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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * SPI_PPC4XX SPI controller driver.
4 *
5 * Copyright (C) 2007 Gary Jennejohn <garyj@denx.de>
6 * Copyright 2008 Stefan Roese <sr@denx.de>, DENX Software Engineering
7 * Copyright 2009 Harris Corporation, Steven A. Falco <sfalco@harris.com>
8 *
9 * Based in part on drivers/spi/spi_s3c24xx.c
10 *
11 * Copyright (c) 2006 Ben Dooks
12 * Copyright (c) 2006 Simtec Electronics
13 * Ben Dooks <ben@simtec.co.uk>
14 */
15
16/*
17 * The PPC4xx SPI controller has no FIFO so each sent/received byte will
18 * generate an interrupt to the CPU. This can cause high CPU utilization.
19 * This driver allows platforms to reduce the interrupt load on the CPU
20 * during SPI transfers by setting max_speed_hz via the device tree.
21 */
22
23#include <linux/module.h>
24#include <linux/sched.h>
25#include <linux/slab.h>
26#include <linux/errno.h>
27#include <linux/wait.h>
28#include <linux/of_address.h>
29#include <linux/of_irq.h>
30#include <linux/of_platform.h>
31#include <linux/interrupt.h>
32#include <linux/delay.h>
33
34#include <linux/spi/spi.h>
35#include <linux/spi/spi_bitbang.h>
36
37#include <linux/io.h>
38#include <asm/dcr.h>
39#include <asm/dcr-regs.h>
40
41/* bits in mode register - bit 0 is MSb */
42
43/*
44 * SPI_PPC4XX_MODE_SCP = 0 means "data latched on trailing edge of clock"
45 * SPI_PPC4XX_MODE_SCP = 1 means "data latched on leading edge of clock"
46 * Note: This is the inverse of CPHA.
47 */
48#define SPI_PPC4XX_MODE_SCP (0x80 >> 3)
49
50/* SPI_PPC4XX_MODE_SPE = 1 means "port enabled" */
51#define SPI_PPC4XX_MODE_SPE (0x80 >> 4)
52
53/*
54 * SPI_PPC4XX_MODE_RD = 0 means "MSB first" - this is the normal mode
55 * SPI_PPC4XX_MODE_RD = 1 means "LSB first" - this is bit-reversed mode
56 * Note: This is identical to SPI_LSB_FIRST.
57 */
58#define SPI_PPC4XX_MODE_RD (0x80 >> 5)
59
60/*
61 * SPI_PPC4XX_MODE_CI = 0 means "clock idles low"
62 * SPI_PPC4XX_MODE_CI = 1 means "clock idles high"
63 * Note: This is identical to CPOL.
64 */
65#define SPI_PPC4XX_MODE_CI (0x80 >> 6)
66
67/*
68 * SPI_PPC4XX_MODE_IL = 0 means "loopback disable"
69 * SPI_PPC4XX_MODE_IL = 1 means "loopback enable"
70 */
71#define SPI_PPC4XX_MODE_IL (0x80 >> 7)
72
73/* bits in control register */
74/* starts a transfer when set */
75#define SPI_PPC4XX_CR_STR (0x80 >> 7)
76
77/* bits in status register */
78/* port is busy with a transfer */
79#define SPI_PPC4XX_SR_BSY (0x80 >> 6)
80/* RxD ready */
81#define SPI_PPC4XX_SR_RBR (0x80 >> 7)
82
83/* clock settings (SCP and CI) for various SPI modes */
84#define SPI_CLK_MODE0 (SPI_PPC4XX_MODE_SCP | 0)
85#define SPI_CLK_MODE1 (0 | 0)
86#define SPI_CLK_MODE2 (SPI_PPC4XX_MODE_SCP | SPI_PPC4XX_MODE_CI)
87#define SPI_CLK_MODE3 (0 | SPI_PPC4XX_MODE_CI)
88
89#define DRIVER_NAME "spi_ppc4xx_of"
90
91struct spi_ppc4xx_regs {
92 u8 mode;
93 u8 rxd;
94 u8 txd;
95 u8 cr;
96 u8 sr;
97 u8 dummy;
98 /*
99 * Clock divisor modulus register
100 * This uses the following formula:
101 * SCPClkOut = OPBCLK/(4(CDM + 1))
102 * or
103 * CDM = (OPBCLK/4*SCPClkOut) - 1
104 * bit 0 is the MSb!
