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Merge branch 'upstream' of git://git.linux-mips.org/pub/scm/upstream-linus
[linux-btrfs-devel.git] / drivers / spi / spi-ti-ssp.c
blobee22795c7973fdf250a94f50b215afc8419bcb0c
1 /*
2 * Sequencer Serial Port (SSP) based SPI master driver
3 *
4 * Copyright (C) 2010 Texas Instruments Inc
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation; either version 2 of the License, or
9 * (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 Free Software
18 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
19 */
20
21 #include <linux/kernel.h>
22 #include <linux/err.h>
23 #include <linux/completion.h>
24 #include <linux/delay.h>
25 #include <linux/platform_device.h>
26 #include <linux/spi/spi.h>
27 #include <linux/mfd/ti_ssp.h>
28
29 #define MODE_BITS (SPI_CPHA | SPI_CPOL | SPI_CS_HIGH)
30
31 struct ti_ssp_spi {
32 struct spi_master *master;
33 struct device *dev;
34 spinlock_t lock;
35 struct list_head msg_queue;
36 struct completion complete;
37 bool shutdown;
38 struct workqueue_struct *workqueue;
39 struct work_struct work;
40 u8 mode, bpw;
41 int cs_active;
42 u32 pc_en, pc_dis, pc_wr, pc_rd;
43 void (*select)(int cs);
44 };
45
46 static u32 ti_ssp_spi_rx(struct ti_ssp_spi *hw)
47 {
48 u32 ret;
49
50 ti_ssp_run(hw->dev, hw->pc_rd, 0, &ret);
51 return ret;
52 }
53
54 static void ti_ssp_spi_tx(struct ti_ssp_spi *hw, u32 data)
55 {
56 ti_ssp_run(hw->dev, hw->pc_wr, data << (32 - hw->bpw), NULL);
57 }
58
59 static int ti_ssp_spi_txrx(struct ti_ssp_spi *hw, struct spi_message *msg,
60 struct spi_transfer *t)
61 {
62 int count;
63
64 if (hw->bpw <= 8) {
65 u8 *rx = t->rx_buf;
66 const u8 *tx = t->tx_buf;
67
68 for (count = 0; count < t->len; count += 1) {
69 if (t->tx_buf)
70 ti_ssp_spi_tx(hw, *tx++);
71 if (t->rx_buf)
72 *rx++ = ti_ssp_spi_rx(hw);
73 }
74 } else if (hw->bpw <= 16) {
75 u16 *rx = t->rx_buf;
76 const u16 *tx = t->tx_buf;
77
78 for (count = 0; count < t->len; count += 2) {
79 if (t->tx_buf)
80 ti_ssp_spi_tx(hw, *tx++);
81 if (t->rx_buf)
82 *rx++ = ti_ssp_spi_rx(hw);
83 }
84 } else {
85 u32 *rx = t->rx_buf;
86 const u32 *tx = t->tx_buf;
87
88 for (count = 0; count < t->len; count += 4) {
89 if (t->tx_buf)
90 ti_ssp_spi_tx(hw, *tx++);
91 if (t->rx_buf)
92 *rx++ = ti_ssp_spi_rx(hw);
93 }
94 }
95
96 msg->actual_length += count; /* bytes transferred */
97
98 dev_dbg(&msg->spi->dev, "xfer %s%s, %d bytes, %d bpw, count %d%s\n",
99 t->tx_buf ? "tx" : "", t->rx_buf ? "rx" : "", t->len,
100 hw->bpw, count, (count < t->len) ? " (under)" : "");
101
102 return (count < t->len) ? -EIO : 0; /* left over data */
103 }
104
105 static void ti_ssp_spi_chip_select(struct ti_ssp_spi *hw, int cs_active)
106 {
107 cs_active = !!cs_active;
108 if (cs_active == hw->cs_active)
109 return;
110 ti_ssp_run(hw->dev, cs_active ? hw->pc_en : hw->pc_dis, 0, NULL);
111 hw->cs_active = cs_active;
112 }
113
114 #define __SHIFT_OUT(bits) (SSP_OPCODE_SHIFT | SSP_OUT_MODE | \
115 cs_en | clk | SSP_COUNT((bits) * 2 - 1))
116 #define __SHIFT_IN(bits) (SSP_OPCODE_SHIFT | SSP_IN_MODE | \
117 cs_en | clk | SSP_COUNT((bits) * 2 - 1))
118
119 static int ti_ssp_spi_setup_transfer(struct ti_ssp_spi *hw, u8 bpw, u8 mode)
120 {
121 int error, idx = 0;
122 u32 seqram[16];
123 u32 cs_en, cs_dis, clk;
124 u32 topbits, botbits;
125
126 mode &= MODE_BITS;
127 if (mode == hw->mode && bpw == hw->bpw)
128 return 0;
129
130 cs_en = (mode & SPI_CS_HIGH) ? SSP_CS_HIGH : SSP_CS_LOW;
