tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
1/*
2 * OMAP7xx SPI 100k controller driver
3 * Author: Fabrice Crohas <fcrohas@gmail.com>
4 * from original omap1_mcspi driver
5 *
6 * Copyright (C) 2005, 2006 Nokia Corporation
7 * Author: Samuel Ortiz <samuel.ortiz@nokia.com> and
8 * Juha Yrj�l� <juha.yrjola@nokia.com>
9 *
10 * This program is free software; you can redistribute it and/or modify
11 * it under the terms of the GNU General Public License as published by
12 * the Free Software Foundation; either version 2 of the License, or
13 * (at your option) any later version.
14 *
15 * This program is distributed in the hope that it will be useful,
16 * but WITHOUT ANY WARRANTY; without even the implied warranty of
17 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
18 * GNU General Public License for more details.
19 *
20 * You should have received a copy of the GNU General Public License
21 * along with this program; if not, write to the Free Software
22 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
23 *
24 */
25#include <linux/kernel.h>
26#include <linux/init.h>
27#include <linux/interrupt.h>
28#include <linux/module.h>
29#include <linux/device.h>
30#include <linux/delay.h>
31#include <linux/platform_device.h>
32#include <linux/err.h>
33#include <linux/clk.h>
34#include <linux/io.h>
35#include <linux/gpio.h>
36#include <linux/slab.h>
37
38#include <linux/spi/spi.h>
39
40#define OMAP1_SPI100K_MAX_FREQ 48000000
41
42#define ICR_SPITAS (OMAP7XX_ICR_BASE + 0x12)
43
44#define SPI_SETUP1 0x00
45#define SPI_SETUP2 0x02
46#define SPI_CTRL 0x04
47#define SPI_STATUS 0x06
48#define SPI_TX_LSB 0x08
49#define SPI_TX_MSB 0x0a
50#define SPI_RX_LSB 0x0c
51#define SPI_RX_MSB 0x0e
52
53#define SPI_SETUP1_INT_READ_ENABLE (1UL << 5)
54#define SPI_SETUP1_INT_WRITE_ENABLE (1UL << 4)
55#define SPI_SETUP1_CLOCK_DIVISOR(x) ((x) << 1)
56#define SPI_SETUP1_CLOCK_ENABLE (1UL << 0)
57
58#define SPI_SETUP2_ACTIVE_EDGE_FALLING (0UL << 0)
59#define SPI_SETUP2_ACTIVE_EDGE_RISING (1UL << 0)
60#define SPI_SETUP2_NEGATIVE_LEVEL (0UL << 5)
61#define SPI_SETUP2_POSITIVE_LEVEL (1UL << 5)
62#define SPI_SETUP2_LEVEL_TRIGGER (0UL << 10)
63#define SPI_SETUP2_EDGE_TRIGGER (1UL << 10)
64
65#define SPI_CTRL_SEN(x) ((x) << 7)
66#define SPI_CTRL_WORD_SIZE(x) (((x) - 1) << 2)
67#define SPI_CTRL_WR (1UL << 1)
68#define SPI_CTRL_RD (1UL << 0)
69
70#define SPI_STATUS_WE (1UL << 1)
71#define SPI_STATUS_RD (1UL << 0)
72
73#define WRITE 0
74#define READ 1
75
76
77/* use PIO for small transfers, avoiding DMA setup/teardown overhead and
78 * cache operations; better heuristics consider wordsize and bitrate.
