1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * OMAP7xx SPI 100k controller driver
4 * Author: Fabrice Crohas <fcrohas@gmail.com>
5 * from original omap1_mcspi driver
6 *
7 * Copyright (C) 2005, 2006 Nokia Corporation
8 * Author: Samuel Ortiz <samuel.ortiz@nokia.com> and
9 * Juha Yrjola <juha.yrjola@nokia.com>
10 */
11 #include <linux/kernel.h>
12 #include <linux/init.h>
13 #include <linux/interrupt.h>
14 #include <linux/module.h>
15 #include <linux/device.h>
16 #include <linux/delay.h>
17 #include <linux/platform_device.h>
18 #include <linux/pm_runtime.h>
19 #include <linux/err.h>
20 #include <linux/clk.h>
21 #include <linux/io.h>
22 #include <linux/slab.h>
23
24 #include <linux/spi/spi.h>
25
26 #define OMAP1_SPI100K_MAX_FREQ 48000000
27
28 #define ICR_SPITAS (OMAP7XX_ICR_BASE + 0x12)
29
30 #define SPI_SETUP1 0x00
31 #define SPI_SETUP2 0x02
32 #define SPI_CTRL 0x04
33 #define SPI_STATUS 0x06
34 #define SPI_TX_LSB 0x08
35 #define SPI_TX_MSB 0x0a
36 #define SPI_RX_LSB 0x0c
37 #define SPI_RX_MSB 0x0e
38
39 #define SPI_SETUP1_INT_READ_ENABLE (1UL << 5)
40 #define SPI_SETUP1_INT_WRITE_ENABLE (1UL << 4)
41 #define SPI_SETUP1_CLOCK_DIVISOR(x) ((x) << 1)
42 #define SPI_SETUP1_CLOCK_ENABLE (1UL << 0)
43
44 #define SPI_SETUP2_ACTIVE_EDGE_FALLING (0UL << 0)
45 #define SPI_SETUP2_ACTIVE_EDGE_RISING (1UL << 0)
46 #define SPI_SETUP2_NEGATIVE_LEVEL (0UL << 5)
47 #define SPI_SETUP2_POSITIVE_LEVEL (1UL << 5)
48 #define SPI_SETUP2_LEVEL_TRIGGER (0UL << 10)
49 #define SPI_SETUP2_EDGE_TRIGGER (1UL << 10)
50
51 #define SPI_CTRL_SEN(x) ((x) << 7)
52 #define SPI_CTRL_WORD_SIZE(x) (((x) - 1) << 2)
53 #define SPI_CTRL_WR (1UL << 1)
54 #define SPI_CTRL_RD (1UL << 0)
55
56 #define SPI_STATUS_WE (1UL << 1)
57 #define SPI_STATUS_RD (1UL << 0)
58
59 /* use PIO for small transfers, avoiding DMA setup/teardown overhead and
60 * cache operations; better heuristics consider wordsize and bitrate.
61 */
62 #define DMA_MIN_BYTES 8
63
64 #define SPI_RUNNING 0
65 #define SPI_SHUTDOWN 1
66
67 struct omap1_spi100k {
68 struct clk *ick;
69 struct clk *fck;
70
71 /* Virtual base address of the controller */
72 void __iomem *base;
73 };
74
75 struct omap1_spi100k_cs {
76 void __iomem *base;
77 int word_len;
78 };
79
spi100k_enable_clock(struct spi_master * master)80 static void spi100k_enable_clock(struct spi_master *master)
81 {
82 unsigned int val;
83 struct omap1_spi100k *spi100k = spi_master_get_devdata(master);
84
85 /* enable SPI */
86 val = readw(spi100k->base + SPI_SETUP1);
87 val |= SPI_SETUP1_CLOCK_ENABLE;
88 writew(val, spi100k->base + SPI_SETUP1);
89 }
90
spi100k_disable_clock(struct spi_master * master)91 static void spi100k_disable_clock(struct spi_master *master)
92 {
93 unsigned int val;
94 struct omap1_spi100k *spi100k = spi_master_get_devdata(master);
95
96 /* disable SPI */
97 val = readw(spi100k->base + SPI_SETUP1);
98 val &= ~SPI_SETUP1_CLOCK_ENABLE;
99 writew(val, spi100k->base + SPI_SETUP1);
100 }
101
spi100k_write_data(struct spi_master * master,int len,int data)102 static void spi100k_write_data(struct spi_master *master, int len, int data)
103 {
104 struct omap1_spi100k *spi100k = spi_master_get_devdata(master);
105
106 /* write 16-bit word, shifting 8-bit data if necessary */
107 if (len <= 8) {
108 data <<= 8;
109 len = 16;
110 }
111
112 spi100k_enable_clock(master);
113 writew(data, spi100k->base + SPI_TX_MSB);
114
115 writew(SPI_CTRL_SEN(0) |
116 SPI_CTRL_WORD_SIZE(len) |
117 SPI_CTRL_WR,
118 spi100k->base + SPI_CTRL);
119
