Version:  2.0.40 2.2.26 2.4.37 3.6 3.7 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

Linux/drivers/i2c/busses/i2c-pmcmsp.c

  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 
 23 #include <linux/kernel.h>
 24 #include <linux/module.h>
 25 #include <linux/platform_device.h>
 26 #include <linux/i2c.h>
 27 #include <linux/interrupt.h>
 28 #include <linux/completion.h>
 29 #include <linux/mutex.h>
 30 #include <linux/delay.h>
 31 #include <linux/io.h>
 32 
 33 #define DRV_NAME        "pmcmsptwi"
 34 
 35 #define MSP_TWI_SF_CLK_REG_OFFSET       0x00
 36 #define MSP_TWI_HS_CLK_REG_OFFSET       0x04
 37 #define MSP_TWI_CFG_REG_OFFSET          0x08
 38 #define MSP_TWI_CMD_REG_OFFSET          0x0c
 39 #define MSP_TWI_ADD_REG_OFFSET          0x10
 40 #define MSP_TWI_DAT_0_REG_OFFSET        0x14
 41 #define MSP_TWI_DAT_1_REG_OFFSET        0x18
 42 #define MSP_TWI_INT_STS_REG_OFFSET      0x1c
 43 #define MSP_TWI_INT_MSK_REG_OFFSET      0x20
 44 #define MSP_TWI_BUSY_REG_OFFSET         0x24
 45 
 46 #define MSP_TWI_INT_STS_DONE                    (1 << 0)
 47 #define MSP_TWI_INT_STS_LOST_ARBITRATION        (1 << 1)
 48 #define MSP_TWI_INT_STS_NO_RESPONSE             (1 << 2)
 49 #define MSP_TWI_INT_STS_DATA_COLLISION          (1 << 3)
 50 #define MSP_TWI_INT_STS_BUSY                    (1 << 4)
 51 #define MSP_TWI_INT_STS_ALL                     0x1f
 52 
 53 #define MSP_MAX_BYTES_PER_RW            8
 54 #define MSP_MAX_POLL                    5
 55 #define MSP_POLL_DELAY                  10
 56 #define MSP_IRQ_TIMEOUT                 (MSP_MAX_POLL * MSP_POLL_DELAY)
 57 
 58 /* IO Operation macros */
 59 #define pmcmsptwi_readl         __raw_readl
 60 #define pmcmsptwi_writel        __raw_writel
 61 
 62 /* TWI command type */
 63 enum pmcmsptwi_cmd_type {
 64         MSP_TWI_CMD_WRITE       = 0,    /* Write only */
 65         MSP_TWI_CMD_READ        = 1,    /* Read only */
 66         MSP_TWI_CMD_WRITE_READ  = 2,    /* Write then Read */
 67 };
 68 
 69 /* The possible results of the xferCmd */
 70 enum pmcmsptwi_xfer_result {
 71         MSP_TWI_XFER_OK = 0,
 72         MSP_TWI_XFER_TIMEOUT,
 73         MSP_TWI_XFER_BUSY,
 74         MSP_TWI_XFER_DATA_COLLISION,
 75         MSP_TWI_XFER_NO_RESPONSE,
 76         MSP_TWI_XFER_LOST_ARBITRATION,
 77 };
 78 
 79 /* Corresponds to a PMCTWI clock configuration register */
 80 struct pmcmsptwi_clock {
 81         u8 filter;      /* Bits 15:12,  default = 0x03 */
 82         u16 clock;      /* Bits 9:0,    default = 0x001f */
 83 };
 84 
 85 struct pmcmsptwi_clockcfg {
 86         struct pmcmsptwi_clock standard;  /* The standard/fast clock config */
 87         struct pmcmsptwi_clock highspeed; /* The highspeed clock config */
 88 };
 89 
 90 /* Corresponds to the main TWI configuration register */
 91 struct pmcmsptwi_cfg {
 92         u8 arbf;        /* Bits 15:12,  default=0x03 */
 93         u8 nak;         /* Bits 11:8,   default=0x03 */
 94         u8 add10;       /* Bit 7,       default=0x00 */
 95         u8 mst_code;    /* Bits 6:4,    default=0x00 */
 96         u8 arb;         /* Bit 1,       default=0x01 */
 97         u8 highspeed;   /* Bit 0,       default=0x00 */
 98 };
 99 
100 /* A single pmctwi command to issue */
101 struct pmcmsptwi_cmd {
102         u16 addr;       /* The slave address (7 or 10 bits) */
103         enum pmcmsptwi_cmd_type type;   /* The command type */
104         u8 write_len;   /* Number of bytes in the write buffer */
105         u8 read_len;    /* Number of bytes in the read buffer */
106         u8 *write_data; /* Buffer of characters to send */
107         u8 *read_data;  /* Buffer to fill with incoming data */
108 };
109 
110 /* The private data */
111 struct pmcmsptwi_data {
112         void __iomem *iobase;                   /* iomapped base for IO */
