1 /*
2 * Copyright (C) 2012-2013 Uwe Kleine-Koenig for Pengutronix
3 *
4 * This program is free software; you can redistribute it and/or modify it under
5 * the terms of the GNU General Public License version 2 as published by the
6 * Free Software Foundation.
7 */
8 #include <linux/kernel.h>
9 #include <linux/io.h>
10 #include <linux/spi/spi.h>
11 #include <linux/spi/spi_bitbang.h>
12 #include <linux/gpio.h>
13 #include <linux/interrupt.h>
14 #include <linux/platform_device.h>
15 #include <linux/clk.h>
16 #include <linux/err.h>
17 #include <linux/module.h>
18 #include <linux/of_gpio.h>
19 #include <linux/platform_data/efm32-spi.h>
20
21 #define DRIVER_NAME "efm32-spi"
22
23 #define MASK_VAL(mask, val) ((val << __ffs(mask)) & mask)
24
25 #define REG_CTRL 0x00
26 #define REG_CTRL_SYNC 0x0001
27 #define REG_CTRL_CLKPOL 0x0100
28 #define REG_CTRL_CLKPHA 0x0200
29 #define REG_CTRL_MSBF 0x0400
30 #define REG_CTRL_TXBIL 0x1000
31
32 #define REG_FRAME 0x04
33 #define REG_FRAME_DATABITS__MASK 0x000f
34 #define REG_FRAME_DATABITS(n) ((n) - 3)
35
36 #define REG_CMD 0x0c
37 #define REG_CMD_RXEN 0x0001
38 #define REG_CMD_RXDIS 0x0002
39 #define REG_CMD_TXEN 0x0004
40 #define REG_CMD_TXDIS 0x0008
41 #define REG_CMD_MASTEREN 0x0010
42
43 #define REG_STATUS 0x10
44 #define REG_STATUS_TXENS 0x0002
45 #define REG_STATUS_TXC 0x0020
46 #define REG_STATUS_TXBL 0x0040
47 #define REG_STATUS_RXDATAV 0x0080
48
49 #define REG_CLKDIV 0x14
50
51 #define REG_RXDATAX 0x18
52 #define REG_RXDATAX_RXDATA__MASK 0x01ff
53 #define REG_RXDATAX_PERR 0x4000
54 #define REG_RXDATAX_FERR 0x8000
55
56 #define REG_TXDATA 0x34
57
58 #define REG_IF 0x40
59 #define REG_IF_TXBL 0x0002
60 #define REG_IF_RXDATAV 0x0004
61
62 #define REG_IFS 0x44
63 #define REG_IFC 0x48
64 #define REG_IEN 0x4c
65
66 #define REG_ROUTE 0x54
67 #define REG_ROUTE_RXPEN 0x0001
68 #define REG_ROUTE_TXPEN 0x0002
69 #define REG_ROUTE_CLKPEN 0x0008
70 #define REG_ROUTE_LOCATION__MASK 0x0700
71 #define REG_ROUTE_LOCATION(n) MASK_VAL(REG_ROUTE_LOCATION__MASK, (n))
72
73 struct efm32_spi_ddata {
74 struct spi_bitbang bitbang;
75
76 spinlock_t lock;
77
78 struct clk *clk;
79 void __iomem *base;
80 unsigned int rxirq, txirq;
81 struct efm32_spi_pdata pdata;
82
83 /* irq data */
84 struct completion done;
85 const u8 *tx_buf;
86 u8 *rx_buf;
87 unsigned tx_len, rx_len;
88
89 /* chip selects */
90 unsigned csgpio[];
91 };
92
93 #define ddata_to_dev(ddata) (&(ddata->bitbang.master->dev))
94 #define efm32_spi_vdbg(ddata, format, arg...) \
95 dev_vdbg(ddata_to_dev(ddata), format, ##arg)
96
efm32_spi_write32(struct efm32_spi_ddata * ddata,u32 value,unsigned offset)97 static void efm32_spi_write32(struct efm32_spi_ddata *ddata,
98 u32 value, unsigned offset)
99 {
100 writel_relaxed(value, ddata->base + offset);
101 }
102
