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treewide: remove redundant IS_ERR() before error code check
[linux/fpc-iii.git] / drivers / spi / spi-lantiq-ssc.c
blob1fd7ee53d45104107a23d68e586ba90c311ff7e5
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * Copyright (C) 2011-2015 Daniel Schwierzeck <daniel.schwierzeck@gmail.com>
4 * Copyright (C) 2016 Hauke Mehrtens <hauke@hauke-m.de>
5 */
6
7 #include <linux/kernel.h>
8 #include <linux/module.h>
9 #include <linux/of_device.h>
10 #include <linux/clk.h>
11 #include <linux/io.h>
12 #include <linux/delay.h>
13 #include <linux/interrupt.h>
14 #include <linux/sched.h>
15 #include <linux/completion.h>
16 #include <linux/spinlock.h>
17 #include <linux/err.h>
18 #include <linux/gpio.h>
19 #include <linux/pm_runtime.h>
20 #include <linux/spi/spi.h>
21
22 #ifdef CONFIG_LANTIQ
23 #include <lantiq_soc.h>
24 #endif
25
26 #define LTQ_SPI_RX_IRQ_NAME "spi_rx"
27 #define LTQ_SPI_TX_IRQ_NAME "spi_tx"
28 #define LTQ_SPI_ERR_IRQ_NAME "spi_err"
29 #define LTQ_SPI_FRM_IRQ_NAME "spi_frm"
30
31 #define LTQ_SPI_CLC 0x00
32 #define LTQ_SPI_PISEL 0x04
33 #define LTQ_SPI_ID 0x08
34 #define LTQ_SPI_CON 0x10
35 #define LTQ_SPI_STAT 0x14
36 #define LTQ_SPI_WHBSTATE 0x18
37 #define LTQ_SPI_TB 0x20
38 #define LTQ_SPI_RB 0x24
39 #define LTQ_SPI_RXFCON 0x30
40 #define LTQ_SPI_TXFCON 0x34
41 #define LTQ_SPI_FSTAT 0x38
42 #define LTQ_SPI_BRT 0x40
43 #define LTQ_SPI_BRSTAT 0x44
44 #define LTQ_SPI_SFCON 0x60
45 #define LTQ_SPI_SFSTAT 0x64
46 #define LTQ_SPI_GPOCON 0x70
47 #define LTQ_SPI_GPOSTAT 0x74
48 #define LTQ_SPI_FPGO 0x78
49 #define LTQ_SPI_RXREQ 0x80
50 #define LTQ_SPI_RXCNT 0x84
51 #define LTQ_SPI_DMACON 0xec
52 #define LTQ_SPI_IRNEN 0xf4
53 #define LTQ_SPI_IRNICR 0xf8
54 #define LTQ_SPI_IRNCR 0xfc
55
56 #define LTQ_SPI_CLC_SMC_S 16 /* Clock divider for sleep mode */
57 #define LTQ_SPI_CLC_SMC_M (0xFF << LTQ_SPI_CLC_SMC_S)
58 #define LTQ_SPI_CLC_RMC_S 8 /* Clock divider for normal run mode */
59 #define LTQ_SPI_CLC_RMC_M (0xFF << LTQ_SPI_CLC_RMC_S)
60 #define LTQ_SPI_CLC_DISS BIT(1) /* Disable status bit */
61 #define LTQ_SPI_CLC_DISR BIT(0) /* Disable request bit */
62
63 #define LTQ_SPI_ID_TXFS_S 24 /* Implemented TX FIFO size */
64 #define LTQ_SPI_ID_TXFS_M (0x3F << LTQ_SPI_ID_TXFS_S)
65 #define LTQ_SPI_ID_RXFS_S 16 /* Implemented RX FIFO size */
66 #define LTQ_SPI_ID_RXFS_M (0x3F << LTQ_SPI_ID_RXFS_S)
67 #define LTQ_SPI_ID_MOD_S 8 /* Module ID */
68 #define LTQ_SPI_ID_MOD_M (0xff << LTQ_SPI_ID_MOD_S)
69 #define LTQ_SPI_ID_CFG_S 5 /* DMA interface support */
70 #define LTQ_SPI_ID_CFG_M (1 << LTQ_SPI_ID_CFG_S)
71 #define LTQ_SPI_ID_REV_M 0x1F /* Hardware revision number */
72
73 #define LTQ_SPI_CON_BM_S 16 /* Data width selection */
74 #define LTQ_SPI_CON_BM_M (0x1F << LTQ_SPI_CON_BM_S)
75 #define LTQ_SPI_CON_EM BIT(24) /* Echo mode */
76 #define LTQ_SPI_CON_IDLE BIT(23) /* Idle bit value */
77 #define LTQ_SPI_CON_ENBV BIT(22) /* Enable byte valid control */
78 #define LTQ_SPI_CON_RUEN BIT(12) /* Receive underflow error enable */
79 #define LTQ_SPI_CON_TUEN BIT(11) /* Transmit underflow error enable */
80 #define LTQ_SPI_CON_AEN BIT(10) /* Abort error enable */
81 #define LTQ_SPI_CON_REN BIT(9) /* Receive overflow error enable */
82 #define LTQ_SPI_CON_TEN BIT(8) /* Transmit overflow error enable */
83 #define LTQ_SPI_CON_LB BIT(7) /* Loopback control */
84 #define LTQ_SPI_CON_PO BIT(6) /* Clock polarity control */
85 #define LTQ_SPI_CON_PH BIT(5) /* Clock phase control */
86 #define LTQ_SPI_CON_HB BIT(4) /* Heading control */