120 /* Wait for bit ack send change */
121 while ((readw(spi100k->base + SPI_STATUS) & SPI_STATUS_WE) != SPI_STATUS_WE)
122 ;
123 udelay(1000);
124
125 spi100k_disable_clock(master);
126 }
127
spi100k_read_data(struct spi_master * master,int len)128 static int spi100k_read_data(struct spi_master *master, int len)
129 {
130 int dataL;
131 struct omap1_spi100k *spi100k = spi_master_get_devdata(master);
132
133 /* Always do at least 16 bits */
134 if (len <= 8)
135 len = 16;
136
137 spi100k_enable_clock(master);
138 writew(SPI_CTRL_SEN(0) |
139 SPI_CTRL_WORD_SIZE(len) |
140 SPI_CTRL_RD,
141 spi100k->base + SPI_CTRL);
142
143 while ((readw(spi100k->base + SPI_STATUS) & SPI_STATUS_RD) != SPI_STATUS_RD)
144 ;
145 udelay(1000);
146
147 dataL = readw(spi100k->base + SPI_RX_LSB);
148 readw(spi100k->base + SPI_RX_MSB);
149 spi100k_disable_clock(master);
150
151 return dataL;
152 }
153
spi100k_open(struct spi_master * master)154 static void spi100k_open(struct spi_master *master)
155 {
156 /* get control of SPI */
157 struct omap1_spi100k *spi100k = spi_master_get_devdata(master);
158
159 writew(SPI_SETUP1_INT_READ_ENABLE |
160 SPI_SETUP1_INT_WRITE_ENABLE |
161 SPI_SETUP1_CLOCK_DIVISOR(0), spi100k->base + SPI_SETUP1);
162
163 /* configure clock and interrupts */
164 writew(SPI_SETUP2_ACTIVE_EDGE_FALLING |
165 SPI_SETUP2_NEGATIVE_LEVEL |
166 SPI_SETUP2_LEVEL_TRIGGER, spi100k->base + SPI_SETUP2);
167 }
168
omap1_spi100k_force_cs(struct omap1_spi100k * spi100k,int enable)169 static void omap1_spi100k_force_cs(struct omap1_spi100k *spi100k, int enable)
170 {
171 if (enable)
172 writew(0x05fc, spi100k->base + SPI_CTRL);
173 else
174 writew(0x05fd, spi100k->base + SPI_CTRL);
175 }
176
177 static unsigned
omap1_spi100k_txrx_pio(struct spi_device * spi,struct spi_transfer * xfer)178 omap1_spi100k_txrx_pio(struct spi_device *spi, struct spi_transfer *xfer)
179 {
180 struct omap1_spi100k_cs *cs = spi->controller_state;
181 unsigned int count, c;
182 int word_len;
183
184 count = xfer->len;
185 c = count;
186 word_len = cs->word_len;
187
188 if (word_len <= 8) {
189 u8 *rx;
190 const u8 *tx;
191
192 rx = xfer->rx_buf;
193 tx = xfer->tx_buf;
194 do {
195 c -= 1;
196 if (xfer->tx_buf != NULL)
197 spi100k_write_data(spi->master, word_len, *tx++);
198 if (xfer->rx_buf != NULL)
199 *rx++ = spi100k_read_data(spi->master, word_len);
200 } while (c);
201 } else if (word_len <= 16) {
202 u16 *rx;
203 const u16 *tx;
204
205 rx = xfer->rx_buf;
206 tx = xfer->tx_buf;
207 do {
208 c -= 2;
209 if (xfer->tx_buf != NULL)
210 spi100k_write_data(spi->master, word_len, *tx++);
211 if (xfer->rx_buf != NULL)
212 *rx++ = spi100k_read_data(spi->master, word_len);
213 } while (c);
214 } else if (word_len <= 32) {
215 u32 *rx;
216 const u32 *tx;
217
218 rx = xfer->rx_buf;
219 tx = xfer->tx_buf;
220 do {
221 c -= 4;
222 if (xfer->tx_buf != NULL)
223 spi100k_write_data(spi->master, word_len, *tx);
224 if (xfer->rx_buf != NULL)
225 *rx = spi100k_read_data(spi->master, word_len);
226 } while (c);
227 }
228 return count - c;
229 }
230
231 /* called only when no transfer is active to this device */
omap1_spi100k_setup_transfer(struct spi_device * spi,struct spi_transfer * t)232 static int omap1_spi100k_setup_transfer(struct spi_device *spi,
233 struct spi_transfer *t)
234 {
235 struct omap1_spi100k *spi100k = spi_master_get_devdata(spi->master);
236 struct omap1_spi100k_cs *cs = spi->controller_state;
237 u8 word_len;
238
239 if (t != NULL)
240 word_len = t->bits_per_word;
