2 * Specific bus support for PMC-TWI compliant implementation on MSP71xx.
4 * Copyright 2005-2007 PMC-Sierra, Inc.
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.
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.
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>
33 #define DRV_NAME "pmcmsptwi"
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
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
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)
58 /* IO Operation macros */
59 #define pmcmsptwi_readl __raw_readl
60 #define pmcmsptwi_writel __raw_writel
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 */
69 /* The possible results of the xferCmd */
70 enum pmcmsptwi_xfer_result {
74 MSP_TWI_XFER_DATA_COLLISION,
75 MSP_TWI_XFER_NO_RESPONSE,
76 MSP_TWI_XFER_LOST_ARBITRATION,
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 */
85 struct pmcmsptwi_clockcfg {
86 struct pmcmsptwi_clock standard; /* The standard/fast clock config */
87 struct pmcmsptwi_clock highspeed; /* The highspeed clock config */
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 */
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 */
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 */
119 /* The default settings */
120 static const struct pmcmsptwi_clockcfg pmcmsptwi_defclockcfg = {
131 static const struct pmcmsptwi_cfg pmcmsptwi_defcfg = {
140 static struct pmcmsptwi_data pmcmsptwi_data;
142 static struct i2c_adapter pmcmsptwi_adapter;
144 /* inline helper functions */
145 static inline u32 pmcmsptwi_clock_to_reg(
146 const struct pmcmsptwi_clock *clock)
148 return ((clock->filter & 0xf) << 12) | (clock->clock & 0x03ff);
151 static inline void pmcmsptwi_reg_to_clock(
152 u32 reg, struct pmcmsptwi_clock *clock)
154 clock->filter = (reg >> 12) & 0xf;
155 clock->clock = reg & 0x03ff;
158 static inline u32 pmcmsptwi_cfg_to_reg(const struct pmcmsptwi_cfg *cfg)
160 return ((cfg->arbf & 0xf) << 12) |
161 ((cfg->nak & 0xf) << 8) |
162 ((cfg->add10 & 0x1) << 7) |
163 ((cfg->mst_code & 0x7) << 4) |
164 ((cfg->arb & 0x1) << 1) |
165 (cfg->highspeed & 0x1);
168 static inline void pmcmsptwi_reg_to_cfg(u32 reg, struct pmcmsptwi_cfg *cfg)
170 cfg->arbf = (reg >> 12) & 0xf;
171 cfg->nak = (reg >> 8) & 0xf;
172 cfg->add10 = (reg >> 7) & 0x1;
173 cfg->mst_code = (reg >> 4) & 0x7;
174 cfg->arb = (reg >> 1) & 0x1;
175 cfg->highspeed = reg & 0x1;
179 * Sets the current clock configuration
181 static void pmcmsptwi_set_clock_config(const struct pmcmsptwi_clockcfg *cfg,
182 struct pmcmsptwi_data *data)
184 mutex_lock(&data->lock);
185 pmcmsptwi_writel(pmcmsptwi_clock_to_reg(&cfg->standard),
186 data->iobase + MSP_TWI_SF_CLK_REG_OFFSET);
187 pmcmsptwi_writel(pmcmsptwi_clock_to_reg(&cfg->highspeed),
188 data->iobase + MSP_TWI_HS_CLK_REG_OFFSET);
189 mutex_unlock(&data->lock);
193 * Gets the current TWI bus configuration
195 static void pmcmsptwi_get_twi_config(struct pmcmsptwi_cfg *cfg,
196 struct pmcmsptwi_data *data)
198 mutex_lock(&data->lock);
199 pmcmsptwi_reg_to_cfg(pmcmsptwi_readl(
200 data->iobase + MSP_TWI_CFG_REG_OFFSET), cfg);
201 mutex_unlock(&data->lock);
205 * Sets the current TWI bus configuration
207 static void pmcmsptwi_set_twi_config(const struct pmcmsptwi_cfg *cfg,
208 struct pmcmsptwi_data *data)
210 mutex_lock(&data->lock);
211 pmcmsptwi_writel(pmcmsptwi_cfg_to_reg(cfg),
212 data->iobase + MSP_TWI_CFG_REG_OFFSET);
213 mutex_unlock(&data->lock);
217 * Parses the 'int_sts' register and returns a well-defined error code
219 static enum pmcmsptwi_xfer_result pmcmsptwi_get_result(u32 reg)
221 if (reg & MSP_TWI_INT_STS_LOST_ARBITRATION) {
222 dev_dbg(&pmcmsptwi_adapter.dev,
223 "Result: Lost arbitration\n");
224 return MSP_TWI_XFER_LOST_ARBITRATION;
225 } else if (reg & MSP_TWI_INT_STS_NO_RESPONSE) {
226 dev_dbg(&pmcmsptwi_adapter.dev,
227 "Result: No response\n");
228 return MSP_TWI_XFER_NO_RESPONSE;
229 } else if (reg & MSP_TWI_INT_STS_DATA_COLLISION) {
230 dev_dbg(&pmcmsptwi_adapter.dev,
231 "Result: Data collision\n");
232 return MSP_TWI_XFER_DATA_COLLISION;
233 } else if (reg & MSP_TWI_INT_STS_BUSY) {
234 dev_dbg(&pmcmsptwi_adapter.dev,
235 "Result: Bus busy\n");
236 return MSP_TWI_XFER_BUSY;
239 dev_dbg(&pmcmsptwi_adapter.dev, "Result: Operation succeeded\n");
240 return MSP_TWI_XFER_OK;
244 * In interrupt mode, handle the interrupt.
