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/errno.h>
20 #include <linux/interrupt.h>
21 #include <linux/of_address.h>
22 #include <linux/of_irq.h>
23 #include <linux/of_platform.h>
24 #include <linux/completion.h>
25 #include <linux/io.h>
26 #include <linux/delay.h>
27 #include <linux/clk.h>
28 #include <linux/spi/spi.h>
29 #include <linux/fsl_devices.h>
30 #include <linux/gpio.h>
31 #include <asm/mpc52xx_psc.h>
32
33 enum {
34 TYPE_MPC5121,
35 TYPE_MPC5125,
36 };
37
38 /*
39 * This macro abstracts the differences in the PSC register layout between
40 * MPC5121 (which uses a struct mpc52xx_psc) and MPC5125 (using mpc5125_psc).
41 */
42 #define psc_addr(mps, regname) ({ \
43 void *__ret = NULL; \
44 switch (mps->type) { \
45 case TYPE_MPC5121: { \
46 struct mpc52xx_psc __iomem *psc = mps->psc; \
47 __ret = &psc->regname; \
48 }; \
49 break; \
50 case TYPE_MPC5125: { \
51 struct mpc5125_psc __iomem *psc = mps->psc; \
52 __ret = &psc->regname; \
53 }; \
54 break; \
55 } \
56 __ret; })
57
58 struct mpc512x_psc_spi {
59 void (*cs_control)(struct spi_device *spi, bool on);
60
61 /* driver internal data */
62 int type;
63 void __iomem *psc;
64 struct mpc512x_psc_fifo __iomem *fifo;
65 unsigned int irq;
66 u8 bits_per_word;
67 struct clk *clk_mclk;
68 struct clk *clk_ipg;
69 u32 mclk_rate;
70
71 struct completion txisrdone;
72 };
73
74 /* controller state */
75 struct mpc512x_psc_spi_cs {
76 int bits_per_word;
77 int speed_hz;
78 };
79
80 /* set clock freq, clock ramp, bits per work
81 * if t is NULL then reset the values to the default values
82 */
mpc512x_psc_spi_transfer_setup(struct spi_device * spi,struct spi_transfer * t)83 static int mpc512x_psc_spi_transfer_setup(struct spi_device *spi,
84 struct spi_transfer *t)
85 {
86 struct mpc512x_psc_spi_cs *cs = spi->controller_state;
87
88 cs->speed_hz = (t && t->speed_hz)
89 ? t->speed_hz : spi->max_speed_hz;
90 cs->bits_per_word = (t && t->bits_per_word)
91 ? t->bits_per_word : spi->bits_per_word;
92 cs->bits_per_word = ((cs->bits_per_word + 7) / 8) * 8;
93 return 0;
94 }
95
mpc512x_psc_spi_activate_cs(struct spi_device * spi)96 static void mpc512x_psc_spi_activate_cs(struct spi_device *spi)
97 {
98 struct mpc512x_psc_spi_cs *cs = spi->controller_state;
99 struct mpc512x_psc_spi *mps = spi_master_get_devdata(spi->master);
100 u32 sicr;
101 u32 ccr;
102 int speed;
103 u16 bclkdiv;
104
105 sicr = in_be32(psc_addr(mps, sicr));
106
107 /* Set clock phase and polarity */
108 if (spi->mode & SPI_CPHA)
109 sicr |= 0x00001000;
110 else
111 sicr &= ~0x00001000;
112
113 if (spi->mode & SPI_CPOL)
114 sicr |= 0x00002000;
115 else
116 sicr &= ~0x00002000;
117
118 if (spi->mode & SPI_LSB_FIRST)
119 sicr |= 0x10000000;
120 else
121 sicr &= ~0x10000000;
122 out_be32(psc_addr(mps, sicr), sicr);
123
124 ccr = in_be32(psc_addr(mps, ccr));
125 ccr &= 0xFF000000;
126 speed = cs->speed_hz;
127 if (!speed)
128 speed = 1000000; /* default 1MHz */
129 bclkdiv = (mps->mclk_rate / speed) - 1;
130
131 ccr |= (((bclkdiv & 0xff) << 16) | (((bclkdiv >> 8) & 0xff) << 8));
132 out_be32(psc_addr(mps, ccr), ccr);
