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 u32
pmcmsptwi_cfg_to_reg(const struct pmcmsptwi_cfg
*cfg
)
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);
161 static inline void pmcmsptwi_reg_to_cfg(u32 reg
, struct pmcmsptwi_cfg
*cfg
)
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;
172 * Sets the current clock configuration
174 static void pmcmsptwi_set_clock_config(const struct pmcmsptwi_clockcfg
*cfg
,
175 struct pmcmsptwi_data
*data
)
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
);
186 * Gets the current TWI bus configuration
188 static void pmcmsptwi_get_twi_config(struct pmcmsptwi_cfg
*cfg
,
189 struct pmcmsptwi_data
*data
)
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
);
198 * Sets the current TWI bus configuration
200 static void pmcmsptwi_set_twi_config(const struct pmcmsptwi_cfg
*cfg
,
201 struct pmcmsptwi_data
*data
)
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
);
210 * Parses the 'int_sts' register and returns a well-defined error code
212 static enum pmcmsptwi_xfer_result
pmcmsptwi_get_result(u32 reg
)
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
;
232 dev_dbg(&pmcmsptwi_adapter
.dev
, "Result: Operation succeeded\n");
233 return MSP_TWI_XFER_OK
;
237 * In interrupt mode, handle the interrupt.
238 * NOTE: Assumes data->lock is held.
240 static irqreturn_t
pmcmsptwi_interrupt(int irq
, void *ptr
)
242 struct pmcmsptwi_data
*data
= ptr
;
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
);
248 dev_dbg(&pmcmsptwi_adapter
.dev
, "Got interrupt 0x%08x\n", reason
);
249 if (!(reason
& MSP_TWI_INT_STS_DONE
))
252 data
->last_result
= pmcmsptwi_get_result(reason
);
253 complete(&data
->wait
);
259 * Probe for and register the device and return 0 if there is one.
261 static int pmcmsptwi_probe(struct platform_device
*pldev
)
263 struct resource
*res
;
266 /* get the static platform resources */
267 res
= platform_get_resource(pldev
, IORESOURCE_MEM
, 0);
269 dev_err(&pldev
->dev
, "IOMEM resource not found\n");
273 /* reserve the memory region */
274 if (!request_mem_region(res
->start
, resource_size(res
),
277 "Unable to get memory/io address region 0x%08x\n",
283 /* remap the memory */
284 pmcmsptwi_data
.iobase
= ioremap_nocache(res
->start
,
286 if (!pmcmsptwi_data
.iobase
) {
288 "Unable to ioremap address 0x%08x\n", res
->start
);
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
);
300 * Enable 'DONE' interrupt only.
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.
307 pmcmsptwi_writel(MSP_TWI_INT_STS_DONE
,
308 pmcmsptwi_data
.iobase
+
309 MSP_TWI_INT_MSK_REG_OFFSET
);
311 dev_warn(&pldev
->dev
,
312 "Could not assign TWI IRQ handler "
313 "to irq %d (continuing with poll)\n",
315 pmcmsptwi_data
.irq
= 0;
319 init_completion(&pmcmsptwi_data
.wait
);
320 mutex_init(&pmcmsptwi_data
.lock
);
322 pmcmsptwi_set_clock_config(&pmcmsptwi_defclockcfg
, &pmcmsptwi_data
);
323 pmcmsptwi_set_twi_config(&pmcmsptwi_defcfg
, &pmcmsptwi_data
);
325 printk(KERN_INFO DRV_NAME
": Registering MSP71xx I2C adapter\n");
327 pmcmsptwi_adapter
.dev
.parent
= &pldev
->dev
;
328 platform_set_drvdata(pldev
, &pmcmsptwi_adapter
);
329 i2c_set_adapdata(&pmcmsptwi_adapter
, &pmcmsptwi_data
);
331 rc
= i2c_add_adapter(&pmcmsptwi_adapter
);
333 dev_err(&pldev
->dev
, "Unable to register I2C adapter\n");
340 if (pmcmsptwi_data
.irq
) {
342 pmcmsptwi_data
.iobase
+ MSP_TWI_INT_MSK_REG_OFFSET
);
343 free_irq(pmcmsptwi_data
.irq
, &pmcmsptwi_data
);
346 iounmap(pmcmsptwi_data
.iobase
);
349 release_mem_region(res
->start
, resource_size(res
));
356 * Release the device and return 0 if there is one.
358 static int pmcmsptwi_remove(struct platform_device
*pldev
)
360 struct resource
*res
;
362 i2c_del_adapter(&pmcmsptwi_adapter
);
364 if (pmcmsptwi_data
.irq
) {
366 pmcmsptwi_data
.iobase
+ MSP_TWI_INT_MSK_REG_OFFSET
);
367 free_irq(pmcmsptwi_data
.irq
, &pmcmsptwi_data
);
370 iounmap(pmcmsptwi_data
.iobase
);
372 res
= platform_get_resource(pldev
, IORESOURCE_MEM
, 0);
373 release_mem_region(res
->start
, resource_size(res
));
379 * Polls the 'busy' register until the command is complete.
380 * NOTE: Assumes data->lock is held.