113         int irq;                                /* IRQ to use (0 disables) */
114         struct completion wait;                 /* Completion for xfer */
115         struct mutex lock;                      /* Used for threadsafeness */
116         enum pmcmsptwi_xfer_result last_result; /* result of last xfer */
117 };
118 
119 /* The default settings */
120 static const struct pmcmsptwi_clockcfg pmcmsptwi_defclockcfg = {
121         .standard = {
122                 .filter = 0x3,
123                 .clock  = 0x1f,
124         },
125         .highspeed = {
126                 .filter = 0x3,
127                 .clock  = 0x1f,
128         },
129 };
130 
131 static const struct pmcmsptwi_cfg pmcmsptwi_defcfg = {
132         .arbf           = 0x03,
133         .nak            = 0x03,
134         .add10          = 0x00,
135         .mst_code       = 0x00,
136         .arb            = 0x01,
137         .highspeed      = 0x00,
138 };
139 
140 static struct pmcmsptwi_data pmcmsptwi_data;
141 
142 static struct i2c_adapter pmcmsptwi_adapter;
143 
144 /* inline helper functions */
145 static inline u32 pmcmsptwi_clock_to_reg(
146                         const struct pmcmsptwi_clock *clock)
147 {
148         return ((clock->filter & 0xf) << 12) | (clock->clock & 0x03ff);
149 }
150 
151 static inline u32 pmcmsptwi_cfg_to_reg(const struct pmcmsptwi_cfg *cfg)
152 {
153         return ((cfg->arbf & 0xf) << 12) |
154                 ((cfg->nak & 0xf) << 8) |
155                 ((cfg->add10 & 0x1) << 7) |
156                 ((cfg->mst_code & 0x7) << 4) |
157                 ((cfg->arb & 0x1) << 1) |
158                 (cfg->highspeed & 0x1);
159 }
160 
161 static inline void pmcmsptwi_reg_to_cfg(u32 reg, struct pmcmsptwi_cfg *cfg)
162 {
163         cfg->arbf = (reg >> 12) & 0xf;
164         cfg->nak = (reg >> 8) & 0xf;
165         cfg->add10 = (reg >> 7) & 0x1;
166         cfg->mst_code = (reg >> 4) & 0x7;
167         cfg->arb = (reg >> 1) & 0x1;
168         cfg->highspeed = reg & 0x1;
169 }
170 
171 /*
172  * Sets the current clock configuration
173  */
174 static void pmcmsptwi_set_clock_config(const struct pmcmsptwi_clockcfg *cfg,
175                                         struct pmcmsptwi_data *data)
176 {
177         mutex_lock(&data->lock);
178         pmcmsptwi_writel(pmcmsptwi_clock_to_reg(&cfg->standard),
179                                 data->iobase + MSP_TWI_SF_CLK_REG_OFFSET);
180         pmcmsptwi_writel(pmcmsptwi_clock_to_reg(&cfg->highspeed),
181                                 data->iobase + MSP_TWI_HS_CLK_REG_OFFSET);
182         mutex_unlock(&data->lock);
183 }
184 
185 /*
186  * Gets the current TWI bus configuration
187  */
188 static void pmcmsptwi_get_twi_config(struct pmcmsptwi_cfg *cfg,
189                                         struct pmcmsptwi_data *data)
190 {
191         mutex_lock(&data->lock);
192         pmcmsptwi_reg_to_cfg(pmcmsptwi_readl(
193                                 data->iobase + MSP_TWI_CFG_REG_OFFSET), cfg);
194         mutex_unlock(&data->lock);
195 }
196 
197 /*
198  * Sets the current TWI bus configuration
199  */
200 static void pmcmsptwi_set_twi_config(const struct pmcmsptwi_cfg *cfg,
201                                         struct pmcmsptwi_data *data)
202 {
203         mutex_lock(&data->lock);
204         pmcmsptwi_writel(pmcmsptwi_cfg_to_reg(cfg),
205                                 data->iobase + MSP_TWI_CFG_REG_OFFSET);
206         mutex_unlock(&data->lock);
207 }
208 
209 /*
210  * Parses the 'int_sts' register and returns a well-defined error code
211  */
212 static enum pmcmsptwi_xfer_result pmcmsptwi_get_result(u32 reg)
213 {
214         if (reg & MSP_TWI_INT_STS_LOST_ARBITRATION) {
215                 dev_dbg(&pmcmsptwi_adapter.dev,