241 else
242 word_len = spi->bits_per_word;
243
244 if (word_len > 32)
245 return -EINVAL;
246 cs->word_len = word_len;
247
248 /* SPI init before transfer */
249 writew(0x3e, spi100k->base + SPI_SETUP1);
250 writew(0x00, spi100k->base + SPI_STATUS);
251 writew(0x3e, spi100k->base + SPI_CTRL);
252
253 return 0;
254 }
255
256 /* the spi->mode bits understood by this driver: */
257 #define MODEBITS (SPI_CPOL | SPI_CPHA | SPI_CS_HIGH)
258
omap1_spi100k_setup(struct spi_device * spi)259 static int omap1_spi100k_setup(struct spi_device *spi)
260 {
261 int ret;
262 struct omap1_spi100k *spi100k;
263 struct omap1_spi100k_cs *cs = spi->controller_state;
264
265 spi100k = spi_master_get_devdata(spi->master);
266
267 if (!cs) {
268 cs = devm_kzalloc(&spi->dev, sizeof(*cs), GFP_KERNEL);
269 if (!cs)
270 return -ENOMEM;
271 cs->base = spi100k->base + spi->chip_select * 0x14;
272 spi->controller_state = cs;
273 }
274
275 spi100k_open(spi->master);
276
277 clk_prepare_enable(spi100k->ick);
278 clk_prepare_enable(spi100k->fck);
279
280 ret = omap1_spi100k_setup_transfer(spi, NULL);
281
282 clk_disable_unprepare(spi100k->ick);
283 clk_disable_unprepare(spi100k->fck);
284
285 return ret;
286 }
287
omap1_spi100k_transfer_one_message(struct spi_master * master,struct spi_message * m)288 static int omap1_spi100k_transfer_one_message(struct spi_master *master,
289 struct spi_message *m)
290 {
291 struct omap1_spi100k *spi100k = spi_master_get_devdata(master);
292 struct spi_device *spi = m->spi;
293 struct spi_transfer *t = NULL;
294 int cs_active = 0;
295 int status = 0;
296
297 list_for_each_entry(t, &m->transfers, transfer_list) {
298 if (t->tx_buf == NULL && t->rx_buf == NULL && t->len) {
299 break;
300 }
301 status = omap1_spi100k_setup_transfer(spi, t);
302 if (status < 0)
303 break;
304
305 if (!cs_active) {
306 omap1_spi100k_force_cs(spi100k, 1);
307 cs_active = 1;
308 }
309
310 if (t->len) {
311 unsigned count;
312
313 count = omap1_spi100k_txrx_pio(spi, t);
314 m->actual_length += count;
315
316 if (count != t->len) {
317 break;
318 }
319 }
320
321 spi_transfer_delay_exec(t);
322
323 /* ignore the "leave it on after last xfer" hint */
324
325 if (t->cs_change) {
326 omap1_spi100k_force_cs(spi100k, 0);
327 cs_active = 0;
328 }
329 }
330
331 status = omap1_spi100k_setup_transfer(spi, NULL);
332
333 if (cs_active)
334 omap1_spi100k_force_cs(spi100k, 0);
335
336 m->status = status;
337
338 spi_finalize_current_message(master);
339
340 return status;
341 }
342
omap1_spi100k_probe(struct platform_device * pdev)343 static int omap1_spi100k_probe(struct platform_device *pdev)
344 {
345 struct spi_master *master;
346 struct omap1_spi100k *spi100k;
347 int status = 0;
348
349 if (!pdev->id)
350 return -EINVAL;
351
352 master = spi_alloc_master(&pdev->dev, sizeof(*spi100k));
353 if (master == NULL) {
354 dev_dbg(&pdev->dev, "master allocation failed\n");
355 return -ENOMEM;
356 }
357
358 if (pdev->id != -1)
359 master->bus_num = pdev->id;
360
361 master->setup = omap1_spi100k_setup;
362 master->transfer_one_message = omap1_spi100k_transfer_one_message;
363 master->num_chipselect = 2;
364 master->mode_bits = MODEBITS;
365 master->bits_per_word_mask = SPI_BPW_RANGE_MASK(4, 32);
366 master->min_speed_hz = OMAP1_SPI100K_MAX_FREQ/(1<<16);
367 master->max_speed_hz = OMAP1_SPI100K_MAX_FREQ;
368 master->auto_runtime_pm = true;
369
370 spi100k = spi_master_get_devdata(master);
371
372 /*
373 * The memory region base address is taken as the platform_data.
