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Merge branch 'tip/perf/core' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt...
[linux-2.6/x86.git] / drivers / i2c / busses / i2c-pmcmsp.c
blobdfa7ae9c1b8ee8374cf6eaa0f791defc58c98206
1 /*
2 * Specific bus support for PMC-TWI compliant implementation on MSP71xx.
3 *
4 * Copyright 2005-2007 PMC-Sierra, Inc.
5 *
6 * This program is free software; you can redistribute it and/or modify it
7 * under the terms of the GNU General Public License as published by the
8 * Free Software Foundation; either version 2 of the License, or (at your
9 * option) any later version.
10 *
11 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
12 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
13 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN
14 * NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
15 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
16 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
17 * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
18 * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
19 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
20 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
21 *
22 * You should have received a copy of the GNU General Public License along
23 * with this program; if not, write to the Free Software Foundation, Inc.,
24 * 675 Mass Ave, Cambridge, MA 02139, USA.
25 */
26
27 #include <linux/kernel.h>
28 #include <linux/module.h>
29 #include <linux/init.h>
30 #include <linux/platform_device.h>
31 #include <linux/i2c.h>
32 #include <linux/interrupt.h>
33 #include <linux/completion.h>
34 #include <linux/mutex.h>
35 #include <linux/delay.h>
36 #include <linux/io.h>
37
38 #define DRV_NAME "pmcmsptwi"
39
40 #define MSP_TWI_SF_CLK_REG_OFFSET 0x00
41 #define MSP_TWI_HS_CLK_REG_OFFSET 0x04
42 #define MSP_TWI_CFG_REG_OFFSET 0x08
43 #define MSP_TWI_CMD_REG_OFFSET 0x0c
44 #define MSP_TWI_ADD_REG_OFFSET 0x10
45 #define MSP_TWI_DAT_0_REG_OFFSET 0x14
46 #define MSP_TWI_DAT_1_REG_OFFSET 0x18
47 #define MSP_TWI_INT_STS_REG_OFFSET 0x1c
48 #define MSP_TWI_INT_MSK_REG_OFFSET 0x20
49 #define MSP_TWI_BUSY_REG_OFFSET 0x24
50
51 #define MSP_TWI_INT_STS_DONE (1 << 0)
52 #define MSP_TWI_INT_STS_LOST_ARBITRATION (1 << 1)
53 #define MSP_TWI_INT_STS_NO_RESPONSE (1 << 2)
54 #define MSP_TWI_INT_STS_DATA_COLLISION (1 << 3)
55 #define MSP_TWI_INT_STS_BUSY (1 << 4)
56 #define MSP_TWI_INT_STS_ALL 0x1f
57
58 #define MSP_MAX_BYTES_PER_RW 8
59 #define MSP_MAX_POLL 5
60 #define MSP_POLL_DELAY 10
61 #define MSP_IRQ_TIMEOUT (MSP_MAX_POLL * MSP_POLL_DELAY)
62
63 /* IO Operation macros */
64 #define pmcmsptwi_readl __raw_readl
65 #define pmcmsptwi_writel __raw_writel
66
67 /* TWI command type */
68 enum pmcmsptwi_cmd_type {
69 MSP_TWI_CMD_WRITE = 0, /* Write only */
70 MSP_TWI_CMD_READ = 1, /* Read only */
71 MSP_TWI_CMD_WRITE_READ = 2, /* Write then Read */
72 };
73
74 /* The possible results of the xferCmd */
