Version:  2.0.40 2.2.26 2.4.37 3.8 3.9 3.10 3.11 3.12 3.13 3.14 3.15 3.16 3.17 3.18 3.19 4.0 4.1 4.2 4.3 4.4

Linux/drivers/spi/spi-davinci.c

  1 /*
  2  * Copyright (C) 2009 Texas Instruments.
  3  * Copyright (C) 2010 EF Johnson Technologies
  4  *
  5  * This program is free software; you can redistribute it and/or modify
  6  * it under the terms of the GNU General Public License as published by
  7  * the Free Software Foundation; either version 2 of the License, or
  8  * (at your option) any later version.
  9  *
 10  * This program is distributed in the hope that it will be useful,
 11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
 12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 13  * GNU General Public License for more details.
 14  */
 15 
 16 #include <linux/interrupt.h>
 17 #include <linux/io.h>
 18 #include <linux/gpio.h>
 19 #include <linux/module.h>
 20 #include <linux/delay.h>
 21 #include <linux/platform_device.h>
 22 #include <linux/err.h>
 23 #include <linux/clk.h>
 24 #include <linux/dmaengine.h>
 25 #include <linux/dma-mapping.h>
 26 #include <linux/edma.h>
 27 #include <linux/of.h>
 28 #include <linux/of_device.h>
 29 #include <linux/of_gpio.h>
 30 #include <linux/spi/spi.h>
 31 #include <linux/spi/spi_bitbang.h>
 32 #include <linux/slab.h>
 33 
 34 #include <linux/platform_data/spi-davinci.h>
 35 
 36 #define SPI_NO_RESOURCE         ((resource_size_t)-1)
 37 
 38 #define CS_DEFAULT      0xFF
 39 
 40 #define SPIFMT_PHASE_MASK       BIT(16)
 41 #define SPIFMT_POLARITY_MASK    BIT(17)
 42 #define SPIFMT_DISTIMER_MASK    BIT(18)
 43 #define SPIFMT_SHIFTDIR_MASK    BIT(20)
 44 #define SPIFMT_WAITENA_MASK     BIT(21)
 45 #define SPIFMT_PARITYENA_MASK   BIT(22)
 46 #define SPIFMT_ODD_PARITY_MASK  BIT(23)
 47 #define SPIFMT_WDELAY_MASK      0x3f000000u
 48 #define SPIFMT_WDELAY_SHIFT     24
 49 #define SPIFMT_PRESCALE_SHIFT   8
 50 
 51 /* SPIPC0 */
 52 #define SPIPC0_DIFUN_MASK       BIT(11)         /* MISO */
 53 #define SPIPC0_DOFUN_MASK       BIT(10)         /* MOSI */
 54 #define SPIPC0_CLKFUN_MASK      BIT(9)          /* CLK */
 55 #define SPIPC0_SPIENA_MASK      BIT(8)          /* nREADY */
 56 
 57 #define SPIINT_MASKALL          0x0101035F
 58 #define SPIINT_MASKINT          0x0000015F
 59 #define SPI_INTLVL_1            0x000001FF
 60 #define SPI_INTLVL_0            0x00000000
 61 
 62 /* SPIDAT1 (upper 16 bit defines) */
 63 #define SPIDAT1_CSHOLD_MASK     BIT(12)
 64 #define SPIDAT1_WDEL            BIT(10)
 65 
 66 /* SPIGCR1 */
 67 #define SPIGCR1_CLKMOD_MASK     BIT(1)
 68 #define SPIGCR1_MASTER_MASK     BIT(0)
 69 #define SPIGCR1_POWERDOWN_MASK  BIT(8)
 70 #define SPIGCR1_LOOPBACK_MASK   BIT(16)
 71 #define SPIGCR1_SPIENA_MASK     BIT(24)
 72 
 73 /* SPIBUF */
 74 #define SPIBUF_TXFULL_MASK      BIT(29)
 75 #define SPIBUF_RXEMPTY_MASK     BIT(31)
 76 
 77 /* SPIDELAY */
 78 #define SPIDELAY_C2TDELAY_SHIFT 24
 79 #define SPIDELAY_C2TDELAY_MASK  (0xFF << SPIDELAY_C2TDELAY_SHIFT)
 80 #define SPIDELAY_T2CDELAY_SHIFT 16
 81 #define SPIDELAY_T2CDELAY_MASK  (0xFF << SPIDELAY_T2CDELAY_SHIFT)
 82 #define SPIDELAY_T2EDELAY_SHIFT 8
 83 #define SPIDELAY_T2EDELAY_MASK  (0xFF << SPIDELAY_T2EDELAY_SHIFT)
 84 #define SPIDELAY_C2EDELAY_SHIFT 0
 85 #define SPIDELAY_C2EDELAY_MASK  0xFF
 86 
 87 /* Error Masks */
 88 #define SPIFLG_DLEN_ERR_MASK            BIT(0)
 89 #define SPIFLG_TIMEOUT_MASK             BIT(1)
 90 #define SPIFLG_PARERR_MASK              BIT(2)
 91 #define SPIFLG_DESYNC_MASK              BIT(3)
 92 #define SPIFLG_BITERR_MASK              BIT(4)
 93 #define SPIFLG_OVRRUN_MASK              BIT(6)
 94 #define SPIFLG_BUF_INIT_ACTIVE_MASK     BIT(24)
 95 #define SPIFLG_ERROR_MASK               (SPIFLG_DLEN_ERR_MASK \
 96                                 | SPIFLG_TIMEOUT_MASK | SPIFLG_PARERR_MASK \
 97                                 | SPIFLG_DESYNC_MASK | SPIFLG_BITERR_MASK \
 98                                 | SPIFLG_OVRRUN_MASK)
 99 
100 #define SPIINT_DMA_REQ_EN       BIT(16)
101 
102 /* SPI Controller registers */
103 #define SPIGCR0         0x00
104 #define SPIGCR1         0x04
105 #define SPIINT          0x08
106 #define SPILVL          0x0c
107 #define SPIFLG          0x10
108 #define SPIPC0          0x14
109 #define SPIDAT1         0x3c
110 #define SPIBUF          0x40
111 #define SPIDELAY        0x48
112 #define SPIDEF          0x4c
113 #define SPIFMT0         0x50
114 
115 /* SPI Controller driver's private data. */
116 struct davinci_spi {
117         struct spi_bitbang      bitbang;
118         struct clk              *clk;
119 
120         u8                      version;
121         resource_size_t         pbase;
122         void __iomem            *base;
123         u32                     irq;
124         struct completion       done;
125 
126         const void              *tx;
127         void                    *rx;