105 */
106 u8 cdm;
107};
108
109/* SPI Controller driver's private data. */
110struct ppc4xx_spi {
111 /* bitbang has to be first */
112 struct spi_bitbang bitbang;
113 struct completion done;
114
115 u64 mapbase;
116 u64 mapsize;
117 int irqnum;
118 /* need this to set the SPI clock */
119 unsigned int opb_freq;
120
121 /* for transfers */
122 int len;
123 int count;
124 /* data buffers */
125 const unsigned char *tx;
126 unsigned char *rx;
127
128 struct spi_ppc4xx_regs __iomem *regs; /* pointer to the registers */
129 struct spi_master *master;
130 struct device *dev;
131};
132
133/* need this so we can set the clock in the chipselect routine */
134struct spi_ppc4xx_cs {
135 u8 mode;
136};
137
138static int spi_ppc4xx_txrx(struct spi_device *spi, struct spi_transfer *t)
139{
140 struct ppc4xx_spi *hw;
141 u8 data;
142
143 dev_dbg(&spi->dev, "txrx: tx %p, rx %p, len %d\n",
144 t->tx_buf, t->rx_buf, t->len);
145
146 hw = spi_master_get_devdata(spi->master);
147
148 hw->tx = t->tx_buf;
149 hw->rx = t->rx_buf;
150 hw->len = t->len;
151 hw->count = 0;
152
153 /* send the first byte */
154 data = hw->tx ? hw->tx[0] : 0;
155 out_8(&hw->regs->txd, data);
156 out_8(&hw->regs->cr, SPI_PPC4XX_CR_STR);
157 wait_for_completion(&hw->done);
158
159 return hw->count;
160}
161
162static int spi_ppc4xx_setupxfer(struct spi_device *spi, struct spi_transfer *t)
163{
164 struct ppc4xx_spi *hw = spi_master_get_devdata(spi->master);
165 struct spi_ppc4xx_cs *cs = spi->controller_state;
166 int scr;
167 u8 cdm = 0;
168 u32 speed;
169 u8 bits_per_word;
170
171 /* Start with the generic configuration for this device. */
172 bits_per_word = spi->bits_per_word;
173 speed = spi->max_speed_hz;
174
175 /*
176 * Modify the configuration if the transfer overrides it. Do not allow
177 * the transfer to overwrite the generic configuration with zeros.
178 */
179 if (t) {
180 if (t->bits_per_word)
181 bits_per_word = t->bits_per_word;
182
183 if (t->speed_hz)
184 speed = min(t->speed_hz, spi->max_speed_hz);
185 }
186
187 if (!speed || (speed > spi->max_speed_hz)) {
188 dev_err(&spi->dev, "invalid speed_hz (%d)\n", speed);
189 return -EINVAL;
190 }
191
192 /* Write new configuration */
193 out_8(&hw->regs->mode, cs->mode);
194
195 /* Set the clock */
196 /* opb_freq was already divided by 4 */
197 scr = (hw->opb_freq / speed) - 1;
198 if (scr > 0)
199 cdm = min(scr, 0xff);
200
201 dev_dbg(&spi->dev, "setting pre-scaler to %d (hz %d)\n", cdm, speed);
202
203 if (in_8(&hw->regs->cdm) != cdm)
204 out_8(&hw->regs->cdm, cdm);
205
206 mutex_lock(&hw->bitbang.lock);
207 if (!hw->bitbang.busy) {
208 hw->bitbang.chipselect(spi, BITBANG_CS_INACTIVE);
209 /* Need to ndelay here? */
210 }
211 mutex_unlock(&hw->bitbang.lock);
212
213 return 0;
214}
215
216static int spi_ppc4xx_setup(struct spi_device *spi)
217{
218 struct spi_ppc4xx_cs *cs = spi->controller_state;
219
220 if (!spi->max_speed_hz) {
221 dev_err(&spi->dev, "invalid max_speed_hz (must be non-zero)\n");
222 return -EINVAL;
223 }
224
225 if (cs == NULL) {
226 cs = kzalloc(sizeof(*cs), GFP_KERNEL);
227 if (!cs)
228 return -ENOMEM;
229 spi->controller_state = cs;
230 }
231
232 /*
233 * We set all bits of the SPI0_MODE register, so,
234 * no need to read-modify-write
235 */
236 cs->mode = SPI_PPC4XX_MODE_SPE;
237
238 switch (spi->mode & SPI_MODE_X_MASK) {
239 case SPI_MODE_0:
240 cs->mode |= SPI_CLK_MODE0;
241 break;
242 case SPI_MODE_1:
243 cs->mode |= SPI_CLK_MODE1;
244 break;
245 case SPI_MODE_2:
246 cs->mode |= SPI_CLK_MODE2;
247 break;
248 case SPI_MODE_3:
249 cs->mode |= SPI_CLK_MODE3;
250 break;
251 }
252
253 if (spi->mode & SPI_LSB_FIRST)
254 cs->mode |= SPI_PPC4XX_MODE_RD;
255
256 return 0;
257}
258
259static irqreturn_t spi_ppc4xx_int(int irq, void *dev_id)
260{
261 struct ppc4xx_spi *hw;
262 u8 status;
263 u8 data;
264 unsigned int count;
265
266 hw = (struct ppc4xx_spi *)dev_id;
267
268 status = in_8(&hw->regs->sr);
269 if (!status)
270 return IRQ_NONE;
271
272 /*
273 * BSY de-asserts one cycle after the transfer is complete. The
274 * interrupt is asserted after the transfer is complete. The exact
275 * relationship is not documented, hence this code.