216                         "Result: Lost arbitration\n");
217                 return MSP_TWI_XFER_LOST_ARBITRATION;
218         } else if (reg & MSP_TWI_INT_STS_NO_RESPONSE) {
219                 dev_dbg(&pmcmsptwi_adapter.dev,
220                         "Result: No response\n");
221                 return MSP_TWI_XFER_NO_RESPONSE;
222         } else if (reg & MSP_TWI_INT_STS_DATA_COLLISION) {
223                 dev_dbg(&pmcmsptwi_adapter.dev,
224                         "Result: Data collision\n");
225                 return MSP_TWI_XFER_DATA_COLLISION;
226         } else if (reg & MSP_TWI_INT_STS_BUSY) {
227                 dev_dbg(&pmcmsptwi_adapter.dev,
228                         "Result: Bus busy\n");
229                 return MSP_TWI_XFER_BUSY;
230         }
231 
232         dev_dbg(&pmcmsptwi_adapter.dev, "Result: Operation succeeded\n");
233         return MSP_TWI_XFER_OK;
234 }
235 
236 /*
237  * In interrupt mode, handle the interrupt.
238  * NOTE: Assumes data->lock is held.
239  */
240 static irqreturn_t pmcmsptwi_interrupt(int irq, void *ptr)
241 {
242         struct pmcmsptwi_data *data = ptr;
243 
244         u32 reason = pmcmsptwi_readl(data->iobase +
245                                         MSP_TWI_INT_STS_REG_OFFSET);
246         pmcmsptwi_writel(reason, data->iobase + MSP_TWI_INT_STS_REG_OFFSET);
247 
248         dev_dbg(&pmcmsptwi_adapter.dev, "Got interrupt 0x%08x\n", reason);
249         if (!(reason & MSP_TWI_INT_STS_DONE))
250                 return IRQ_NONE;
251 
252         data->last_result = pmcmsptwi_get_result(reason);
253         complete(&data->wait);
254 
255         return IRQ_HANDLED;
256 }
257 
258 /*
259  * Probe for and register the device and return 0 if there is one.
260  */
261 static int pmcmsptwi_probe(struct platform_device *pldev)
262 {
263         struct resource *res;
264         int rc = -ENODEV;
265 
266         /* get the static platform resources */
267         res = platform_get_resource(pldev, IORESOURCE_MEM, 0);
268         if (!res) {
269                 dev_err(&pldev->dev, "IOMEM resource not found\n");
270                 goto ret_err;
271         }
272 
273         /* reserve the memory region */
274         if (!request_mem_region(res->start, resource_size(res),
275                                 pldev->name)) {
276                 dev_err(&pldev->dev,
277                         "Unable to get memory/io address region 0x%08x\n",
278                         res->start);
279                 rc = -EBUSY;
280                 goto ret_err;
281         }
282 
283         /* remap the memory */
284         pmcmsptwi_data.iobase = ioremap_nocache(res->start,
285                                                 resource_size(res));
286         if (!pmcmsptwi_data.iobase) {
287                 dev_err(&pldev->dev,
288                         "Unable to ioremap address 0x%08x\n", res->start);
289                 rc = -EIO;
290                 goto ret_unreserve;
291         }
292 
293         /* request the irq */
294         pmcmsptwi_data.irq = platform_get_irq(pldev, 0);
295         if (pmcmsptwi_data.irq) {
296                 rc = request_irq(pmcmsptwi_data.irq, &pmcmsptwi_interrupt,
297                                  IRQF_SHARED, pldev->name, &pmcmsptwi_data);
298                 if (rc == 0) {
299                         /*
300                          * Enable 'DONE' interrupt only.
301                          *
302                          * If you enable all interrupts, you will get one on
303                          * error and another when the operation completes.
304                          * This way you only have to handle one interrupt,
305                          * but you can still check all result flags.