245 * NOTE: Assumes data->lock is held.
247 static irqreturn_t pmcmsptwi_interrupt(int irq, void *ptr)
249 struct pmcmsptwi_data *data = ptr;
251 u32 reason = pmcmsptwi_readl(data->iobase +
252 MSP_TWI_INT_STS_REG_OFFSET);
253 pmcmsptwi_writel(reason, data->iobase + MSP_TWI_INT_STS_REG_OFFSET);
255 dev_dbg(&pmcmsptwi_adapter.dev, "Got interrupt 0x%08x\n", reason);
256 if (!(reason & MSP_TWI_INT_STS_DONE))
259 data->last_result = pmcmsptwi_get_result(reason);
260 complete(&data->wait);
266 * Probe for and register the device and return 0 if there is one.
268 static int pmcmsptwi_probe(struct platform_device *pldev)
270 struct resource *res;
273 /* get the static platform resources */
274 res = platform_get_resource(pldev, IORESOURCE_MEM, 0);
276 dev_err(&pldev->dev, "IOMEM resource not found\n");
280 /* reserve the memory region */
281 if (!request_mem_region(res->start, resource_size(res),
284 "Unable to get memory/io address region 0x%08x\n",
290 /* remap the memory */
291 pmcmsptwi_data.iobase = ioremap_nocache(res->start,
293 if (!pmcmsptwi_data.iobase) {
295 "Unable to ioremap address 0x%08x\n", res->start);
300 /* request the irq */
301 pmcmsptwi_data.irq = platform_get_irq(pldev, 0);
302 if (pmcmsptwi_data.irq) {
303 rc = request_irq(pmcmsptwi_data.irq, &pmcmsptwi_interrupt,
304 IRQF_SHARED, pldev->name, &pmcmsptwi_data);
307 * Enable 'DONE' interrupt only.
309 * If you enable all interrupts, you will get one on
310 * error and another when the operation completes.
311 * This way you only have to handle one interrupt,
312 * but you can still check all result flags.
314 pmcmsptwi_writel(MSP_TWI_INT_STS_DONE,
315 pmcmsptwi_data.iobase +
316 MSP_TWI_INT_MSK_REG_OFFSET);
318 dev_warn(&pldev->dev,
319 "Could not assign TWI IRQ handler "
320 "to irq %d (continuing with poll)\n",
322 pmcmsptwi_data.irq = 0;
326 init_completion(&pmcmsptwi_data.wait);
327 mutex_init(&pmcmsptwi_data.lock);
329 pmcmsptwi_set_clock_config(&pmcmsptwi_defclockcfg, &pmcmsptwi_data);
330 pmcmsptwi_set_twi_config(&pmcmsptwi_defcfg, &pmcmsptwi_data);
332 printk(KERN_INFO DRV_NAME ": Registering MSP71xx I2C adapter\n");
334 pmcmsptwi_adapter.dev.parent = &pldev->dev;
335 platform_set_drvdata(pldev, &pmcmsptwi_adapter);
336 i2c_set_adapdata(&pmcmsptwi_adapter, &pmcmsptwi_data);
338 rc = i2c_add_adapter(&pmcmsptwi_adapter);
340 dev_err(&pldev->dev, "Unable to register I2C adapter\n");
347 if (pmcmsptwi_data.irq) {
349 pmcmsptwi_data.iobase + MSP_TWI_INT_MSK_REG_OFFSET);
350 free_irq(pmcmsptwi_data.irq, &pmcmsptwi_data);
353 iounmap(pmcmsptwi_data.iobase);
356 release_mem_region(res->start, resource_size(res));
363 * Release the device and return 0 if there is one.
365 static int pmcmsptwi_remove(struct platform_device *pldev)
367 struct resource *res;
369 i2c_del_adapter(&pmcmsptwi_adapter);
371 if (pmcmsptwi_data.irq) {
373 pmcmsptwi_data.iobase + MSP_TWI_INT_MSK_REG_OFFSET);
374 free_irq(pmcmsptwi_data.irq, &pmcmsptwi_data);
377 iounmap(pmcmsptwi_data.iobase);
379 res = platform_get_resource(pldev, IORESOURCE_MEM, 0);
380 release_mem_region(res->start, resource_size(res));
386 * Polls the 'busy' register until the command is complete.
