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