efm32_spi_read32(struct efm32_spi_ddata * ddata,unsigned offset)103 static u32 efm32_spi_read32(struct efm32_spi_ddata *ddata, unsigned offset)
104 {
105 return readl_relaxed(ddata->base + offset);
106 }
107
efm32_spi_chipselect(struct spi_device * spi,int is_on)108 static void efm32_spi_chipselect(struct spi_device *spi, int is_on)
109 {
110 struct efm32_spi_ddata *ddata = spi_master_get_devdata(spi->master);
111 int value = !(spi->mode & SPI_CS_HIGH) == !(is_on == BITBANG_CS_ACTIVE);
112
113 gpio_set_value(ddata->csgpio[spi->chip_select], value);
114 }
115
efm32_spi_setup_transfer(struct spi_device * spi,struct spi_transfer * t)116 static int efm32_spi_setup_transfer(struct spi_device *spi,
117 struct spi_transfer *t)
118 {
119 struct efm32_spi_ddata *ddata = spi_master_get_devdata(spi->master);
120
121 unsigned bpw = t->bits_per_word ?: spi->bits_per_word;
122 unsigned speed = t->speed_hz ?: spi->max_speed_hz;
123 unsigned long clkfreq = clk_get_rate(ddata->clk);
124 u32 clkdiv;
125
126 efm32_spi_write32(ddata, REG_CTRL_SYNC | REG_CTRL_MSBF |
127 (spi->mode & SPI_CPHA ? REG_CTRL_CLKPHA : 0) |
128 (spi->mode & SPI_CPOL ? REG_CTRL_CLKPOL : 0), REG_CTRL);
129
130 efm32_spi_write32(ddata,
131 REG_FRAME_DATABITS(bpw), REG_FRAME);
132
133 if (2 * speed >= clkfreq)
134 clkdiv = 0;
135 else
136 clkdiv = 64 * (DIV_ROUND_UP(2 * clkfreq, speed) - 4);
137
138 if (clkdiv > (1U << 21))
139 return -EINVAL;
140
141 efm32_spi_write32(ddata, clkdiv, REG_CLKDIV);
142 efm32_spi_write32(ddata, REG_CMD_MASTEREN, REG_CMD);
143 efm32_spi_write32(ddata, REG_CMD_RXEN | REG_CMD_TXEN, REG_CMD);
144
145 return 0;
146 }
147
efm32_spi_tx_u8(struct efm32_spi_ddata * ddata)148 static void efm32_spi_tx_u8(struct efm32_spi_ddata *ddata)
149 {
150 u8 val = 0;
151
152 if (ddata->tx_buf) {
153 val = *ddata->tx_buf;
154 ddata->tx_buf++;
155 }
156
157 ddata->tx_len--;
158 efm32_spi_write32(ddata, val, REG_TXDATA);
159 efm32_spi_vdbg(ddata, "%s: tx 0x%x\n", __func__, val);
160 }
161
efm32_spi_rx_u8(struct efm32_spi_ddata * ddata)162 static void efm32_spi_rx_u8(struct efm32_spi_ddata *ddata)
163 {
164 u32 rxdata = efm32_spi_read32(ddata, REG_RXDATAX);
165 efm32_spi_vdbg(ddata, "%s: rx 0x%x\n", __func__, rxdata);
166
167 if (ddata->rx_buf) {
168 *ddata->rx_buf = rxdata;
169 ddata->rx_buf++;
170 }
171
172 ddata->rx_len--;
173 }
174
efm32_spi_filltx(struct efm32_spi_ddata * ddata)175 static void efm32_spi_filltx(struct efm32_spi_ddata *ddata)
176 {
177 while (ddata->tx_len &&
178 ddata->tx_len + 2 > ddata->rx_len &&
179 efm32_spi_read32(ddata, REG_STATUS) & REG_STATUS_TXBL) {
180 efm32_spi_tx_u8(ddata);
181 }
182 }
183
efm32_spi_txrx_bufs(struct spi_device * spi,struct spi_transfer * t)184 static int efm32_spi_txrx_bufs(struct spi_device *spi, struct spi_transfer *t)
185 {
186 struct efm32_spi_ddata *ddata = spi_master_get_devdata(spi->master);
187 int ret = -EBUSY;
188
189 spin_lock_irq(&ddata->lock);