131 cs_dis = (mode & SPI_CS_HIGH) ? SSP_CS_LOW : SSP_CS_HIGH;
132 clk = (mode & SPI_CPOL) ? SSP_CLK_HIGH : SSP_CLK_LOW;
133
134 /* Construct instructions */
135
136 /* Disable Chip Select */
137 hw->pc_dis = idx;
138 seqram[idx++] = SSP_OPCODE_DIRECT | SSP_OUT_MODE | cs_dis | clk;
139 seqram[idx++] = SSP_OPCODE_STOP | SSP_OUT_MODE | cs_dis | clk;
140
141 /* Enable Chip Select */
142 hw->pc_en = idx;
143 seqram[idx++] = SSP_OPCODE_DIRECT | SSP_OUT_MODE | cs_en | clk;
144 seqram[idx++] = SSP_OPCODE_STOP | SSP_OUT_MODE | cs_en | clk;
145
146 /* Reads and writes need to be split for bpw > 16 */
147 topbits = (bpw > 16) ? 16 : bpw;
148 botbits = bpw - topbits;
149
150 /* Write */
151 hw->pc_wr = idx;
152 seqram[idx++] = __SHIFT_OUT(topbits) | SSP_ADDR_REG;
153 if (botbits)
154 seqram[idx++] = __SHIFT_OUT(botbits) | SSP_DATA_REG;
155 seqram[idx++] = SSP_OPCODE_STOP | SSP_OUT_MODE | cs_en | clk;
156
157 /* Read */
158 hw->pc_rd = idx;
159 if (botbits)
160 seqram[idx++] = __SHIFT_IN(botbits) | SSP_ADDR_REG;
161 seqram[idx++] = __SHIFT_IN(topbits) | SSP_DATA_REG;
162 seqram[idx++] = SSP_OPCODE_STOP | SSP_OUT_MODE | cs_en | clk;
163
164 error = ti_ssp_load(hw->dev, 0, seqram, idx);
165 if (error < 0)
166 return error;
167
168 error = ti_ssp_set_mode(hw->dev, ((mode & SPI_CPHA) ?
169 0 : SSP_EARLY_DIN));
170 if (error < 0)
171 return error;
172
173 hw->bpw = bpw;
174 hw->mode = mode;
175
176 return error;
177 }
178
179 static void ti_ssp_spi_work(struct work_struct *work)
180 {
181 struct ti_ssp_spi *hw = container_of(work, struct ti_ssp_spi, work);
182
183 spin_lock(&hw->lock);
184
185 while (!list_empty(&hw->msg_queue)) {
186 struct spi_message *m;
187 struct spi_device *spi;
188 struct spi_transfer *t = NULL;
189 int status = 0;
190
191 m = container_of(hw->msg_queue.next, struct spi_message,
192 queue);
193
194 list_del_init(&m->queue);
195
196 spin_unlock(&hw->lock);
197
198 spi = m->spi;
199
200 if (hw->select)
201 hw->select(spi->chip_select);
202
203 list_for_each_entry(t, &m->transfers, transfer_list) {
204 int bpw = spi->bits_per_word;
205 int xfer_status;
206
207 if (t->bits_per_word)
208 bpw = t->bits_per_word;
209
210 if (ti_ssp_spi_setup_transfer(hw, bpw, spi->mode) < 0)
211 break;
212
213 ti_ssp_spi_chip_select(hw, 1);
214
215 xfer_status = ti_ssp_spi_txrx(hw, m, t);
216 if (xfer_status < 0)
217 status = xfer_status;
218
219 if (t->delay_usecs)
220 udelay(t->delay_usecs);
221
222 if (t->cs_change)
223 ti_ssp_spi_chip_select(hw, 0);
224 }
225
226 ti_ssp_spi_chip_select(hw, 0);
227 m->status = status;
228 m->complete(m->context);
229
230 spin_lock(&hw->lock);
231 }
232
233 if (hw->shutdown)
234 complete(&hw->complete);
235
236 spin_unlock(&hw->lock);
237 }
238
239 static int ti_ssp_spi_setup(struct spi_device *spi)
240 {
241 if (spi->bits_per_word > 32)
242 return -EINVAL;
243
244 return 0;
245 }
246
247 static int ti_ssp_spi_transfer(struct spi_device *spi, struct spi_message *m)
248 {
249 struct ti_ssp_spi *hw;
250 struct spi_transfer *t;
251 int error = 0;
252
253 m->actual_length = 0;
254 m->status = -EINPROGRESS;
255
256 hw = spi_master_get_devdata(spi->master);
257
258 if (list_empty(&m->transfers) || !m->complete)
259 return -EINVAL;
260
261 list_for_each_entry(t, &m->transfers, transfer_list) {
262 if (t->len && !(t->rx_buf || t->tx_buf)) {
263 dev_err(&spi->dev, "invalid xfer, no buffer\n");
264 return -EINVAL;
265 }
266