276 */
277
278 if (unlikely(status & SPI_PPC4XX_SR_BSY)) {
279 u8 lstatus;
280 int cnt = 0;
281
282 dev_dbg(hw->dev, "got interrupt but spi still busy?\n");
283 do {
284 ndelay(10);
285 lstatus = in_8(&hw->regs->sr);
286 } while (++cnt < 100 && lstatus & SPI_PPC4XX_SR_BSY);
287
288 if (cnt >= 100) {
289 dev_err(hw->dev, "busywait: too many loops!\n");
290 complete(&hw->done);
291 return IRQ_HANDLED;
292 } else {
293 /* status is always 1 (RBR) here */
294 status = in_8(&hw->regs->sr);
295 dev_dbg(hw->dev, "loops %d status %x\n", cnt, status);
296 }
297 }
298
299 count = hw->count;
300 hw->count++;
301
302 /* RBR triggered this interrupt. Therefore, data must be ready. */
303 data = in_8(&hw->regs->rxd);
304 if (hw->rx)
305 hw->rx[count] = data;
306
307 count++;
308
309 if (count < hw->len) {
310 data = hw->tx ? hw->tx[count] : 0;
311 out_8(&hw->regs->txd, data);
312 out_8(&hw->regs->cr, SPI_PPC4XX_CR_STR);
313 } else {
314 complete(&hw->done);
315 }
316
317 return IRQ_HANDLED;
318}
319
320static void spi_ppc4xx_cleanup(struct spi_device *spi)
321{
322 kfree(spi->controller_state);
323}
324
325static void spi_ppc4xx_enable(struct ppc4xx_spi *hw)
326{
327 /*
328 * On all 4xx PPC's the SPI bus is shared/multiplexed with
329 * the 2nd I2C bus. We need to enable the SPI bus before
330 * using it.
331 */
332
333 /* need to clear bit 14 to enable SPC */
334 dcri_clrset(SDR0, SDR0_PFC1, 0x80000000 >> 14, 0);
335}
336
337/*
338 * platform_device layer stuff...
339 */
340static int spi_ppc4xx_of_probe(struct platform_device *op)
341{
342 struct ppc4xx_spi *hw;
343 struct spi_master *master;
344 struct spi_bitbang *bbp;
345 struct resource resource;
346 struct device_node *np = op->dev.of_node;
347 struct device *dev = &op->dev;
348 struct device_node *opbnp;
349 int ret;
350 const unsigned int *clk;
351
352 master = spi_alloc_master(dev, sizeof(*hw));
353 if (master == NULL)
354 return -ENOMEM;
355 master->dev.of_node = np;
356 platform_set_drvdata(op, master);
357 hw = spi_master_get_devdata(master);
358 hw->master = master;
359 hw->dev = dev;
360
361 init_completion(&hw->done);
362
363 /* Setup the state for the bitbang driver */
364 bbp = &hw->bitbang;
365 bbp->master = hw->master;
366 bbp->setup_transfer = spi_ppc4xx_setupxfer;
367 bbp->txrx_bufs = spi_ppc4xx_txrx;
368 bbp->use_dma = 0;
369 bbp->master->setup = spi_ppc4xx_setup;
370 bbp->master->cleanup = spi_ppc4xx_cleanup;
371 bbp->master->bits_per_word_mask = SPI_BPW_MASK(8);
372 bbp->master->use_gpio_descriptors = true;
373 /*
374 * The SPI core will count the number of GPIO descriptors to figure
375 * out the number of chip selects available on the platform.