128         int                     rcount;
129         int                     wcount;
130 
131         struct dma_chan         *dma_rx;
132         struct dma_chan         *dma_tx;
133         int                     dma_rx_chnum;
134         int                     dma_tx_chnum;
135 
136         struct davinci_spi_platform_data pdata;
137 
138         void                    (*get_rx)(u32 rx_data, struct davinci_spi *);
139         u32                     (*get_tx)(struct davinci_spi *);
140 
141         u8                      *bytes_per_word;
142 
143         u8                      prescaler_limit;
144 };
145 
146 static struct davinci_spi_config davinci_spi_default_cfg;
147 
148 static void davinci_spi_rx_buf_u8(u32 data, struct davinci_spi *dspi)
149 {
150         if (dspi->rx) {
151                 u8 *rx = dspi->rx;
152                 *rx++ = (u8)data;
153                 dspi->rx = rx;
154         }
155 }
156 
157 static void davinci_spi_rx_buf_u16(u32 data, struct davinci_spi *dspi)
158 {
159         if (dspi->rx) {
160                 u16 *rx = dspi->rx;
161                 *rx++ = (u16)data;
162                 dspi->rx = rx;
163         }
164 }
165 
166 static u32 davinci_spi_tx_buf_u8(struct davinci_spi *dspi)
167 {
168         u32 data = 0;
169 
170         if (dspi->tx) {
171                 const u8 *tx = dspi->tx;
172 
173                 data = *tx++;
174                 dspi->tx = tx;
175         }
176         return data;
177 }
178 
179 static u32 davinci_spi_tx_buf_u16(struct davinci_spi *dspi)
180 {
181         u32 data = 0;
182 
183         if (dspi->tx) {
184                 const u16 *tx = dspi->tx;
185 
186                 data = *tx++;
187                 dspi->tx = tx;
188         }
189         return data;
190 }
191 
192 static inline void set_io_bits(void __iomem *addr, u32 bits)
193 {
194         u32 v = ioread32(addr);
195 
196         v |= bits;
197         iowrite32(v, addr);
198 }
199 
200 static inline void clear_io_bits(void __iomem *addr, u32 bits)
201 {
202         u32 v = ioread32(addr);
203 
204         v &= ~bits;
205         iowrite32(v, addr);
206 }
207 
208 /*
209  * Interface to control the chip select signal
210  */
211 static void davinci_spi_chipselect(struct spi_device *spi, int value)
212 {
213         struct davinci_spi *dspi;
214         struct davinci_spi_platform_data *pdata;
215         struct davinci_spi_config *spicfg = spi->controller_data;
216         u8 chip_sel = spi->chip_select;
217         u16 spidat1 = CS_DEFAULT;
218 
219         dspi = spi_master_get_devdata(spi->master);
220         pdata = &dspi->pdata;
221 
222         /* program delay transfers if tx_delay is non zero */
223         if (spicfg->wdelay)
224                 spidat1 |= SPIDAT1_WDEL;
225 
226         /*
227          * Board specific chip select logic decides the polarity and cs
228          * line for the controller
229          */
230         if (spi->cs_gpio >= 0) {
231                 if (value == BITBANG_CS_ACTIVE)
232                         gpio_set_value(spi->cs_gpio, spi->mode & SPI_CS_HIGH);
233                 else
234                         gpio_set_value(spi->cs_gpio,
235                                 !(spi->mode & SPI_CS_HIGH));
236         } else {
237                 if (value == BITBANG_CS_ACTIVE) {
238                         spidat1 |= SPIDAT1_CSHOLD_MASK;
239                         spidat1 &= ~(0x1 << chip_sel);
240                 }
241         }
242 
243         iowrite16(spidat1, dspi->base + SPIDAT1 + 2);
244 }
245 
246 /**
247  * davinci_spi_get_prescale - Calculates the correct prescale value
248  * @maxspeed_hz: the maximum rate the SPI clock can run at
249  *
250  * This function calculates the prescale value that generates a clock rate
251  * less than or equal to the specified maximum.
252  *
253  * Returns: calculated prescale value for easy programming into SPI registers
254  * or negative error number if valid prescalar cannot be updated.
255  */
256 static inline int davinci_spi_get_prescale(struct davinci_spi *dspi,
257                                                         u32 max_speed_hz)
258 {
259         int ret;
260 
261         /* Subtract 1 to match what will be programmed into SPI register. */
262         ret = DIV_ROUND_UP(clk_get_rate(dspi->clk), max_speed_hz) - 1;
263 
264         if (ret < dspi->prescaler_limit || ret > 255)
265                 return -EINVAL;
266 
267         return ret;
268 }
269 
270 /**
271  * davinci_spi_setup_transfer - This functions will determine transfer method
272  * @spi: spi device on which data transfer to be done
273  * @t: spi transfer in which transfer info is filled
274  *
275  * This function determines data transfer method (8/16/32 bit transfer).
276  * It will also set the SPI Clock Control register according to
277  * SPI slave device freq.