75 enum pmcmsptwi_xfer_result {
76 MSP_TWI_XFER_OK = 0,
77 MSP_TWI_XFER_TIMEOUT,
78 MSP_TWI_XFER_BUSY,
79 MSP_TWI_XFER_DATA_COLLISION,
80 MSP_TWI_XFER_NO_RESPONSE,
81 MSP_TWI_XFER_LOST_ARBITRATION,
82 };
83
84 /* Corresponds to a PMCTWI clock configuration register */
85 struct pmcmsptwi_clock {
86 u8 filter; /* Bits 15:12, default = 0x03 */
87 u16 clock; /* Bits 9:0, default = 0x001f */
88 };
89
90 struct pmcmsptwi_clockcfg {
91 struct pmcmsptwi_clock standard; /* The standard/fast clock config */
92 struct pmcmsptwi_clock highspeed; /* The highspeed clock config */
93 };
94
95 /* Corresponds to the main TWI configuration register */
96 struct pmcmsptwi_cfg {
97 u8 arbf; /* Bits 15:12, default=0x03 */
98 u8 nak; /* Bits 11:8, default=0x03 */
99 u8 add10; /* Bit 7, default=0x00 */
100 u8 mst_code; /* Bits 6:4, default=0x00 */
101 u8 arb; /* Bit 1, default=0x01 */
102 u8 highspeed; /* Bit 0, default=0x00 */
103 };
104
105 /* A single pmctwi command to issue */
106 struct pmcmsptwi_cmd {
107 u16 addr; /* The slave address (7 or 10 bits) */
108 enum pmcmsptwi_cmd_type type; /* The command type */
109 u8 write_len; /* Number of bytes in the write buffer */
110 u8 read_len; /* Number of bytes in the read buffer */
111 u8 *write_data; /* Buffer of characters to send */
112 u8 *read_data; /* Buffer to fill with incoming data */
113 };
114
115 /* The private data */
116 struct pmcmsptwi_data {
117 void __iomem *iobase; /* iomapped base for IO */
118 int irq; /* IRQ to use (0 disables) */
119 struct completion wait; /* Completion for xfer */
120 struct mutex lock; /* Used for threadsafeness */
121 enum pmcmsptwi_xfer_result last_result; /* result of last xfer */
122 };
123
124 /* The default settings */
125 static const struct pmcmsptwi_clockcfg pmcmsptwi_defclockcfg = {
126 .standard = {
127 .filter = 0x3,
128 .clock = 0x1f,
129 },
130 .highspeed = {
131 .filter = 0x3,
132 .clock = 0x1f,
133 },
134 };
135
136 static const struct pmcmsptwi_cfg pmcmsptwi_defcfg = {
137 .arbf = 0x03,
138 .nak = 0x03,
139 .add10 = 0x00,
140 .mst_code = 0x00,
141 .arb = 0x01,
142 .highspeed = 0x00,
143 };
144
145 static struct pmcmsptwi_data pmcmsptwi_data;
146
147 static struct i2c_adapter pmcmsptwi_adapter;
148
149 /* inline helper functions */
150 static inline u32 pmcmsptwi_clock_to_reg(
151 const struct pmcmsptwi_clock *clock)
152 {
153 return ((clock->filter & 0xf) << 12) | (clock->clock & 0x03ff);
154 }
155
156 static inline void pmcmsptwi_reg_to_clock(
157 u32 reg, struct pmcmsptwi_clock *clock)
158 {
159 clock->filter = (reg >> 12) & 0xf;
160 clock->clock = reg & 0x03ff;
161 }
162
163 static inline u32 pmcmsptwi_cfg_to_reg(const struct pmcmsptwi_cfg *cfg)
164 {
165 return ((cfg->arbf & 0xf) << 12) |
166 ((cfg->nak & 0xf) << 8) |
167 ((cfg->add10 & 0x1) << 7) |
168 ((cfg->mst_code & 0x7) << 4) |
169 ((cfg->arb & 0x1) << 1) |
170 (cfg->highspeed & 0x1);
171 }
172
173 static inline void pmcmsptwi_reg_to_cfg(u32 reg, struct pmcmsptwi_cfg *cfg)
