[brcm63xx] make SPI work in full-duplex mode by default
[openwrt/svn-archive/archive.git] / target / linux / brcm63xx / files / drivers / spi / bcm63xx_spi.c
1 /*
2 * Broadcom BCM63xx SPI controller support
3 *
4 * Copyright (C) 2009 Florian Fainelli <florian@openwrt.org>
5 *
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public License
8 * as published by the Free Software Foundation; either version 2
9 * of the License, or (at your option) any later version.
10 *
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
15 *
16 * You should have received a copy of the GNU General Public License
17 * along with this program; if not, write to the
18 * Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
19 */
20
21 #include <linux/kernel.h>
22 #include <linux/init.h>
23 #include <linux/clk.h>
24 #include <linux/module.h>
25 #include <linux/platform_device.h>
26 #include <linux/delay.h>
27 #include <linux/interrupt.h>
28 #include <linux/spi/spi.h>
29 #include <linux/spi/spi_bitbang.h>
30 #include <linux/gpio.h>
31 #include <linux/completion.h>
32 #include <linux/err.h>
33
34 #include <bcm63xx_io.h>
35 #include <bcm63xx_regs.h>
36 #include <bcm63xx_dev_spi.h>
37
38 #define PFX KBUILD_MODNAME
39 #define DRV_VER "0.1.1"
40
41 struct bcm63xx_spi {
42 /* bitbang has to be first */
43 struct spi_bitbang bitbang;
44 struct completion done;
45
46 void __iomem *regs;
47 int irq;
48
49 /* Platform data */
50 u32 speed_hz;
51 unsigned msg_fifo_size;
52 unsigned rx_fifo_size;
53
54 /* Data buffers */
55 const unsigned char *tx_ptr;
56 unsigned char *rx_ptr;
57 int remaining_bytes;
58
59 struct clk *clk;
60 struct resource *ioarea;
61 struct platform_device *pdev;
62 };
63
64 static void bcm63xx_spi_chipselect(struct spi_device *spi, int is_on)
65 {
66 u16 val;
67
68 val = bcm_spi_readw(SPI_CMD);
69 if (is_on == BITBANG_CS_INACTIVE)
70 val |= SPI_CMD_NOOP;
71 else if (is_on == BITBANG_CS_ACTIVE)
72 val |= (1 << spi->chip_select << SPI_CMD_DEVICE_ID_SHIFT);
73 bcm_spi_writew(val, SPI_CMD);
74 }
75
76 static int bcm63xx_spi_setup_transfer(struct spi_device *spi,
77 struct spi_transfer *t)
78 {
79 u8 bits_per_word;
80 u8 clk_cfg;
81 u32 hz;
82 unsigned int div;
83
84 struct bcm63xx_spi *bs = spi_master_get_devdata(spi->master);
85
86 bits_per_word = (t) ? t->bits_per_word : spi->bits_per_word;
87 hz = (t) ? t->speed_hz : spi->max_speed_hz;
88 if (bits_per_word != 8) {
89 dev_err(&spi->dev, "%s, unsupported bits_per_word=%d\n",
90 __func__, bits_per_word);
91 return -EINVAL;
92 }
93
94 if (spi->chip_select > spi->master->num_chipselect) {
95 dev_err(&spi->dev, "%s, unsupported slave %d\n",
96 __func__, spi->chip_select);
97 return -EINVAL;
98 }
99
100 /* Check clock setting */
101 div = (bs->speed_hz / hz);
102 switch (div) {
103 case 2:
104 clk_cfg = SPI_CLK_25MHZ;
105 break;
106 case 4:
107 clk_cfg = SPI_CLK_12_50MHZ;
108 break;
109 case 8:
110 clk_cfg = SPI_CLK_6_250MHZ;
111 break;
112 case 16:
113 clk_cfg = SPI_CLK_3_125MHZ;
114 break;
115 case 32:
116 clk_cfg = SPI_CLK_1_563MHZ;
117 break;
118 case 128:
119 clk_cfg = SPI_CLK_0_781MHZ;
120 break;
121 case 64:
122 default:
123 /* Set to slowest mode for compatibility */
124 clk_cfg = SPI_CLK_0_781MHZ;
125 break;
126 }
127
128 bcm_spi_writeb(clk_cfg, SPI_CLK_CFG);
129 dev_dbg(&spi->dev, "Setting clock register to %d (hz %d, cmd %02x)\n",
130 div, hz, clk_cfg);
131
132 return 0;
133 }
134
135 /* the spi->mode bits understood by this driver: */
136 #define MODEBITS (SPI_CPOL | SPI_CPHA)
137
138 static int bcm63xx_spi_setup(struct spi_device *spi)
139 {
140 struct spi_bitbang *bitbang;
141 struct bcm63xx_spi *bs;
142 int retval;
143
144 bs = spi_master_get_devdata(spi->master);
145 bitbang = &bs->bitbang;
146
147 if (!spi->bits_per_word)
148 spi->bits_per_word = 8;
149
150 if (spi->mode & ~MODEBITS) {
151 dev_err(&spi->dev, "%s, unsupported mode bits %x\n",
152 __func__, spi->mode & ~MODEBITS);
153 return -EINVAL;
154 }
155
156 retval = bcm63xx_spi_setup_transfer(spi, NULL);
157 if (retval < 0) {
158 dev_err(&spi->dev, "setup: unsupported mode bits %x\n",
159 spi->mode & ~MODEBITS);
160 return retval;
161 }
162
163 dev_dbg(&spi->dev, "%s, mode %d, %u bits/w, %u nsec/bit\n",
164 __func__, spi->mode & MODEBITS, spi->bits_per_word, 0);
165
166 return 0;
167 }
168
169 /* Fill the TX FIFO with as many bytes as possible */
170 static void bcm63xx_spi_fill_tx_fifo(struct bcm63xx_spi *bs)
171 {
172 u8 tail;
173
174 /* Fill the Tx FIFO with as many bytes as possible */
175 tail = bcm_spi_readb(SPI_MSG_TAIL);
176 while ((tail < bs->msg_fifo_size) && (bs->remaining_bytes > 0)) {
177 if (bs->tx_ptr)
178 bcm_spi_writeb(*bs->tx_ptr++, SPI_MSG_DATA);
179 else
180 bcm_spi_writeb(0, SPI_MSG_DATA);
181 bs->remaining_bytes--;
182 tail = bcm_spi_readb(SPI_MSG_TAIL);
183 }
184 }
185
186 static int bcm63xx_txrx_bufs(struct spi_device *spi, struct spi_transfer *t)
187 {
188 struct bcm63xx_spi *bs = spi_master_get_devdata(spi->master);
189 u8 msg_ctl;
190 u16 cmd;
191
192 dev_dbg(&spi->dev, "txrx: tx %p, rx %p, len %d\n",
193 t->tx_buf, t->rx_buf, t->len);
194
195 /* Transmitter is inhibited */
196 bs->tx_ptr = t->tx_buf;
197 bs->rx_ptr = t->rx_buf;
198 bs->remaining_bytes = t->len;
199 init_completion(&bs->done);
200
201 bcm63xx_spi_fill_tx_fifo(bs);
202
203 /* Enable the command done interrupt which
204 * we use to determine completion of a command */
205 bcm_writeb(SPI_INTR_CMD_DONE, SPI_INT_MASK);
206
207 /* Fill in the Message control register */
208 msg_ctl = bcm_spi_readb(SPI_MSG_CTL);
209 msg_ctl |= (t->len << SPI_BYTE_CNT_SHIFT);
210 msg_ctl |= (SPI_FD_RW << SPI_MSG_TYPE_SHIFT);
211 bcm_spi_writeb(msg_ctl, SPI_MSG_CTL);
212
213 /* Issue the transfer */
214 cmd = bcm_spi_readb(SPI_CMD);
215 cmd |= SPI_CMD_START_IMMEDIATE;
216 cmd |= (0 << SPI_CMD_PREPEND_BYTE_CNT_SHIFT);
