1 /*
2 * 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 <linux/module.h>
29 #include <asm/gpio.h>
30
31
32 #define SPI_FIFO_SIZE 4
33 #define SPI_MAX_DIVIDER 0xff /* Max. value for SPCR1.SER */
34 #define SPI_MIN_DIVIDER 1 /* Min. value for SPCR1.SER */
35
36 #define TXx9_SPMCR 0x00
37 #define TXx9_SPCR0 0x04
38 #define TXx9_SPCR1 0x08
39 #define TXx9_SPFS 0x0c
40 #define TXx9_SPSR 0x14
41 #define TXx9_SPDR 0x18
42
43 /* SPMCR : SPI Master Control */
44 #define TXx9_SPMCR_OPMODE 0xc0
45 #define TXx9_SPMCR_CONFIG 0x40
46 #define TXx9_SPMCR_ACTIVE 0x80
47 #define TXx9_SPMCR_SPSTP 0x02
48 #define TXx9_SPMCR_BCLR 0x01
49
50 /* SPCR0 : SPI Control 0 */
51 #define TXx9_SPCR0_TXIFL_MASK 0xc000
52 #define TXx9_SPCR0_RXIFL_MASK 0x3000
53 #define TXx9_SPCR0_SIDIE 0x0800
54 #define TXx9_SPCR0_SOEIE 0x0400
55 #define TXx9_SPCR0_RBSIE 0x0200
56 #define TXx9_SPCR0_TBSIE 0x0100
57 #define TXx9_SPCR0_IFSPSE 0x0010
58 #define TXx9_SPCR0_SBOS 0x0004
59 #define TXx9_SPCR0_SPHA 0x0002
60 #define TXx9_SPCR0_SPOL 0x0001
61
62 /* SPSR : SPI Status */
63 #define TXx9_SPSR_TBSI 0x8000
64 #define TXx9_SPSR_RBSI 0x4000
65 #define TXx9_SPSR_TBS_MASK 0x3800
66 #define TXx9_SPSR_RBS_MASK 0x0700
67 #define TXx9_SPSR_SPOE 0x0080
68 #define TXx9_SPSR_IFSD 0x0008
69 #define TXx9_SPSR_SIDLE 0x0004
70 #define TXx9_SPSR_STRDY 0x0002
71 #define TXx9_SPSR_SRRDY 0x0001
72
73
74 struct txx9spi {
75 struct workqueue_struct *workqueue;
76 struct work_struct work;
77 spinlock_t lock; /* protect 'queue' */
78 struct list_head queue;
79 wait_queue_head_t waitq;
80 void __iomem *membase;
81 int baseclk;
82 struct clk *clk;
83 u32 max_speed_hz, min_speed_hz;
84 int last_chipselect;
85 int last_chipselect_val;
86 };
87
txx9spi_rd(struct txx9spi * c,int reg)88 static u32 txx9spi_rd(struct txx9spi *c, int reg)
89 {
90 return __raw_readl(c->membase + reg);
91 }
txx9spi_wr(struct txx9spi * c,u32 val,int reg)92 static void txx9spi_wr(struct txx9spi *c, u32 val, int reg)
93 {
94 __raw_writel(val, c->membase + reg);
95 }
96
txx9spi_cs_func(struct spi_device * spi,struct txx9spi * c,int on,unsigned int cs_delay)97 static void txx9spi_cs_func(struct spi_device *spi, struct txx9spi *c,
98 int on, unsigned int cs_delay)
99 {
100 int val = (spi->mode & SPI_CS_HIGH) ? on : !on;
101 if (on) {
102 /* deselect the chip with cs_change hint in last transfer */
103 if (c->last_chipselect >= 0)
104 gpio_set_value(c->last_chipselect,
105 !c->last_chipselect_val);
106 c->last_chipselect = spi->chip_select;
107 c->last_chipselect_val = val;
108 } else {
109 c->last_chipselect = -1;
110 ndelay(cs_delay); /* CS Hold Time */
111 }
112 gpio_set_value(spi->chip_select, val);
113 ndelay(cs_delay); /* CS Setup Time / CS Recovery Time */
114 }
115
txx9spi_setup(struct spi_device * spi)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->max_speed_hz
122 || spi->max_speed_hz > c->max_speed_hz
123 || spi->max_speed_hz < c->min_speed_hz)
124 return -EINVAL;
125
126 bits_per_word = spi->bits_per_word;
127 if (bits_per_word != 8 && bits_per_word != 16)
128 return -EINVAL;
129
130 if (gpio_direction_output(spi->chip_select,
131 !(spi->mode & SPI_CS_HIGH))) {
132 dev_err(&spi->dev, "Cannot setup GPIO for chipselect.\n");
133 return -EINVAL;
134 }
135