376 */
377 bbp->master->num_chipselect = 0;
378
379 /* the spi->mode bits understood by this driver: */
380 bbp->master->mode_bits =
381 SPI_CPHA | SPI_CPOL | SPI_CS_HIGH | SPI_LSB_FIRST;
382
383 /* Get the clock for the OPB */
384 opbnp = of_find_compatible_node(NULL, NULL, "ibm,opb");
385 if (opbnp == NULL) {
386 dev_err(dev, "OPB: cannot find node\n");
387 ret = -ENODEV;
388 goto free_master;
389 }
390 /* Get the clock (Hz) for the OPB */
391 clk = of_get_property(opbnp, "clock-frequency", NULL);
392 if (clk == NULL) {
393 dev_err(dev, "OPB: no clock-frequency property set\n");
394 of_node_put(opbnp);
395 ret = -ENODEV;
396 goto free_master;
397 }
398 hw->opb_freq = *clk;
399 hw->opb_freq >>= 2;
400 of_node_put(opbnp);
401
402 ret = of_address_to_resource(np, 0, &resource);
403 if (ret) {
404 dev_err(dev, "error while parsing device node resource\n");
405 goto free_master;
406 }
407 hw->mapbase = resource.start;
408 hw->mapsize = resource_size(&resource);
409
410 /* Sanity check */
411 if (hw->mapsize < sizeof(struct spi_ppc4xx_regs)) {
412 dev_err(dev, "too small to map registers\n");
413 ret = -EINVAL;
414 goto free_master;
415 }
416
417 /* Request IRQ */
418 hw->irqnum = irq_of_parse_and_map(np, 0);
419 ret = request_irq(hw->irqnum, spi_ppc4xx_int,
420 0, "spi_ppc4xx_of", (void *)hw);
421 if (ret) {
422 dev_err(dev, "unable to allocate interrupt\n");
423 goto free_master;
424 }
425
426 if (!request_mem_region(hw->mapbase, hw->mapsize, DRIVER_NAME)) {
427 dev_err(dev, "resource unavailable\n");
428 ret = -EBUSY;
429 goto request_mem_error;
430 }
431
432 hw->regs = ioremap(hw->mapbase, sizeof(struct spi_ppc4xx_regs));
433
434 if (!hw->regs) {
435 dev_err(dev, "unable to memory map registers\n");
436 ret = -ENXIO;
437 goto map_io_error;
438 }
439
440 spi_ppc4xx_enable(hw);
441
442 /* Finally register our spi controller */
443 dev->dma_mask = 0;
444 ret = spi_bitbang_start(bbp);
445 if (ret) {
446 dev_err(dev, "failed to register SPI master\n");
447 goto unmap_regs;
448 }
449
450 dev_info(dev, "driver initialized\n");
451
452 return 0;
453
454unmap_regs:
455 iounmap(hw->regs);
456map_io_error:
457 release_mem_region(hw->mapbase, hw->mapsize);
458request_mem_error:
459 free_irq(hw->irqnum, hw);
460free_master:
461 spi_master_put(master);
462
463 dev_err(dev, "initialization failed\n");
464 return ret;
465}
466
467static int spi_ppc4xx_of_remove(struct platform_device *op)
468{
469 struct spi_master *master = platform_get_drvdata(op);
470 struct ppc4xx_spi *hw = spi_master_get_devdata(master);
471
472 spi_bitbang_stop(&hw->bitbang);
473 release_mem_region(hw->mapbase, hw->mapsize);
474 free_irq(hw->irqnum, hw);
475 iounmap(hw->regs);
476 spi_master_put(master);
477 return 0;
478}
479
480static const struct of_device_id spi_ppc4xx_of_match[] = {
481 { .compatible = "ibm,ppc4xx-spi", },
482 {},
483};
484
485MODULE_DEVICE_TABLE(of, spi_ppc4xx_of_match);
486
487static struct platform_driver spi_ppc4xx_of_driver = {
488 .probe = spi_ppc4xx_of_probe,
489 .remove = spi_ppc4xx_of_remove,
490 .driver = {
491 .name = DRIVER_NAME,
492 .of_match_table = spi_ppc4xx_of_match,
493 },
494};
495module_platform_driver(spi_ppc4xx_of_driver);
496
497MODULE_AUTHOR("Gary Jennejohn & Stefan Roese");
498MODULE_DESCRIPTION("Simple PPC4xx SPI Driver");
499MODULE_LICENSE("GPL");
1/*
2 * SPI_PPC4XX SPI controller driver.
3 *
4 * Copyright (C) 2007 Gary Jennejohn <garyj@denx.de>
5 * Copyright 2008 Stefan Roese <sr@denx.de>, DENX Software Engineering
6 * Copyright 2009 Harris Corporation, Steven A. Falco <sfalco@harris.com>
7 *
8 * Based in part on drivers/spi/spi_s3c24xx.c
9 *
10 * Copyright (c) 2006 Ben Dooks
11 * Copyright (c) 2006 Simtec Electronics
12 * Ben Dooks <ben@simtec.co.uk>
13 *
14 * This program is free software; you can redistribute it and/or modify it
15 * under the terms of the GNU General Public License version 2 as published
16 * by the Free Software Foundation.
17 */
18
19/*
20 * The PPC4xx SPI controller has no FIFO so each sent/received byte will
21 * generate an interrupt to the CPU. This can cause high CPU utilization.
22 * This driver allows platforms to reduce the interrupt load on the CPU
23 * during SPI transfers by setting max_speed_hz via the device tree.
24 */
25
26#include <linux/module.h>
27#include <linux/init.h>
28#include <linux/sched.h>
29#include <linux/slab.h>
30#include <linux/errno.h>
31#include <linux/wait.h>
32#include <linux/of_platform.h>
33#include <linux/of_spi.h>
34#include <linux/of_gpio.h>
35#include <linux/interrupt.h>
36#include <linux/delay.h>
37
38#include <linux/gpio.h>
39#include <linux/spi/spi.h>
40#include <linux/spi/spi_bitbang.h>
41
42#include <asm/io.h>
43#include <asm/dcr.h>
44#include <asm/dcr-regs.h>
45
46/* bits in mode register - bit 0 is MSb */
47
48/*
49 * SPI_PPC4XX_MODE_SCP = 0 means "data latched on trailing edge of clock"
50 * SPI_PPC4XX_MODE_SCP = 1 means "data latched on leading edge of clock"
51 * Note: This is the inverse of CPHA.
