1 /*
2 * spi_txx9.c - TXx9 SPI controller driver.
3 *
4 * Based on linux/arch/mips/tx4938/toshiba_rbtx4938/spi_txx9.c
5 * Copyright (C) 2000-2001 Toshiba Corporation
6 *
7 * 2003-2005 (c) MontaVista Software, Inc. This file is licensed under the
8 * terms of the GNU General Public License version 2. This program is
9 * licensed "as is" without any warranty of any kind, whether express
10 * or implied.
11 *
12 * Support for TX4938 in 2.6 - Manish Lachwani (mlachwani@mvista.com)
13 *
14 * Convert to generic SPI framework - Atsushi Nemoto (anemo@mba.ocn.ne.jp)
15 */
16 #include <linux/init.h>
17 #include <linux/delay.h>
18 #include <linux/errno.h>
19 #include <linux/interrupt.h>
20 #include <linux/platform_device.h>
21 #include <linux/sched.h>
22 #include <linux/spinlock.h>
23 #include <linux/workqueue.h>
24 #include <linux/spi/spi.h>
25 #include <linux/err.h>
26 #include <linux/clk.h>
27 #include <linux/io.h>
28 #include <asm/gpio.h>
29
30
31 #define SPI_FIFO_SIZE 4
32
33 #define TXx9_SPMCR 0x00
34 #define TXx9_SPCR0 0x04
35 #define TXx9_SPCR1 0x08
36 #define TXx9_SPFS 0x0c
37 #define TXx9_SPSR 0x14
38 #define TXx9_SPDR 0x18
39
40 /* SPMCR : SPI Master Control */
41 #define TXx9_SPMCR_OPMODE 0xc0
42 #define TXx9_SPMCR_CONFIG 0x40
43 #define TXx9_SPMCR_ACTIVE 0x80
44 #define TXx9_SPMCR_SPSTP 0x02
45 #define TXx9_SPMCR_BCLR 0x01
46
47 /* SPCR0 : SPI Control 0 */
48 #define TXx9_SPCR0_TXIFL_MASK 0xc000
49 #define TXx9_SPCR0_RXIFL_MASK 0x3000
50 #define TXx9_SPCR0_SIDIE 0x0800
51 #define TXx9_SPCR0_SOEIE 0x0400
52 #define TXx9_SPCR0_RBSIE 0x0200
53 #define TXx9_SPCR0_TBSIE 0x0100
54 #define TXx9_SPCR0_IFSPSE 0x0010
55 #define TXx9_SPCR0_SBOS 0x0004
56 #define TXx9_SPCR0_SPHA 0x0002
57 #define TXx9_SPCR0_SPOL 0x0001
58
59 /* SPSR : SPI Status */
60 #define TXx9_SPSR_TBSI 0x8000
61 #define TXx9_SPSR_RBSI 0x4000
62 #define TXx9_SPSR_TBS_MASK 0x3800
63 #define TXx9_SPSR_RBS_MASK 0x0700
64 #define TXx9_SPSR_SPOE 0x0080
65 #define TXx9_SPSR_IFSD 0x0008
66 #define TXx9_SPSR_SIDLE 0x0004
67 #define TXx9_SPSR_STRDY 0x0002
68 #define TXx9_SPSR_SRRDY 0x0001
69
70
71 struct txx9spi {
72 struct workqueue_struct *workqueue;
73 struct work_struct work;
74 spinlock_t lock; /* protect 'queue' */
75 struct list_head queue;
76 wait_queue_head_t waitq;
77 void __iomem *membase;
78 int baseclk;
79 struct clk *clk;
80 u32 max_speed_hz, min_speed_hz;
81 int last_chipselect;
82 int last_chipselect_val;
83 };
84
85 static u32 txx9spi_rd(struct txx9spi *c, int reg)
86 {
87 return __raw_readl(c->membase + reg);
88 }
89 static void txx9spi_wr(struct txx9spi *c, u32 val, int reg)
90 {
91 __raw_writel(val, c->membase + reg);
92 }
93
94 static void txx9spi_cs_func(struct spi_device *spi, struct txx9spi *c,
95 int on, unsigned int cs_delay)
96 {
97 int val = (spi->mode & SPI_CS_HIGH) ? on : !on;
98 if (on) {
99 /* deselect the chip with cs_change hint in last transfer */
100 if (c->last_chipselect >= 0)
101 gpio_set_value(c->last_chipselect,
102 !c->last_chipselect_val);
103 c->last_chipselect = spi->chip_select;
104 c->last_chipselect_val = val;
105 } else {
106 c->last_chipselect = -1;
107 ndelay(cs_delay); /* CS Hold Time */
108 }
109 gpio_set_value(spi->chip_select, val);
110 ndelay(cs_delay); /* CS Setup Time / CS Recovery Time */
111 }
112
113 /* the spi->mode bits understood by this driver: */