278  */
279 static int davinci_spi_setup_transfer(struct spi_device *spi,
280                 struct spi_transfer *t)
281 {
282 
283         struct davinci_spi *dspi;
284         struct davinci_spi_config *spicfg;
285         u8 bits_per_word = 0;
286         u32 hz = 0, spifmt = 0;
287         int prescale;
288 
289         dspi = spi_master_get_devdata(spi->master);
290         spicfg = spi->controller_data;
291         if (!spicfg)
292                 spicfg = &davinci_spi_default_cfg;
293 
294         if (t) {
295                 bits_per_word = t->bits_per_word;
296                 hz = t->speed_hz;
297         }
298 
299         /* if bits_per_word is not set then set it default */
300         if (!bits_per_word)
301                 bits_per_word = spi->bits_per_word;
302 
303         /*
304          * Assign function pointer to appropriate transfer method
305          * 8bit, 16bit or 32bit transfer
306          */
307         if (bits_per_word <= 8) {
308                 dspi->get_rx = davinci_spi_rx_buf_u8;
309                 dspi->get_tx = davinci_spi_tx_buf_u8;
310                 dspi->bytes_per_word[spi->chip_select] = 1;
311         } else {
312                 dspi->get_rx = davinci_spi_rx_buf_u16;
313                 dspi->get_tx = davinci_spi_tx_buf_u16;
314                 dspi->bytes_per_word[spi->chip_select] = 2;
315         }
316 
317         if (!hz)
318                 hz = spi->max_speed_hz;
319 
320         /* Set up SPIFMTn register, unique to this chipselect. */
321 
322         prescale = davinci_spi_get_prescale(dspi, hz);
323         if (prescale < 0)
324                 return prescale;
325 
326         spifmt = (prescale << SPIFMT_PRESCALE_SHIFT) | (bits_per_word & 0x1f);
327 
328         if (spi->mode & SPI_LSB_FIRST)
329                 spifmt |= SPIFMT_SHIFTDIR_MASK;
330 
331         if (spi->mode & SPI_CPOL)
332                 spifmt |= SPIFMT_POLARITY_MASK;
333 
334         if (!(spi->mode & SPI_CPHA))
335                 spifmt |= SPIFMT_PHASE_MASK;
336 
337         /*
338         * Assume wdelay is used only on SPI peripherals that has this field
339         * in SPIFMTn register and when it's configured from board file or DT.
340         */
341         if (spicfg->wdelay)
342                 spifmt |= ((spicfg->wdelay << SPIFMT_WDELAY_SHIFT)
343                                 & SPIFMT_WDELAY_MASK);
344 
345         /*
346          * Version 1 hardware supports two basic SPI modes:
347          *  - Standard SPI mode uses 4 pins, with chipselect
348          *  - 3 pin SPI is a 4 pin variant without CS (SPI_NO_CS)
349          *      (distinct from SPI_3WIRE, with just one data wire;
350          *      or similar variants without MOSI or without MISO)
351          *
352          * Version 2 hardware supports an optional handshaking signal,
353          * so it can support two more modes:
354          *  - 5 pin SPI variant is standard SPI plus SPI_READY
355          *  - 4 pin with enable is (SPI_READY | SPI_NO_CS)
356          */
357 
358         if (dspi->version == SPI_VERSION_2) {
359 
360                 u32 delay = 0;
361 
362                 if (spicfg->odd_parity)
363                         spifmt |= SPIFMT_ODD_PARITY_MASK;
364 
365                 if (spicfg->parity_enable)
366                         spifmt |= SPIFMT_PARITYENA_MASK;
367 
368                 if (spicfg->timer_disable) {
369                         spifmt |= SPIFMT_DISTIMER_MASK;
370                 } else {
371                         delay |= (spicfg->c2tdelay << SPIDELAY_C2TDELAY_SHIFT)
372                                                 & SPIDELAY_C2TDELAY_MASK;
373                         delay |= (spicfg->t2cdelay << SPIDELAY_T2CDELAY_SHIFT)
374                                                 & SPIDELAY_T2CDELAY_MASK;
375                 }
376 
377                 if (spi->mode & SPI_READY) {
378                         spifmt |= SPIFMT_WAITENA_MASK;
379                         delay |= (spicfg->t2edelay << SPIDELAY_T2EDELAY_SHIFT)
380                                                 & SPIDELAY_T2EDELAY_MASK;
381                         delay |= (spicfg->c2edelay << SPIDELAY_C2EDELAY_SHIFT)
382                                                 & SPIDELAY_C2EDELAY_MASK;
383                 }
384 
385                 iowrite32(delay, dspi->base + SPIDELAY);
386         }
387 
388         iowrite32(spifmt, dspi->base + SPIFMT0);
389 
390         return 0;
391 }
392 
393 static int davinci_spi_of_setup(struct spi_device *spi)
394 {
395         struct davinci_spi_config *spicfg = spi->controller_data;
396         struct device_node *np = spi->dev.of_node;
397         u32 prop;
398 
399         if (spicfg == NULL && np) {
400                 spicfg = kzalloc(sizeof(*spicfg), GFP_KERNEL);
401                 if (!spicfg)
402                         return -ENOMEM;
403                 *spicfg = davinci_spi_default_cfg;
404                 /* override with dt configured values */
405                 if (!of_property_read_u32(np, "ti,spi-wdelay", &prop))
406                         spicfg->wdelay = (u8)prop;
407                 spi->controller_data = spicfg;
408         }
409 
410         return 0;
411 }
412 
413 /**
414  * davinci_spi_setup - This functions will set default transfer method
415  * @spi: spi device on which data transfer to be done
416  *
417  * This functions sets the default transfer method.