52 */
53#define SPI_PPC4XX_MODE_SCP (0x80 >> 3)
54
55/* SPI_PPC4XX_MODE_SPE = 1 means "port enabled" */
56#define SPI_PPC4XX_MODE_SPE (0x80 >> 4)
57
58/*
59 * SPI_PPC4XX_MODE_RD = 0 means "MSB first" - this is the normal mode
60 * SPI_PPC4XX_MODE_RD = 1 means "LSB first" - this is bit-reversed mode
61 * Note: This is identical to SPI_LSB_FIRST.
62 */
63#define SPI_PPC4XX_MODE_RD (0x80 >> 5)
64
65/*
66 * SPI_PPC4XX_MODE_CI = 0 means "clock idles low"
67 * SPI_PPC4XX_MODE_CI = 1 means "clock idles high"
68 * Note: This is identical to CPOL.
69 */
70#define SPI_PPC4XX_MODE_CI (0x80 >> 6)
71
72/*
73 * SPI_PPC4XX_MODE_IL = 0 means "loopback disable"
74 * SPI_PPC4XX_MODE_IL = 1 means "loopback enable"
75 */
76#define SPI_PPC4XX_MODE_IL (0x80 >> 7)
77
78/* bits in control register */
79/* starts a transfer when set */
80#define SPI_PPC4XX_CR_STR (0x80 >> 7)
81
82/* bits in status register */
83/* port is busy with a transfer */
84#define SPI_PPC4XX_SR_BSY (0x80 >> 6)
85/* RxD ready */
86#define SPI_PPC4XX_SR_RBR (0x80 >> 7)
87
88/* clock settings (SCP and CI) for various SPI modes */
89#define SPI_CLK_MODE0 (SPI_PPC4XX_MODE_SCP | 0)
90#define SPI_CLK_MODE1 (0 | 0)
91#define SPI_CLK_MODE2 (SPI_PPC4XX_MODE_SCP | SPI_PPC4XX_MODE_CI)
92#define SPI_CLK_MODE3 (0 | SPI_PPC4XX_MODE_CI)
93
94#define DRIVER_NAME "spi_ppc4xx_of"
95
96struct spi_ppc4xx_regs {
97 u8 mode;
98 u8 rxd;
99 u8 txd;
100 u8 cr;
101 u8 sr;
102 u8 dummy;
103 /*
104 * Clock divisor modulus register
105 * This uses the follwing formula:
106 * SCPClkOut = OPBCLK/(4(CDM + 1))
107 * or
108 * CDM = (OPBCLK/4*SCPClkOut) - 1
109 * bit 0 is the MSb!
110 */
111 u8 cdm;
112};
113
114/* SPI Controller driver's private data. */
115struct ppc4xx_spi {
116 /* bitbang has to be first */
117 struct spi_bitbang bitbang;
118 struct completion done;
119
120 u64 mapbase;
121 u64 mapsize;
122 int irqnum;
123 /* need this to set the SPI clock */
124 unsigned int opb_freq;
125
126 /* for transfers */
127 int len;
128 int count;
129 /* data buffers */
130 const unsigned char *tx;
131 unsigned char *rx;
132
133 int *gpios;
134
135 struct spi_ppc4xx_regs __iomem *regs; /* pointer to the registers */
136 struct spi_master *master;
137 struct device *dev;
138};
139
140/* need this so we can set the clock in the chipselect routine */
141struct spi_ppc4xx_cs {
142 u8 mode;
143};
144
145static int spi_ppc4xx_txrx(struct spi_device *spi, struct spi_transfer *t)
146{
147 struct ppc4xx_spi *hw;
148 u8 data;
149
150 dev_dbg(&spi->dev, "txrx: tx %p, rx %p, len %d\n",
151 t->tx_buf, t->rx_buf, t->len);
152
153 hw = spi_master_get_devdata(spi->master);
154
155 hw->tx = t->tx_buf;
156 hw->rx = t->rx_buf;
157 hw->len = t->len;
158 hw->count = 0;
159
160 /* send the first byte */
161 data = hw->tx ? hw->tx[0] : 0;
162 out_8(&hw->regs->txd, data);
163 out_8(&hw->regs->cr, SPI_PPC4XX_CR_STR);
164 wait_for_completion(&hw->done);
165
166 return hw->count;
167}
168
169static int spi_ppc4xx_setupxfer(struct spi_device *spi, struct spi_transfer *t)
170{
171 struct ppc4xx_spi *hw = spi_master_get_devdata(spi->master);
172 struct spi_ppc4xx_cs *cs = spi->controller_state;
173 int scr;
174 u8 cdm = 0;
175 u32 speed;
176 u8 bits_per_word;
177
178 /* Start with the generic configuration for this device. */
179 bits_per_word = spi->bits_per_word;
180 speed = spi->max_speed_hz;
181
182 /*
183 * Modify the configuration if the transfer overrides it. Do not allow
184 * the transfer to overwrite the generic configuration with zeros.