114 #define MODEBITS (SPI_CS_HIGH|SPI_CPOL|SPI_CPHA)
115
116 static int txx9spi_setup(struct spi_device *spi)
117 {
118 struct txx9spi *c = spi_master_get_devdata(spi->master);
119 u8 bits_per_word;
120
121 if (spi->mode & ~MODEBITS)
122 return -EINVAL;
123
124 if (!spi->max_speed_hz
125 || spi->max_speed_hz > c->max_speed_hz
126 || spi->max_speed_hz < c->min_speed_hz)
127 return -EINVAL;
128
129 bits_per_word = spi->bits_per_word ? : 8;
130 if (bits_per_word != 8 && bits_per_word != 16)
131 return -EINVAL;
132
133 if (gpio_direction_output(spi->chip_select,
134 !(spi->mode & SPI_CS_HIGH))) {
135 dev_err(&spi->dev, "Cannot setup GPIO for chipselect.\n");
136 return -EINVAL;
137 }
138
139 /* deselect chip */
140 spin_lock(&c->lock);
141 txx9spi_cs_func(spi, c, 0, (NSEC_PER_SEC / 2) / spi->max_speed_hz);
142 spin_unlock(&c->lock);
143
144 return 0;
145 }
146
147 static irqreturn_t txx9spi_interrupt(int irq, void *dev_id)
148 {
149 struct txx9spi *c = dev_id;
150
151 /* disable rx intr */
152 txx9spi_wr(c, txx9spi_rd(c, TXx9_SPCR0) & ~TXx9_SPCR0_RBSIE,
153 TXx9_SPCR0);
154 wake_up(&c->waitq);
155 return IRQ_HANDLED;
156 }
157
158 static void txx9spi_work_one(struct txx9spi *c, struct spi_message *m)
159 {
160 struct spi_device *spi = m->spi;
161 struct spi_transfer *t;
162 unsigned int cs_delay;
163 unsigned int cs_change = 1;
164 int status = 0;
165 u32 mcr;
166 u32 prev_speed_hz = 0;
167 u8 prev_bits_per_word = 0;
168
169 /* CS setup/hold/recovery time in nsec */
170 cs_delay = 100 + (NSEC_PER_SEC / 2) / spi->max_speed_hz;
171
172 mcr = txx9spi_rd(c, TXx9_SPMCR);
173 if (unlikely((mcr & TXx9_SPMCR_OPMODE) == TXx9_SPMCR_ACTIVE)) {
174 dev_err(&spi->dev, "Bad mode.\n");
175 status = -EIO;
176 goto exit;
177 }
178 mcr &= ~(TXx9_SPMCR_OPMODE | TXx9_SPMCR_SPSTP | TXx9_SPMCR_BCLR);
179
180 /* enter config mode */
181 txx9spi_wr(c, mcr | TXx9_SPMCR_CONFIG | TXx9_SPMCR_BCLR, TXx9_SPMCR);
182 txx9spi_wr(c, TXx9_SPCR0_SBOS
183 | ((spi->mode & SPI_CPOL) ? TXx9_SPCR0_SPOL : 0)
184 | ((spi->mode & SPI_CPHA) ? TXx9_SPCR0_SPHA : 0)
185 | 0x08,
186 TXx9_SPCR0);
187
188 list_for_each_entry (t, &m->transfers, transfer_list) {
189 const void *txbuf = t->tx_buf;
190 void *rxbuf = t->rx_buf;
191 u32 data;
192 unsigned int len = t->len;
193 unsigned int wsize;
194 u32 speed_hz = t->speed_hz ? : spi->max_speed_hz;
195 u8 bits_per_word = t->bits_per_word ? : spi->bits_per_word;
196
197 bits_per_word = bits_per_word ? : 8;
198 wsize = bits_per_word >> 3; /* in bytes */
199
200 if (prev_speed_hz != speed_hz
201 || prev_bits_per_word != bits_per_word) {
202 u32 n = (c->baseclk + speed_hz - 1) / speed_hz;
203 if (n < 1)
204 n = 1;
205 else if (n > 0xff)
206 n = 0xff;
207 /* enter config mode */
208 txx9spi_wr(c, mcr | TXx9_SPMCR_CONFIG | TXx9_SPMCR_BCLR,
209 TXx9_SPMCR);
210 txx9spi_wr(c, (n << 8) | bits_per_word, TXx9_SPCR1);
211 /* enter active mode */
212 txx9spi_wr(c, mcr | TXx9_SPMCR_ACTIVE, TXx9_SPMCR);
213
214 prev_speed_hz = speed_hz;
215 prev_bits_per_word = bits_per_word;
216 }
217
218 if (cs_change)
219 txx9spi_cs_func(spi, c, 1, cs_delay);
220 cs_change = t->cs_change;
221 while (len) {
222 unsigned int count = SPI_FIFO_SIZE;
223 int i;
224 u32 cr0;
225
226 if (len < count * wsize)
227 count = len / wsize;
228 /* now tx must be idle... */
229 while (!(txx9spi_rd(c, TXx9_SPSR) & TXx9_SPSR_SIDLE))
230 cpu_relax();