418  */
419 static int davinci_spi_setup(struct spi_device *spi)
420 {
421         int retval = 0;
422         struct davinci_spi *dspi;
423         struct davinci_spi_platform_data *pdata;
424         struct spi_master *master = spi->master;
425         struct device_node *np = spi->dev.of_node;
426         bool internal_cs = true;
427 
428         dspi = spi_master_get_devdata(spi->master);
429         pdata = &dspi->pdata;
430 
431         if (!(spi->mode & SPI_NO_CS)) {
432                 if (np && (master->cs_gpios != NULL) && (spi->cs_gpio >= 0)) {
433                         retval = gpio_direction_output(
434                                       spi->cs_gpio, !(spi->mode & SPI_CS_HIGH));
435                         internal_cs = false;
436                 } else if (pdata->chip_sel &&
437                            spi->chip_select < pdata->num_chipselect &&
438                            pdata->chip_sel[spi->chip_select] != SPI_INTERN_CS) {
439                         spi->cs_gpio = pdata->chip_sel[spi->chip_select];
440                         retval = gpio_direction_output(
441                                       spi->cs_gpio, !(spi->mode & SPI_CS_HIGH));
442                         internal_cs = false;
443                 }
444 
445                 if (retval) {
446                         dev_err(&spi->dev, "GPIO %d setup failed (%d)\n",
447                                 spi->cs_gpio, retval);
448                         return retval;
449                 }
450 
451                 if (internal_cs)
452                         set_io_bits(dspi->base + SPIPC0, 1 << spi->chip_select);
453         }
454 
455         if (spi->mode & SPI_READY)
456                 set_io_bits(dspi->base + SPIPC0, SPIPC0_SPIENA_MASK);
457 
458         if (spi->mode & SPI_LOOP)
459                 set_io_bits(dspi->base + SPIGCR1, SPIGCR1_LOOPBACK_MASK);
460         else
461                 clear_io_bits(dspi->base + SPIGCR1, SPIGCR1_LOOPBACK_MASK);
462 
463         return davinci_spi_of_setup(spi);
464 }
465 
466 static void davinci_spi_cleanup(struct spi_device *spi)
467 {
468         struct davinci_spi_config *spicfg = spi->controller_data;
469 
470         spi->controller_data = NULL;
471         if (spi->dev.of_node)
472                 kfree(spicfg);
473 }
474 
475 static int davinci_spi_check_error(struct davinci_spi *dspi, int int_status)
476 {
477         struct device *sdev = dspi->bitbang.master->dev.parent;
478 
479         if (int_status & SPIFLG_TIMEOUT_MASK) {
480                 dev_dbg(sdev, "SPI Time-out Error\n");
481                 return -ETIMEDOUT;
482         }
483         if (int_status & SPIFLG_DESYNC_MASK) {
484                 dev_dbg(sdev, "SPI Desynchronization Error\n");
485                 return -EIO;
486         }
487         if (int_status & SPIFLG_BITERR_MASK) {
488                 dev_dbg(sdev, "SPI Bit error\n");
489                 return -EIO;
490         }
491 
492         if (dspi->version == SPI_VERSION_2) {
493                 if (int_status & SPIFLG_DLEN_ERR_MASK) {
494                         dev_dbg(sdev, "SPI Data Length Error\n");
495                         return -EIO;
496                 }
497                 if (int_status & SPIFLG_PARERR_MASK) {
498                         dev_dbg(sdev, "SPI Parity Error\n");
499                         return -EIO;
500                 }
501                 if (int_status & SPIFLG_OVRRUN_MASK) {
502                         dev_dbg(sdev, "SPI Data Overrun error\n");
503                         return -EIO;
504                 }
505                 if (int_status & SPIFLG_BUF_INIT_ACTIVE_MASK) {
506                         dev_dbg(sdev, "SPI Buffer Init Active\n");
507                         return -EBUSY;
508                 }
509         }
510 
511         return 0;
512 }
513 
514 /**
515  * davinci_spi_process_events - check for and handle any SPI controller events
516  * @dspi: the controller data
517  *
518  * This function will check the SPIFLG register and handle any events that are
519  * detected there
520  */
521 static int davinci_spi_process_events(struct davinci_spi *dspi)
522 {
523         u32 buf, status, errors = 0, spidat1;
524 
525         buf = ioread32(dspi->base + SPIBUF);
526 
527         if (dspi->rcount > 0 && !(buf & SPIBUF_RXEMPTY_MASK)) {
528                 dspi->get_rx(buf & 0xFFFF, dspi);
529                 dspi->rcount--;
530         }
531 
532         status = ioread32(dspi->base + SPIFLG);
533 
534         if (unlikely(status & SPIFLG_ERROR_MASK)) {
535                 errors = status & SPIFLG_ERROR_MASK;
536                 goto out;
537         }
538 
539         if (dspi->wcount > 0 && !(buf & SPIBUF_TXFULL_MASK)) {
540                 spidat1 = ioread32(dspi->base + SPIDAT1);
541                 dspi->wcount--;
542                 spidat1 &= ~0xFFFF;
543                 spidat1 |= 0xFFFF & dspi->get_tx(dspi);
544                 iowrite32(spidat1, dspi->base + SPIDAT1);
545         }
546 
547 out:
548         return errors;
549 }
550 
551 static void davinci_spi_dma_rx_callback(void *data)
552 {
553         struct davinci_spi *dspi = (struct davinci_spi *)data;
554 
555         dspi->rcount = 0;
556 
557         if (!dspi->wcount && !dspi->rcount)
558                 complete(&dspi->done);
559 }
560 
561 static void davinci_spi_dma_tx_callback(void *data)
562 {
563         struct davinci_spi *dspi = (struct davinci_spi *)data;
564 
565         dspi->wcount = 0;
566 
567         if (!dspi->wcount && !dspi->rcount)
568                 complete(&dspi->done);
569 }
570 
571 /**
572  * davinci_spi_bufs - functions which will handle transfer data
573  * @spi: spi device on which data transfer to be done
574  * @t: spi transfer in which transfer info is filled
575  *
576  * This function will put data to be transferred into data register
577  * of SPI controller and then wait until the completion will be marked
578  * by the IRQ Handler.