217 bcm_spi_writeb(cmd, SPI_CMD);
218
219 wait_for_completion(&bs->done);
220
221 /* Disable the CMD_DONE interrupt */
222 bcm_spi_writeb(~(SPI_INTR_CMD_DONE), SPI_INT_MASK);
223
224 return t->len - bs->remaining_bytes;
225 }
226
227 /* This driver supports single master mode only. Hence
228 * CMD_DONE is the only interrupt we care about
229 */
230 static irqreturn_t bcm63xx_spi_interrupt(int irq, void *dev_id)
231 {
232 struct spi_master *master = (struct spi_master *)dev_id;
233 struct bcm63xx_spi *bs = spi_master_get_devdata(master);
234 u8 intr;
235 u16 cmd;
236
237 /* Read interupts and clear them immediately */
238 intr = bcm_spi_readb(SPI_INT_STATUS);
239 bcm_writeb(SPI_INTR_CLEAR_ALL, SPI_INT_STATUS);
240
241 /* A tansfer completed */
242 if (intr & SPI_INTR_CMD_DONE) {
243 u8 rx_empty;
244
245 rx_empty = bcm_spi_readb(SPI_ST);
246 /* Read out all the data */
247 while ((rx_empty & SPI_RX_EMPTY) == 0) {
248 u8 data;
249
250 data = bcm_spi_readb(SPI_RX_DATA);
251 if (bs->rx_ptr)
252 *bs->rx_ptr++ = data;
253
254 rx_empty = bcm_spi_readb(SPI_RX_EMPTY);
255 }
256
257 /* See if there is more data to send */
258 if (bs->remaining_bytes > 0) {
259 bcm63xx_spi_fill_tx_fifo(bs);
260
261 /* Start the transfer */
262 cmd = bcm_spi_readb(SPI_CMD);
263 cmd |= SPI_CMD_START_IMMEDIATE;
264 cmd |= (0 << SPI_CMD_PREPEND_BYTE_CNT_SHIFT);
265 bcm_spi_writeb(cmd, SPI_CMD);
266 } else
267 complete(&bs->done);
268 }
269
270 return IRQ_HANDLED;
271 }
272
273
274 static int __init bcm63xx_spi_probe(struct platform_device *pdev)
275 {
276 struct resource *r;
277 struct bcm63xx_spi_pdata *pdata = pdev->dev.platform_data;
278 int irq;
279 struct spi_master *master;
280 struct clk *clk;
281 struct bcm63xx_spi *bs;
282 int ret;
283
284 r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
285 if (!r) {
286 ret = -ENXIO;
287 goto out;
288 }
289
290 irq = platform_get_irq(pdev, 0);
291 if (irq < 0) {
292 ret = -ENXIO;
293 goto out;
294 }
295
296 clk = clk_get(&pdev->dev, "spi");
297 if (IS_ERR(clk)) {
298 dev_err(&pdev->dev, "No clock for device\n");
299 ret = -ENODEV;
300 goto out;
301 }
302
303 master = spi_alloc_master(&pdev->dev, sizeof(struct bcm63xx_spi));
304 if (!master) {
305 ret = -ENOMEM;
306 goto out_free;
307 }
308
309 bs = spi_master_get_devdata(master);
310 bs->bitbang.master = spi_master_get(master);
311 bs->bitbang.chipselect = bcm63xx_spi_chipselect;
312 bs->bitbang.setup_transfer = bcm63xx_spi_setup_transfer;
313 bs->bitbang.txrx_bufs = bcm63xx_txrx_bufs;
314 bs->bitbang.master->setup = bcm63xx_spi_setup;
315 init_completion(&bs->done);
316
317 platform_set_drvdata(pdev, master);
318 bs->pdev = pdev;
319
320 bs->regs = ioremap_nocache(r->start, r->end - r->start);
321 if (!bs->regs) {
322 printk(KERN_ERR PFX " unable to ioremap regs\n");
323 ret = -ENOMEM;
324 goto out_free;
325 }
326 bs->irq = irq;
327 bs->clk = clk;