133 mps->bits_per_word = cs->bits_per_word;
134
135 if (mps->cs_control && gpio_is_valid(spi->cs_gpio))
136 mps->cs_control(spi, (spi->mode & SPI_CS_HIGH) ? 1 : 0);
137 }
138
mpc512x_psc_spi_deactivate_cs(struct spi_device * spi)139 static void mpc512x_psc_spi_deactivate_cs(struct spi_device *spi)
140 {
141 struct mpc512x_psc_spi *mps = spi_master_get_devdata(spi->master);
142
143 if (mps->cs_control && gpio_is_valid(spi->cs_gpio))
144 mps->cs_control(spi, (spi->mode & SPI_CS_HIGH) ? 0 : 1);
145
146 }
147
148 /* extract and scale size field in txsz or rxsz */
149 #define MPC512x_PSC_FIFO_SZ(sz) ((sz & 0x7ff) << 2);
150
151 #define EOFBYTE 1
152
mpc512x_psc_spi_transfer_rxtx(struct spi_device * spi,struct spi_transfer * t)153 static int mpc512x_psc_spi_transfer_rxtx(struct spi_device *spi,
154 struct spi_transfer *t)
155 {
156 struct mpc512x_psc_spi *mps = spi_master_get_devdata(spi->master);
157 struct mpc512x_psc_fifo __iomem *fifo = mps->fifo;
158 size_t tx_len = t->len;
159 size_t rx_len = t->len;
160 u8 *tx_buf = (u8 *)t->tx_buf;
161 u8 *rx_buf = (u8 *)t->rx_buf;
162
163 if (!tx_buf && !rx_buf && t->len)
164 return -EINVAL;
165
166 while (rx_len || tx_len) {
167 size_t txcount;
168 u8 data;
169 size_t fifosz;
170 size_t rxcount;
171 int rxtries;
172
173 /*
174 * send the TX bytes in as large a chunk as possible
175 * but neither exceed the TX nor the RX FIFOs
176 */
177 fifosz = MPC512x_PSC_FIFO_SZ(in_be32(&fifo->txsz));
178 txcount = min(fifosz, tx_len);
179 fifosz = MPC512x_PSC_FIFO_SZ(in_be32(&fifo->rxsz));
180 fifosz -= in_be32(&fifo->rxcnt) + 1;
181 txcount = min(fifosz, txcount);
182 if (txcount) {
183
184 /* fill the TX FIFO */
185 while (txcount-- > 0) {
186 data = tx_buf ? *tx_buf++ : 0;
187 if (tx_len == EOFBYTE && t->cs_change)
188 setbits32(&fifo->txcmd,
189 MPC512x_PSC_FIFO_EOF);
190 out_8(&fifo->txdata_8, data);
191 tx_len--;
192 }
193
194 /* have the ISR trigger when the TX FIFO is empty */
195 reinit_completion(&mps->txisrdone);
196 out_be32(&fifo->txisr, MPC512x_PSC_FIFO_EMPTY);
197 out_be32(&fifo->tximr, MPC512x_PSC_FIFO_EMPTY);
198 wait_for_completion(&mps->txisrdone);
199 }
200
201 /*
202 * consume as much RX data as the FIFO holds, while we
203 * iterate over the transfer's TX data length
204 *
205 * only insist in draining all the remaining RX bytes
206 * when the TX bytes were exhausted (that's at the very
207 * end of this transfer, not when still iterating over
208 * the transfer's chunks)
209 */
210 rxtries = 50;
211 do {
212
213 /*
214 * grab whatever was in the FIFO when we started
215 * looking, don't bother fetching what was added to
216 * the FIFO while we read from it -- we'll return
217 * here eventually and prefer sending out remaining
218 * TX data
219 */
220 fifosz = in_be32(&fifo->rxcnt);
221 rxcount = min(fifosz, rx_len);
222 while (rxcount-- > 0) {
223 data = in_8(&fifo->rxdata_8);
224 if (rx_buf)
225 *rx_buf++ = data;
226 rx_len--;
227 }
228
229 /*
230 * come back later if there still is TX data to send,
231 * bail out of the RX drain loop if all of the TX data
232 * was sent and all of the RX data was received (i.e.