231 cr0 = txx9spi_rd(c, TXx9_SPCR0);
232 cr0 &= ~TXx9_SPCR0_RXIFL_MASK;
233 cr0 |= (count - 1) << 12;
234 /* enable rx intr */
235 cr0 |= TXx9_SPCR0_RBSIE;
236 txx9spi_wr(c, cr0, TXx9_SPCR0);
237 /* send */
238 for (i = 0; i < count; i++) {
239 if (txbuf) {
240 data = (wsize == 1)
241 ? *(const u8 *)txbuf
242 : *(const u16 *)txbuf;
243 txx9spi_wr(c, data, TXx9_SPDR);
244 txbuf += wsize;
245 } else
246 txx9spi_wr(c, 0, TXx9_SPDR);
247 }
248 /* wait all rx data */
249 wait_event(c->waitq,
250 txx9spi_rd(c, TXx9_SPSR) & TXx9_SPSR_RBSI);
251 /* receive */
252 for (i = 0; i < count; i++) {
253 data = txx9spi_rd(c, TXx9_SPDR);
254 if (rxbuf) {
255 if (wsize == 1)
256 *(u8 *)rxbuf = data;
257 else
258 *(u16 *)rxbuf = data;
259 rxbuf += wsize;
260 }
261 }
262 len -= count * wsize;
263 }
264 m->actual_length += t->len;
265 if (t->delay_usecs)
266 udelay(t->delay_usecs);
267
268 if (!cs_change)
269 continue;
270 if (t->transfer_list.next == &m->transfers)
271 break;
272 /* sometimes a short mid-message deselect of the chip
273 * may be needed to terminate a mode or command
274 */
275 txx9spi_cs_func(spi, c, 0, cs_delay);
276 }
277
278 exit:
279 m->status = status;
280 m->complete(m->context);
281
282 /* normally deactivate chipselect ... unless no error and
283 * cs_change has hinted that the next message will probably
284 * be for this chip too.
285 */
286 if (!(status == 0 && cs_change))
287 txx9spi_cs_func(spi, c, 0, cs_delay);
288
289 /* enter config mode */
290 txx9spi_wr(c, mcr | TXx9_SPMCR_CONFIG | TXx9_SPMCR_BCLR, TXx9_SPMCR);
291 }
292
293 static void txx9spi_work(struct work_struct *work)
294 {
295 struct txx9spi *c = container_of(work, struct txx9spi, work);
296 unsigned long flags;
297
298 spin_lock_irqsave(&c->lock, flags);
299 while (!list_empty(&c->queue)) {
300 struct spi_message *m;
301
302 m = container_of(c->queue.next, struct spi_message, queue);
303 list_del_init(&m->queue);
304 spin_unlock_irqrestore(&c->lock, flags);
305
306 txx9spi_work_one(c, m);
307
308 spin_lock_irqsave(&c->lock, flags);
309 }
310 spin_unlock_irqrestore(&c->lock, flags);
311 }
312
313 static int txx9spi_transfer(struct spi_device *spi, struct spi_message *m)
314 {
315 struct spi_master *master = spi->master;
316 struct txx9spi *c = spi_master_get_devdata(master);
317 struct spi_transfer *t;
318 unsigned long flags;
319
320 m->actual_length = 0;
321
322 /* check each transfer's parameters */
323 list_for_each_entry (t, &m->transfers, transfer_list) {
324 u32 speed_hz = t->speed_hz ? : spi->max_speed_hz;
325 u8 bits_per_word = t->bits_per_word ? : spi->bits_per_word;
326
327 bits_per_word = bits_per_word ? : 8;
328 if (!t->tx_buf && !t->rx_buf && t->len)
329 return -EINVAL;
330 if (bits_per_word != 8 && bits_per_word != 16)
331 return -EINVAL;
332 if (t->len & ((bits_per_word >> 3) - 1))
333 return -EINVAL;
334 if (speed_hz < c->min_speed_hz || speed_hz > c->max_speed_hz)
335 return -EINVAL;
336 }
337
338 spin_lock_irqsave(&c->lock, flags);
339 list_add_tail(&m->queue, &c->queue);
340 queue_work(c->workqueue, &c->work);
341 spin_unlock_irqrestore(&c->lock, flags);
342
343 return 0;
344 }
345
346 static int __init txx9spi_probe(struct platform_device *dev)
347 {
348 struct spi_master *master;
349 struct txx9spi *c;
350 struct resource *res;
351 int ret = -ENODEV;
352 u32 mcr;
353 int irq;
354