185 */
186 if (t) {
187 if (t->bits_per_word)
188 bits_per_word = t->bits_per_word;
189
190 if (t->speed_hz)
191 speed = min(t->speed_hz, spi->max_speed_hz);
192 }
193
194 if (bits_per_word != 8) {
195 dev_err(&spi->dev, "invalid bits-per-word (%d)\n",
196 bits_per_word);
197 return -EINVAL;
198 }
199
200 if (!speed || (speed > spi->max_speed_hz)) {
201 dev_err(&spi->dev, "invalid speed_hz (%d)\n", speed);
202 return -EINVAL;
203 }
204
205 /* Write new configration */
206 out_8(&hw->regs->mode, cs->mode);
207
208 /* Set the clock */
209 /* opb_freq was already divided by 4 */
210 scr = (hw->opb_freq / speed) - 1;
211 if (scr > 0)
212 cdm = min(scr, 0xff);
213
214 dev_dbg(&spi->dev, "setting pre-scaler to %d (hz %d)\n", cdm, speed);
215
216 if (in_8(&hw->regs->cdm) != cdm)
217 out_8(&hw->regs->cdm, cdm);
218
219 spin_lock(&hw->bitbang.lock);
220 if (!hw->bitbang.busy) {
221 hw->bitbang.chipselect(spi, BITBANG_CS_INACTIVE);
222 /* Need to ndelay here? */
223 }
224 spin_unlock(&hw->bitbang.lock);
225
226 return 0;
227}
228
229static int spi_ppc4xx_setup(struct spi_device *spi)
230{
231 struct spi_ppc4xx_cs *cs = spi->controller_state;
232
233 if (spi->bits_per_word != 8) {
234 dev_err(&spi->dev, "invalid bits-per-word (%d)\n",
235 spi->bits_per_word);
236 return -EINVAL;
237 }
238
239 if (!spi->max_speed_hz) {
240 dev_err(&spi->dev, "invalid max_speed_hz (must be non-zero)\n");
241 return -EINVAL;
242 }
243
244 if (cs == NULL) {
245 cs = kzalloc(sizeof *cs, GFP_KERNEL);
246 if (!cs)
247 return -ENOMEM;
248 spi->controller_state = cs;
249 }
250
251 /*
252 * We set all bits of the SPI0_MODE register, so,
253 * no need to read-modify-write
254 */
255 cs->mode = SPI_PPC4XX_MODE_SPE;
256
257 switch (spi->mode & (SPI_CPHA | SPI_CPOL)) {
258 case SPI_MODE_0:
259 cs->mode |= SPI_CLK_MODE0;
260 break;
261 case SPI_MODE_1:
262 cs->mode |= SPI_CLK_MODE1;
263 break;
264 case SPI_MODE_2:
265 cs->mode |= SPI_CLK_MODE2;
266 break;
267 case SPI_MODE_3:
268 cs->mode |= SPI_CLK_MODE3;
269 break;
270 }
271
272 if (spi->mode & SPI_LSB_FIRST)
273 cs->mode |= SPI_PPC4XX_MODE_RD;
274
275 return 0;
276}
277
278static void spi_ppc4xx_chipsel(struct spi_device *spi, int value)
279{
280 struct ppc4xx_spi *hw = spi_master_get_devdata(spi->master);
281 unsigned int cs = spi->chip_select;
282 unsigned int cspol;
283
284 /*
285 * If there are no chip selects at all, or if this is the special
286 * case of a non-existent (dummy) chip select, do nothing.
287 */
288
289 if (!hw->master->num_chipselect || hw->gpios[cs] == -EEXIST)
290 return;
291
292 cspol = spi->mode & SPI_CS_HIGH ? 1 : 0;
293 if (value == BITBANG_CS_INACTIVE)
294 cspol = !cspol;
295
296 gpio_set_value(hw->gpios[cs], cspol);
297}
298
299static irqreturn_t spi_ppc4xx_int(int irq, void *dev_id)
300{
301 struct ppc4xx_spi *hw;
302 u8 status;
303 u8 data;
304 unsigned int count;
305
306 hw = (struct ppc4xx_spi *)dev_id;
307
308 status = in_8(&hw->regs->sr);
309 if (!status)
310 return IRQ_NONE;
311
312 /*
313 * BSY de-asserts one cycle after the transfer is complete. The
314 * interrupt is asserted after the transfer is complete. The exact
315 * relationship is not documented, hence this code.