190
191 if (ddata->tx_buf || ddata->rx_buf)
192 goto out_unlock;
193
194 ddata->tx_buf = t->tx_buf;
195 ddata->rx_buf = t->rx_buf;
196 ddata->tx_len = ddata->rx_len =
197 t->len * DIV_ROUND_UP(t->bits_per_word, 8);
198
199 efm32_spi_filltx(ddata);
200
201 reinit_completion(&ddata->done);
202
203 efm32_spi_write32(ddata, REG_IF_TXBL | REG_IF_RXDATAV, REG_IEN);
204
205 spin_unlock_irq(&ddata->lock);
206
207 wait_for_completion(&ddata->done);
208
209 spin_lock_irq(&ddata->lock);
210
211 ret = t->len - max(ddata->tx_len, ddata->rx_len);
212
213 efm32_spi_write32(ddata, 0, REG_IEN);
214 ddata->tx_buf = ddata->rx_buf = NULL;
215
216 out_unlock:
217 spin_unlock_irq(&ddata->lock);
218
219 return ret;
220 }
221
efm32_spi_rxirq(int irq,void * data)222 static irqreturn_t efm32_spi_rxirq(int irq, void *data)
223 {
224 struct efm32_spi_ddata *ddata = data;
225 irqreturn_t ret = IRQ_NONE;
226
227 spin_lock(&ddata->lock);
228
229 while (ddata->rx_len > 0 &&
230 efm32_spi_read32(ddata, REG_STATUS) &
231 REG_STATUS_RXDATAV) {
232 efm32_spi_rx_u8(ddata);
233
234 ret = IRQ_HANDLED;
235 }
236
237 if (!ddata->rx_len) {
238 u32 ien = efm32_spi_read32(ddata, REG_IEN);
239
240 ien &= ~REG_IF_RXDATAV;
241
242 efm32_spi_write32(ddata, ien, REG_IEN);
243
244 complete(&ddata->done);
245 }
246
247 spin_unlock(&ddata->lock);
248
249 return ret;
250 }
251
efm32_spi_txirq(int irq,void * data)252 static irqreturn_t efm32_spi_txirq(int irq, void *data)
253 {
254 struct efm32_spi_ddata *ddata = data;
255
256 efm32_spi_vdbg(ddata,
257 "%s: txlen = %u, rxlen = %u, if=0x%08x, stat=0x%08x\n",
258 __func__, ddata->tx_len, ddata->rx_len,
259 efm32_spi_read32(ddata, REG_IF),
260 efm32_spi_read32(ddata, REG_STATUS));
261
262 spin_lock(&ddata->lock);
263
264 efm32_spi_filltx(ddata);
265
266 efm32_spi_vdbg(ddata, "%s: txlen = %u, rxlen = %u\n",
267 __func__, ddata->tx_len, ddata->rx_len);
268
269 if (!ddata->tx_len) {
270 u32 ien = efm32_spi_read32(ddata, REG_IEN);
271
272 ien &= ~REG_IF_TXBL;
273
274 efm32_spi_write32(ddata, ien, REG_IEN);
275 efm32_spi_vdbg(ddata, "disable TXBL\n");
276 }
277
278 spin_unlock(&ddata->lock);
279
280 return IRQ_HANDLED;
281 }
282
efm32_spi_get_configured_location(struct efm32_spi_ddata * ddata)283 static u32 efm32_spi_get_configured_location(struct efm32_spi_ddata *ddata)
284 {
285 u32 reg = efm32_spi_read32(ddata, REG_ROUTE);
286
287 return (reg & REG_ROUTE_LOCATION__MASK) >> __ffs(REG_ROUTE_LOCATION__MASK);
288 }
289
efm32_spi_probe_dt(struct platform_device * pdev,struct spi_master * master,struct efm32_spi_ddata * ddata)290 static void efm32_spi_probe_dt(struct platform_device *pdev,
291 struct spi_master *master, struct efm32_spi_ddata *ddata)
292 {
293 struct device_node *np = pdev->dev.of_node;
294 u32 location;
295 int ret;
296
297 ret = of_property_read_u32(np, "energymicro,location", &location);
298