87 #define LTQ_SPI_CON_RXOFF BIT(1) /* Switch receiver off */
88 #define LTQ_SPI_CON_TXOFF BIT(0) /* Switch transmitter off */
89
90 #define LTQ_SPI_STAT_RXBV_S 28
91 #define LTQ_SPI_STAT_RXBV_M (0x7 << LTQ_SPI_STAT_RXBV_S)
92 #define LTQ_SPI_STAT_BSY BIT(13) /* Busy flag */
93 #define LTQ_SPI_STAT_RUE BIT(12) /* Receive underflow error flag */
94 #define LTQ_SPI_STAT_TUE BIT(11) /* Transmit underflow error flag */
95 #define LTQ_SPI_STAT_AE BIT(10) /* Abort error flag */
96 #define LTQ_SPI_STAT_RE BIT(9) /* Receive error flag */
97 #define LTQ_SPI_STAT_TE BIT(8) /* Transmit error flag */
98 #define LTQ_SPI_STAT_ME BIT(7) /* Mode error flag */
99 #define LTQ_SPI_STAT_MS BIT(1) /* Master/slave select bit */
100 #define LTQ_SPI_STAT_EN BIT(0) /* Enable bit */
101 #define LTQ_SPI_STAT_ERRORS (LTQ_SPI_STAT_ME | LTQ_SPI_STAT_TE | \
102 LTQ_SPI_STAT_RE | LTQ_SPI_STAT_AE | \
103 LTQ_SPI_STAT_TUE | LTQ_SPI_STAT_RUE)
104
105 #define LTQ_SPI_WHBSTATE_SETTUE BIT(15) /* Set transmit underflow error flag */
106 #define LTQ_SPI_WHBSTATE_SETAE BIT(14) /* Set abort error flag */
107 #define LTQ_SPI_WHBSTATE_SETRE BIT(13) /* Set receive error flag */
108 #define LTQ_SPI_WHBSTATE_SETTE BIT(12) /* Set transmit error flag */
109 #define LTQ_SPI_WHBSTATE_CLRTUE BIT(11) /* Clear transmit underflow error flag */
110 #define LTQ_SPI_WHBSTATE_CLRAE BIT(10) /* Clear abort error flag */
111 #define LTQ_SPI_WHBSTATE_CLRRE BIT(9) /* Clear receive error flag */
112 #define LTQ_SPI_WHBSTATE_CLRTE BIT(8) /* Clear transmit error flag */
113 #define LTQ_SPI_WHBSTATE_SETME BIT(7) /* Set mode error flag */
114 #define LTQ_SPI_WHBSTATE_CLRME BIT(6) /* Clear mode error flag */
115 #define LTQ_SPI_WHBSTATE_SETRUE BIT(5) /* Set receive underflow error flag */
116 #define LTQ_SPI_WHBSTATE_CLRRUE BIT(4) /* Clear receive underflow error flag */
117 #define LTQ_SPI_WHBSTATE_SETMS BIT(3) /* Set master select bit */
118 #define LTQ_SPI_WHBSTATE_CLRMS BIT(2) /* Clear master select bit */
119 #define LTQ_SPI_WHBSTATE_SETEN BIT(1) /* Set enable bit (operational mode) */
120 #define LTQ_SPI_WHBSTATE_CLREN BIT(0) /* Clear enable bit (config mode */
121 #define LTQ_SPI_WHBSTATE_CLR_ERRORS (LTQ_SPI_WHBSTATE_CLRRUE | \
122 LTQ_SPI_WHBSTATE_CLRME | \
123 LTQ_SPI_WHBSTATE_CLRTE | \
124 LTQ_SPI_WHBSTATE_CLRRE | \
125 LTQ_SPI_WHBSTATE_CLRAE | \
126 LTQ_SPI_WHBSTATE_CLRTUE)
127
128 #define LTQ_SPI_RXFCON_RXFITL_S 8 /* FIFO interrupt trigger level */
129 #define LTQ_SPI_RXFCON_RXFITL_M (0x3F << LTQ_SPI_RXFCON_RXFITL_S)
130 #define LTQ_SPI_RXFCON_RXFLU BIT(1) /* FIFO flush */
131 #define LTQ_SPI_RXFCON_RXFEN BIT(0) /* FIFO enable */
132
133 #define LTQ_SPI_TXFCON_TXFITL_S 8 /* FIFO interrupt trigger level */
134 #define LTQ_SPI_TXFCON_TXFITL_M (0x3F << LTQ_SPI_TXFCON_TXFITL_S)
135 #define LTQ_SPI_TXFCON_TXFLU BIT(1) /* FIFO flush */
136 #define LTQ_SPI_TXFCON_TXFEN BIT(0) /* FIFO enable */
137
138 #define LTQ_SPI_FSTAT_RXFFL_S 0
139 #define LTQ_SPI_FSTAT_RXFFL_M (0x3f << LTQ_SPI_FSTAT_RXFFL_S)
140 #define LTQ_SPI_FSTAT_TXFFL_S 8
141 #define LTQ_SPI_FSTAT_TXFFL_M (0x3f << LTQ_SPI_FSTAT_TXFFL_S)
142
143 #define LTQ_SPI_GPOCON_ISCSBN_S 8
144 #define LTQ_SPI_GPOCON_INVOUTN_S 0
145
146 #define LTQ_SPI_FGPO_SETOUTN_S 8
147 #define LTQ_SPI_FGPO_CLROUTN_S 0
148
149 #define LTQ_SPI_RXREQ_RXCNT_M 0xFFFF /* Receive count value */
150 #define LTQ_SPI_RXCNT_TODO_M 0xFFFF /* Recevie to-do value */
151
152 #define LTQ_SPI_IRNEN_TFI BIT(4) /* TX finished interrupt */