267 if (t->len && t->rx_buf && t->tx_buf) {
268 dev_err(&spi->dev, "invalid xfer, full duplex\n");
269 return -EINVAL;
270 }
271
272 if (t->bits_per_word > 32) {
273 dev_err(&spi->dev, "invalid xfer width %d\n",
274 t->bits_per_word);
275 return -EINVAL;
276 }
277 }
278
279 spin_lock(&hw->lock);
280 if (hw->shutdown) {
281 error = -ESHUTDOWN;
282 goto error_unlock;
283 }
284 list_add_tail(&m->queue, &hw->msg_queue);
285 queue_work(hw->workqueue, &hw->work);
286 error_unlock:
287 spin_unlock(&hw->lock);
288 return error;
289 }
290
291 static int __devinit ti_ssp_spi_probe(struct platform_device *pdev)
292 {
293 const struct ti_ssp_spi_data *pdata;
294 struct ti_ssp_spi *hw;
295 struct spi_master *master;
296 struct device *dev = &pdev->dev;
297 int error = 0;
298
299 pdata = dev->platform_data;
300 if (!pdata) {
301 dev_err(dev, "platform data not found\n");
302 return -EINVAL;
303 }
304
305 master = spi_alloc_master(dev, sizeof(struct ti_ssp_spi));
306 if (!master) {
307 dev_err(dev, "cannot allocate SPI master\n");
308 return -ENOMEM;
309 }
310
311 hw = spi_master_get_devdata(master);
312 platform_set_drvdata(pdev, hw);
313
314 hw->master = master;
315 hw->dev = dev;
316 hw->select = pdata->select;
317
318 spin_lock_init(&hw->lock);
319 init_completion(&hw->complete);
320 INIT_LIST_HEAD(&hw->msg_queue);
321 INIT_WORK(&hw->work, ti_ssp_spi_work);
322
323 hw->workqueue = create_singlethread_workqueue(dev_name(dev));
324 if (!hw->workqueue) {
325 error = -ENOMEM;
326 dev_err(dev, "work queue creation failed\n");
327 goto error_wq;
328 }
329
330 error = ti_ssp_set_iosel(hw->dev, pdata->iosel);
331 if (error < 0) {
332 dev_err(dev, "io setup failed\n");
333 goto error_iosel;
334 }
335
336 master->bus_num = pdev->id;
337 master->num_chipselect = pdata->num_cs;
338 master->mode_bits = MODE_BITS;
339 master->flags = SPI_MASTER_HALF_DUPLEX;
340 master->setup = ti_ssp_spi_setup;
341 master->transfer = ti_ssp_spi_transfer;
342
343 error = spi_register_master(master);
344 if (error) {
345 dev_err(dev, "master registration failed\n");
346 goto error_reg;
347 }
348
349 return 0;
350
351 error_reg:
352 error_iosel:
353 destroy_workqueue(hw->workqueue);
354 error_wq:
355 spi_master_put(master);
356 return error;
357 }
358
359 static int __devexit ti_ssp_spi_remove(struct platform_device *pdev)
360 {
361 struct ti_ssp_spi *hw = platform_get_drvdata(pdev);
362 int error;
363
364 hw->shutdown = 1;
365 while (!list_empty(&hw->msg_queue)) {
366 error = wait_for_completion_interruptible(&hw->complete);
367 if (error < 0) {
368 hw->shutdown = 0;
369 return error;
370 }
371 }
372 destroy_workqueue(hw->workqueue);
373 spi_unregister_master(hw->master);
374
375 return 0;
376 }
377
378 static struct platform_driver ti_ssp_spi_driver = {
379 .probe = ti_ssp_spi_probe,
380 .remove = __devexit_p(ti_ssp_spi_remove),
381 .driver = {
382 .name = "ti-ssp-spi",
383 .owner = THIS_MODULE,
384 },
385 };
386
387 static int __init ti_ssp_spi_init(void)
388 {
389 return platform_driver_register(&ti_ssp_spi_driver);
390 }
391 module_init(ti_ssp_spi_init);
392
393 static void __exit ti_ssp_spi_exit(void)
394 {
395 platform_driver_unregister(&ti_ssp_spi_driver);
396 }
397 module_exit(ti_ssp_spi_exit);
398
399 MODULE_DESCRIPTION("SSP SPI Master");
400 MODULE_AUTHOR("Cyril Chemparathy");
401 MODULE_LICENSE("GPL");
402 MODULE_ALIAS("platform:ti-ssp-spi");
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