306                          */
307                         pmcmsptwi_writel(MSP_TWI_INT_STS_DONE,
308                                         pmcmsptwi_data.iobase +
309                                         MSP_TWI_INT_MSK_REG_OFFSET);
310                 } else {
311                         dev_warn(&pldev->dev,
312                                 "Could not assign TWI IRQ handler "
313                                 "to irq %d (continuing with poll)\n",
314                                 pmcmsptwi_data.irq);
315                         pmcmsptwi_data.irq = 0;
316                 }
317         }
318 
319         init_completion(&pmcmsptwi_data.wait);
320         mutex_init(&pmcmsptwi_data.lock);
321 
322         pmcmsptwi_set_clock_config(&pmcmsptwi_defclockcfg, &pmcmsptwi_data);
323         pmcmsptwi_set_twi_config(&pmcmsptwi_defcfg, &pmcmsptwi_data);
324 
325         printk(KERN_INFO DRV_NAME ": Registering MSP71xx I2C adapter\n");
326 
327         pmcmsptwi_adapter.dev.parent = &pldev->dev;
328         platform_set_drvdata(pldev, &pmcmsptwi_adapter);
329         i2c_set_adapdata(&pmcmsptwi_adapter, &pmcmsptwi_data);
330 
331         rc = i2c_add_adapter(&pmcmsptwi_adapter);
332         if (rc) {
333                 dev_err(&pldev->dev, "Unable to register I2C adapter\n");
334                 goto ret_unmap;
335         }
336 
337         return 0;
338 
339 ret_unmap:
340         if (pmcmsptwi_data.irq) {
341                 pmcmsptwi_writel(0,
342                         pmcmsptwi_data.iobase + MSP_TWI_INT_MSK_REG_OFFSET);
343                 free_irq(pmcmsptwi_data.irq, &pmcmsptwi_data);
344         }
345 
346         iounmap(pmcmsptwi_data.iobase);
347 
348 ret_unreserve:
349         release_mem_region(res->start, resource_size(res));
350 
351 ret_err:
352         return rc;
353 }
354 
355 /*
356  * Release the device and return 0 if there is one.
357  */
358 static int pmcmsptwi_remove(struct platform_device *pldev)
359 {
360         struct resource *res;
361 
362         i2c_del_adapter(&pmcmsptwi_adapter);
363 
364         if (pmcmsptwi_data.irq) {
365                 pmcmsptwi_writel(0,
366                         pmcmsptwi_data.iobase + MSP_TWI_INT_MSK_REG_OFFSET);
367                 free_irq(pmcmsptwi_data.irq, &pmcmsptwi_data);
368         }
369 
370         iounmap(pmcmsptwi_data.iobase);
371 
372         res = platform_get_resource(pldev, IORESOURCE_MEM, 0);
373         release_mem_region(res->start, resource_size(res));
374 
375         return 0;
376 }
377 
378 /*
379  * Polls the 'busy' register until the command is complete.
380  * NOTE: Assumes data->lock is held.
381  */
382 static void pmcmsptwi_poll_complete(struct pmcmsptwi_data *data)
383 {
384         int i;
385 
386         for (i = 0; i < MSP_MAX_POLL; i++) {
387                 u32 val = pmcmsptwi_readl(data->iobase +
388                                                 MSP_TWI_BUSY_REG_OFFSET);
389                 if (val == 0) {
390                         u32 reason = pmcmsptwi_readl(data->iobase +
391                                                 MSP_TWI_INT_STS_REG_OFFSET);
392                         pmcmsptwi_writel(reason, data->iobase +
393                                                 MSP_TWI_INT_STS_REG_OFFSET);
394                         data->last_result = pmcmsptwi_get_result(reason);
395                         return;
396                 }
397                 udelay(MSP_POLL_DELAY);
398         }
399 
400         dev_dbg(&pmcmsptwi_adapter.dev, "Result: Poll timeout\n");
401         data->last_result = MSP_TWI_XFER_TIMEOUT;
402 }
403 
404 /*
405  * Do the transfer (low level):
406  *   May use interrupt-driven or polling, depending on if an IRQ is
407  *   presently registered.
408  * NOTE: Assumes data->lock is held.