136 /* deselect chip */
137 spin_lock(&c->lock);
138 txx9spi_cs_func(spi, c, 0, (NSEC_PER_SEC / 2) / spi->max_speed_hz);
139 spin_unlock(&c->lock);
140
141 return 0;
142 }
143
txx9spi_interrupt(int irq,void * dev_id)144 static irqreturn_t txx9spi_interrupt(int irq, void *dev_id)
145 {
146 struct txx9spi *c = dev_id;
147
148 /* disable rx intr */
149 txx9spi_wr(c, txx9spi_rd(c, TXx9_SPCR0) & ~TXx9_SPCR0_RBSIE,
150 TXx9_SPCR0);
151 wake_up(&c->waitq);
152 return IRQ_HANDLED;
153 }
154
txx9spi_work_one(struct txx9spi * c,struct spi_message * m)155 static void txx9spi_work_one(struct txx9spi *c, struct spi_message *m)
156 {
157 struct spi_device *spi = m->spi;
158 struct spi_transfer *t;
159 unsigned int cs_delay;
160 unsigned int cs_change = 1;
161 int status = 0;
162 u32 mcr;
163 u32 prev_speed_hz = 0;
164 u8 prev_bits_per_word = 0;
165
166 /* CS setup/hold/recovery time in nsec */
167 cs_delay = 100 + (NSEC_PER_SEC / 2) / spi->max_speed_hz;
168
169 mcr = txx9spi_rd(c, TXx9_SPMCR);
170 if (unlikely((mcr & TXx9_SPMCR_OPMODE) == TXx9_SPMCR_ACTIVE)) {
171 dev_err(&spi->dev, "Bad mode.\n");
172 status = -EIO;
173 goto exit;
174 }
175 mcr &= ~(TXx9_SPMCR_OPMODE | TXx9_SPMCR_SPSTP | TXx9_SPMCR_BCLR);
176
177 /* enter config mode */
178 txx9spi_wr(c, mcr | TXx9_SPMCR_CONFIG | TXx9_SPMCR_BCLR, TXx9_SPMCR);
179 txx9spi_wr(c, TXx9_SPCR0_SBOS
180 | ((spi->mode & SPI_CPOL) ? TXx9_SPCR0_SPOL : 0)
181 | ((spi->mode & SPI_CPHA) ? TXx9_SPCR0_SPHA : 0)
182 | 0x08,
183 TXx9_SPCR0);
184
185 list_for_each_entry (t, &m->transfers, transfer_list) {
186 const void *txbuf = t->tx_buf;
187 void *rxbuf = t->rx_buf;
188 u32 data;
189 unsigned int len = t->len;
190 unsigned int wsize;
191 u32 speed_hz = t->speed_hz ? : spi->max_speed_hz;
192 u8 bits_per_word = t->bits_per_word ? : spi->bits_per_word;
193
194 bits_per_word = bits_per_word ? : 8;
195 wsize = bits_per_word >> 3; /* in bytes */
196
197 if (prev_speed_hz != speed_hz
198 || prev_bits_per_word != bits_per_word) {
199 int n = DIV_ROUND_UP(c->baseclk, speed_hz) - 1;
200 n = clamp(n, SPI_MIN_DIVIDER, SPI_MAX_DIVIDER);
201 /* enter config mode */
202 txx9spi_wr(c, mcr | TXx9_SPMCR_CONFIG | TXx9_SPMCR_BCLR,
203 TXx9_SPMCR);
204 txx9spi_wr(c, (n << 8) | bits_per_word, TXx9_SPCR1);
205 /* enter active mode */
206 txx9spi_wr(c, mcr | TXx9_SPMCR_ACTIVE, TXx9_SPMCR);
207
208 prev_speed_hz = speed_hz;
209 prev_bits_per_word = bits_per_word;
210 }
211
212 if (cs_change)
213 txx9spi_cs_func(spi, c, 1, cs_delay);
214 cs_change = t->cs_change;
215 while (len) {
216 unsigned int count = SPI_FIFO_SIZE;
217 int i;
218 u32 cr0;
219
220 if (len < count * wsize)
221 count = len / wsize;
222 /* now tx must be idle... */
223 while (!(txx9spi_rd(c, TXx9_SPSR) & TXx9_SPSR_SIDLE))
224 cpu_relax();
225 cr0 = txx9spi_rd(c, TXx9_SPCR0);
226 cr0 &= ~TXx9_SPCR0_RXIFL_MASK;
227 cr0 |= (count - 1) << 12;
228 /* enable rx intr */
229 cr0 |= TXx9_SPCR0_RBSIE;
230 txx9spi_wr(c, cr0, TXx9_SPCR0);
231 /* send */
232 for (i = 0; i < count; i++) {
233 if (txbuf) {
234 data = (wsize == 1)
235 ? *(const u8 *)txbuf
236 : *(const u16 *)txbuf;
237 txx9spi_wr(c, data, TXx9_SPDR);
238 txbuf += wsize;
239 } else
240 txx9spi_wr(c, 0, TXx9_SPDR);
241 }
242 /* wait all rx data */
243 wait_event(c->waitq,