579  */
580 static int davinci_spi_bufs(struct spi_device *spi, struct spi_transfer *t)
581 {
582         struct davinci_spi *dspi;
583         int data_type, ret = -ENOMEM;
584         u32 tx_data, spidat1;
585         u32 errors = 0;
586         struct davinci_spi_config *spicfg;
587         struct davinci_spi_platform_data *pdata;
588         unsigned uninitialized_var(rx_buf_count);
589         void *dummy_buf = NULL;
590         struct scatterlist sg_rx, sg_tx;
591 
592         dspi = spi_master_get_devdata(spi->master);
593         pdata = &dspi->pdata;
594         spicfg = (struct davinci_spi_config *)spi->controller_data;
595         if (!spicfg)
596                 spicfg = &davinci_spi_default_cfg;
597 
598         /* convert len to words based on bits_per_word */
599         data_type = dspi->bytes_per_word[spi->chip_select];
600 
601         dspi->tx = t->tx_buf;
602         dspi->rx = t->rx_buf;
603         dspi->wcount = t->len / data_type;
604         dspi->rcount = dspi->wcount;
605 
606         spidat1 = ioread32(dspi->base + SPIDAT1);
607 
608         clear_io_bits(dspi->base + SPIGCR1, SPIGCR1_POWERDOWN_MASK);
609         set_io_bits(dspi->base + SPIGCR1, SPIGCR1_SPIENA_MASK);
610 
611         reinit_completion(&dspi->done);
612 
613         if (spicfg->io_type == SPI_IO_TYPE_INTR)
614                 set_io_bits(dspi->base + SPIINT, SPIINT_MASKINT);
615 
616         if (spicfg->io_type != SPI_IO_TYPE_DMA) {
617                 /* start the transfer */
618                 dspi->wcount--;
619                 tx_data = dspi->get_tx(dspi);
620                 spidat1 &= 0xFFFF0000;
621                 spidat1 |= tx_data & 0xFFFF;
622                 iowrite32(spidat1, dspi->base + SPIDAT1);
623         } else {
624                 struct dma_slave_config dma_rx_conf = {
625                         .direction = DMA_DEV_TO_MEM,
626                         .src_addr = (unsigned long)dspi->pbase + SPIBUF,
627                         .src_addr_width = data_type,
628                         .src_maxburst = 1,
629                 };
630                 struct dma_slave_config dma_tx_conf = {
631                         .direction = DMA_MEM_TO_DEV,
632                         .dst_addr = (unsigned long)dspi->pbase + SPIDAT1,
633                         .dst_addr_width = data_type,
634                         .dst_maxburst = 1,
635                 };
636                 struct dma_async_tx_descriptor *rxdesc;
637                 struct dma_async_tx_descriptor *txdesc;
638                 void *buf;
639 
640                 dummy_buf = kzalloc(t->len, GFP_KERNEL);
641                 if (!dummy_buf)
642                         goto err_alloc_dummy_buf;
643 
644                 dmaengine_slave_config(dspi->dma_rx, &dma_rx_conf);
645                 dmaengine_slave_config(dspi->dma_tx, &dma_tx_conf);
646 
647                 sg_init_table(&sg_rx, 1);
648                 if (!t->rx_buf)
649                         buf = dummy_buf;
650                 else
651                         buf = t->rx_buf;
652                 t->rx_dma = dma_map_single(&spi->dev, buf,
653                                 t->len, DMA_FROM_DEVICE);
654                 if (!t->rx_dma) {
655                         ret = -EFAULT;
656                         goto err_rx_map;
657                 }
658                 sg_dma_address(&sg_rx) = t->rx_dma;
659                 sg_dma_len(&sg_rx) = t->len;
660 
661                 sg_init_table(&sg_tx, 1);
662                 if (!t->tx_buf)
663                         buf = dummy_buf;
664                 else
665                         buf = (void *)t->tx_buf;
666                 t->tx_dma = dma_map_single(&spi->dev, buf,
667                                 t->len, DMA_TO_DEVICE);
668                 if (!t->tx_dma) {
669                         ret = -EFAULT;
670                         goto err_tx_map;
671                 }
672                 sg_dma_address(&sg_tx) = t->tx_dma;
673                 sg_dma_len(&sg_tx) = t->len;
674 
675                 rxdesc = dmaengine_prep_slave_sg(dspi->dma_rx,
676                                 &sg_rx, 1, DMA_DEV_TO_MEM,
677                                 DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
678                 if (!rxdesc)
679                         goto err_desc;
680 
681                 txdesc = dmaengine_prep_slave_sg(dspi->dma_tx,
682                                 &sg_tx, 1, DMA_MEM_TO_DEV,
683                                 DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
684                 if (!txdesc)
685                         goto err_desc;
686 
687                 rxdesc->callback = davinci_spi_dma_rx_callback;
688                 rxdesc->callback_param = (void *)dspi;
689                 txdesc->callback = davinci_spi_dma_tx_callback;
690                 txdesc->callback_param = (void *)dspi;
691 
692                 if (pdata->cshold_bug)
693                         iowrite16(spidat1 >> 16, dspi->base + SPIDAT1 + 2);
694 
695                 dmaengine_submit(rxdesc);
696                 dmaengine_submit(txdesc);
697 
698                 dma_async_issue_pending(dspi->dma_rx);
699                 dma_async_issue_pending(dspi->dma_tx);
700 
701                 set_io_bits(dspi->base + SPIINT, SPIINT_DMA_REQ_EN);
702         }
703 
704         /* Wait for the transfer to complete */
705         if (spicfg->io_type != SPI_IO_TYPE_POLL) {
706                 wait_for_completion_interruptible(&(dspi->done));
707         } else {
708                 while (dspi->rcount > 0 || dspi->wcount > 0) {
709                         errors = davinci_spi_process_events(dspi);