174 {
175 cfg->arbf = (reg >> 12) & 0xf;
176 cfg->nak = (reg >> 8) & 0xf;
177 cfg->add10 = (reg >> 7) & 0x1;
178 cfg->mst_code = (reg >> 4) & 0x7;
179 cfg->arb = (reg >> 1) & 0x1;
180 cfg->highspeed = reg & 0x1;
181 }
182
183 /*
184 * Sets the current clock configuration
185 */
186 static void pmcmsptwi_set_clock_config(const struct pmcmsptwi_clockcfg *cfg,
187 struct pmcmsptwi_data *data)
188 {
189 mutex_lock(&data->lock);
190 pmcmsptwi_writel(pmcmsptwi_clock_to_reg(&cfg->standard),
191 data->iobase + MSP_TWI_SF_CLK_REG_OFFSET);
192 pmcmsptwi_writel(pmcmsptwi_clock_to_reg(&cfg->highspeed),
193 data->iobase + MSP_TWI_HS_CLK_REG_OFFSET);
194 mutex_unlock(&data->lock);
195 }
196
197 /*
198 * Gets the current TWI bus configuration
199 */
200 static void pmcmsptwi_get_twi_config(struct pmcmsptwi_cfg *cfg,
201 struct pmcmsptwi_data *data)
202 {
203 mutex_lock(&data->lock);
204 pmcmsptwi_reg_to_cfg(pmcmsptwi_readl(
205 data->iobase + MSP_TWI_CFG_REG_OFFSET), cfg);
206 mutex_unlock(&data->lock);
207 }
208
209 /*
210 * Sets the current TWI bus configuration
211 */
212 static void pmcmsptwi_set_twi_config(const struct pmcmsptwi_cfg *cfg,
213 struct pmcmsptwi_data *data)
214 {
215 mutex_lock(&data->lock);
216 pmcmsptwi_writel(pmcmsptwi_cfg_to_reg(cfg),
217 data->iobase + MSP_TWI_CFG_REG_OFFSET);
218 mutex_unlock(&data->lock);
219 }
220
221 /*
222 * Parses the 'int_sts' register and returns a well-defined error code
223 */
224 static enum pmcmsptwi_xfer_result pmcmsptwi_get_result(u32 reg)
225 {
226 if (reg & MSP_TWI_INT_STS_LOST_ARBITRATION) {
227 dev_dbg(&pmcmsptwi_adapter.dev,
228 "Result: Lost arbitration\n");
229 return MSP_TWI_XFER_LOST_ARBITRATION;
230 } else if (reg & MSP_TWI_INT_STS_NO_RESPONSE) {
231 dev_dbg(&pmcmsptwi_adapter.dev,
232 "Result: No response\n");
233 return MSP_TWI_XFER_NO_RESPONSE;
234 } else if (reg & MSP_TWI_INT_STS_DATA_COLLISION) {
235 dev_dbg(&pmcmsptwi_adapter.dev,
236 "Result: Data collision\n");
237 return MSP_TWI_XFER_DATA_COLLISION;
238 } else if (reg & MSP_TWI_INT_STS_BUSY) {
239 dev_dbg(&pmcmsptwi_adapter.dev,
240 "Result: Bus busy\n");
241 return MSP_TWI_XFER_BUSY;
242 }
243
244 dev_dbg(&pmcmsptwi_adapter.dev, "Result: Operation succeeded\n");
245 return MSP_TWI_XFER_OK;
246 }
247
248 /*
249 * In interrupt mode, handle the interrupt.
250 * NOTE: Assumes data->lock is held.
251 */
252 static irqreturn_t pmcmsptwi_interrupt(int irq, void *ptr)
253 {
254 struct pmcmsptwi_data *data = ptr;
255
256 u32 reason = pmcmsptwi_readl(data->iobase +
257 MSP_TWI_INT_STS_REG_OFFSET);
258 pmcmsptwi_writel(reason, data->iobase + MSP_TWI_INT_STS_REG_OFFSET);
259
260 dev_dbg(&pmcmsptwi_adapter.dev, "Got interrupt 0x%08x\n", reason);
261 if (!(reason & MSP_TWI_INT_STS_DONE))
262 return IRQ_NONE;
263
264 data->last_result = pmcmsptwi_get_result(reason);
265 complete(&data->wait);
266
267 return IRQ_HANDLED;
268 }
269
270 /*
271 * Probe for and register the device and return 0 if there is one.