316 */
317
318 if (unlikely(status & SPI_PPC4XX_SR_BSY)) {
319 u8 lstatus;
320 int cnt = 0;
321
322 dev_dbg(hw->dev, "got interrupt but spi still busy?\n");
323 do {
324 ndelay(10);
325 lstatus = in_8(&hw->regs->sr);
326 } while (++cnt < 100 && lstatus & SPI_PPC4XX_SR_BSY);
327
328 if (cnt >= 100) {
329 dev_err(hw->dev, "busywait: too many loops!\n");
330 complete(&hw->done);
331 return IRQ_HANDLED;
332 } else {
333 /* status is always 1 (RBR) here */
334 status = in_8(&hw->regs->sr);
335 dev_dbg(hw->dev, "loops %d status %x\n", cnt, status);
336 }
337 }
338
339 count = hw->count;
340 hw->count++;
341
342 /* RBR triggered this interrupt. Therefore, data must be ready. */
343 data = in_8(&hw->regs->rxd);
344 if (hw->rx)
345 hw->rx[count] = data;
346
347 count++;
348
349 if (count < hw->len) {
350 data = hw->tx ? hw->tx[count] : 0;
351 out_8(&hw->regs->txd, data);
352 out_8(&hw->regs->cr, SPI_PPC4XX_CR_STR);
353 } else {
354 complete(&hw->done);
355 }
356
357 return IRQ_HANDLED;
358}
359
360static void spi_ppc4xx_cleanup(struct spi_device *spi)
361{
362 kfree(spi->controller_state);
363}
364
365static void spi_ppc4xx_enable(struct ppc4xx_spi *hw)
366{
367 /*
368 * On all 4xx PPC's the SPI bus is shared/multiplexed with
369 * the 2nd I2C bus. We need to enable the the SPI bus before
370 * using it.
371 */
372
373 /* need to clear bit 14 to enable SPC */
374 dcri_clrset(SDR0, SDR0_PFC1, 0x80000000 >> 14, 0);
375}
376
377static void free_gpios(struct ppc4xx_spi *hw)
378{
379 if (hw->master->num_chipselect) {
380 int i;
381 for (i = 0; i < hw->master->num_chipselect; i++)
382 if (gpio_is_valid(hw->gpios[i]))
383 gpio_free(hw->gpios[i]);
384
385 kfree(hw->gpios);
386 hw->gpios = NULL;
387 }
388}
389
390/*
391 * platform_device layer stuff...
392 */
393static int __init spi_ppc4xx_of_probe(struct platform_device *op)
394{
395 struct ppc4xx_spi *hw;
396 struct spi_master *master;
397 struct spi_bitbang *bbp;
398 struct resource resource;
399 struct device_node *np = op->dev.of_node;
400 struct device *dev = &op->dev;
401 struct device_node *opbnp;
402 int ret;
403 int num_gpios;
404 const unsigned int *clk;
405
406 master = spi_alloc_master(dev, sizeof *hw);
407 if (master == NULL)
408 return -ENOMEM;
409 master->dev.of_node = np;
410 dev_set_drvdata(dev, master);
411 hw = spi_master_get_devdata(master);
412 hw->master = spi_master_get(master);
413 hw->dev = dev;
414
415 init_completion(&hw->done);
416
417 /*
418 * A count of zero implies a single SPI device without any chip-select.
419 * Note that of_gpio_count counts all gpios assigned to this spi master.
420 * This includes both "null" gpio's and real ones.
421 */
422 num_gpios = of_gpio_count(np);
423 if (num_gpios) {
424 int i;
425
426 hw->gpios = kzalloc(sizeof(int) * num_gpios, GFP_KERNEL);
427 if (!hw->gpios) {
428 ret = -ENOMEM;
429 goto free_master;
430 }
431
432 for (i = 0; i < num_gpios; i++) {
433 int gpio;
434 enum of_gpio_flags flags;
435
436 gpio = of_get_gpio_flags(np, i, &flags);
437 hw->gpios[i] = gpio;
438
439 if (gpio_is_valid(gpio)) {
440 /* Real CS - set the initial state. */
441 ret = gpio_request(gpio, np->name);
442 if (ret < 0) {
443 dev_err(dev, "can't request gpio "
444 "#%d: %d\n", i, ret);
445 goto free_gpios;
446 }
447
448 gpio_direction_output(gpio,
449 !!(flags & OF_GPIO_ACTIVE_LOW));
450 } else if (gpio == -EEXIST) {
451 ; /* No CS, but that's OK. */
452 } else {
453 dev_err(dev, "invalid gpio #%d: %d\n", i, gpio);
454 ret = -EINVAL;
455 goto free_gpios;
456 }
457 }
458 }
459
460 /* Setup the state for the bitbang driver */
461 bbp = &hw->bitbang;
462 bbp->master = hw->master;
463 bbp->setup_transfer = spi_ppc4xx_setupxfer;
464 bbp->chipselect = spi_ppc4xx_chipsel;
465 bbp->txrx_bufs = spi_ppc4xx_txrx;
466 bbp->use_dma = 0;
467 bbp->master->setup = spi_ppc4xx_setup;
468 bbp->master->cleanup = spi_ppc4xx_cleanup;