328 bs->msg_fifo_size = pdata->msg_fifo_size;
329 bs->rx_fifo_size = pdata->rx_fifo_size;
330
331 ret = request_irq(irq, bcm63xx_spi_interrupt, 0,
332 pdev->dev.bus_id, master);
333 if (ret) {
334 printk(KERN_ERR PFX " unable to request irq\n");
335 goto out_unmap;
336 }
337
338 master->bus_num = pdata->bus_num;
339 master->num_chipselect = pdata->num_chipselect;
340 bs->speed_hz = pdata->speed_hz;
341
342 /* Initialize hardware */
343 clk_enable(bs->clk);
344 bcm_spi_writew(SPI_CMD_HARD_RESET, SPI_CMD);
345 bcm_spi_writeb(SPI_INTR_CLEAR_ALL, SPI_INT_MASK);
346
347 dev_info(&pdev->dev, PFX " at 0x%08x (irq %d) %s\n",
348 r->start, irq, DRV_VER);
349
350 ret = spi_bitbang_start(&bs->bitbang);
351 if (ret) {
352 dev_err(&pdev->dev, "spi_bitbang_start FAILED\n");
353 goto out_reset_hw;
354 }
355
356 return ret;
357
358 out_reset_hw:
359 clk_disable(clk);
360 free_irq(irq, master);
361 out_unmap:
362 iounmap(bs->regs);
363 out_free:
364 clk_put(clk);
365 spi_master_put(master);
366 out:
367 return ret;
368 }
369
370 static int __exit bcm63xx_spi_remove(struct platform_device *pdev)
371 {
372 struct spi_master *master = platform_get_drvdata(pdev);
373 struct bcm63xx_spi *bs = spi_master_get_devdata(master);
374
375 spi_bitbang_stop(&bs->bitbang);
376 clk_disable(bs->clk);
377 clk_put(bs->clk);
378 free_irq(bs->irq, master);
379 iounmap(bs->regs);
380 platform_set_drvdata(pdev, 0);
381 spi_master_put(bs->bitbang.master);
382
383 return 0;
384 }
385
386 #ifdef CONFIG_PM
387 static int bcm63xx_spi_suspend(struct platform_device *pdev, pm_message_t mesg)
388 {
389 struct spi_master *master = platform_get_drvdata(pdev);
390 struct bcm63xx_spi *bs = spi_master_get_devdata(master);
391
392 clk_disable(bs->clk);
393
394 return 0;
395 }
396
397 static int bcm63xx_spi_resume(struct platform_device *pdev)
398 {
399 struct bcm63xx_spi *bs = spi_master_get_devdata(master);
400 struct bcm63xx_spi *bs = spi_master_get_devdata(master);
401
402 clk_enable(bs->clk);
403
404 return 0;
405 }
406 #else
407 #define bcm63xx_spi_suspend NULL
408 #define bcm63xx_spi_resume NULL
409 #endif
410
411 static struct platform_driver bcm63xx_spi_driver = {
412 .driver = {
413 .name = "bcm63xx-spi",
414 .owner = THIS_MODULE,
415 },
416 .probe = bcm63xx_spi_probe,
417 .remove = bcm63xx_spi_remove,
418 .suspend = bcm63xx_spi_suspend,
419 .resume = bcm63xx_spi_resume,
420 };
421
422
423 static int __init bcm63xx_spi_init(void)
424 {
425 return platform_driver_register(&bcm63xx_spi_driver);
426 }
427
428 static void __exit bcm63xx_spi_exit(void)
429 {
430 platform_driver_unregister(&bcm63xx_spi_driver);
431 }
432
433 module_init(bcm63xx_spi_init);
434 module_exit(bcm63xx_spi_exit);
435
436 MODULE_ALIAS("platform:bcm63xx_spi");
437 MODULE_AUTHOR("Florian Fainelli <florian@openwrt.org>");
438 MODULE_DESCRIPTION("Broadcom BCM63xx SPI Controller driver");
439 MODULE_LICENSE("GPL");