233 * when the transmission has completed)
234 */
235 if (tx_len)
236 break;
237 if (!rx_len)
238 break;
239
240 /*
241 * TX data transmission has completed while RX data
242 * is still pending -- that's a transient situation
243 * which depends on wire speed and specific
244 * hardware implementation details (buffering) yet
245 * should resolve very quickly
246 *
247 * just yield for a moment to not hog the CPU for
248 * too long when running SPI at low speed
249 *
250 * the timeout range is rather arbitrary and tries
251 * to balance throughput against system load; the
252 * chosen values result in a minimal timeout of 50
253 * times 10us and thus work at speeds as low as
254 * some 20kbps, while the maximum timeout at the
255 * transfer's end could be 5ms _if_ nothing else
256 * ticks in the system _and_ RX data still wasn't
257 * received, which only occurs in situations that
258 * are exceptional; removing the unpredictability
259 * of the timeout either decreases throughput
260 * (longer timeouts), or puts more load on the
261 * system (fixed short timeouts) or requires the
262 * use of a timeout API instead of a counter and an
263 * unknown inner delay
264 */
265 usleep_range(10, 100);
266
267 } while (--rxtries > 0);
268 if (!tx_len && rx_len && !rxtries) {
269 /*
270 * not enough RX bytes even after several retries
271 * and the resulting rather long timeout?
272 */
273 rxcount = in_be32(&fifo->rxcnt);
274 dev_warn(&spi->dev,
275 "short xfer, missing %zd RX bytes, FIFO level %zd\n",
276 rx_len, rxcount);
277 }
278
279 /*
280 * drain and drop RX data which "should not be there" in
281 * the first place, for undisturbed transmission this turns
282 * into a NOP (except for the FIFO level fetch)
283 */
284 if (!tx_len && !rx_len) {
285 while (in_be32(&fifo->rxcnt))
286 in_8(&fifo->rxdata_8);
287 }
288
289 }
290 return 0;
291 }
292
mpc512x_psc_spi_msg_xfer(struct spi_master * master,struct spi_message * m)293 static int mpc512x_psc_spi_msg_xfer(struct spi_master *master,
294 struct spi_message *m)
295 {
296 struct spi_device *spi;
297 unsigned cs_change;
298 int status;
299 struct spi_transfer *t;
300
301 spi = m->spi;
302 cs_change = 1;
303 status = 0;
304 list_for_each_entry(t, &m->transfers, transfer_list) {
305 status = mpc512x_psc_spi_transfer_setup(spi, t);
306 if (status < 0)
307 break;
308
309 if (cs_change)
310 mpc512x_psc_spi_activate_cs(spi);
311 cs_change = t->cs_change;
312
313 status = mpc512x_psc_spi_transfer_rxtx(spi, t);
314 if (status)
315 break;
316 m->actual_length += t->len;
317
318 if (t->delay_usecs)
319 udelay(t->delay_usecs);
320
321 if (cs_change)
322 mpc512x_psc_spi_deactivate_cs(spi);
323 }
324
325 m->status = status;
326 if (m->complete)
327 m->complete(m->context);
328
329 if (status || !cs_change)
330 mpc512x_psc_spi_deactivate_cs(spi);
331
332 mpc512x_psc_spi_transfer_setup(spi, NULL);
333
334 spi_finalize_current_message(master);
335 return status;
336 }
337
mpc512x_psc_spi_prep_xfer_hw(struct spi_master * master)338 static int mpc512x_psc_spi_prep_xfer_hw(struct spi_master *master)