299 if (ret)
300 /* fall back to wrongly namespaced property */
301 ret = of_property_read_u32(np, "efm32,location", &location);
302
303 if (ret)
304 /* fall back to old and (wrongly) generic property "location" */
305 ret = of_property_read_u32(np, "location", &location);
306
307 if (!ret) {
308 dev_dbg(&pdev->dev, "using location %u\n", location);
309 } else {
310 /* default to location configured in hardware */
311 location = efm32_spi_get_configured_location(ddata);
312
313 dev_info(&pdev->dev, "fall back to location %u\n", location);
314 }
315
316 ddata->pdata.location = location;
317 }
318
efm32_spi_probe(struct platform_device * pdev)319 static int efm32_spi_probe(struct platform_device *pdev)
320 {
321 struct efm32_spi_ddata *ddata;
322 struct resource *res;
323 int ret;
324 struct spi_master *master;
325 struct device_node *np = pdev->dev.of_node;
326 int num_cs, i;
327
328 if (!np)
329 return -EINVAL;
330
331 num_cs = of_gpio_named_count(np, "cs-gpios");
332 if (num_cs < 0)
333 return num_cs;
334
335 master = spi_alloc_master(&pdev->dev,
336 sizeof(*ddata) + num_cs * sizeof(unsigned));
337 if (!master) {
338 dev_dbg(&pdev->dev,
339 "failed to allocate spi master controller\n");
340 return -ENOMEM;
341 }
342 platform_set_drvdata(pdev, master);
343
344 master->dev.of_node = pdev->dev.of_node;
345
346 master->num_chipselect = num_cs;
347 master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_CS_HIGH;
348 master->bits_per_word_mask = SPI_BPW_RANGE_MASK(4, 16);
349
350 ddata = spi_master_get_devdata(master);
351
352 ddata->bitbang.master = master;
353 ddata->bitbang.chipselect = efm32_spi_chipselect;
354 ddata->bitbang.setup_transfer = efm32_spi_setup_transfer;
355 ddata->bitbang.txrx_bufs = efm32_spi_txrx_bufs;
356
357 spin_lock_init(&ddata->lock);
358 init_completion(&ddata->done);
359
360 ddata->clk = devm_clk_get(&pdev->dev, NULL);
361 if (IS_ERR(ddata->clk)) {
362 ret = PTR_ERR(ddata->clk);
363 dev_err(&pdev->dev, "failed to get clock: %d\n", ret);
364 goto err;
365 }
366
367 for (i = 0; i < num_cs; ++i) {
368 ret = of_get_named_gpio(np, "cs-gpios", i);
369 if (ret < 0) {
370 dev_err(&pdev->dev, "failed to get csgpio#%u (%d)\n",
371 i, ret);
372 goto err;
373 }
374 ddata->csgpio[i] = ret;
375 dev_dbg(&pdev->dev, "csgpio#%u = %u\n", i, ddata->csgpio[i]);
376 ret = devm_gpio_request_one(&pdev->dev, ddata->csgpio[i],
377 GPIOF_OUT_INIT_LOW, DRIVER_NAME);
378 if (ret < 0) {
379 dev_err(&pdev->dev,
380 "failed to configure csgpio#%u (%d)\n",
381 i, ret);
382 goto err;
383 }
384 }
385
386 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
387 if (!res) {
388 ret = -ENODEV;
389 dev_err(&pdev->dev, "failed to determine base address\n");
390 goto err;
391 }
392
393 if (resource_size(res) < 0x60) {
394 ret = -EINVAL;
395 dev_err(&pdev->dev, "memory resource too small\n");
396 goto err;
397 }