79 */
80#define DMA_MIN_BYTES 8
81
82#define SPI_RUNNING 0
83#define SPI_SHUTDOWN 1
84
85struct omap1_spi100k {
86 struct spi_master *master;
87 struct clk *ick;
88 struct clk *fck;
89
90 /* Virtual base address of the controller */
91 void __iomem *base;
92
93 /* State of the SPI */
94 unsigned int state;
95};
96
97struct omap1_spi100k_cs {
98 void __iomem *base;
99 int word_len;
100};
101
102#define MOD_REG_BIT(val, mask, set) do { \
103 if (set) \
104 val |= mask; \
105 else \
106 val &= ~mask; \
107} while (0)
108
109static void spi100k_enable_clock(struct spi_master *master)
110{
111 unsigned int val;
112 struct omap1_spi100k *spi100k = spi_master_get_devdata(master);
113
114 /* enable SPI */
115 val = readw(spi100k->base + SPI_SETUP1);
116 val |= SPI_SETUP1_CLOCK_ENABLE;
117 writew(val, spi100k->base + SPI_SETUP1);
118}
119
120static void spi100k_disable_clock(struct spi_master *master)
121{
122 unsigned int val;
123 struct omap1_spi100k *spi100k = spi_master_get_devdata(master);
124
125 /* disable SPI */
126 val = readw(spi100k->base + SPI_SETUP1);
127 val &= ~SPI_SETUP1_CLOCK_ENABLE;
128 writew(val, spi100k->base + SPI_SETUP1);
129}
130
131static void spi100k_write_data(struct spi_master *master, int len, int data)
132{
133 struct omap1_spi100k *spi100k = spi_master_get_devdata(master);
134
135 /* write 16-bit word, shifting 8-bit data if necessary */
136 if (len <= 8) {
137 data <<= 8;
138 len = 16;
139 }
140
141 spi100k_enable_clock(master);
142 writew( data , spi100k->base + SPI_TX_MSB);
143
144 writew(SPI_CTRL_SEN(0) |
145 SPI_CTRL_WORD_SIZE(len) |
146 SPI_CTRL_WR,
147 spi100k->base + SPI_CTRL);
148
149 /* Wait for bit ack send change */
150 while((readw(spi100k->base + SPI_STATUS) & SPI_STATUS_WE) != SPI_STATUS_WE);
151 udelay(1000);
152
153 spi100k_disable_clock(master);
154}
155
156static int spi100k_read_data(struct spi_master *master, int len)
157{
158 int dataH,dataL;
159 struct omap1_spi100k *spi100k = spi_master_get_devdata(master);
160
161 /* Always do at least 16 bits */
162 if (len <= 8)
163 len = 16;
164
165 spi100k_enable_clock(master);
166 writew(SPI_CTRL_SEN(0) |
167 SPI_CTRL_WORD_SIZE(len) |
168 SPI_CTRL_RD,
169 spi100k->base + SPI_CTRL);
170
171 while((readw(spi100k->base + SPI_STATUS) & SPI_STATUS_RD) != SPI_STATUS_RD);
172 udelay(1000);
173
174 dataL = readw(spi100k->base + SPI_RX_LSB);
175 dataH = readw(spi100k->base + SPI_RX_MSB);
176 spi100k_disable_clock(master);
177
178 return dataL;
179}
180
181static void spi100k_open(struct spi_master *master)
182{
183 /* get control of SPI */
184 struct omap1_spi100k *spi100k = spi_master_get_devdata(master);
185
186 writew(SPI_SETUP1_INT_READ_ENABLE |
187 SPI_SETUP1_INT_WRITE_ENABLE |
188 SPI_SETUP1_CLOCK_DIVISOR(0), spi100k->base + SPI_SETUP1);
189
190 /* configure clock and interrupts */
191 writew(SPI_SETUP2_ACTIVE_EDGE_FALLING |
192 SPI_SETUP2_NEGATIVE_LEVEL |
193 SPI_SETUP2_LEVEL_TRIGGER, spi100k->base + SPI_SETUP2);
194}
195
196static void omap1_spi100k_force_cs(struct omap1_spi100k *spi100k, int enable)
197{
198 if (enable)
199 writew(0x05fc, spi100k->base + SPI_CTRL);
200 else
201 writew(0x05fd, spi100k->base + SPI_CTRL);
202}
203
204static unsigned
205omap1_spi100k_txrx_pio(struct spi_device *spi, struct spi_transfer *xfer)
206{
207 struct omap1_spi100k *spi100k;
208 struct omap1_spi100k_cs *cs = spi->controller_state;
209 unsigned int count, c;
210 int word_len;
211
212 spi100k = spi_master_get_devdata(spi->master);
213 count = xfer->len;
214 c = count;
215 word_len = cs->word_len;
216
217 if (word_len <= 8) {
218 u8 *rx;
219 const u8 *tx;
220
221 rx = xfer->rx_buf;
