 return mpc512x_psc_spi_do_remove(&op->dev);
599 }
600
601 static struct of_device_id mpc512x_psc_spi_of_match[] = {
602 { .compatible = "fsl,mpc5121-psc-spi", },
603 {},
604 };
605
606 MODULE_DEVICE_TABLE(of, mpc512x_psc_spi_of_match);
607
608 static struct platform_driver mpc512x_psc_spi_of_driver = {
609 .probe = mpc512x_psc_spi_of_probe,
610 .remove = mpc512x_psc_spi_of_remove,
611 .driver = {
612 .name = "mpc512x-psc-spi",
613 .owner = THIS_MODULE,
614 .of_match_table = mpc512x_psc_spi_of_match,
615 },
616 };
617 module_platform_driver(mpc512x_psc_spi_of_driver);
618
619 MODULE_AUTHOR("John Rigby");
620 MODULE_DESCRIPTION("MPC512x PSC SPI Driver");
621 MODULE_LICENSE("GPL");