153 #define LTQ_SPI_IRNEN_F BIT(3) /* Frame end interrupt request */
154 #define LTQ_SPI_IRNEN_E BIT(2) /* Error end interrupt request */
155 #define LTQ_SPI_IRNEN_T_XWAY BIT(1) /* Transmit end interrupt request */
156 #define LTQ_SPI_IRNEN_R_XWAY BIT(0) /* Receive end interrupt request */
157 #define LTQ_SPI_IRNEN_R_XRX BIT(1) /* Transmit end interrupt request */
158 #define LTQ_SPI_IRNEN_T_XRX BIT(0) /* Receive end interrupt request */
159 #define LTQ_SPI_IRNEN_ALL 0x1F
160
161 struct lantiq_ssc_hwcfg {
162 unsigned int irnen_r;
163 unsigned int irnen_t;
164 };
165
166 struct lantiq_ssc_spi {
167 struct spi_master *master;
168 struct device *dev;
169 void __iomem *regbase;
170 struct clk *spi_clk;
171 struct clk *fpi_clk;
172 const struct lantiq_ssc_hwcfg *hwcfg;
173
174 spinlock_t lock;
175 struct workqueue_struct *wq;
176 struct work_struct work;
177
178 const u8 *tx;
179 u8 *rx;
180 unsigned int tx_todo;
181 unsigned int rx_todo;
182 unsigned int bits_per_word;
183 unsigned int speed_hz;
184 unsigned int tx_fifo_size;
185 unsigned int rx_fifo_size;
186 unsigned int base_cs;
187 };
188
189 static u32 lantiq_ssc_readl(const struct lantiq_ssc_spi *spi, u32 reg)
190 {
191 return __raw_readl(spi->regbase + reg);
192 }
193
194 static void lantiq_ssc_writel(const struct lantiq_ssc_spi *spi, u32 val,
195 u32 reg)
196 {
197 __raw_writel(val, spi->regbase + reg);
198 }
199
200 static void lantiq_ssc_maskl(const struct lantiq_ssc_spi *spi, u32 clr,
201 u32 set, u32 reg)
202 {
203 u32 val = __raw_readl(spi->regbase + reg);
204
205 val &= ~clr;
206 val |= set;
207 __raw_writel(val, spi->regbase + reg);
208 }
209
210 static unsigned int tx_fifo_level(const struct lantiq_ssc_spi *spi)
211 {
212 u32 fstat = lantiq_ssc_readl(spi, LTQ_SPI_FSTAT);
213
214 return (fstat & LTQ_SPI_FSTAT_TXFFL_M) >> LTQ_SPI_FSTAT_TXFFL_S;
215 }
216
217 static unsigned int rx_fifo_level(const struct lantiq_ssc_spi *spi)
218 {
219 u32 fstat = lantiq_ssc_readl(spi, LTQ_SPI_FSTAT);
220
221 return fstat & LTQ_SPI_FSTAT_RXFFL_M;
222 }
223
224 static unsigned int tx_fifo_free(const struct lantiq_ssc_spi *spi)
225 {
226 return spi->tx_fifo_size - tx_fifo_level(spi);
227 }
228
229 static void rx_fifo_reset(const struct lantiq_ssc_spi *spi)
230 {
231 u32 val = spi->rx_fifo_size << LTQ_SPI_RXFCON_RXFITL_S;
232
233 val |= LTQ_SPI_RXFCON_RXFEN | LTQ_SPI_RXFCON_RXFLU;
234 lantiq_ssc_writel(spi, val, LTQ_SPI_RXFCON);
235 }
236
237 static void tx_fifo_reset(const struct lantiq_ssc_spi *spi)
238 {
239 u32 val = 1 << LTQ_SPI_TXFCON_TXFITL_S;
240
241 val |= LTQ_SPI_TXFCON_TXFEN | LTQ_SPI_TXFCON_TXFLU;
242 lantiq_ssc_writel(spi, val, LTQ_SPI_TXFCON);
243 }
244
245 static void rx_fifo_flush(const struct lantiq_ssc_spi *spi)
246 {
247 lantiq_ssc_maskl(spi, 0, LTQ_SPI_RXFCON_RXFLU, LTQ_SPI_RXFCON);
248 }
249
250 static void tx_fifo_flush(const struct lantiq_ssc_spi *spi)
251 {
252 lantiq_ssc_maskl(spi, 0, LTQ_SPI_TXFCON_TXFLU, LTQ_SPI_TXFCON);
253 }
254
255 static void hw_enter_config_mode(const struct lantiq_ssc_spi *spi)
256 {
257 lantiq_ssc_writel(spi, LTQ_SPI_WHBSTATE_CLREN, LTQ_SPI_WHBSTATE);
258 }
259
260 static void hw_enter_active_mode(const struct lantiq_ssc_spi *spi)
261 {
262 lantiq_ssc_writel(spi, LTQ_SPI_WHBSTATE_SETEN, LTQ_SPI_WHBSTATE);
263 }
264
265 static void hw_setup_speed_hz(const struct lantiq_ssc_spi *spi,
266 unsigned int max_speed_hz)
267 {
268 u32 spi_clk, brt;
269
270 /*
271 * SPI module clock is derived from FPI bus clock dependent on
272 * divider value in CLC.RMS which is always set to 1.