382 static void pmcmsptwi_poll_complete(struct pmcmsptwi_data
*data
)
386 for (i
= 0; i
< MSP_MAX_POLL
; i
++) {
387 u32 val
= pmcmsptwi_readl(data
->iobase
+
388 MSP_TWI_BUSY_REG_OFFSET
);
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
);
397 udelay(MSP_POLL_DELAY
);
400 dev_dbg(&pmcmsptwi_adapter
.dev
, "Result: Poll timeout\n");
401 data
->last_result
= MSP_TWI_XFER_TIMEOUT
;
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.
410 static enum pmcmsptwi_xfer_result
pmcmsptwi_do_xfer(
411 u32 reg
, struct pmcmsptwi_data
*data
)
413 dev_dbg(&pmcmsptwi_adapter
.dev
, "Writing cmd reg 0x%08x\n", reg
);
414 pmcmsptwi_writel(reg
, data
->iobase
+ MSP_TWI_CMD_REG_OFFSET
);
416 unsigned long timeleft
= wait_for_completion_timeout(
417 &data
->wait
, MSP_IRQ_TIMEOUT
);
419 dev_dbg(&pmcmsptwi_adapter
.dev
,
420 "Result: IRQ timeout\n");
421 complete(&data
->wait
);
422 data
->last_result
= MSP_TWI_XFER_TIMEOUT
;
425 pmcmsptwi_poll_complete(data
);
427 return data
->last_result
;
431 * Helper routine, converts 'pmctwi_cmd' struct to register format
433 static inline u32
pmcmsptwi_cmd_to_reg(const struct pmcmsptwi_cmd
*cmd
)
435 return ((cmd
->type
& 0x3) << 8) |
436 (((cmd
->write_len
- 1) & 0x7) << 4) |
437 ((cmd
->read_len
- 1) & 0x7);
441 * Do the transfer (high level)
443 static enum pmcmsptwi_xfer_result
pmcmsptwi_xfer_cmd(
444 struct pmcmsptwi_cmd
*cmd
,
445 struct pmcmsptwi_data
*data
)
447 enum pmcmsptwi_xfer_result retval
;
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",
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
);
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
);
476 retval
= pmcmsptwi_do_xfer(pmcmsptwi_cmd_to_reg(cmd
), data
);
477 if (retval
!= MSP_TWI_XFER_OK
)
480 if (cmd
->type
== MSP_TWI_CMD_READ
||
481 cmd
->type
== MSP_TWI_CMD_WRITE_READ
) {
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;
490 dev_dbg(&pmcmsptwi_adapter
.dev
, "Read 0x%016llx\n", tmp
);
492 for (i
= 0; i
< cmd
->read_len
; i
++)
493 cmd
->read_data
[i
] = tmp
>> i
;
497 mutex_unlock(&data
->lock
);
502 /* -- Algorithm functions -- */
505 * Sends an i2c command out on the adapter
507 static int pmcmsptwi_master_xfer(struct i2c_adapter
*adap
,
508 struct i2c_msg
*msg
, int num
)
510 struct pmcmsptwi_data
*data
= i2c_get_adapdata(adap
);
511 struct pmcmsptwi_cmd cmd
;
512 struct pmcmsptwi_cfg oldcfg
, newcfg
;
516 struct i2c_msg
*nextmsg
= msg
+ 1;
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
;
528 cmd
.write_data
= NULL
;
530 cmd
.type
= MSP_TWI_CMD_WRITE
;
532 cmd
.read_data
= NULL
;
533 cmd
.write_len
= msg
->len
;
534 cmd
.write_data
= msg
->buf
;
538 dev_err(&adap
->dev
, "Zero-byte messages unsupported\n");
542 cmd
.addr
= msg
->addr
;
544 if (msg
->flags
& I2C_M_TEN
) {
545 pmcmsptwi_get_twi_config(&newcfg
, data
);
546 memcpy(&oldcfg
, &newcfg
, sizeof(oldcfg
));
548 /* Set the special 10-bit address flag */
551 pmcmsptwi_set_twi_config(&newcfg
, data
);
554 /* Execute the command */
555 ret
= pmcmsptwi_xfer_cmd(&cmd
, data
);
557 if (msg
->flags
& I2C_M_TEN
)
558 pmcmsptwi_set_twi_config(&oldcfg
, data
);
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");
564 if (ret
!= MSP_TWI_XFER_OK
) {
566 * TODO: We could potentially loop and retry in the case
567 * of MSP_TWI_XFER_TIMEOUT.
575 static u32
pmcmsptwi_i2c_func(struct i2c_adapter
*adapter
)
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
;
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
,
590 /* -- Initialization -- */
592 static struct i2c_algorithm pmcmsptwi_algo
= {
593 .master_xfer
= pmcmsptwi_master_xfer
,
594 .functionality
= pmcmsptwi_i2c_func
,
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
,
605 static struct platform_driver pmcmsptwi_driver
= {
606 .probe
= pmcmsptwi_probe
,
607 .remove
= pmcmsptwi_remove
,
613 module_platform_driver(pmcmsptwi_driver
);
615 MODULE_DESCRIPTION("PMC MSP TWI/SMBus/I2C driver");
616 MODULE_LICENSE("GPL");
617 MODULE_ALIAS("platform:" DRV_NAME
);