387 * NOTE: Assumes data->lock is held.
389 static void pmcmsptwi_poll_complete(struct pmcmsptwi_data *data)
393 for (i = 0; i < MSP_MAX_POLL; i++) {
394 u32 val = pmcmsptwi_readl(data->iobase +
395 MSP_TWI_BUSY_REG_OFFSET);
397 u32 reason = pmcmsptwi_readl(data->iobase +
398 MSP_TWI_INT_STS_REG_OFFSET);
399 pmcmsptwi_writel(reason, data->iobase +
400 MSP_TWI_INT_STS_REG_OFFSET);
401 data->last_result = pmcmsptwi_get_result(reason);
404 udelay(MSP_POLL_DELAY);
407 dev_dbg(&pmcmsptwi_adapter.dev, "Result: Poll timeout\n");
408 data->last_result = MSP_TWI_XFER_TIMEOUT;
412 * Do the transfer (low level):
413 * May use interrupt-driven or polling, depending on if an IRQ is
414 * presently registered.
415 * NOTE: Assumes data->lock is held.
417 static enum pmcmsptwi_xfer_result pmcmsptwi_do_xfer(
418 u32 reg, struct pmcmsptwi_data *data)
420 dev_dbg(&pmcmsptwi_adapter.dev, "Writing cmd reg 0x%08x\n", reg);
421 pmcmsptwi_writel(reg, data->iobase + MSP_TWI_CMD_REG_OFFSET);
423 unsigned long timeleft = wait_for_completion_timeout(
424 &data->wait, MSP_IRQ_TIMEOUT);
426 dev_dbg(&pmcmsptwi_adapter.dev,
427 "Result: IRQ timeout\n");
428 complete(&data->wait);
429 data->last_result = MSP_TWI_XFER_TIMEOUT;
432 pmcmsptwi_poll_complete(data);
434 return data->last_result;
438 * Helper routine, converts 'pmctwi_cmd' struct to register format
440 static inline u32 pmcmsptwi_cmd_to_reg(const struct pmcmsptwi_cmd *cmd)
442 return ((cmd->type & 0x3) << 8) |
443 (((cmd->write_len - 1) & 0x7) << 4) |
444 ((cmd->read_len - 1) & 0x7);
448 * Do the transfer (high level)
450 static enum pmcmsptwi_xfer_result pmcmsptwi_xfer_cmd(
451 struct pmcmsptwi_cmd *cmd,
452 struct pmcmsptwi_data *data)
454 enum pmcmsptwi_xfer_result retval;
456 if ((cmd->type == MSP_TWI_CMD_WRITE && cmd->write_len == 0) ||
457 (cmd->type == MSP_TWI_CMD_READ && cmd->read_len == 0) ||
458 (cmd->type == MSP_TWI_CMD_WRITE_READ &&
459 (cmd->read_len == 0 || cmd->write_len == 0))) {
460 dev_err(&pmcmsptwi_adapter.dev,
461 "%s: Cannot transfer less than 1 byte\n",
466 if (cmd->read_len > MSP_MAX_BYTES_PER_RW ||
467 cmd->write_len > MSP_MAX_BYTES_PER_RW) {
468 dev_err(&pmcmsptwi_adapter.dev,
469 "%s: Cannot transfer more than %d bytes\n",
470 __func__, MSP_MAX_BYTES_PER_RW);
474 mutex_lock(&data->lock);
475 dev_dbg(&pmcmsptwi_adapter.dev,
476 "Setting address to 0x%04x\n", cmd->addr);
477 pmcmsptwi_writel(cmd->addr, data->iobase + MSP_TWI_ADD_REG_OFFSET);
479 if (cmd->type == MSP_TWI_CMD_WRITE ||
480 cmd->type == MSP_TWI_CMD_WRITE_READ) {
481 u64 tmp = be64_to_cpup((__be64 *)cmd->write_data);
482 tmp >>= (MSP_MAX_BYTES_PER_RW - cmd->write_len) * 8;
483 dev_dbg(&pmcmsptwi_adapter.dev, "Writing 0x%016llx\n", tmp);
484 pmcmsptwi_writel(tmp & 0x00000000ffffffffLL,
485 data->iobase + MSP_TWI_DAT_0_REG_OFFSET);
486 if (cmd->write_len > 4)
487 pmcmsptwi_writel(tmp >> 32,
488 data->iobase + MSP_TWI_DAT_1_REG_OFFSET);
491 retval = pmcmsptwi_do_xfer(pmcmsptwi_cmd_to_reg(cmd), data);
492 if (retval != MSP_TWI_XFER_OK)
495 if (cmd->type == MSP_TWI_CMD_READ ||
496 cmd->type == MSP_TWI_CMD_WRITE_READ) {