469
470 /* Allocate bus num dynamically. */
471 bbp->master->bus_num = -1;
472
473 /* the spi->mode bits understood by this driver: */
474 bbp->master->mode_bits =
475 SPI_CPHA | SPI_CPOL | SPI_CS_HIGH | SPI_LSB_FIRST;
476
477 /* this many pins in all GPIO controllers */
478 bbp->master->num_chipselect = num_gpios;
479
480 /* Get the clock for the OPB */
481 opbnp = of_find_compatible_node(NULL, NULL, "ibm,opb");
482 if (opbnp == NULL) {
483 dev_err(dev, "OPB: cannot find node\n");
484 ret = -ENODEV;
485 goto free_gpios;
486 }
487 /* Get the clock (Hz) for the OPB */
488 clk = of_get_property(opbnp, "clock-frequency", NULL);
489 if (clk == NULL) {
490 dev_err(dev, "OPB: no clock-frequency property set\n");
491 of_node_put(opbnp);
492 ret = -ENODEV;
493 goto free_gpios;
494 }
495 hw->opb_freq = *clk;
496 hw->opb_freq >>= 2;
497 of_node_put(opbnp);
498
499 ret = of_address_to_resource(np, 0, &resource);
500 if (ret) {
501 dev_err(dev, "error while parsing device node resource\n");
502 goto free_gpios;
503 }
504 hw->mapbase = resource.start;
505 hw->mapsize = resource_size(&resource);
506
507 /* Sanity check */
508 if (hw->mapsize < sizeof(struct spi_ppc4xx_regs)) {
509 dev_err(dev, "too small to map registers\n");
510 ret = -EINVAL;
511 goto free_gpios;
512 }
513
514 /* Request IRQ */
515 hw->irqnum = irq_of_parse_and_map(np, 0);
516 ret = request_irq(hw->irqnum, spi_ppc4xx_int,
517 IRQF_DISABLED, "spi_ppc4xx_of", (void *)hw);
518 if (ret) {
519 dev_err(dev, "unable to allocate interrupt\n");
520 goto free_gpios;
521 }
522
523 if (!request_mem_region(hw->mapbase, hw->mapsize, DRIVER_NAME)) {
524 dev_err(dev, "resource unavailable\n");
525 ret = -EBUSY;
526 goto request_mem_error;
527 }
528
529 hw->regs = ioremap(hw->mapbase, sizeof(struct spi_ppc4xx_regs));
530
531 if (!hw->regs) {
532 dev_err(dev, "unable to memory map registers\n");
533 ret = -ENXIO;
534 goto map_io_error;
535 }
536
537 spi_ppc4xx_enable(hw);
538
539 /* Finally register our spi controller */
540 dev->dma_mask = 0;
541 ret = spi_bitbang_start(bbp);
542 if (ret) {
543 dev_err(dev, "failed to register SPI master\n");
544 goto unmap_regs;
545 }
546
547 dev_info(dev, "driver initialized\n");
548
549 return 0;
550
551unmap_regs:
552 iounmap(hw->regs);
553map_io_error:
554 release_mem_region(hw->mapbase, hw->mapsize);
555request_mem_error:
556 free_irq(hw->irqnum, hw);
557free_gpios:
558 free_gpios(hw);
559free_master:
560 dev_set_drvdata(dev, NULL);
561 spi_master_put(master);
562
563 dev_err(dev, "initialization failed\n");
564 return ret;
565}
566
567static int __exit spi_ppc4xx_of_remove(struct platform_device *op)
568{
569 struct spi_master *master = dev_get_drvdata(&op->dev);
570 struct ppc4xx_spi *hw = spi_master_get_devdata(master);
571
572 spi_bitbang_stop(&hw->bitbang);
573 dev_set_drvdata(&op->dev, NULL);
574 release_mem_region(hw->mapbase, hw->mapsize);
575 free_irq(hw->irqnum, hw);
576 iounmap(hw->regs);
577 free_gpios(hw);
578 return 0;
579}
580
581static const struct of_device_id spi_ppc4xx_of_match[] = {
582 { .compatible = "ibm,ppc4xx-spi", },
583 {},
584};
585
586MODULE_DEVICE_TABLE(of, spi_ppc4xx_of_match);
587
588static struct platform_driver spi_ppc4xx_of_driver = {
589 .probe = spi_ppc4xx_of_probe,
590 .remove = __exit_p(spi_ppc4xx_of_remove),
591 .driver = {
592 .name = DRIVER_NAME,
593 .owner = THIS_MODULE,
594 .of_match_table = spi_ppc4xx_of_match,
595 },
596};
597
598static int __init spi_ppc4xx_init(void)
599{
600 return platform_driver_register(&spi_ppc4xx_of_driver);
601}
602module_init(spi_ppc4xx_init);
603
604static void __exit spi_ppc4xx_exit(void)
605{
606 platform_driver_unregister(&spi_ppc4xx_of_driver);
607}
608module_exit(spi_ppc4xx_exit);
609
610MODULE_AUTHOR("Gary Jennejohn & Stefan Roese");
611MODULE_DESCRIPTION("Simple PPC4xx SPI Driver");
612MODULE_LICENSE("GPL");