273 *
274 * f_SPI
275 * baudrate = --------------
276 * 2 * (BR + 1)
277 */
278 spi_clk = clk_get_rate(spi->fpi_clk) / 2;
279
280 if (max_speed_hz > spi_clk)
281 brt = 0;
282 else
283 brt = spi_clk / max_speed_hz - 1;
284
285 if (brt > 0xFFFF)
286 brt = 0xFFFF;
287
288 dev_dbg(spi->dev, "spi_clk %u, max_speed_hz %u, brt %u\n",
289 spi_clk, max_speed_hz, brt);
290
291 lantiq_ssc_writel(spi, brt, LTQ_SPI_BRT);
292 }
293
294 static void hw_setup_bits_per_word(const struct lantiq_ssc_spi *spi,
295 unsigned int bits_per_word)
296 {
297 u32 bm;
298
299 /* CON.BM value = bits_per_word - 1 */
300 bm = (bits_per_word - 1) << LTQ_SPI_CON_BM_S;
301
302 lantiq_ssc_maskl(spi, LTQ_SPI_CON_BM_M, bm, LTQ_SPI_CON);
303 }
304
305 static void hw_setup_clock_mode(const struct lantiq_ssc_spi *spi,
306 unsigned int mode)
307 {
308 u32 con_set = 0, con_clr = 0;
309
310 /*
311 * SPI mode mapping in CON register:
312 * Mode CPOL CPHA CON.PO CON.PH
313 * 0 0 0 0 1
314 * 1 0 1 0 0
315 * 2 1 0 1 1
316 * 3 1 1 1 0
317 */
318 if (mode & SPI_CPHA)
319 con_clr |= LTQ_SPI_CON_PH;
320 else
321 con_set |= LTQ_SPI_CON_PH;
322
323 if (mode & SPI_CPOL)
324 con_set |= LTQ_SPI_CON_PO | LTQ_SPI_CON_IDLE;
325 else
326 con_clr |= LTQ_SPI_CON_PO | LTQ_SPI_CON_IDLE;
327
328 /* Set heading control */
329 if (mode & SPI_LSB_FIRST)
330 con_clr |= LTQ_SPI_CON_HB;
331 else
332 con_set |= LTQ_SPI_CON_HB;
333
334 /* Set loopback mode */
335 if (mode & SPI_LOOP)
336 con_set |= LTQ_SPI_CON_LB;
337 else
338 con_clr |= LTQ_SPI_CON_LB;
339
340 lantiq_ssc_maskl(spi, con_clr, con_set, LTQ_SPI_CON);
341 }
342
343 static void lantiq_ssc_hw_init(const struct lantiq_ssc_spi *spi)
344 {
345 const struct lantiq_ssc_hwcfg *hwcfg = spi->hwcfg;
346
347 /*
348 * Set clock divider for run mode to 1 to
349 * run at same frequency as FPI bus
350 */
351 lantiq_ssc_writel(spi, 1 << LTQ_SPI_CLC_RMC_S, LTQ_SPI_CLC);
352
353 /* Put controller into config mode */
354 hw_enter_config_mode(spi);
355
356 /* Clear error flags */
357 lantiq_ssc_maskl(spi, 0, LTQ_SPI_WHBSTATE_CLR_ERRORS, LTQ_SPI_WHBSTATE);
358
359 /* Enable error checking, disable TX/RX */
360 lantiq_ssc_writel(spi, LTQ_SPI_CON_RUEN | LTQ_SPI_CON_AEN |
361 LTQ_SPI_CON_TEN | LTQ_SPI_CON_REN | LTQ_SPI_CON_TXOFF |
362 LTQ_SPI_CON_RXOFF, LTQ_SPI_CON);
363
364 /* Setup default SPI mode */
365 hw_setup_bits_per_word(spi, spi->bits_per_word);
366 hw_setup_clock_mode(spi, SPI_MODE_0);
367
368 /* Enable master mode and clear error flags */
369 lantiq_ssc_writel(spi, LTQ_SPI_WHBSTATE_SETMS |
370 LTQ_SPI_WHBSTATE_CLR_ERRORS,
371 LTQ_SPI_WHBSTATE);
372
373 /* Reset GPIO/CS registers */
374 lantiq_ssc_writel(spi, 0, LTQ_SPI_GPOCON);
375 lantiq_ssc_writel(spi, 0xFF00, LTQ_SPI_FPGO);
376
377 /* Enable and flush FIFOs */
378 rx_fifo_reset(spi);
379 tx_fifo_reset(spi);
380
381 /* Enable interrupts */
382 lantiq_ssc_writel(spi, hwcfg->irnen_t | hwcfg->irnen_r |
383 LTQ_SPI_IRNEN_E, LTQ_SPI_IRNEN);
384 }
385
386 static int lantiq_ssc_setup(struct spi_device *spidev)
387 {
388 struct spi_master *master = spidev->master;
389 struct lantiq_ssc_spi *spi = spi_master_get_devdata(master);
390 unsigned int cs = spidev->chip_select;
391 u32 gpocon;
392
393 /* GPIOs are used for CS */
394 if (gpio_is_valid(spidev->cs_gpio))
395 return 0;
396
397 dev_dbg(spi->dev, "using internal chipselect %u\n", cs);
398
399 if (cs < spi->base_cs) {
400 dev_err(spi->dev,
401 "chipselect %i too small (min %i)\n", cs, spi->base_cs);
402 return -EINVAL;
403 }
404
405 /* set GPO pin to CS mode */
406 gpocon = 1 << ((cs - spi->base_cs) + LTQ_SPI_GPOCON_ISCSBN_S);