409  */
410 static enum pmcmsptwi_xfer_result pmcmsptwi_do_xfer(
411                         u32 reg, struct pmcmsptwi_data *data)
412 {
413         dev_dbg(&pmcmsptwi_adapter.dev, "Writing cmd reg 0x%08x\n", reg);
414         pmcmsptwi_writel(reg, data->iobase + MSP_TWI_CMD_REG_OFFSET);
415         if (data->irq) {
416                 unsigned long timeleft = wait_for_completion_timeout(
417                                                 &data->wait, MSP_IRQ_TIMEOUT);
418                 if (timeleft == 0) {
419                         dev_dbg(&pmcmsptwi_adapter.dev,
420                                 "Result: IRQ timeout\n");
421                         complete(&data->wait);
422                         data->last_result = MSP_TWI_XFER_TIMEOUT;
423                 }
424         } else
425                 pmcmsptwi_poll_complete(data);
426 
427         return data->last_result;
428 }
429 
430 /*
431  * Helper routine, converts 'pmctwi_cmd' struct to register format
432  */
433 static inline u32 pmcmsptwi_cmd_to_reg(const struct pmcmsptwi_cmd *cmd)
434 {
435         return ((cmd->type & 0x3) << 8) |
436                 (((cmd->write_len - 1) & 0x7) << 4) |
437                 ((cmd->read_len - 1) & 0x7);
438 }
439 
440 /*
441  * Do the transfer (high level)
442  */
443 static enum pmcmsptwi_xfer_result pmcmsptwi_xfer_cmd(
444                         struct pmcmsptwi_cmd *cmd,
445                         struct pmcmsptwi_data *data)
446 {
447         enum pmcmsptwi_xfer_result retval;
448 
449         if ((cmd->type == MSP_TWI_CMD_WRITE && cmd->write_len == 0) ||
450             (cmd->type == MSP_TWI_CMD_READ && cmd->read_len == 0) ||
451             (cmd->type == MSP_TWI_CMD_WRITE_READ &&
452             (cmd->read_len == 0 || cmd->write_len == 0))) {
453                 dev_err(&pmcmsptwi_adapter.dev,
454                         "%s: Cannot transfer less than 1 byte\n",
455                         __func__);
456                 return -EINVAL;
457         }
458 
459         mutex_lock(&data->lock);
460         dev_dbg(&pmcmsptwi_adapter.dev,
461                 "Setting address to 0x%04x\n", cmd->addr);
462         pmcmsptwi_writel(cmd->addr, data->iobase + MSP_TWI_ADD_REG_OFFSET);
463 
464         if (cmd->type == MSP_TWI_CMD_WRITE ||
465             cmd->type == MSP_TWI_CMD_WRITE_READ) {
466                 u64 tmp = be64_to_cpup((__be64 *)cmd->write_data);
467                 tmp >>= (MSP_MAX_BYTES_PER_RW - cmd->write_len) * 8;
468                 dev_dbg(&pmcmsptwi_adapter.dev, "Writing 0x%016llx\n", tmp);
469                 pmcmsptwi_writel(tmp & 0x00000000ffffffffLL,
470                                 data->iobase + MSP_TWI_DAT_0_REG_OFFSET);
471                 if (cmd->write_len > 4)
472                         pmcmsptwi_writel(tmp >> 32,
473                                 data->iobase + MSP_TWI_DAT_1_REG_OFFSET);
474         }
475 
476         retval = pmcmsptwi_do_xfer(pmcmsptwi_cmd_to_reg(cmd), data);
477         if (retval != MSP_TWI_XFER_OK)
478                 goto xfer_err;
479 
480         if (cmd->type == MSP_TWI_CMD_READ ||
481             cmd->type == MSP_TWI_CMD_WRITE_READ) {
482                 int i;
483                 u64 rmsk = ~(0xffffffffffffffffLL << (cmd->read_len * 8));
484                 u64 tmp = (u64)pmcmsptwi_readl(data->iobase +
485                                         MSP_TWI_DAT_0_REG_OFFSET);
486                 if (cmd->read_len > 4)
487                         tmp |= (u64)pmcmsptwi_readl(data->iobase +
488                                         MSP_TWI_DAT_1_REG_OFFSET) << 32;
489                 tmp &= rmsk;
490                 dev_dbg(&pmcmsptwi_adapter.dev, "Read 0x%016llx\n", tmp);
491 
492                 for (i = 0; i < cmd->read_len; i++)
493                         cmd->read_data[i] = tmp >> i;
494         }
495 
496 xfer_err:
497         mutex_unlock(&data->lock);
498 
499         return retval;
500 }
501 
502 /* -- Algorithm functions -- */
503 
504 /*
505  * Sends an i2c command out on the adapter
506  */