339 {
340 struct mpc512x_psc_spi *mps = spi_master_get_devdata(master);
341
342 dev_dbg(&master->dev, "%s()\n", __func__);
343
344 /* Zero MR2 */
345 in_8(psc_addr(mps, mr2));
346 out_8(psc_addr(mps, mr2), 0x0);
347
348 /* enable transmitter/receiver */
349 out_8(psc_addr(mps, command), MPC52xx_PSC_TX_ENABLE | MPC52xx_PSC_RX_ENABLE);
350
351 return 0;
352 }
353
mpc512x_psc_spi_unprep_xfer_hw(struct spi_master * master)354 static int mpc512x_psc_spi_unprep_xfer_hw(struct spi_master *master)
355 {
356 struct mpc512x_psc_spi *mps = spi_master_get_devdata(master);
357 struct mpc512x_psc_fifo __iomem *fifo = mps->fifo;
358
359 dev_dbg(&master->dev, "%s()\n", __func__);
360
361 /* disable transmitter/receiver and fifo interrupt */
362 out_8(psc_addr(mps, command), MPC52xx_PSC_TX_DISABLE | MPC52xx_PSC_RX_DISABLE);
363 out_be32(&fifo->tximr, 0);
364
365 return 0;
366 }
367
mpc512x_psc_spi_setup(struct spi_device * spi)368 static int mpc512x_psc_spi_setup(struct spi_device *spi)
369 {
370 struct mpc512x_psc_spi_cs *cs = spi->controller_state;
371 int ret;
372
373 if (spi->bits_per_word % 8)
374 return -EINVAL;
375
376 if (!cs) {
377 cs = kzalloc(sizeof *cs, GFP_KERNEL);
378 if (!cs)
379 return -ENOMEM;
380
381 if (gpio_is_valid(spi->cs_gpio)) {
382 ret = gpio_request(spi->cs_gpio, dev_name(&spi->dev));
383 if (ret) {
384 dev_err(&spi->dev, "can't get CS gpio: %d\n",
385 ret);
386 kfree(cs);
387 return ret;
388 }
389 gpio_direction_output(spi->cs_gpio,
390 spi->mode & SPI_CS_HIGH ? 0 : 1);
391 }
392
393 spi->controller_state = cs;
394 }
395
396 cs->bits_per_word = spi->bits_per_word;
397 cs->speed_hz = spi->max_speed_hz;
398
399 return 0;
400 }
401
mpc512x_psc_spi_cleanup(struct spi_device * spi)402 static void mpc512x_psc_spi_cleanup(struct spi_device *spi)
403 {
404 if (gpio_is_valid(spi->cs_gpio))
405 gpio_free(spi->cs_gpio);
406 kfree(spi->controller_state);
407 }
408
mpc512x_psc_spi_port_config(struct spi_master * master,struct mpc512x_psc_spi * mps)409 static int mpc512x_psc_spi_port_config(struct spi_master *master,
410 struct mpc512x_psc_spi *mps)
411 {
412 struct mpc512x_psc_fifo __iomem *fifo = mps->fifo;
413 u32 sicr;
414 u32 ccr;
415 int speed;
416 u16 bclkdiv;
417
418 /* Reset the PSC into a known state */
419 out_8(psc_addr(mps, command), MPC52xx_PSC_RST_RX);
420 out_8(psc_addr(mps, command), MPC52xx_PSC_RST_TX);
421 out_8(psc_addr(mps, command), MPC52xx_PSC_TX_DISABLE | MPC52xx_PSC_RX_DISABLE);
422
423 /* Disable psc interrupts all useful interrupts are in fifo */
424 out_be16(psc_addr(mps, isr_imr.imr), 0);
425
426 /* Disable fifo interrupts, will be enabled later */
427 out_be32(&fifo->tximr, 0);
428 out_be32(&fifo->rximr, 0);
429
430 /* Setup fifo slice address and size */
431 /*out_be32(&fifo->txsz, 0x0fe00004);*/
432 /*out_be32(&fifo->rxsz, 0x0ff00004);*/
433
434 sicr = 0x01000000 | /* SIM = 0001 -- 8 bit */
435 0x00800000 | /* GenClk = 1 -- internal clk */
436 0x00008000 | /* SPI = 1 */
437 0x00004000 | /* MSTR = 1 -- SPI master */