222 tx = xfer->tx_buf;
223 do {
224 c-=1;
225 if (xfer->tx_buf != NULL)
226 spi100k_write_data(spi->master, word_len, *tx++);
227 if (xfer->rx_buf != NULL)
228 *rx++ = spi100k_read_data(spi->master, word_len);
229 } while(c);
230 } else if (word_len <= 16) {
231 u16 *rx;
232 const u16 *tx;
233
234 rx = xfer->rx_buf;
235 tx = xfer->tx_buf;
236 do {
237 c-=2;
238 if (xfer->tx_buf != NULL)
239 spi100k_write_data(spi->master,word_len, *tx++);
240 if (xfer->rx_buf != NULL)
241 *rx++ = spi100k_read_data(spi->master,word_len);
242 } while(c);
243 } else if (word_len <= 32) {
244 u32 *rx;
245 const u32 *tx;
246
247 rx = xfer->rx_buf;
248 tx = xfer->tx_buf;
249 do {
250 c-=4;
251 if (xfer->tx_buf != NULL)
252 spi100k_write_data(spi->master,word_len, *tx);
253 if (xfer->rx_buf != NULL)
254 *rx = spi100k_read_data(spi->master,word_len);
255 } while(c);
256 }
257 return count - c;
258}
259
260/* called only when no transfer is active to this device */
261static int omap1_spi100k_setup_transfer(struct spi_device *spi,
262 struct spi_transfer *t)
263{
264 struct omap1_spi100k *spi100k = spi_master_get_devdata(spi->master);
265 struct omap1_spi100k_cs *cs = spi->controller_state;
266 u8 word_len = spi->bits_per_word;
267
268 if (t != NULL && t->bits_per_word)
269 word_len = t->bits_per_word;
270 if (!word_len)
271 word_len = 8;
272
273 if (spi->bits_per_word > 32)
274 return -EINVAL;
275 cs->word_len = word_len;
276
277 /* SPI init before transfer */
278 writew(0x3e , spi100k->base + SPI_SETUP1);
279 writew(0x00 , spi100k->base + SPI_STATUS);
280 writew(0x3e , spi100k->base + SPI_CTRL);
281
282 return 0;
283}
284
285/* the spi->mode bits understood by this driver: */
286#define MODEBITS (SPI_CPOL | SPI_CPHA | SPI_CS_HIGH)
287
288static int omap1_spi100k_setup(struct spi_device *spi)
289{
290 int ret;
291 struct omap1_spi100k *spi100k;
292 struct omap1_spi100k_cs *cs = spi->controller_state;
293
294 spi100k = spi_master_get_devdata(spi->master);
295
296 if (!cs) {
297 cs = kzalloc(sizeof *cs, GFP_KERNEL);
298 if (!cs)
299 return -ENOMEM;
300 cs->base = spi100k->base + spi->chip_select * 0x14;
301 spi->controller_state = cs;
302 }
303
304 spi100k_open(spi->master);
305
306 clk_prepare_enable(spi100k->ick);
307 clk_prepare_enable(spi100k->fck);
308
309 ret = omap1_spi100k_setup_transfer(spi, NULL);
310
311 clk_disable_unprepare(spi100k->ick);
312 clk_disable_unprepare(spi100k->fck);
313
314 return ret;
315}
316
317static int omap1_spi100k_prepare_hardware(struct spi_master *master)
318{
319 struct omap1_spi100k *spi100k = spi_master_get_devdata(master);
320
321 clk_prepare_enable(spi100k->ick);
322 clk_prepare_enable(spi100k->fck);
323
324 return 0;
325}
326
327static int omap1_spi100k_transfer_one_message(struct spi_master *master,
328 struct spi_message *m)
329{
330 struct omap1_spi100k *spi100k = spi_master_get_devdata(master);
331 struct spi_device *spi = m->spi;
332 struct spi_transfer *t = NULL;
333 int cs_active = 0;
334 int par_override = 0;
335 int status = 0;
336
337 list_for_each_entry(t, &m->transfers, transfer_list) {
338 if (t->tx_buf == NULL && t->rx_buf == NULL && t->len) {
339 status = -EINVAL;
340 break;
341 }
342 if (par_override || t->speed_hz || t->bits_per_word) {
343 par_override = 1;
344 status = omap1_spi100k_setup_transfer(spi, t);
345 if (status < 0)
346 break;
347 if (!t->speed_hz && !t->bits_per_word)
348 par_override = 0;
349 }
350
351 if (!cs_active) {
352 omap1_spi100k_force_cs(spi100k, 1);
353 cs_active = 1;
354 }
355
356 if (t->len) {
357 unsigned count;
358
359 count = omap1_spi100k_txrx_pio(spi, t);
360 m->actual_length += count;
361
