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kernel: rename is_single_threaded(task) to current_is_single_threaded(void)
[linux-2.6/mini2440.git] / drivers / spi / spi_txx9.c
blob96057de133ad311a3159944c69adcb70b63930ec
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 static int txx9spi_setup(struct spi_device *spi)
114 {
115 struct txx9spi *c = spi_master_get_devdata(spi->master);
116 u8 bits_per_word;
117
118 if (!spi->max_speed_hz
119 || spi->max_speed_hz > c->max_speed_hz
120 || spi->max_speed_hz < c->min_speed_hz)
121 return -EINVAL;
122
123 bits_per_word = spi->bits_per_word;
124 if (bits_per_word != 8 && bits_per_word != 16)
125 return -EINVAL;
126
127 if (gpio_direction_output(spi->chip_select,
128 !(spi->mode & SPI_CS_HIGH))) {
129 dev_err(&spi->dev, "Cannot setup GPIO for chipselect.\n");
130 return -EINVAL;
131 }
132
133 /* deselect chip */
134 spin_lock(&c->lock);
135 txx9spi_cs_func(spi, c, 0, (NSEC_PER_SEC / 2) / spi->max_speed_hz);
136 spin_unlock(&c->lock);
137
138 return 0;
139 }
140
141 static irqreturn_t txx9spi_interrupt(int irq, void *dev_id)
142 {
143 struct txx9spi *c = dev_id;
144
145 /* disable rx intr */
146 txx9spi_wr(c, txx9spi_rd(c, TXx9_SPCR0) & ~TXx9_SPCR0_RBSIE,
147 TXx9_SPCR0);
148 wake_up(&c->waitq);
149 return IRQ_HANDLED;
150 }
151
152 static void txx9spi_work_one(struct txx9spi *c, struct spi_message *m)
153 {
154 struct spi_device *spi = m->spi;
155 struct spi_transfer *t;
156 unsigned int cs_delay;
157 unsigned int cs_change = 1;
158 int status = 0;
159 u32 mcr;
160 u32 prev_speed_hz = 0;
161 u8 prev_bits_per_word = 0;
162
163 /* CS setup/hold/recovery time in nsec */
164 cs_delay = 100 + (NSEC_PER_SEC / 2) / spi->max_speed_hz;
165
166 mcr = txx9spi_rd(c, TXx9_SPMCR);
167 if (unlikely((mcr & TXx9_SPMCR_OPMODE) == TXx9_SPMCR_ACTIVE)) {
168 dev_err(&spi->dev, "Bad mode.\n");
169 status = -EIO;
170 goto exit;
171 }
172 mcr &= ~(TXx9_SPMCR_OPMODE | TXx9_SPMCR_SPSTP | TXx9_SPMCR_BCLR);
173
174 /* enter config mode */
175 txx9spi_wr(c, mcr | TXx9_SPMCR_CONFIG | TXx9_SPMCR_BCLR, TXx9_SPMCR);
176 txx9spi_wr(c, TXx9_SPCR0_SBOS
177 | ((spi->mode & SPI_CPOL) ? TXx9_SPCR0_SPOL : 0)
178 | ((spi->mode & SPI_CPHA) ? TXx9_SPCR0_SPHA : 0)
179 | 0x08,
180 TXx9_SPCR0);
181
182 list_for_each_entry (t, &m->transfers, transfer_list) {
183 const void *txbuf = t->tx_buf;
184 void *rxbuf = t->rx_buf;
185 u32 data;
186 unsigned int len = t->len;
187 unsigned int wsize;
188 u32 speed_hz = t->speed_hz ? : spi->max_speed_hz;
189 u8 bits_per_word = t->bits_per_word ? : spi->bits_per_word;
190
191 bits_per_word = bits_per_word ? : 8;
192 wsize = bits_per_word >> 3; /* in bytes */
193
194 if (prev_speed_hz != speed_hz
195 || prev_bits_per_word != bits_per_word) {
196 u32 n = (c->baseclk + speed_hz - 1) / speed_hz;
197 if (n < 1)
198 n = 1;
199 else if (n > 0xff)
200 n = 0xff;
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