244 txx9spi_rd(c, TXx9_SPSR) & TXx9_SPSR_RBSI);
245 /* receive */
246 for (i = 0; i < count; i++) {
247 data = txx9spi_rd(c, TXx9_SPDR);
248 if (rxbuf) {
249 if (wsize == 1)
250 *(u8 *)rxbuf = data;
251 else
252 *(u16 *)rxbuf = data;
253 rxbuf += wsize;
254 }
255 }
256 len -= count * wsize;
257 }
258 m->actual_length += t->len;
259 if (t->delay_usecs)
260 udelay(t->delay_usecs);
261
262 if (!cs_change)
263 continue;
264 if (t->transfer_list.next == &m->transfers)
265 break;
266 /* sometimes a short mid-message deselect of the chip
267 * may be needed to terminate a mode or command
268 */
269 txx9spi_cs_func(spi, c, 0, cs_delay);
270 }
271
272 exit:
273 m->status = status;
274 m->complete(m->context);
275
276 /* normally deactivate chipselect ... unless no error and
277 * cs_change has hinted that the next message will probably
278 * be for this chip too.
279 */
280 if (!(status == 0 && cs_change))
281 txx9spi_cs_func(spi, c, 0, cs_delay);
282
283 /* enter config mode */
284 txx9spi_wr(c, mcr | TXx9_SPMCR_CONFIG | TXx9_SPMCR_BCLR, TXx9_SPMCR);
285 }
286
txx9spi_work(struct work_struct * work)287 static void txx9spi_work(struct work_struct *work)
288 {
289 struct txx9spi *c = container_of(work, struct txx9spi, work);
290 unsigned long flags;
291
292 spin_lock_irqsave(&c->lock, flags);
293 while (!list_empty(&c->queue)) {
294 struct spi_message *m;
295
296 m = container_of(c->queue.next, struct spi_message, queue);
297 list_del_init(&m->queue);
298 spin_unlock_irqrestore(&c->lock, flags);
299
300 txx9spi_work_one(c, m);
301
302 spin_lock_irqsave(&c->lock, flags);
303 }
304 spin_unlock_irqrestore(&c->lock, flags);
305 }
306
txx9spi_transfer(struct spi_device * spi,struct spi_message * m)307 static int txx9spi_transfer(struct spi_device *spi, struct spi_message *m)
308 {
309 struct spi_master *master = spi->master;
310 struct txx9spi *c = spi_master_get_devdata(master);
311 struct spi_transfer *t;
312 unsigned long flags;
313
314 m->actual_length = 0;
315
316 /* check each transfer's parameters */
317 list_for_each_entry (t, &m->transfers, transfer_list) {
318 u32 speed_hz = t->speed_hz ? : spi->max_speed_hz;
319 u8 bits_per_word = t->bits_per_word ? : spi->bits_per_word;
320
321 bits_per_word = bits_per_word ? : 8;
322 if (!t->tx_buf && !t->rx_buf && t->len)
323 return -EINVAL;
324 if (bits_per_word != 8 && bits_per_word != 16)
325 return -EINVAL;
326 if (t->len & ((bits_per_word >> 3) - 1))
327 return -EINVAL;
328 if (speed_hz < c->min_speed_hz || speed_hz > c->max_speed_hz)
329 return -EINVAL;
330 }
331
332 spin_lock_irqsave(&c->lock, flags);
333 list_add_tail(&m->queue, &c->queue);
334 queue_work(c->workqueue, &c->work);
335 spin_unlock_irqrestore(&c->lock, flags);
336
337 return 0;
338 }
339
txx9spi_probe(struct platform_device * dev)340 static int __init txx9spi_probe(struct platform_device *dev)
341 {
342 struct spi_master *master;
343 struct txx9spi *c;
344 struct resource *res;
345 int ret = -ENODEV;
346 u32 mcr;
347 int irq;
348
349 master = spi_alloc_master(&dev->dev, sizeof(*c));
350 if (!master)
351 return ret;
352 c = spi_master_get_devdata(master);
353 platform_set_drvdata(dev, master);
354
355 INIT_WORK(&c->work, txx9spi_work);
356 spin_lock_init(&c->lock);
357 INIT_LIST_HEAD(&c->queue);