710                         if (errors)
711                                 break;
712                         cpu_relax();
713                 }
714         }
715 
716         clear_io_bits(dspi->base + SPIINT, SPIINT_MASKALL);
717         if (spicfg->io_type == SPI_IO_TYPE_DMA) {
718                 clear_io_bits(dspi->base + SPIINT, SPIINT_DMA_REQ_EN);
719 
720                 dma_unmap_single(&spi->dev, t->rx_dma,
721                                 t->len, DMA_FROM_DEVICE);
722                 dma_unmap_single(&spi->dev, t->tx_dma,
723                                 t->len, DMA_TO_DEVICE);
724                 kfree(dummy_buf);
725         }
726 
727         clear_io_bits(dspi->base + SPIGCR1, SPIGCR1_SPIENA_MASK);
728         set_io_bits(dspi->base + SPIGCR1, SPIGCR1_POWERDOWN_MASK);
729 
730         /*
731          * Check for bit error, desync error,parity error,timeout error and
732          * receive overflow errors
733          */
734         if (errors) {
735                 ret = davinci_spi_check_error(dspi, errors);
736                 WARN(!ret, "%s: error reported but no error found!\n",
737                                                         dev_name(&spi->dev));
738                 return ret;
739         }
740 
741         if (dspi->rcount != 0 || dspi->wcount != 0) {
742                 dev_err(&spi->dev, "SPI data transfer error\n");
743                 return -EIO;
744         }
745 
746         return t->len;
747 
748 err_desc:
749         dma_unmap_single(&spi->dev, t->tx_dma, t->len, DMA_TO_DEVICE);
750 err_tx_map:
751         dma_unmap_single(&spi->dev, t->rx_dma, t->len, DMA_FROM_DEVICE);
752 err_rx_map:
753         kfree(dummy_buf);
754 err_alloc_dummy_buf:
755         return ret;
756 }
757 
758 /**
759  * dummy_thread_fn - dummy thread function
760  * @irq: IRQ number for this SPI Master
761  * @context_data: structure for SPI Master controller davinci_spi
762  *
763  * This is to satisfy the request_threaded_irq() API so that the irq
764  * handler is called in interrupt context.
765  */
766 static irqreturn_t dummy_thread_fn(s32 irq, void *data)
767 {
768         return IRQ_HANDLED;
769 }
770 
771 /**
772  * davinci_spi_irq - Interrupt handler for SPI Master Controller
773  * @irq: IRQ number for this SPI Master
774  * @context_data: structure for SPI Master controller davinci_spi
775  *
776  * ISR will determine that interrupt arrives either for READ or WRITE command.
777  * According to command it will do the appropriate action. It will check
778  * transfer length and if it is not zero then dispatch transfer command again.
779  * If transfer length is zero then it will indicate the COMPLETION so that
780  * davinci_spi_bufs function can go ahead.
781  */
782 static irqreturn_t davinci_spi_irq(s32 irq, void *data)
783 {
784         struct davinci_spi *dspi = data;
785         int status;
786 
787         status = davinci_spi_process_events(dspi);
788         if (unlikely(status != 0))
789                 clear_io_bits(dspi->base + SPIINT, SPIINT_MASKINT);
790 
791         if ((!dspi->rcount && !dspi->wcount) || status)
792                 complete(&dspi->done);
793 
794         return IRQ_HANDLED;
795 }
796 
797 static int davinci_spi_request_dma(struct davinci_spi *dspi)
798 {
799         dma_cap_mask_t mask;
800         struct device *sdev = dspi->bitbang.master->dev.parent;
801         int r;
802 
803         dma_cap_zero(mask);
804         dma_cap_set(DMA_SLAVE, mask);
805 
806         dspi->dma_rx = dma_request_channel(mask, edma_filter_fn,
807                                            &dspi->dma_rx_chnum);
808         if (!dspi->dma_rx) {
809                 dev_err(sdev, "request RX DMA channel failed\n");
810                 r = -ENODEV;
811                 goto rx_dma_failed;
812         }
813 
814         dspi->dma_tx = dma_request_channel(mask, edma_filter_fn,
815                                            &dspi->dma_tx_chnum);
816         if (!dspi->dma_tx) {
817                 dev_err(sdev, "request TX DMA channel failed\n");
818                 r = -ENODEV;
819                 goto tx_dma_failed;
820         }
821 
822         return 0;
823 
824 tx_dma_failed:
825         dma_release_channel(dspi->dma_rx);
826 rx_dma_failed:
827         return r;
828 }
829 
830 #if defined(CONFIG_OF)
831 
832 /* OF SPI data structure */
833 struct davinci_spi_of_data {
834         u8      version;
835         u8      prescaler_limit;
836 };
837 
838 static const struct davinci_spi_of_data dm6441_spi_data = {
839         .version = SPI_VERSION_1,
840         .prescaler_limit = 2,
841 };
842 
843 static const struct davinci_spi_of_data da830_spi_data = {
844         .version = SPI_VERSION_2,
845         .prescaler_limit = 2,
846 };
847 
848 static const struct davinci_spi_of_data keystone_spi_data = {
849         .version = SPI_VERSION_1,
850         .prescaler_limit = 0,
851 };
852 
853 static const struct of_device_id davinci_spi_of_match[] = {
854         {
855                 .compatible = "ti,dm6441-spi",
856                 .data = &dm6441_spi_data,
857         },
858         {
859                 .compatible = "ti,da830-spi",
860                 .data = &da830_spi_data,
861         },
862         {
863                 .compatible = "ti,keystone-spi",
864                 .data = &keystone_spi_data,
865         },
866         { },
867 };
868 MODULE_DEVICE_TABLE(of, davinci_spi_of_match);
869 
870 /**
871  * spi_davinci_get_pdata - Get platform data from DTS binding
872  * @pdev: ptr to platform data
873  * @dspi: ptr to driver data
874  *
875  * Parses and populates pdata in dspi from device tree bindings.
