2 * Copyright (C) 2002 Motorola GSG-China
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public License
6 * as published by the Free Software Foundation; either version 2
7 * of the License, or (at your option) any later version.
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, write to the Free Software
16 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307,
20 * Darius Augulis, Teltonika Inc.
23 * Implementation of I2C Adapter/Algorithm Driver
24 * for I2C Bus integrated in Freescale i.MX/MXC processors
26 * Derived from Motorola GSG China I2C example driver
28 * Copyright (C) 2005 Torsten Koschorrek <koschorrek at synertronixx.de
29 * Copyright (C) 2005 Matthias Blaschke <blaschke at synertronixx.de
30 * Copyright (C) 2007 RightHand Technologies, Inc.
31 * Copyright (C) 2008 Darius Augulis <darius.augulis at teltonika.lt>
35 /** Includes *******************************************************************
36 *******************************************************************************/
38 #include <linux/init.h>
39 #include <linux/kernel.h>
40 #include <linux/module.h>
41 #include <linux/errno.h>
42 #include <linux/err.h>
43 #include <linux/interrupt.h>
44 #include <linux/delay.h>
45 #include <linux/i2c.h>
47 #include <linux/sched.h>
48 #include <linux/platform_device.h>
49 #include <linux/clk.h>
51 #include <mach/irqs.h>
52 #include <mach/hardware.h>
55 /** Defines ********************************************************************
56 *******************************************************************************/
58 /* This will be the driver name the kernel reports */
59 #define DRIVER_NAME "imx-i2c"
62 #define IMX_I2C_BIT_RATE 100000 /* 100kHz */
64 /* IMX I2C registers */
65 #define IMX_I2C_IADR 0x00 /* i2c slave address */
66 #define IMX_I2C_IFDR 0x04 /* i2c frequency divider */
67 #define IMX_I2C_I2CR 0x08 /* i2c control */
68 #define IMX_I2C_I2SR 0x0C /* i2c status */
69 #define IMX_I2C_I2DR 0x10 /* i2c transfer data */
71 /* Bits of IMX I2C registers */
72 #define I2SR_RXAK 0x01
77 #define I2SR_IAAS 0x40
79 #define I2CR_RSTA 0x04
80 #define I2CR_TXAK 0x08
82 #define I2CR_MSTA 0x20
83 #define I2CR_IIEN 0x40
86 /** Variables ******************************************************************
87 *******************************************************************************/
90 * sorted list of clock divider, register value pairs
91 * taken from table 26-5, p.26-9, Freescale i.MX
92 * Integrated Portable System Processor Reference Manual
93 * Document Number: MC9328MXLRM, Rev. 5.1, 06/2007
95 * Duplicated divider values removed from list
98 static u16 __initdata i2c_clk_div
[50][2] = {
99 { 22, 0x20 }, { 24, 0x21 }, { 26, 0x22 }, { 28, 0x23 },
100 { 30, 0x00 }, { 32, 0x24 }, { 36, 0x25 }, { 40, 0x26 },
101 { 42, 0x03 }, { 44, 0x27 }, { 48, 0x28 }, { 52, 0x05 },
102 { 56, 0x29 }, { 60, 0x06 }, { 64, 0x2A }, { 72, 0x2B },
103 { 80, 0x2C }, { 88, 0x09 }, { 96, 0x2D }, { 104, 0x0A },
104 { 112, 0x2E }, { 128, 0x2F }, { 144, 0x0C }, { 160, 0x30 },
105 { 192, 0x31 }, { 224, 0x32 }, { 240, 0x0F }, { 256, 0x33 },
106 { 288, 0x10 }, { 320, 0x34 }, { 384, 0x35 }, { 448, 0x36 },
107 { 480, 0x13 }, { 512, 0x37 }, { 576, 0x14 }, { 640, 0x38 },
108 { 768, 0x39 }, { 896, 0x3A }, { 960, 0x17 }, { 1024, 0x3B },
109 { 1152, 0x18 }, { 1280, 0x3C }, { 1536, 0x3D }, { 1792, 0x3E },
110 { 1920, 0x1B }, { 2048, 0x3F }, { 2304, 0x1C }, { 2560, 0x1D },