498 u64 rmsk = ~(0xffffffffffffffffLL << (cmd->read_len * 8));
499 u64 tmp = (u64)pmcmsptwi_readl(data->iobase +
500 MSP_TWI_DAT_0_REG_OFFSET);
501 if (cmd->read_len > 4)
502 tmp |= (u64)pmcmsptwi_readl(data->iobase +
503 MSP_TWI_DAT_1_REG_OFFSET) << 32;
505 dev_dbg(&pmcmsptwi_adapter.dev, "Read 0x%016llx\n", tmp);
507 for (i = 0; i < cmd->read_len; i++)
508 cmd->read_data[i] = tmp >> i;
512 mutex_unlock(&data->lock);
517 /* -- Algorithm functions -- */
520 * Sends an i2c command out on the adapter
522 static int pmcmsptwi_master_xfer(struct i2c_adapter *adap,
523 struct i2c_msg *msg, int num)
525 struct pmcmsptwi_data *data = i2c_get_adapdata(adap);
526 struct pmcmsptwi_cmd cmd;
527 struct pmcmsptwi_cfg oldcfg, newcfg;
531 dev_dbg(&adap->dev, "%d messages unsupported\n", num);
533 } else if (num == 2) {
534 /* Check for a dual write-then-read command */
535 struct i2c_msg *nextmsg = msg + 1;
536 if (!(msg->flags & I2C_M_RD) &&
537 (nextmsg->flags & I2C_M_RD) &&
538 msg->addr == nextmsg->addr) {
539 cmd.type = MSP_TWI_CMD_WRITE_READ;
540 cmd.write_len = msg->len;
541 cmd.write_data = msg->buf;
542 cmd.read_len = nextmsg->len;
543 cmd.read_data = nextmsg->buf;
546 "Non write-read dual messages unsupported\n");
549 } else if (msg->flags & I2C_M_RD) {
550 cmd.type = MSP_TWI_CMD_READ;
551 cmd.read_len = msg->len;
552 cmd.read_data = msg->buf;
554 cmd.write_data = NULL;
556 cmd.type = MSP_TWI_CMD_WRITE;
558 cmd.read_data = NULL;
559 cmd.write_len = msg->len;
560 cmd.write_data = msg->buf;
564 dev_err(&adap->dev, "Zero-byte messages unsupported\n");
568 cmd.addr = msg->addr;
570 if (msg->flags & I2C_M_TEN) {
571 pmcmsptwi_get_twi_config(&newcfg, data);
572 memcpy(&oldcfg, &newcfg, sizeof(oldcfg));
574 /* Set the special 10-bit address flag */
577 pmcmsptwi_set_twi_config(&newcfg, data);
580 /* Execute the command */
581 ret = pmcmsptwi_xfer_cmd(&cmd, data);
583 if (msg->flags & I2C_M_TEN)
584 pmcmsptwi_set_twi_config(&oldcfg, data);
586 dev_dbg(&adap->dev, "I2C %s of %d bytes %s\n",
587 (msg->flags & I2C_M_RD) ? "read" : "write", msg->len,
588 (ret == MSP_TWI_XFER_OK) ? "succeeded" : "failed");
590 if (ret != MSP_TWI_XFER_OK) {
592 * TODO: We could potentially loop and retry in the case
593 * of MSP_TWI_XFER_TIMEOUT.
601 static u32 pmcmsptwi_i2c_func(struct i2c_adapter *adapter)
603 return I2C_FUNC_I2C | I2C_FUNC_10BIT_ADDR |
604 I2C_FUNC_SMBUS_BYTE | I2C_FUNC_SMBUS_BYTE_DATA |
605 I2C_FUNC_SMBUS_WORD_DATA | I2C_FUNC_SMBUS_PROC_CALL;
608 /* -- Initialization -- */
610 static struct i2c_algorithm pmcmsptwi_algo = {
611 .master_xfer = pmcmsptwi_master_xfer,
612 .functionality = pmcmsptwi_i2c_func,
615 static struct i2c_adapter pmcmsptwi_adapter = {
616 .owner = THIS_MODULE,
617 .class = I2C_CLASS_HWMON | I2C_CLASS_SPD,
618 .algo = &pmcmsptwi_algo,
622 static struct platform_driver pmcmsptwi_driver = {
623 .probe = pmcmsptwi_probe,
624 .remove = pmcmsptwi_remove,
630 module_platform_driver(pmcmsptwi_driver);
632 MODULE_DESCRIPTION("PMC MSP TWI/SMBus/I2C driver");
633 MODULE_LICENSE("GPL");
634 MODULE_ALIAS("platform:" DRV_NAME);