358 init_waitqueue_head(&c->waitq);
359
360 c->clk = clk_get(&dev->dev, "spi-baseclk");
361 if (IS_ERR(c->clk)) {
362 ret = PTR_ERR(c->clk);
363 c->clk = NULL;
364 goto exit;
365 }
366 ret = clk_enable(c->clk);
367 if (ret) {
368 clk_put(c->clk);
369 c->clk = NULL;
370 goto exit;
371 }
372 c->baseclk = clk_get_rate(c->clk);
373 c->min_speed_hz = DIV_ROUND_UP(c->baseclk, SPI_MAX_DIVIDER + 1);
374 c->max_speed_hz = c->baseclk / (SPI_MIN_DIVIDER + 1);
375
376 res = platform_get_resource(dev, IORESOURCE_MEM, 0);
377 if (!res)
378 goto exit_busy;
379 if (!devm_request_mem_region(&dev->dev, res->start, resource_size(res),
380 "spi_txx9"))
381 goto exit_busy;
382 c->membase = devm_ioremap(&dev->dev, res->start, resource_size(res));
383 if (!c->membase)
384 goto exit_busy;
385
386 /* enter config mode */
387 mcr = txx9spi_rd(c, TXx9_SPMCR);
388 mcr &= ~(TXx9_SPMCR_OPMODE | TXx9_SPMCR_SPSTP | TXx9_SPMCR_BCLR);
389 txx9spi_wr(c, mcr | TXx9_SPMCR_CONFIG | TXx9_SPMCR_BCLR, TXx9_SPMCR);
390
391 irq = platform_get_irq(dev, 0);
392 if (irq < 0)
393 goto exit_busy;
394 ret = devm_request_irq(&dev->dev, irq, txx9spi_interrupt, 0,
395 "spi_txx9", c);
396 if (ret)
397 goto exit;
398
399 c->workqueue = create_singlethread_workqueue(
400 dev_name(master->dev.parent));
401 if (!c->workqueue)
402 goto exit_busy;
403 c->last_chipselect = -1;
404
405 dev_info(&dev->dev, "at %#llx, irq %d, %dMHz\n",
406 (unsigned long long)res->start, irq,
407 (c->baseclk + 500000) / 1000000);
408
409 /* the spi->mode bits understood by this driver: */
410 master->mode_bits = SPI_CS_HIGH | SPI_CPOL | SPI_CPHA;
411
412 master->bus_num = dev->id;
413 master->setup = txx9spi_setup;
414 master->transfer = txx9spi_transfer;
415 master->num_chipselect = (u16)UINT_MAX; /* any GPIO numbers */
416
417 ret = spi_register_master(master);
418 if (ret)
419 goto exit;
420 return 0;
421 exit_busy:
422 ret = -EBUSY;
423 exit:
424 if (c->workqueue)
425 destroy_workqueue(c->workqueue);
426 if (c->clk) {
427 clk_disable(c->clk);
428 clk_put(c->clk);
429 }
430 platform_set_drvdata(dev, NULL);
431 spi_master_put(master);
432 return ret;
433 }
434
txx9spi_remove(struct platform_device * dev)435 static int __exit txx9spi_remove(struct platform_device *dev)
436 {
437 struct spi_master *master = spi_master_get(platform_get_drvdata(dev));
438 struct txx9spi *c = spi_master_get_devdata(master);
439
440 spi_unregister_master(master);
441 platform_set_drvdata(dev, NULL);
442 destroy_workqueue(c->workqueue);
443 clk_disable(c->clk);
444 clk_put(c->clk);
445 spi_master_put(master);
446 return 0;
447 }
448
449 /* work with hotplug and coldplug */
450 MODULE_ALIAS("platform:spi_txx9");
451
452 static struct platform_driver txx9spi_driver = {
453 .remove = __exit_p(txx9spi_remove),
454 .driver = {
455 .name = "spi_txx9",
456 .owner = THIS_MODULE,
457 },
458 };
459
txx9spi_init(void)460 static int __init txx9spi_init(void)
461 {
462 return platform_driver_probe(&txx9spi_driver, txx9spi_probe);
463 }
464 subsys_initcall(txx9spi_init);
465
txx9spi_exit(void)466 static void __exit txx9spi_exit(void)
467 {
468 platform_driver_unregister(&txx9spi_driver);
469 }
470 module_exit(txx9spi_exit);
471
472 MODULE_DESCRIPTION("TXx9 SPI Driver");
473 MODULE_LICENSE("GPL");
474