407
408 /* invert GPO pin */
409 if (spidev->mode & SPI_CS_HIGH)
410 gpocon |= 1 << (cs - spi->base_cs);
411
412 lantiq_ssc_maskl(spi, 0, gpocon, LTQ_SPI_GPOCON);
413
414 return 0;
415 }
416
417 static int lantiq_ssc_prepare_message(struct spi_master *master,
418 struct spi_message *message)
419 {
420 struct lantiq_ssc_spi *spi = spi_master_get_devdata(master);
421
422 hw_enter_config_mode(spi);
423 hw_setup_clock_mode(spi, message->spi->mode);
424 hw_enter_active_mode(spi);
425
426 return 0;
427 }
428
429 static void hw_setup_transfer(struct lantiq_ssc_spi *spi,
430 struct spi_device *spidev, struct spi_transfer *t)
431 {
432 unsigned int speed_hz = t->speed_hz;
433 unsigned int bits_per_word = t->bits_per_word;
434 u32 con;
435
436 if (bits_per_word != spi->bits_per_word ||
437 speed_hz != spi->speed_hz) {
438 hw_enter_config_mode(spi);
439 hw_setup_speed_hz(spi, speed_hz);
440 hw_setup_bits_per_word(spi, bits_per_word);
441 hw_enter_active_mode(spi);
442
443 spi->speed_hz = speed_hz;
444 spi->bits_per_word = bits_per_word;
445 }
446
447 /* Configure transmitter and receiver */
448 con = lantiq_ssc_readl(spi, LTQ_SPI_CON);
449 if (t->tx_buf)
450 con &= ~LTQ_SPI_CON_TXOFF;
451 else
452 con |= LTQ_SPI_CON_TXOFF;
453
454 if (t->rx_buf)
455 con &= ~LTQ_SPI_CON_RXOFF;
456 else
457 con |= LTQ_SPI_CON_RXOFF;
458
459 lantiq_ssc_writel(spi, con, LTQ_SPI_CON);
460 }
461
462 static int lantiq_ssc_unprepare_message(struct spi_master *master,
463 struct spi_message *message)
464 {
465 struct lantiq_ssc_spi *spi = spi_master_get_devdata(master);
466
467 flush_workqueue(spi->wq);
468
469 /* Disable transmitter and receiver while idle */
470 lantiq_ssc_maskl(spi, 0, LTQ_SPI_CON_TXOFF | LTQ_SPI_CON_RXOFF,
471 LTQ_SPI_CON);
472
473 return 0;
474 }
475
476 static void tx_fifo_write(struct lantiq_ssc_spi *spi)
477 {
478 const u8 *tx8;
479 const u16 *tx16;
480 const u32 *tx32;
481 u32 data;
482 unsigned int tx_free = tx_fifo_free(spi);
483
484 while (spi->tx_todo && tx_free) {
485 switch (spi->bits_per_word) {
486 case 2 ... 8:
487 tx8 = spi->tx;
488 data = *tx8;
489 spi->tx_todo--;
490 spi->tx++;
491 break;
492 case 16:
493 tx16 = (u16 *) spi->tx;
494 data = *tx16;
495 spi->tx_todo -= 2;
496 spi->tx += 2;
497 break;
498 case 32:
499 tx32 = (u32 *) spi->tx;
500 data = *tx32;
501 spi->tx_todo -= 4;
502 spi->tx += 4;
503 break;
504 default:
505 WARN_ON(1);
506 data = 0;
507 break;
508 }
509
510 lantiq_ssc_writel(spi, data, LTQ_SPI_TB);
511 tx_free--;
512 }
513 }
514
515 static void rx_fifo_read_full_duplex(struct lantiq_ssc_spi *spi)
516 {
517 u8 *rx8;
518 u16 *rx16;
519 u32 *rx32;
520 u32 data;
521 unsigned int rx_fill = rx_fifo_level(spi);
522
523 while (rx_fill) {
524 data = lantiq_ssc_readl(spi, LTQ_SPI_RB);
525
526 switch (spi->bits_per_word) {
527 case 2 ... 8:
528 rx8 = spi->rx;
529 *rx8 = data;
530 spi->rx_todo--;
531 spi->rx++;
532 break;
533 case 16:
534 rx16 = (u16 *) spi->rx;
535 *rx16 = data;
536 spi->rx_todo -= 2;
537 spi->rx += 2;
538 break;
539 case 32:
540 rx32 = (u32 *) spi->rx;
541 *rx32 = data;
542 spi->rx_todo -= 4;
543 spi->rx += 4;
544 break;
545 default:
546 WARN_ON(1);
547 break;
548 }
549
550 rx_fill--;
551 }
552 }
553
554 static void rx_fifo_read_half_duplex(struct lantiq_ssc_spi *spi)
555 {
556 u32 data, *rx32;
557 u8 *rx8;
558 unsigned int rxbv, shift;
559 unsigned int rx_fill = rx_fifo_level(spi);
560
561 /*
562 * In RX-only mode the bits per word value is ignored by HW. A value
563 * of 32 is used instead. Thus all 4 bytes per FIFO must be read.