355 master = spi_alloc_master(&dev->dev, sizeof(*c));
356 if (!master)
357 return ret;
358 c = spi_master_get_devdata(master);
359 platform_set_drvdata(dev, master);
360
361 INIT_WORK(&c->work, txx9spi_work);
362 spin_lock_init(&c->lock);
363 INIT_LIST_HEAD(&c->queue);
364 init_waitqueue_head(&c->waitq);
365
366 c->clk = clk_get(&dev->dev, "spi-baseclk");
367 if (IS_ERR(c->clk)) {
368 ret = PTR_ERR(c->clk);
369 c->clk = NULL;
370 goto exit;
371 }
372 ret = clk_enable(c->clk);
373 if (ret) {
374 clk_put(c->clk);
375 c->clk = NULL;
376 goto exit;
377 }
378 c->baseclk = clk_get_rate(c->clk);
379 c->min_speed_hz = (c->baseclk + 0xff - 1) / 0xff;
380 c->max_speed_hz = c->baseclk;
381
382 res = platform_get_resource(dev, IORESOURCE_MEM, 0);
383 if (!res)
384 goto exit_busy;
385 if (!devm_request_mem_region(&dev->dev,
386 res->start, res->end - res->start + 1,
387 "spi_txx9"))
388 goto exit_busy;
389 c->membase = devm_ioremap(&dev->dev,
390 res->start, res->end - res->start + 1);
391 if (!c->membase)
392 goto exit_busy;
393
394 /* enter config mode */
395 mcr = txx9spi_rd(c, TXx9_SPMCR);
396 mcr &= ~(TXx9_SPMCR_OPMODE | TXx9_SPMCR_SPSTP | TXx9_SPMCR_BCLR);
397 txx9spi_wr(c, mcr | TXx9_SPMCR_CONFIG | TXx9_SPMCR_BCLR, TXx9_SPMCR);
398
399 irq = platform_get_irq(dev, 0);
400 if (irq < 0)
401 goto exit_busy;
402 ret = devm_request_irq(&dev->dev, irq, txx9spi_interrupt, 0,
403 "spi_txx9", c);
404 if (ret)
405 goto exit;
406
407 c->workqueue = create_singlethread_workqueue(master->dev.parent->bus_id);
408 if (!c->workqueue)
409 goto exit_busy;
410 c->last_chipselect = -1;
411
412 dev_info(&dev->dev, "at %#llx, irq %d, %dMHz\n",
413 (unsigned long long)res->start, irq,
414 (c->baseclk + 500000) / 1000000);
415
416 master->bus_num = dev->id;
417 master->setup = txx9spi_setup;
418 master->transfer = txx9spi_transfer;
419 master->num_chipselect = (u16)UINT_MAX; /* any GPIO numbers */
420
421 ret = spi_register_master(master);
422 if (ret)
423 goto exit;
424 return 0;
425 exit_busy:
426 ret = -EBUSY;
427 exit:
428 if (c->workqueue)
429 destroy_workqueue(c->workqueue);
430 if (c->clk) {
431 clk_disable(c->clk);
432 clk_put(c->clk);
433 }
434 platform_set_drvdata(dev, NULL);
435 spi_master_put(master);
436 return ret;
437 }
438
439 static int __exit txx9spi_remove(struct platform_device *dev)
440 {
441 struct spi_master *master = spi_master_get(platform_get_drvdata(dev));
442 struct txx9spi *c = spi_master_get_devdata(master);
443
444 spi_unregister_master(master);
445 platform_set_drvdata(dev, NULL);
446 destroy_workqueue(c->workqueue);
447 clk_disable(c->clk);
448 clk_put(c->clk);
449 spi_master_put(master);
450 return 0;
451 }
452
453 /* work with hotplug and coldplug */
454 MODULE_ALIAS("platform:spi_txx9");
455
456 static struct platform_driver txx9spi_driver = {
457 .remove = __exit_p(txx9spi_remove),
458 .driver = {
459 .name = "spi_txx9",
460 .owner = THIS_MODULE,
461 },
462 };
463
464 static int __init txx9spi_init(void)
465 {
466 return platform_driver_probe(&txx9spi_driver, txx9spi_probe);
467 }
468 subsys_initcall(txx9spi_init);
469
470 static void __exit txx9spi_exit(void)
471 {
472 platform_driver_unregister(&txx9spi_driver);
473 }
474 module_exit(txx9spi_exit);
475
476 MODULE_DESCRIPTION("TXx9 SPI Driver");
477 MODULE_LICENSE("GPL");
478
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