374 * You should allocate this with ioremap() before initializing
375 * the SPI.
376 */
377 spi100k->base = (void __iomem *)dev_get_platdata(&pdev->dev);
378
379 spi100k->ick = devm_clk_get(&pdev->dev, "ick");
380 if (IS_ERR(spi100k->ick)) {
381 dev_dbg(&pdev->dev, "can't get spi100k_ick\n");
382 status = PTR_ERR(spi100k->ick);
383 goto err;
384 }
385
386 spi100k->fck = devm_clk_get(&pdev->dev, "fck");
387 if (IS_ERR(spi100k->fck)) {
388 dev_dbg(&pdev->dev, "can't get spi100k_fck\n");
389 status = PTR_ERR(spi100k->fck);
390 goto err;
391 }
392
393 status = clk_prepare_enable(spi100k->ick);
394 if (status != 0) {
395 dev_err(&pdev->dev, "failed to enable ick: %d\n", status);
396 goto err;
397 }
398
399 status = clk_prepare_enable(spi100k->fck);
400 if (status != 0) {
401 dev_err(&pdev->dev, "failed to enable fck: %d\n", status);
402 goto err_ick;
403 }
404
405 pm_runtime_enable(&pdev->dev);
406 pm_runtime_set_active(&pdev->dev);
407
408 status = devm_spi_register_master(&pdev->dev, master);
409 if (status < 0)
410 goto err_fck;
411
412 return status;
413
414 err_fck:
415 clk_disable_unprepare(spi100k->fck);
416 err_ick:
417 clk_disable_unprepare(spi100k->ick);
418 err:
419 spi_master_put(master);
420 return status;
421 }
422
omap1_spi100k_remove(struct platform_device * pdev)423 static int omap1_spi100k_remove(struct platform_device *pdev)
424 {
425 struct spi_master *master = platform_get_drvdata(pdev);
426 struct omap1_spi100k *spi100k = spi_master_get_devdata(master);
427
428 pm_runtime_disable(&pdev->dev);
429
430 clk_disable_unprepare(spi100k->fck);
431 clk_disable_unprepare(spi100k->ick);
432
433 return 0;
434 }
435
436 #ifdef CONFIG_PM
omap1_spi100k_runtime_suspend(struct device * dev)437 static int omap1_spi100k_runtime_suspend(struct device *dev)
438 {
439 struct spi_master *master = dev_get_drvdata(dev);
440 struct omap1_spi100k *spi100k = spi_master_get_devdata(master);
441
442 clk_disable_unprepare(spi100k->ick);
443 clk_disable_unprepare(spi100k->fck);
444
445 return 0;
446 }
447
omap1_spi100k_runtime_resume(struct device * dev)448 static int omap1_spi100k_runtime_resume(struct device *dev)
449 {
450 struct spi_master *master = dev_get_drvdata(dev);
451 struct omap1_spi100k *spi100k = spi_master_get_devdata(master);
452 int ret;
453
454 ret = clk_prepare_enable(spi100k->ick);
455 if (ret != 0) {
456 dev_err(dev, "Failed to enable ick: %d\n", ret);
457 return ret;
458 }
459
460 ret = clk_prepare_enable(spi100k->fck);
461 if (ret != 0) {
462 dev_err(dev, "Failed to enable fck: %d\n", ret);
463 clk_disable_unprepare(spi100k->ick);
464 return ret;
465 }
466
467 return 0;
468 }
469 #endif
470
471 static const struct dev_pm_ops omap1_spi100k_pm = {
472 SET_RUNTIME_PM_OPS(omap1_spi100k_runtime_suspend,
473 omap1_spi100k_runtime_resume, NULL)
474 };
475
476 static struct platform_driver omap1_spi100k_driver = {
477 .driver = {
478 .name = "omap1_spi100k",
479 .pm = &omap1_spi100k_pm,
480 },
481 .probe = omap1_spi100k_probe,
482 .remove = omap1_spi100k_remove,
483 };
484
485 module_platform_driver(omap1_spi100k_driver);
486
487 MODULE_DESCRIPTION("OMAP7xx SPI 100k controller driver");
488 MODULE_AUTHOR("Fabrice Crohas <fcrohas@gmail.com>");
489 MODULE_LICENSE("GPL");
490