564 * If remaining RX bytes are less than 4, the FIFO must be read
565 * differently. The amount of received and valid bytes is indicated
566 * by STAT.RXBV register value.
567 */
568 while (rx_fill) {
569 if (spi->rx_todo < 4) {
570 rxbv = (lantiq_ssc_readl(spi, LTQ_SPI_STAT) &
571 LTQ_SPI_STAT_RXBV_M) >> LTQ_SPI_STAT_RXBV_S;
572 data = lantiq_ssc_readl(spi, LTQ_SPI_RB);
573
574 shift = (rxbv - 1) * 8;
575 rx8 = spi->rx;
576
577 while (rxbv) {
578 *rx8++ = (data >> shift) & 0xFF;
579 rxbv--;
580 shift -= 8;
581 spi->rx_todo--;
582 spi->rx++;
583 }
584 } else {
585 data = lantiq_ssc_readl(spi, LTQ_SPI_RB);
586 rx32 = (u32 *) spi->rx;
587
588 *rx32++ = data;
589 spi->rx_todo -= 4;
590 spi->rx += 4;
591 }
592 rx_fill--;
593 }
594 }
595
596 static void rx_request(struct lantiq_ssc_spi *spi)
597 {
598 unsigned int rxreq, rxreq_max;
599
600 /*
601 * To avoid receive overflows at high clocks it is better to request
602 * only the amount of bytes that fits into all FIFOs. This value
603 * depends on the FIFO size implemented in hardware.
604 */
605 rxreq = spi->rx_todo;
606 rxreq_max = spi->rx_fifo_size * 4;
607 if (rxreq > rxreq_max)
608 rxreq = rxreq_max;
609
610 lantiq_ssc_writel(spi, rxreq, LTQ_SPI_RXREQ);
611 }
612
613 static irqreturn_t lantiq_ssc_xmit_interrupt(int irq, void *data)
614 {
615 struct lantiq_ssc_spi *spi = data;
616
617 if (spi->tx) {
618 if (spi->rx && spi->rx_todo)
619 rx_fifo_read_full_duplex(spi);
620
621 if (spi->tx_todo)
622 tx_fifo_write(spi);
623 else if (!tx_fifo_level(spi))
624 goto completed;
625 } else if (spi->rx) {
626 if (spi->rx_todo) {
627 rx_fifo_read_half_duplex(spi);
628
629 if (spi->rx_todo)
630 rx_request(spi);
631 else
632 goto completed;
633 } else {
634 goto completed;
635 }
636 }
637
638 return IRQ_HANDLED;
639
640 completed:
641 queue_work(spi->wq, &spi->work);
642
643 return IRQ_HANDLED;
644 }
645
646 static irqreturn_t lantiq_ssc_err_interrupt(int irq, void *data)
647 {
648 struct lantiq_ssc_spi *spi = data;
649 u32 stat = lantiq_ssc_readl(spi, LTQ_SPI_STAT);
650
651 if (!(stat & LTQ_SPI_STAT_ERRORS))
652 return IRQ_NONE;
653
654 if (stat & LTQ_SPI_STAT_RUE)
655 dev_err(spi->dev, "receive underflow error\n");
656 if (stat & LTQ_SPI_STAT_TUE)
657 dev_err(spi->dev, "transmit underflow error\n");
658 if (stat & LTQ_SPI_STAT_AE)
659 dev_err(spi->dev, "abort error\n");
660 if (stat & LTQ_SPI_STAT_RE)
661 dev_err(spi->dev, "receive overflow error\n");
662 if (stat & LTQ_SPI_STAT_TE)
663 dev_err(spi->dev, "transmit overflow error\n");
664 if (stat & LTQ_SPI_STAT_ME)
665 dev_err(spi->dev, "mode error\n");
666
667 /* Clear error flags */
668 lantiq_ssc_maskl(spi, 0, LTQ_SPI_WHBSTATE_CLR_ERRORS, LTQ_SPI_WHBSTATE);
669
670 /* set bad status so it can be retried */
671 if (spi->master->cur_msg)
672 spi->master->cur_msg->status = -EIO;
673 queue_work(spi->wq, &spi->work);
674
675 return IRQ_HANDLED;
676 }
677
678 static int transfer_start(struct lantiq_ssc_spi *spi, struct spi_device *spidev,
679 struct spi_transfer *t)
680 {
681 unsigned long flags;
682
683 spin_lock_irqsave(&spi->lock, flags);
684
685 spi->tx = t->tx_buf;
686 spi->rx = t->rx_buf;
687
688 if (t->tx_buf) {
689 spi->tx_todo = t->len;
690
691 /* initially fill TX FIFO */
692 tx_fifo_write(spi);
693 }
694
695 if (spi->rx) {
696 spi->rx_todo = t->len;
697
698 /* start shift clock in RX-only mode */
699 if (!spi->tx)
700 rx_request(spi);
701 }
702
703 spin_unlock_irqrestore(&spi->lock, flags);
704
705 return t->len;
706 }
707
708 /*
709 * The driver only gets an interrupt when the FIFO is empty, but there
710 * is an additional shift register from which the data is written to
711 * the wire. We get the last interrupt when the controller starts to
712 * write the last word to the wire, not when it is finished. Do busy
713 * waiting till it finishes.