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
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
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 = (c->baseclk + 0xff - 1) / 0xff;
374 c->max_speed_hz = c->baseclk;
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,
380 res->start, res->end - res->start + 1,
381 "spi_txx9"))
382 goto exit_busy;
383 c->membase = devm_ioremap(&dev->dev,
384 res->start, res->end - res->start + 1);
385 if (!c->membase)
386 goto exit_busy;
387
388 /* enter config mode */
389 mcr = txx9spi_rd(c, TXx9_SPMCR);
390 mcr &= ~(TXx9_SPMCR_OPMODE | TXx9_SPMCR_SPSTP | TXx9_SPMCR_BCLR);
391 txx9spi_wr(c, mcr | TXx9_SPMCR_CONFIG | TXx9_SPMCR_BCLR, TXx9_SPMCR);
392
393 irq = platform_get_irq(dev, 0);
394 if (irq < 0)
395 goto exit_busy;
396 ret = devm_request_irq(&dev->dev, irq, txx9spi_interrupt, 0,
397 "spi_txx9", c);
398 if (ret)
399 goto exit;
400
401 c->workqueue = create_singlethread_workqueue(
402 dev_name(master->dev.parent));
403 if (!c->workqueue)
404 goto exit_busy;
405 c->last_chipselect = -1;
406
407 dev_info(&dev->dev, "at %#llx, irq %d, %dMHz\n",
408 (unsigned long long)res->start, irq,
409 (c->baseclk + 500000) / 1000000);
410
411 /* the spi->mode bits understood by this driver: */
412 master->mode_bits = SPI_CS_HIGH | SPI_CPOL | SPI_CPHA;
413
414 master->bus_num = dev->id;
415 master->setup = txx9spi_setup;
416 master->transfer = txx9spi_transfer;
417 master->num_chipselect = (u16)UINT_MAX; /* any GPIO numbers */
418
419 ret = spi_register_master(master);
420 if (ret)
421 goto exit;
422 return 0;
423 exit_busy:
424 ret = -EBUSY;
425 exit:
426 if (c->workqueue)
427 destroy_workqueue(c->workqueue);
428 if (c->clk) {
429 clk_disable(c->clk);
430 clk_put(c->clk);
431 }
432 platform_set_drvdata(dev, NULL);
433 spi_master_put(master);
434 return ret;
435 }
436
437 static int __exit txx9spi_remove(struct platform_device *dev)
438 {
439 struct spi_master *master = spi_master_get(platform_get_drvdata(dev));
440 struct txx9spi *c = spi_master_get_devdata(master);
441
442 spi_unregister_master(master);
443 platform_set_drvdata(dev, NULL);
444 destroy_workqueue(c->workqueue);
445 clk_disable(c->clk);
446 clk_put(c->clk);
447 spi_master_put(master);
448 return 0;
449 }
450
451 /* work with hotplug and coldplug */
452 MODULE_ALIAS("platform:spi_txx9");
453
454 static struct platform_driver txx9spi_driver = {
455 .remove = __exit_p(txx9spi_remove),
456 .driver = {
457 .name = "spi_txx9",
458 .owner = THIS_MODULE,
459 },
460 };
461
462 static int __init txx9spi_init(void)
463 {
464 return platform_driver_probe(&txx9spi_driver, txx9spi_probe);
465 }
466 subsys_initcall(txx9spi_init);
467
468 static void __exit txx9spi_exit(void)
469 {
470 platform_driver_unregister(&txx9spi_driver);
471 }
472 module_exit(txx9spi_exit);
473
474 MODULE_DESCRIPTION("TXx9 SPI Driver");
475 MODULE_LICENSE("GPL");
Support for the Chinese Samsung S3C2440 based development boards