876  *
877  * NOTE: Not all platform data params are supported currently.
878  */
879 static int spi_davinci_get_pdata(struct platform_device *pdev,
880                         struct davinci_spi *dspi)
881 {
882         struct device_node *node = pdev->dev.of_node;
883         struct davinci_spi_of_data *spi_data;
884         struct davinci_spi_platform_data *pdata;
885         unsigned int num_cs, intr_line = 0;
886         const struct of_device_id *match;
887 
888         pdata = &dspi->pdata;
889 
890         match = of_match_device(davinci_spi_of_match, &pdev->dev);
891         if (!match)
892                 return -ENODEV;
893 
894         spi_data = (struct davinci_spi_of_data *)match->data;
895 
896         pdata->version = spi_data->version;
897         pdata->prescaler_limit = spi_data->prescaler_limit;
898         /*
899          * default num_cs is 1 and all chipsel are internal to the chip
900          * indicated by chip_sel being NULL or cs_gpios being NULL or
901          * set to -ENOENT. num-cs includes internal as well as gpios.
902          * indicated by chip_sel being NULL. GPIO based CS is not
903          * supported yet in DT bindings.
904          */
905         num_cs = 1;
906         of_property_read_u32(node, "num-cs", &num_cs);
907         pdata->num_chipselect = num_cs;
908         of_property_read_u32(node, "ti,davinci-spi-intr-line", &intr_line);
909         pdata->intr_line = intr_line;
910         return 0;
911 }
912 #else
913 static struct davinci_spi_platform_data
914         *spi_davinci_get_pdata(struct platform_device *pdev,
915                 struct davinci_spi *dspi)
916 {
917         return -ENODEV;
918 }
919 #endif
920 
921 /**
922  * davinci_spi_probe - probe function for SPI Master Controller
923  * @pdev: platform_device structure which contains plateform specific data
924  *
925  * According to Linux Device Model this function will be invoked by Linux
926  * with platform_device struct which contains the device specific info.
927  * This function will map the SPI controller's memory, register IRQ,
928  * Reset SPI controller and setting its registers to default value.
929  * It will invoke spi_bitbang_start to create work queue so that client driver
930  * can register transfer method to work queue.
931  */
932 static int davinci_spi_probe(struct platform_device *pdev)
933 {
934         struct spi_master *master;
935         struct davinci_spi *dspi;
936         struct davinci_spi_platform_data *pdata;
937         struct resource *r;
938         resource_size_t dma_rx_chan = SPI_NO_RESOURCE;
939         resource_size_t dma_tx_chan = SPI_NO_RESOURCE;
940         int ret = 0;
941         u32 spipc0;
942 
943         master = spi_alloc_master(&pdev->dev, sizeof(struct davinci_spi));
944         if (master == NULL) {
945                 ret = -ENOMEM;
946                 goto err;
947         }
948 
949         platform_set_drvdata(pdev, master);
950 
951         dspi = spi_master_get_devdata(master);
952 
953         if (dev_get_platdata(&pdev->dev)) {
954                 pdata = dev_get_platdata(&pdev->dev);
955                 dspi->pdata = *pdata;
956         } else {
957                 /* update dspi pdata with that from the DT */
958                 ret = spi_davinci_get_pdata(pdev, dspi);
959                 if (ret < 0)
960                         goto free_master;
961         }
962 
963         /* pdata in dspi is now updated and point pdata to that */
964         pdata = &dspi->pdata;
965 
966         dspi->bytes_per_word = devm_kzalloc(&pdev->dev,
967                                             sizeof(*dspi->bytes_per_word) *
968                                             pdata->num_chipselect, GFP_KERNEL);
969         if (dspi->bytes_per_word == NULL) {
970                 ret = -ENOMEM;
971                 goto free_master;
972         }
973 
974         r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
975         if (r == NULL) {
976                 ret = -ENOENT;
977                 goto free_master;
978         }
979 
980         dspi->pbase = r->start;
981 
982         dspi->base = devm_ioremap_resource(&pdev->dev, r);
983         if (IS_ERR(dspi->base)) {
984                 ret = PTR_ERR(dspi->base);
985                 goto free_master;
986         }
987 
988         ret = platform_get_irq(pdev, 0);
989         if (ret == 0)
990                 ret = -EINVAL;
991         if (ret < 0)
992                 goto free_master;
993         dspi->irq = ret;
994 
995         ret = devm_request_threaded_irq(&pdev->dev, dspi->irq, davinci_spi_irq,
996                                 dummy_thread_fn, 0, dev_name(&pdev->dev), dspi);
997         if (ret)
998                 goto free_master;
999 
1000         dspi->bitbang.master = master;
1001 
1002         dspi->clk = devm_clk_get(&pdev->dev, NULL);
1003         if (IS_ERR(dspi->clk)) {
1004                 ret = -ENODEV;
1005                 goto free_master;
1006         }
1007         clk_prepare_enable(dspi->clk);
1008 
1009         master->dev.of_node = pdev->dev.of_node;
1010         master->bus_num = pdev->id;
1011         master->num_chipselect = pdata->num_chipselect;
1012         master->bits_per_word_mask = SPI_BPW_RANGE_MASK(2, 16);
1013         master->setup = davinci_spi_setup;