714 */
715 static void lantiq_ssc_bussy_work(struct work_struct *work)
716 {
717 struct lantiq_ssc_spi *spi;
718 unsigned long long timeout = 8LL * 1000LL;
719 unsigned long end;
720
721 spi = container_of(work, typeof(*spi), work);
722
723 do_div(timeout, spi->speed_hz);
724 timeout += timeout + 100; /* some tolerance */
725
726 end = jiffies + msecs_to_jiffies(timeout);
727 do {
728 u32 stat = lantiq_ssc_readl(spi, LTQ_SPI_STAT);
729
730 if (!(stat & LTQ_SPI_STAT_BSY)) {
731 spi_finalize_current_transfer(spi->master);
732 return;
733 }
734
735 cond_resched();
736 } while (!time_after_eq(jiffies, end));
737
738 if (spi->master->cur_msg)
739 spi->master->cur_msg->status = -EIO;
740 spi_finalize_current_transfer(spi->master);
741 }
742
743 static void lantiq_ssc_handle_err(struct spi_master *master,
744 struct spi_message *message)
745 {
746 struct lantiq_ssc_spi *spi = spi_master_get_devdata(master);
747
748 /* flush FIFOs on timeout */
749 rx_fifo_flush(spi);
750 tx_fifo_flush(spi);
751 }
752
753 static void lantiq_ssc_set_cs(struct spi_device *spidev, bool enable)
754 {
755 struct lantiq_ssc_spi *spi = spi_master_get_devdata(spidev->master);
756 unsigned int cs = spidev->chip_select;
757 u32 fgpo;
758
759 if (!!(spidev->mode & SPI_CS_HIGH) == enable)
760 fgpo = (1 << (cs - spi->base_cs));
761 else
762 fgpo = (1 << (cs - spi->base_cs + LTQ_SPI_FGPO_SETOUTN_S));
763
764 lantiq_ssc_writel(spi, fgpo, LTQ_SPI_FPGO);
765 }
766
767 static int lantiq_ssc_transfer_one(struct spi_master *master,
768 struct spi_device *spidev,
769 struct spi_transfer *t)
770 {
771 struct lantiq_ssc_spi *spi = spi_master_get_devdata(master);
772
773 hw_setup_transfer(spi, spidev, t);
774
775 return transfer_start(spi, spidev, t);
776 }
777
778 static const struct lantiq_ssc_hwcfg lantiq_ssc_xway = {
779 .irnen_r = LTQ_SPI_IRNEN_R_XWAY,
780 .irnen_t = LTQ_SPI_IRNEN_T_XWAY,
781 };
782
783 static const struct lantiq_ssc_hwcfg lantiq_ssc_xrx = {
784 .irnen_r = LTQ_SPI_IRNEN_R_XRX,
785 .irnen_t = LTQ_SPI_IRNEN_T_XRX,
786 };
787
788 static const struct of_device_id lantiq_ssc_match[] = {
789 { .compatible = "lantiq,ase-spi", .data = &lantiq_ssc_xway, },
790 { .compatible = "lantiq,falcon-spi", .data = &lantiq_ssc_xrx, },
791 { .compatible = "lantiq,xrx100-spi", .data = &lantiq_ssc_xrx, },
792 {},
793 };
794 MODULE_DEVICE_TABLE(of, lantiq_ssc_match);
795
796 static int lantiq_ssc_probe(struct platform_device *pdev)
797 {
798 struct device *dev = &pdev->dev;
799 struct spi_master *master;
800 struct lantiq_ssc_spi *spi;
801 const struct lantiq_ssc_hwcfg *hwcfg;
802 const struct of_device_id *match;
803 int err, rx_irq, tx_irq, err_irq;
804 u32 id, supports_dma, revision;
805 unsigned int num_cs;
806
807 match = of_match_device(lantiq_ssc_match, dev);
808 if (!match) {
809 dev_err(dev, "no device match\n");
810 return -EINVAL;
811 }
812 hwcfg = match->data;
813
814 rx_irq = platform_get_irq_byname(pdev, LTQ_SPI_RX_IRQ_NAME);
815 if (rx_irq < 0)
816 return -ENXIO;
817
818 tx_irq = platform_get_irq_byname(pdev, LTQ_SPI_TX_IRQ_NAME);
819 if (tx_irq < 0)
820 return -ENXIO;
821
822 err_irq = platform_get_irq_byname(pdev, LTQ_SPI_ERR_IRQ_NAME);
823 if (err_irq < 0)
824 return -ENXIO;
825
826 master = spi_alloc_master(dev, sizeof(struct lantiq_ssc_spi));
827 if (!master)
828 return -ENOMEM;
829
830 spi = spi_master_get_devdata(master);
831 spi->master = master;
832 spi->dev = dev;
833 spi->hwcfg = hwcfg;
834 platform_set_drvdata(pdev, spi);
835 spi->regbase = devm_platform_ioremap_resource(pdev, 0);
836 if (IS_ERR(spi->regbase)) {
837 err = PTR_ERR(spi->regbase);
838 goto err_master_put;
839 }
840
841 err = devm_request_irq(dev, rx_irq, lantiq_ssc_xmit_interrupt,
842 0, LTQ_SPI_RX_IRQ_NAME, spi);
843 if (err)
844 goto err_master_put;
845
846 err = devm_request_irq(dev, tx_irq, lantiq_ssc_xmit_interrupt,
847 0, LTQ_SPI_TX_IRQ_NAME, spi);
848 if (err)
849 goto err_master_put;
850
851 err = devm_request_irq(dev, err_irq, lantiq_ssc_err_interrupt,
852 0, LTQ_SPI_ERR_IRQ_NAME, spi);
853 if (err)
854 goto err_master_put;
855
856 spi->spi_clk = devm_clk_get(dev, "gate");
857 if (IS_ERR(spi->spi_clk)) {
858 err = PTR_ERR(spi->spi_clk);
859 goto err_master_put;
860 }
861 err = clk_prepare_enable(spi->spi_clk);
862 if (err)
863 goto err_master_put;
864
865 /*
866 * Use the old clk_get_fpi() function on Lantiq platform, till it
867 * supports common clk.