272 */
273 static int __devinit pmcmsptwi_probe(struct platform_device *pldev)
274 {
275 struct resource *res;
276 int rc = -ENODEV;
277
278 /* get the static platform resources */
279 res = platform_get_resource(pldev, IORESOURCE_MEM, 0);
280 if (!res) {
281 dev_err(&pldev->dev, "IOMEM resource not found\n");
282 goto ret_err;
283 }
284
285 /* reserve the memory region */
286 if (!request_mem_region(res->start, resource_size(res),
287 pldev->name)) {
288 dev_err(&pldev->dev,
289 "Unable to get memory/io address region 0x%08x\n",
290 res->start);
291 rc = -EBUSY;
292 goto ret_err;
293 }
294
295 /* remap the memory */
296 pmcmsptwi_data.iobase = ioremap_nocache(res->start,
297 resource_size(res));
298 if (!pmcmsptwi_data.iobase) {
299 dev_err(&pldev->dev,
300 "Unable to ioremap address 0x%08x\n", res->start);
301 rc = -EIO;
302 goto ret_unreserve;
303 }
304
305 /* request the irq */
306 pmcmsptwi_data.irq = platform_get_irq(pldev, 0);
307 if (pmcmsptwi_data.irq) {
308 rc = request_irq(pmcmsptwi_data.irq, &pmcmsptwi_interrupt,
309 IRQF_SHARED | IRQF_DISABLED | IRQF_SAMPLE_RANDOM,
310 pldev->name, &pmcmsptwi_data);
311 if (rc == 0) {
312 /*
313 * Enable 'DONE' interrupt only.
314 *
315 * If you enable all interrupts, you will get one on
316 * error and another when the operation completes.
317 * This way you only have to handle one interrupt,
318 * but you can still check all result flags.
319 */
320 pmcmsptwi_writel(MSP_TWI_INT_STS_DONE,
321 pmcmsptwi_data.iobase +
322 MSP_TWI_INT_MSK_REG_OFFSET);
323 } else {
324 dev_warn(&pldev->dev,
325 "Could not assign TWI IRQ handler "
326 "to irq %d (continuing with poll)\n",
327 pmcmsptwi_data.irq);
328 pmcmsptwi_data.irq = 0;
329 }
330 }
331
332 init_completion(&pmcmsptwi_data.wait);
333 mutex_init(&pmcmsptwi_data.lock);
334
335 pmcmsptwi_set_clock_config(&pmcmsptwi_defclockcfg, &pmcmsptwi_data);
336 pmcmsptwi_set_twi_config(&pmcmsptwi_defcfg, &pmcmsptwi_data);
337
338 printk(KERN_INFO DRV_NAME ": Registering MSP71xx I2C adapter\n");
339
340 pmcmsptwi_adapter.dev.parent = &pldev->dev;
341 platform_set_drvdata(pldev, &pmcmsptwi_adapter);
342 i2c_set_adapdata(&pmcmsptwi_adapter, &pmcmsptwi_data);
343
344 rc = i2c_add_adapter(&pmcmsptwi_adapter);
345 if (rc) {
346 dev_err(&pldev->dev, "Unable to register I2C adapter\n");
347 goto ret_unmap;
348 }
349
350 return 0;
351
352 ret_unmap:
353 platform_set_drvdata(pldev, NULL);
354 if (pmcmsptwi_data.irq) {
355 pmcmsptwi_writel(0,
356 pmcmsptwi_data.iobase + MSP_TWI_INT_MSK_REG_OFFSET);
357 free_irq(pmcmsptwi_data.irq, &pmcmsptwi_data);
358 }
359
360 iounmap(pmcmsptwi_data.iobase);
361
362 ret_unreserve:
363 release_mem_region(res->start, resource_size(res));
364
365 ret_err:
366 return rc;
367 }
368
369 /*
370 * Release the device and return 0 if there is one.