1014         master->cleanup = davinci_spi_cleanup;
1015 
1016         dspi->bitbang.chipselect = davinci_spi_chipselect;
1017         dspi->bitbang.setup_transfer = davinci_spi_setup_transfer;
1018         dspi->prescaler_limit = pdata->prescaler_limit;
1019         dspi->version = pdata->version;
1020 
1021         dspi->bitbang.flags = SPI_NO_CS | SPI_LSB_FIRST | SPI_LOOP;
1022         if (dspi->version == SPI_VERSION_2)
1023                 dspi->bitbang.flags |= SPI_READY;
1024 
1025         if (pdev->dev.of_node) {
1026                 int i;
1027 
1028                 for (i = 0; i < pdata->num_chipselect; i++) {
1029                         int cs_gpio = of_get_named_gpio(pdev->dev.of_node,
1030                                                         "cs-gpios", i);
1031 
1032                         if (cs_gpio == -EPROBE_DEFER) {
1033                                 ret = cs_gpio;
1034                                 goto free_clk;
1035                         }
1036 
1037                         if (gpio_is_valid(cs_gpio)) {
1038                                 ret = devm_gpio_request(&pdev->dev, cs_gpio,
1039                                                         dev_name(&pdev->dev));
1040                                 if (ret)
1041                                         goto free_clk;
1042                         }
1043                 }
1044         }
1045 
1046         r = platform_get_resource(pdev, IORESOURCE_DMA, 0);
1047         if (r)
1048                 dma_rx_chan = r->start;
1049         r = platform_get_resource(pdev, IORESOURCE_DMA, 1);
1050         if (r)
1051                 dma_tx_chan = r->start;
1052 
1053         dspi->bitbang.txrx_bufs = davinci_spi_bufs;
1054         if (dma_rx_chan != SPI_NO_RESOURCE &&
1055             dma_tx_chan != SPI_NO_RESOURCE) {
1056                 dspi->dma_rx_chnum = dma_rx_chan;
1057                 dspi->dma_tx_chnum = dma_tx_chan;
1058 
1059                 ret = davinci_spi_request_dma(dspi);
1060                 if (ret)
1061                         goto free_clk;
1062 
1063                 dev_info(&pdev->dev, "DMA: supported\n");
1064                 dev_info(&pdev->dev, "DMA: RX channel: %pa, TX channel: %pa, event queue: %d\n",
1065                                 &dma_rx_chan, &dma_tx_chan,
1066                                 pdata->dma_event_q);
1067         }
1068 
1069         dspi->get_rx = davinci_spi_rx_buf_u8;
1070         dspi->get_tx = davinci_spi_tx_buf_u8;
1071 
1072         init_completion(&dspi->done);
1073 
1074         /* Reset In/OUT SPI module */
1075         iowrite32(0, dspi->base + SPIGCR0);
1076         udelay(100);
1077         iowrite32(1, dspi->base + SPIGCR0);
1078 
1079         /* Set up SPIPC0.  CS and ENA init is done in davinci_spi_setup */
1080         spipc0 = SPIPC0_DIFUN_MASK | SPIPC0_DOFUN_MASK | SPIPC0_CLKFUN_MASK;
1081         iowrite32(spipc0, dspi->base + SPIPC0);
1082 
1083         if (pdata->intr_line)
1084                 iowrite32(SPI_INTLVL_1, dspi->base + SPILVL);
1085         else
1086                 iowrite32(SPI_INTLVL_0, dspi->base + SPILVL);
1087 
1088         iowrite32(CS_DEFAULT, dspi->base + SPIDEF);
1089 
1090         /* master mode default */
1091         set_io_bits(dspi->base + SPIGCR1, SPIGCR1_CLKMOD_MASK);
1092         set_io_bits(dspi->base + SPIGCR1, SPIGCR1_MASTER_MASK);
1093         set_io_bits(dspi->base + SPIGCR1, SPIGCR1_POWERDOWN_MASK);
1094 
1095         ret = spi_bitbang_start(&dspi->bitbang);
1096         if (ret)
1097                 goto free_dma;
1098 
1099         dev_info(&pdev->dev, "Controller at 0x%p\n", dspi->base);
1100 
1101         return ret;
1102 
1103 free_dma:
1104         dma_release_channel(dspi->dma_rx);
1105         dma_release_channel(dspi->dma_tx);
1106 free_clk:
1107         clk_disable_unprepare(dspi->clk);
1108 free_master:
1109         spi_master_put(master);
1110 err:
1111         return ret;
1112 }
1113 
1114 /**
1115  * davinci_spi_remove - remove function for SPI Master Controller
1116  * @pdev: platform_device structure which contains plateform specific data
1117  *
1118  * This function will do the reverse action of davinci_spi_probe function
1119  * It will free the IRQ and SPI controller's memory region.
1120  * It will also call spi_bitbang_stop to destroy the work queue which was
1121  * created by spi_bitbang_start.
1122  */
1123 static int davinci_spi_remove(struct platform_device *pdev)
1124 {
1125         struct davinci_spi *dspi;
1126         struct spi_master *master;
1127 
1128         master = platform_get_drvdata(pdev);
1129         dspi = spi_master_get_devdata(master);
1130 
1131         spi_bitbang_stop(&dspi->bitbang);
1132 
1133         clk_disable_unprepare(dspi->clk);
1134         spi_master_put(master);
1135 
1136         return 0;
1137 }
1138 
1139 static struct platform_driver davinci_spi_driver = {
1140         .driver = {
1141                 .name = "spi_davinci",
1142                 .of_match_table = of_match_ptr(davinci_spi_of_match),
1143         },
1144         .probe = davinci_spi_probe,
1145         .remove = davinci_spi_remove,
1146 };
1147 module_platform_driver(davinci_spi_driver);
1148 
1149 MODULE_DESCRIPTION("TI DaVinci SPI Master Controller Driver");
1150 MODULE_LICENSE("GPL");
1151 

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