398
399 ddata->base = devm_ioremap_resource(&pdev->dev, res);
400 if (IS_ERR(ddata->base)) {
401 ret = PTR_ERR(ddata->base);
402 goto err;
403 }
404
405 ret = platform_get_irq(pdev, 0);
406 if (ret <= 0) {
407 dev_err(&pdev->dev, "failed to get rx irq (%d)\n", ret);
408 goto err;
409 }
410
411 ddata->rxirq = ret;
412
413 ret = platform_get_irq(pdev, 1);
414 if (ret <= 0)
415 ret = ddata->rxirq + 1;
416
417 ddata->txirq = ret;
418
419 ret = clk_prepare_enable(ddata->clk);
420 if (ret < 0) {
421 dev_err(&pdev->dev, "failed to enable clock (%d)\n", ret);
422 goto err;
423 }
424
425 efm32_spi_probe_dt(pdev, master, ddata);
426
427 efm32_spi_write32(ddata, 0, REG_IEN);
428 efm32_spi_write32(ddata, REG_ROUTE_TXPEN | REG_ROUTE_RXPEN |
429 REG_ROUTE_CLKPEN |
430 REG_ROUTE_LOCATION(ddata->pdata.location), REG_ROUTE);
431
432 ret = request_irq(ddata->rxirq, efm32_spi_rxirq,
433 0, DRIVER_NAME " rx", ddata);
434 if (ret) {
435 dev_err(&pdev->dev, "failed to register rxirq (%d)\n", ret);
436 goto err_disable_clk;
437 }
438
439 ret = request_irq(ddata->txirq, efm32_spi_txirq,
440 0, DRIVER_NAME " tx", ddata);
441 if (ret) {
442 dev_err(&pdev->dev, "failed to register txirq (%d)\n", ret);
443 goto err_free_rx_irq;
444 }
445
446 ret = spi_bitbang_start(&ddata->bitbang);
447 if (ret) {
448 dev_err(&pdev->dev, "spi_bitbang_start failed (%d)\n", ret);
449
450 free_irq(ddata->txirq, ddata);
451 err_free_rx_irq:
452 free_irq(ddata->rxirq, ddata);
453 err_disable_clk:
454 clk_disable_unprepare(ddata->clk);
455 err:
456 spi_master_put(master);
457 }
458
459 return ret;
460 }
461
efm32_spi_remove(struct platform_device * pdev)462 static int efm32_spi_remove(struct platform_device *pdev)
463 {
464 struct spi_master *master = platform_get_drvdata(pdev);
465 struct efm32_spi_ddata *ddata = spi_master_get_devdata(master);
466
467 spi_bitbang_stop(&ddata->bitbang);
468
469 efm32_spi_write32(ddata, 0, REG_IEN);
470
471 free_irq(ddata->txirq, ddata);
472 free_irq(ddata->rxirq, ddata);
473 clk_disable_unprepare(ddata->clk);
474 spi_master_put(master);
475
476 return 0;
477 }
478
479 static const struct of_device_id efm32_spi_dt_ids[] = {
480 {
481 .compatible = "energymicro,efm32-spi",
482 }, {
483 /* doesn't follow the "vendor,device" scheme, don't use */
484 .compatible = "efm32,spi",
485 }, {
486 /* sentinel */
487 }
488 };
489 MODULE_DEVICE_TABLE(of, efm32_spi_dt_ids);
490
491 static struct platform_driver efm32_spi_driver = {
492 .probe = efm32_spi_probe,
493 .remove = efm32_spi_remove,
494
495 .driver = {
496 .name = DRIVER_NAME,
497 .of_match_table = efm32_spi_dt_ids,
498 },
499 };
500 module_platform_driver(efm32_spi_driver);
501
502 MODULE_AUTHOR("Uwe Kleine-Koenig <u.kleine-koenig@pengutronix.de>");
503 MODULE_DESCRIPTION("EFM32 SPI driver");
504 MODULE_LICENSE("GPL v2");
505 MODULE_ALIAS("platform:" DRIVER_NAME);
506