371 */
372 static int __devexit pmcmsptwi_remove(struct platform_device *pldev)
373 {
374 struct resource *res;
375
376 i2c_del_adapter(&pmcmsptwi_adapter);
377
378 platform_set_drvdata(pldev, NULL);
379 if (pmcmsptwi_data.irq) {
380 pmcmsptwi_writel(0,
381 pmcmsptwi_data.iobase + MSP_TWI_INT_MSK_REG_OFFSET);
382 free_irq(pmcmsptwi_data.irq, &pmcmsptwi_data);
383 }
384
385 iounmap(pmcmsptwi_data.iobase);
386
387 res = platform_get_resource(pldev, IORESOURCE_MEM, 0);
388 release_mem_region(res->start, resource_size(res));
389
390 return 0;
391 }
392
393 /*
394 * Polls the 'busy' register until the command is complete.
395 * NOTE: Assumes data->lock is held.
396 */
397 static void pmcmsptwi_poll_complete(struct pmcmsptwi_data *data)
398 {
399 int i;
400
401 for (i = 0; i < MSP_MAX_POLL; i++) {
402 u32 val = pmcmsptwi_readl(data->iobase +
403 MSP_TWI_BUSY_REG_OFFSET);
404 if (val == 0) {
405 u32 reason = pmcmsptwi_readl(data->iobase +
406 MSP_TWI_INT_STS_REG_OFFSET);
407 pmcmsptwi_writel(reason, data->iobase +
408 MSP_TWI_INT_STS_REG_OFFSET);
409 data->last_result = pmcmsptwi_get_result(reason);
410 return;
411 }
412 udelay(MSP_POLL_DELAY);
413 }
414
415 dev_dbg(&pmcmsptwi_adapter.dev, "Result: Poll timeout\n");
416 data->last_result = MSP_TWI_XFER_TIMEOUT;
417 }
418
419 /*
420 * Do the transfer (low level):
421 * May use interrupt-driven or polling, depending on if an IRQ is
422 * presently registered.
423 * NOTE: Assumes data->lock is held.
424 */
425 static enum pmcmsptwi_xfer_result pmcmsptwi_do_xfer(
426 u32 reg, struct pmcmsptwi_data *data)
427 {
428 dev_dbg(&pmcmsptwi_adapter.dev, "Writing cmd reg 0x%08x\n", reg);
429 pmcmsptwi_writel(reg, data->iobase + MSP_TWI_CMD_REG_OFFSET);
430 if (data->irq) {
431 unsigned long timeleft = wait_for_completion_timeout(
432 &data->wait, MSP_IRQ_TIMEOUT);
433 if (timeleft == 0) {
434 dev_dbg(&pmcmsptwi_adapter.dev,
435 "Result: IRQ timeout\n");
436 complete(&data->wait);
437 data->last_result = MSP_TWI_XFER_TIMEOUT;
438 }
439 } else
440 pmcmsptwi_poll_complete(data);
441
442 return data->last_result;
443 }
444
445 /*
446 * Helper routine, converts 'pmctwi_cmd' struct to register format
447 */
448 static inline u32 pmcmsptwi_cmd_to_reg(const struct pmcmsptwi_cmd *cmd)
449 {
450 return ((cmd->type & 0x3) << 8) |
451 (((cmd->write_len - 1) & 0x7) << 4) |
452 ((cmd->read_len - 1) & 0x7);
453 }
454
455 /*
456 * Do the transfer (high level)
457 */
458 static enum pmcmsptwi_xfer_result pmcmsptwi_xfer_cmd(
459 struct pmcmsptwi_cmd *cmd,
460 struct pmcmsptwi_data *data)
461 {
462 enum pmcmsptwi_xfer_result retval;
463
464 if ((cmd->type == MSP_TWI_CMD_WRITE && cmd->write_len == 0) ||
465 (cmd->type == MSP_TWI_CMD_READ && cmd->read_len == 0) ||