438 0x00000800; /* UseEOF = 1 -- SS low until EOF */
439
440 out_be32(psc_addr(mps, sicr), sicr);
441
442 ccr = in_be32(psc_addr(mps, ccr));
443 ccr &= 0xFF000000;
444 speed = 1000000; /* default 1MHz */
445 bclkdiv = (mps->mclk_rate / speed) - 1;
446 ccr |= (((bclkdiv & 0xff) << 16) | (((bclkdiv >> 8) & 0xff) << 8));
447 out_be32(psc_addr(mps, ccr), ccr);
448
449 /* Set 2ms DTL delay */
450 out_8(psc_addr(mps, ctur), 0x00);
451 out_8(psc_addr(mps, ctlr), 0x82);
452
453 /* we don't use the alarms */
454 out_be32(&fifo->rxalarm, 0xfff);
455 out_be32(&fifo->txalarm, 0);
456
457 /* Enable FIFO slices for Rx/Tx */
458 out_be32(&fifo->rxcmd,
459 MPC512x_PSC_FIFO_ENABLE_SLICE | MPC512x_PSC_FIFO_ENABLE_DMA);
460 out_be32(&fifo->txcmd,
461 MPC512x_PSC_FIFO_ENABLE_SLICE | MPC512x_PSC_FIFO_ENABLE_DMA);
462
463 mps->bits_per_word = 8;
464
465 return 0;
466 }
467
mpc512x_psc_spi_isr(int irq,void * dev_id)468 static irqreturn_t mpc512x_psc_spi_isr(int irq, void *dev_id)
469 {
470 struct mpc512x_psc_spi *mps = (struct mpc512x_psc_spi *)dev_id;
471 struct mpc512x_psc_fifo __iomem *fifo = mps->fifo;
472
473 /* clear interrupt and wake up the rx/tx routine */
474 if (in_be32(&fifo->txisr) &
475 in_be32(&fifo->tximr) & MPC512x_PSC_FIFO_EMPTY) {
476 out_be32(&fifo->txisr, MPC512x_PSC_FIFO_EMPTY);
477 out_be32(&fifo->tximr, 0);
478 complete(&mps->txisrdone);
479 return IRQ_HANDLED;
480 }
481 return IRQ_NONE;
482 }
483
mpc512x_spi_cs_control(struct spi_device * spi,bool onoff)484 static void mpc512x_spi_cs_control(struct spi_device *spi, bool onoff)
485 {
486 gpio_set_value(spi->cs_gpio, onoff);
487 }
488
mpc512x_psc_spi_do_probe(struct device * dev,u32 regaddr,u32 size,unsigned int irq)489 static int mpc512x_psc_spi_do_probe(struct device *dev, u32 regaddr,
490 u32 size, unsigned int irq)
491 {
492 struct fsl_spi_platform_data *pdata = dev_get_platdata(dev);
493 struct mpc512x_psc_spi *mps;
494 struct spi_master *master;
495 int ret;
496 void *tempp;
497 struct clk *clk;
498
499 master = spi_alloc_master(dev, sizeof *mps);
500 if (master == NULL)
501 return -ENOMEM;
502
503 dev_set_drvdata(dev, master);
504 mps = spi_master_get_devdata(master);
505 mps->type = (int)of_device_get_match_data(dev);
506 mps->irq = irq;
507
508 if (pdata == NULL) {
509 mps->cs_control = mpc512x_spi_cs_control;
510 } else {
511 mps->cs_control = pdata->cs_control;
512 master->bus_num = pdata->bus_num;
513 master->num_chipselect = pdata->max_chipselect;
514 }
515
516 master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_CS_HIGH | SPI_LSB_FIRST;
517 master->setup = mpc512x_psc_spi_setup;
518 master->prepare_transfer_hardware = mpc512x_psc_spi_prep_xfer_hw;
519 master->transfer_one_message = mpc512x_psc_spi_msg_xfer;
520 master->unprepare_transfer_hardware = mpc512x_psc_spi_unprep_xfer_hw;
521 master->cleanup = mpc512x_psc_spi_cleanup;
522 master->dev.of_node = dev->of_node;
523
524 tempp = devm_ioremap(dev, regaddr, size);
525 if (!tempp) {
526 dev_err(dev, "could not ioremap I/O port range\n");
