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