466 (cmd->type == MSP_TWI_CMD_WRITE_READ &&
467 (cmd->read_len == 0 || cmd->write_len == 0))) {
468 dev_err(&pmcmsptwi_adapter.dev,
469 "%s: Cannot transfer less than 1 byte\n",
470 __func__);
471 return -EINVAL;
472 }
473
474 if (cmd->read_len > MSP_MAX_BYTES_PER_RW ||
475 cmd->write_len > MSP_MAX_BYTES_PER_RW) {
476 dev_err(&pmcmsptwi_adapter.dev,
477 "%s: Cannot transfer more than %d bytes\n",
478 __func__, MSP_MAX_BYTES_PER_RW);
479 return -EINVAL;
480 }
481
482 mutex_lock(&data->lock);
483 dev_dbg(&pmcmsptwi_adapter.dev,
484 "Setting address to 0x%04x\n", cmd->addr);
485 pmcmsptwi_writel(cmd->addr, data->iobase + MSP_TWI_ADD_REG_OFFSET);
486
487 if (cmd->type == MSP_TWI_CMD_WRITE ||
488 cmd->type == MSP_TWI_CMD_WRITE_READ) {
489 u64 tmp = be64_to_cpup((__be64 *)cmd->write_data);
490 tmp >>= (MSP_MAX_BYTES_PER_RW - cmd->write_len) * 8;
491 dev_dbg(&pmcmsptwi_adapter.dev, "Writing 0x%016llx\n", tmp);
492 pmcmsptwi_writel(tmp & 0x00000000ffffffffLL,
493 data->iobase + MSP_TWI_DAT_0_REG_OFFSET);
494 if (cmd->write_len > 4)
495 pmcmsptwi_writel(tmp >> 32,
496 data->iobase + MSP_TWI_DAT_1_REG_OFFSET);
497 }
498
499 retval = pmcmsptwi_do_xfer(pmcmsptwi_cmd_to_reg(cmd), data);
500 if (retval != MSP_TWI_XFER_OK)
501 goto xfer_err;
502
503 if (cmd->type == MSP_TWI_CMD_READ ||
504 cmd->type == MSP_TWI_CMD_WRITE_READ) {
505 int i;
506 u64 rmsk = ~(0xffffffffffffffffLL << (cmd->read_len * 8));
507 u64 tmp = (u64)pmcmsptwi_readl(data->iobase +
508 MSP_TWI_DAT_0_REG_OFFSET);
509 if (cmd->read_len > 4)
510 tmp |= (u64)pmcmsptwi_readl(data->iobase +
511 MSP_TWI_DAT_1_REG_OFFSET) << 32;
512 tmp &= rmsk;
513 dev_dbg(&pmcmsptwi_adapter.dev, "Read 0x%016llx\n", tmp);
514
515 for (i = 0; i < cmd->read_len; i++)
516 cmd->read_data[i] = tmp >> i;
517 }
518
519 xfer_err:
520 mutex_unlock(&data->lock);
521
522 return retval;
523 }
524
525 /* -- Algorithm functions -- */
526
527 /*
528 * Sends an i2c command out on the adapter
529 */
530 static int pmcmsptwi_master_xfer(struct i2c_adapter *adap,
531 struct i2c_msg *msg, int num)
532 {
533 struct pmcmsptwi_data *data = i2c_get_adapdata(adap);
534 struct pmcmsptwi_cmd cmd;
535 struct pmcmsptwi_cfg oldcfg, newcfg;
536 int ret;
537
538 if (num > 2) {
539 dev_dbg(&adap->dev, "%d messages unsupported\n", num);
540 return -EINVAL;
541 } else if (num == 2) {
542 /* Check for a dual write-then-read command */
543 struct i2c_msg *nextmsg = msg + 1;
544 if (!(msg->flags & I2C_M_RD) &&
545 (nextmsg->flags & I2C_M_RD) &&
546 msg->addr == nextmsg->addr) {
547 cmd.type = MSP_TWI_CMD_WRITE_READ;
548 cmd.write_len = msg->len;
549 cmd.write_data = msg->buf;
550 cmd.read_len = nextmsg->len;
551 cmd.read_data = nextmsg->buf;