868 */
869 #if defined(CONFIG_LANTIQ) && !defined(CONFIG_COMMON_CLK)
870 spi->fpi_clk = clk_get_fpi();
871 #else
872 spi->fpi_clk = clk_get(dev, "freq");
873 #endif
874 if (IS_ERR(spi->fpi_clk)) {
875 err = PTR_ERR(spi->fpi_clk);
876 goto err_clk_disable;
877 }
878
879 num_cs = 8;
880 of_property_read_u32(pdev->dev.of_node, "num-cs", &num_cs);
881
882 spi->base_cs = 1;
883 of_property_read_u32(pdev->dev.of_node, "base-cs", &spi->base_cs);
884
885 spin_lock_init(&spi->lock);
886 spi->bits_per_word = 8;
887 spi->speed_hz = 0;
888
889 master->dev.of_node = pdev->dev.of_node;
890 master->num_chipselect = num_cs;
891 master->setup = lantiq_ssc_setup;
892 master->set_cs = lantiq_ssc_set_cs;
893 master->handle_err = lantiq_ssc_handle_err;
894 master->prepare_message = lantiq_ssc_prepare_message;
895 master->unprepare_message = lantiq_ssc_unprepare_message;
896 master->transfer_one = lantiq_ssc_transfer_one;
897 master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_LSB_FIRST | SPI_CS_HIGH |
898 SPI_LOOP;
899 master->bits_per_word_mask = SPI_BPW_RANGE_MASK(2, 8) |
900 SPI_BPW_MASK(16) | SPI_BPW_MASK(32);
901
902 spi->wq = alloc_ordered_workqueue(dev_name(dev), 0);
903 if (!spi->wq) {
904 err = -ENOMEM;
905 goto err_clk_put;
906 }
907 INIT_WORK(&spi->work, lantiq_ssc_bussy_work);
908
909 id = lantiq_ssc_readl(spi, LTQ_SPI_ID);
910 spi->tx_fifo_size = (id & LTQ_SPI_ID_TXFS_M) >> LTQ_SPI_ID_TXFS_S;
911 spi->rx_fifo_size = (id & LTQ_SPI_ID_RXFS_M) >> LTQ_SPI_ID_RXFS_S;
912 supports_dma = (id & LTQ_SPI_ID_CFG_M) >> LTQ_SPI_ID_CFG_S;
913 revision = id & LTQ_SPI_ID_REV_M;
914
915 lantiq_ssc_hw_init(spi);
916
917 dev_info(dev,
918 "Lantiq SSC SPI controller (Rev %i, TXFS %u, RXFS %u, DMA %u)\n",
919 revision, spi->tx_fifo_size, spi->rx_fifo_size, supports_dma);
920
921 err = devm_spi_register_master(dev, master);
922 if (err) {
923 dev_err(dev, "failed to register spi_master\n");
924 goto err_wq_destroy;
925 }
926
927 return 0;
928
929 err_wq_destroy:
930 destroy_workqueue(spi->wq);
931 err_clk_put:
932 clk_put(spi->fpi_clk);
933 err_clk_disable:
934 clk_disable_unprepare(spi->spi_clk);
935 err_master_put:
936 spi_master_put(master);
937
938 return err;
939 }
940
941 static int lantiq_ssc_remove(struct platform_device *pdev)
942 {
943 struct lantiq_ssc_spi *spi = platform_get_drvdata(pdev);
944
945 lantiq_ssc_writel(spi, 0, LTQ_SPI_IRNEN);
946 lantiq_ssc_writel(spi, 0, LTQ_SPI_CLC);
947 rx_fifo_flush(spi);
948 tx_fifo_flush(spi);
949 hw_enter_config_mode(spi);
950
951 destroy_workqueue(spi->wq);
952 clk_disable_unprepare(spi->spi_clk);
953 clk_put(spi->fpi_clk);
954
955 return 0;
956 }
957
958 static struct platform_driver lantiq_ssc_driver = {
959 .probe = lantiq_ssc_probe,
960 .remove = lantiq_ssc_remove,
961 .driver = {
962 .name = "spi-lantiq-ssc",
963 .of_match_table = lantiq_ssc_match,
964 },
965 };
966 module_platform_driver(lantiq_ssc_driver);
967
968 MODULE_DESCRIPTION("Lantiq SSC SPI controller driver");
969 MODULE_AUTHOR("Daniel Schwierzeck <daniel.schwierzeck@gmail.com>");
970 MODULE_AUTHOR("Hauke Mehrtens <hauke@hauke-m.de>");
971 MODULE_LICENSE("GPL");
972 MODULE_ALIAS("platform:spi-lantiq-ssc");
Linux with added FPC-III support