507 static int pmcmsptwi_master_xfer(struct i2c_adapter *adap,
508                                 struct i2c_msg *msg, int num)
509 {
510         struct pmcmsptwi_data *data = i2c_get_adapdata(adap);
511         struct pmcmsptwi_cmd cmd;
512         struct pmcmsptwi_cfg oldcfg, newcfg;
513         int ret;
514 
515         if (num == 2) {
516                 struct i2c_msg *nextmsg = msg + 1;
517 
518                 cmd.type = MSP_TWI_CMD_WRITE_READ;
519                 cmd.write_len = msg->len;
520                 cmd.write_data = msg->buf;
521                 cmd.read_len = nextmsg->len;
522                 cmd.read_data = nextmsg->buf;
523         } else if (msg->flags & I2C_M_RD) {
524                 cmd.type = MSP_TWI_CMD_READ;
525                 cmd.read_len = msg->len;
526                 cmd.read_data = msg->buf;
527                 cmd.write_len = 0;
528                 cmd.write_data = NULL;
529         } else {
530                 cmd.type = MSP_TWI_CMD_WRITE;
531                 cmd.read_len = 0;
532                 cmd.read_data = NULL;
533                 cmd.write_len = msg->len;
534                 cmd.write_data = msg->buf;
535         }
536 
537         if (msg->len == 0) {
538                 dev_err(&adap->dev, "Zero-byte messages unsupported\n");
539                 return -EINVAL;
540         }
541 
542         cmd.addr = msg->addr;
543 
544         if (msg->flags & I2C_M_TEN) {
545                 pmcmsptwi_get_twi_config(&newcfg, data);
546                 memcpy(&oldcfg, &newcfg, sizeof(oldcfg));
547 
548                 /* Set the special 10-bit address flag */
549                 newcfg.add10 = 1;
550 
551                 pmcmsptwi_set_twi_config(&newcfg, data);
552         }
553 
554         /* Execute the command */
555         ret = pmcmsptwi_xfer_cmd(&cmd, data);
556 
557         if (msg->flags & I2C_M_TEN)
558                 pmcmsptwi_set_twi_config(&oldcfg, data);
559 
560         dev_dbg(&adap->dev, "I2C %s of %d bytes %s\n",
561                 (msg->flags & I2C_M_RD) ? "read" : "write", msg->len,
562                 (ret == MSP_TWI_XFER_OK) ? "succeeded" : "failed");
563 
564         if (ret != MSP_TWI_XFER_OK) {
565                 /*
566                  * TODO: We could potentially loop and retry in the case
567                  * of MSP_TWI_XFER_TIMEOUT.
568                  */
569                 return -1;
570         }
571 
572         return 0;
573 }
574 
575 static u32 pmcmsptwi_i2c_func(struct i2c_adapter *adapter)
576 {
577         return I2C_FUNC_I2C | I2C_FUNC_10BIT_ADDR |
578                 I2C_FUNC_SMBUS_BYTE | I2C_FUNC_SMBUS_BYTE_DATA |
579                 I2C_FUNC_SMBUS_WORD_DATA | I2C_FUNC_SMBUS_PROC_CALL;
580 }
581 
582 static struct i2c_adapter_quirks pmcmsptwi_i2c_quirks = {
583         .flags = I2C_AQ_COMB_WRITE_THEN_READ,
584         .max_write_len = MSP_MAX_BYTES_PER_RW,
585         .max_read_len = MSP_MAX_BYTES_PER_RW,
586         .max_comb_1st_msg_len = MSP_MAX_BYTES_PER_RW,
587         .max_comb_2nd_msg_len = MSP_MAX_BYTES_PER_RW,
588 };
589 
590 /* -- Initialization -- */
591 
592 static struct i2c_algorithm pmcmsptwi_algo = {
593         .master_xfer    = pmcmsptwi_master_xfer,
594         .functionality  = pmcmsptwi_i2c_func,
595 };
596 
597 static struct i2c_adapter pmcmsptwi_adapter = {
598         .owner          = THIS_MODULE,
599         .class          = I2C_CLASS_HWMON | I2C_CLASS_SPD,
600         .algo           = &pmcmsptwi_algo,
601         .quirks         = &pmcmsptwi_i2c_quirks,
602         .name           = DRV_NAME,
603 };
604 
605 static struct platform_driver pmcmsptwi_driver = {
606         .probe  = pmcmsptwi_probe,
607         .remove = pmcmsptwi_remove,
608         .driver = {
609                 .name   = DRV_NAME,
610         },
611 };
612 
613 module_platform_driver(pmcmsptwi_driver);
614 
615 MODULE_DESCRIPTION("PMC MSP TWI/SMBus/I2C driver");
616 MODULE_LICENSE("GPL");
617 MODULE_ALIAS("platform:" DRV_NAME);
618 

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