552 } else {
553 dev_dbg(&adap->dev,
554 "Non write-read dual messages unsupported\n");
555 return -EINVAL;
556 }
557 } else if (msg->flags & I2C_M_RD) {
558 cmd.type = MSP_TWI_CMD_READ;
559 cmd.read_len = msg->len;
560 cmd.read_data = msg->buf;
561 cmd.write_len = 0;
562 cmd.write_data = NULL;
563 } else {
564 cmd.type = MSP_TWI_CMD_WRITE;
565 cmd.read_len = 0;
566 cmd.read_data = NULL;
567 cmd.write_len = msg->len;
568 cmd.write_data = msg->buf;
569 }
570
571 if (msg->len == 0) {
572 dev_err(&adap->dev, "Zero-byte messages unsupported\n");
573 return -EINVAL;
574 }
575
576 cmd.addr = msg->addr;
577
578 if (msg->flags & I2C_M_TEN) {
579 pmcmsptwi_get_twi_config(&newcfg, data);
580 memcpy(&oldcfg, &newcfg, sizeof(oldcfg));
581
582 /* Set the special 10-bit address flag */
583 newcfg.add10 = 1;
584
585 pmcmsptwi_set_twi_config(&newcfg, data);
586 }
587
588 /* Execute the command */
589 ret = pmcmsptwi_xfer_cmd(&cmd, data);
590
591 if (msg->flags & I2C_M_TEN)
592 pmcmsptwi_set_twi_config(&oldcfg, data);
593
594 dev_dbg(&adap->dev, "I2C %s of %d bytes %s\n",
595 (msg->flags & I2C_M_RD) ? "read" : "write", msg->len,
596 (ret == MSP_TWI_XFER_OK) ? "succeeded" : "failed");
597
598 if (ret != MSP_TWI_XFER_OK) {
599 /*
600 * TODO: We could potentially loop and retry in the case
601 * of MSP_TWI_XFER_TIMEOUT.
602 */
603 return -1;
604 }
605
606 return 0;
607 }
608
609 static u32 pmcmsptwi_i2c_func(struct i2c_adapter *adapter)
610 {
611 return I2C_FUNC_I2C | I2C_FUNC_10BIT_ADDR |
612 I2C_FUNC_SMBUS_BYTE | I2C_FUNC_SMBUS_BYTE_DATA |
613 I2C_FUNC_SMBUS_WORD_DATA | I2C_FUNC_SMBUS_PROC_CALL;
614 }
615
616 /* -- Initialization -- */
617
618 static struct i2c_algorithm pmcmsptwi_algo = {
619 .master_xfer = pmcmsptwi_master_xfer,
620 .functionality = pmcmsptwi_i2c_func,
621 };
622
623 static struct i2c_adapter pmcmsptwi_adapter = {
624 .owner = THIS_MODULE,
625 .class = I2C_CLASS_HWMON | I2C_CLASS_SPD,
626 .algo = &pmcmsptwi_algo,
627 .name = DRV_NAME,
628 };
629
630 /* work with hotplug and coldplug */
631 MODULE_ALIAS("platform:" DRV_NAME);
632
633 static struct platform_driver pmcmsptwi_driver = {
634 .probe = pmcmsptwi_probe,
635 .remove = __devexit_p(pmcmsptwi_remove),
636 .driver = {
637 .name = DRV_NAME,
638 .owner = THIS_MODULE,
639 },
640 };
641
642 static int __init pmcmsptwi_init(void)
643 {
644 return platform_driver_register(&pmcmsptwi_driver);
645 }
646
647 static void __exit pmcmsptwi_exit(void)
648 {
649 platform_driver_unregister(&pmcmsptwi_driver);
650 }
651
652 MODULE_DESCRIPTION("PMC MSP TWI/SMBus/I2C driver");
653 MODULE_LICENSE("GPL");
654
655 module_init(pmcmsptwi_init);
656 module_exit(pmcmsptwi_exit);
x86 "subsystem" repository