527 ret = -EFAULT;
528 goto free_master;
529 }
530 mps->psc = tempp;
531 mps->fifo =
532 (struct mpc512x_psc_fifo *)(tempp + sizeof(struct mpc52xx_psc));
533 ret = devm_request_irq(dev, mps->irq, mpc512x_psc_spi_isr, IRQF_SHARED,
534 "mpc512x-psc-spi", mps);
535 if (ret)
536 goto free_master;
537 init_completion(&mps->txisrdone);
538
539 clk = devm_clk_get(dev, "mclk");
540 if (IS_ERR(clk)) {
541 ret = PTR_ERR(clk);
542 goto free_master;
543 }
544 ret = clk_prepare_enable(clk);
545 if (ret)
546 goto free_master;
547 mps->clk_mclk = clk;
548 mps->mclk_rate = clk_get_rate(clk);
549
550 clk = devm_clk_get(dev, "ipg");
551 if (IS_ERR(clk)) {
552 ret = PTR_ERR(clk);
553 goto free_mclk_clock;
554 }
555 ret = clk_prepare_enable(clk);
556 if (ret)
557 goto free_mclk_clock;
558 mps->clk_ipg = clk;
559
560 ret = mpc512x_psc_spi_port_config(master, mps);
561 if (ret < 0)
562 goto free_ipg_clock;
563
564 ret = devm_spi_register_master(dev, master);
565 if (ret < 0)
566 goto free_ipg_clock;
567
568 return ret;
569
570 free_ipg_clock:
571 clk_disable_unprepare(mps->clk_ipg);
572 free_mclk_clock:
573 clk_disable_unprepare(mps->clk_mclk);
574 free_master:
575 spi_master_put(master);
576
577 return ret;
578 }
579
mpc512x_psc_spi_do_remove(struct device * dev)580 static int mpc512x_psc_spi_do_remove(struct device *dev)
581 {
582 struct spi_master *master = dev_get_drvdata(dev);
583 struct mpc512x_psc_spi *mps = spi_master_get_devdata(master);
584
585 clk_disable_unprepare(mps->clk_mclk);
586 clk_disable_unprepare(mps->clk_ipg);
587
588 return 0;
589 }
590
mpc512x_psc_spi_of_probe(struct platform_device * op)591 static int mpc512x_psc_spi_of_probe(struct platform_device *op)
592 {
593 const u32 *regaddr_p;
594 u64 regaddr64, size64;
595
596 regaddr_p = of_get_address(op->dev.of_node, 0, &size64, NULL);
597 if (!regaddr_p) {
598 dev_err(&op->dev, "Invalid PSC address\n");
599 return -EINVAL;
600 }
601 regaddr64 = of_translate_address(op->dev.of_node, regaddr_p);
602
603 return mpc512x_psc_spi_do_probe(&op->dev, (u32) regaddr64, (u32) size64,
604 irq_of_parse_and_map(op->dev.of_node, 0));
605 }
606
mpc512x_psc_spi_of_remove(struct platform_device * op)607 static int mpc512x_psc_spi_of_remove(struct platform_device *op)
608 {
609 return mpc512x_psc_spi_do_remove(&op->dev);
610 }
611
612 static const struct of_device_id mpc512x_psc_spi_of_match[] = {
613 { .compatible = "fsl,mpc5121-psc-spi", .data = (void *)TYPE_MPC5121 },
614 { .compatible = "fsl,mpc5125-psc-spi", .data = (void *)TYPE_MPC5125 },
615 {},
616 };
617
618 MODULE_DEVICE_TABLE(of, mpc512x_psc_spi_of_match);
619
620 static struct platform_driver mpc512x_psc_spi_of_driver = {
621 .probe = mpc512x_psc_spi_of_probe,
622 .remove = mpc512x_psc_spi_of_remove,
623 .driver = {
624 .name = "mpc512x-psc-spi",
625 .of_match_table = mpc512x_psc_spi_of_match,
626 },
627 };
628 module_platform_driver(mpc512x_psc_spi_of_driver);
629
630 MODULE_AUTHOR("John Rigby");
631 MODULE_DESCRIPTION("MPC512x PSC SPI Driver");
632 MODULE_LICENSE("GPL");
633