362 if (count != t->len) {
363 status = -EIO;
364 break;
365 }
366 }
367
368 if (t->delay_usecs)
369 udelay(t->delay_usecs);
370
371 /* ignore the "leave it on after last xfer" hint */
372
373 if (t->cs_change) {
374 omap1_spi100k_force_cs(spi100k, 0);
375 cs_active = 0;
376 }
377 }
378
379 /* Restore defaults if they were overriden */
380 if (par_override) {
381 par_override = 0;
382 status = omap1_spi100k_setup_transfer(spi, NULL);
383 }
384
385 if (cs_active)
386 omap1_spi100k_force_cs(spi100k, 0);
387
388 m->status = status;
389
390 spi_finalize_current_message(master);
391
392 return status;
393}
394
395static int omap1_spi100k_unprepare_hardware(struct spi_master *master)
396{
397 struct omap1_spi100k *spi100k = spi_master_get_devdata(master);
398
399 clk_disable_unprepare(spi100k->ick);
400 clk_disable_unprepare(spi100k->fck);
401
402 return 0;
403}
404
405static int omap1_spi100k_probe(struct platform_device *pdev)
406{
407 struct spi_master *master;
408 struct omap1_spi100k *spi100k;
409 int status = 0;
410
411 if (!pdev->id)
412 return -EINVAL;
413
414 master = spi_alloc_master(&pdev->dev, sizeof *spi100k);
415 if (master == NULL) {
416 dev_dbg(&pdev->dev, "master allocation failed\n");
417 return -ENOMEM;
418 }
419
420 if (pdev->id != -1)
421 master->bus_num = pdev->id;
422
423 master->setup = omap1_spi100k_setup;
424 master->transfer_one_message = omap1_spi100k_transfer_one_message;
425 master->prepare_transfer_hardware = omap1_spi100k_prepare_hardware;
426 master->unprepare_transfer_hardware = omap1_spi100k_unprepare_hardware;
427 master->cleanup = NULL;
428 master->num_chipselect = 2;
429 master->mode_bits = MODEBITS;
430 master->bits_per_word_mask = SPI_BPW_RANGE_MASK(4, 32);
431 master->min_speed_hz = OMAP1_SPI100K_MAX_FREQ/(1<<16);
432 master->max_speed_hz = OMAP1_SPI100K_MAX_FREQ;
433
434 platform_set_drvdata(pdev, master);
435
436 spi100k = spi_master_get_devdata(master);
437 spi100k->master = master;
438
439 /*
440 * The memory region base address is taken as the platform_data.
441 * You should allocate this with ioremap() before initializing
442 * the SPI.
443 */
444 spi100k->base = (void __iomem *)dev_get_platdata(&pdev->dev);
445
446 spi100k->ick = devm_clk_get(&pdev->dev, "ick");
447 if (IS_ERR(spi100k->ick)) {
448 dev_dbg(&pdev->dev, "can't get spi100k_ick\n");
449 status = PTR_ERR(spi100k->ick);
450 goto err;
451 }
452
453 spi100k->fck = devm_clk_get(&pdev->dev, "fck");
454 if (IS_ERR(spi100k->fck)) {
455 dev_dbg(&pdev->dev, "can't get spi100k_fck\n");
456 status = PTR_ERR(spi100k->fck);
457 goto err;
458 }
459
460 status = devm_spi_register_master(&pdev->dev, master);
461 if (status < 0)
462 goto err;
463
464 spi100k->state = SPI_RUNNING;
465
466 return status;
467
468err:
469 spi_master_put(master);
470 return status;
471}
472
473static int omap1_spi100k_remove(struct platform_device *pdev)
474{
475 struct spi_master *master;
476 struct omap1_spi100k *spi100k;
477 struct resource *r;
478 int status = 0;
479
480 master = platform_get_drvdata(pdev);
481 spi100k = spi_master_get_devdata(master);
482
483 if (status != 0)
484 return status;
485
486 r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
487
488 return 0;
489}
490
491static struct platform_driver omap1_spi100k_driver = {
492 .driver = {
493 .name = "omap1_spi100k",
494 .owner = THIS_MODULE,
495 },
496 .probe = omap1_spi100k_probe,
497 .remove = omap1_spi100k_remove,
498};
499
500module_platform_driver(omap1_spi100k_driver);
501
502MODULE_DESCRIPTION("OMAP7xx SPI 100k controller driver");
503MODULE_AUTHOR("Fabrice Crohas <fcrohas@gmail.com>");
504MODULE_LICENSE("GPL");
505