111 { 3072, 0x1E }, { 3840, 0x1F }
114 struct imx_i2c_struct
{
115 struct i2c_adapter adapter
;
116 struct resource
*res
;
120 wait_queue_head_t queue
;
122 unsigned int disable_delay
;
125 /** Functions for IMX I2C adapter driver ***************************************
126 *******************************************************************************/
128 static int i2c_imx_bus_busy(struct imx_i2c_struct
*i2c_imx
)
130 unsigned long orig_jiffies
= jiffies
;
132 dev_dbg(&i2c_imx
->adapter
.dev
, "<%s>\n", __func__
);
134 /* wait for bus not busy */
135 while (readb(i2c_imx
->base
+ IMX_I2C_I2SR
) & I2SR_IBB
) {
136 if (signal_pending(current
)) {
137 dev_dbg(&i2c_imx
->adapter
.dev
,
138 "<%s> I2C Interrupted\n", __func__
);
141 if (time_after(jiffies
, orig_jiffies
+ HZ
/ 1000)) {
142 dev_dbg(&i2c_imx
->adapter
.dev
,
143 "<%s> I2C bus is busy\n", __func__
);
152 static int i2c_imx_trx_complete(struct imx_i2c_struct
*i2c_imx
)
156 result
= wait_event_interruptible_timeout(i2c_imx
->queue
,
157 i2c_imx
->i2csr
& I2SR_IIF
, HZ
/ 10);
159 if (unlikely(result
< 0)) {
160 dev_dbg(&i2c_imx
->adapter
.dev
, "<%s> result < 0\n", __func__
);
162 } else if (unlikely(!(i2c_imx
->i2csr
& I2SR_IIF
))) {
163 dev_dbg(&i2c_imx
->adapter
.dev
, "<%s> Timeout\n", __func__
);
166 dev_dbg(&i2c_imx
->adapter
.dev
, "<%s> TRX complete\n", __func__
);
171 static int i2c_imx_acked(struct imx_i2c_struct
*i2c_imx
)
173 if (readb(i2c_imx
->base
+ IMX_I2C_I2SR
) & I2SR_RXAK
) {
174 dev_dbg(&i2c_imx
->adapter
.dev
, "<%s> No ACK\n", __func__
);
175 return -EIO
; /* No ACK */
178 dev_dbg(&i2c_imx
->adapter
.dev
, "<%s> ACK received\n", __func__
);
182 static void i2c_imx_start(struct imx_i2c_struct
*i2c_imx
)
184 unsigned int temp
= 0;
186 dev_dbg(&i2c_imx
->adapter
.dev
, "<%s>\n", __func__
);
188 /* Enable I2C controller */
189 writeb(I2CR_IEN
, i2c_imx
->base
+ IMX_I2C_I2CR
);
190 /* Start I2C transaction */
191 temp
= readb(i2c_imx
->base
+ IMX_I2C_I2CR
);
193 writeb(temp
, i2c_imx
->base
+ IMX_I2C_I2CR
);
194 temp
|= I2CR_IIEN
| I2CR_MTX
| I2CR_TXAK
;
195 writeb(temp
, i2c_imx
->base
+ IMX_I2C_I2CR
);
198 static void i2c_imx_stop(struct imx_i2c_struct
*i2c_imx
)
200 unsigned int temp
= 0;
202 /* Stop I2C transaction */
203 dev_dbg(&i2c_imx
->adapter
.dev
, "<%s>\n", __func__
);
204 temp
= readb(i2c_imx
->base
+ IMX_I2C_I2CR
);
206 writeb(temp
, i2c_imx
->base
+ IMX_I2C_I2CR
);
207 /* setup chip registers to defaults */
208 writeb(I2CR_IEN
, i2c_imx
->base
+ IMX_I2C_I2CR
);
209 writeb(0, i2c_imx
->base
+ IMX_I2C_I2SR
);
211 * This delay caused by an i.MXL hardware bug.
212 * If no (or too short) delay, no "STOP" bit will be generated.
214 udelay(i2c_imx
->disable_delay
);
215 /* Disable I2C controller */
216 writeb(0, i2c_imx
->base
+ IMX_I2C_I2CR
);
219 static void __init
i2c_imx_set_clk(struct imx_i2c_struct
*i2c_imx
,
222 unsigned int i2c_clk_rate
;
226 /* Divider value calculation */
227 i2c_clk_rate
= clk_get_rate(i2c_imx
->clk
);
228 div
= (i2c_clk_rate
+ rate
- 1) / rate
;
229 if (div
< i2c_clk_div
[0][0])
231 else if (div
> i2c_clk_div
[ARRAY_SIZE(i2c_clk_div
) - 1][0])
232 i
= ARRAY_SIZE(i2c_clk_div
) - 1;
234 for (i
= 0; i2c_clk_div
[i
][0] < div
; i
++);
236 /* Write divider value to register */
237 writeb(i2c_clk_div
[i
][1], i2c_imx
->base
+ IMX_I2C_IFDR
);
240 * There dummy delay is calculated.
241 * It should be about one I2C clock period long.
242 * This delay is used in I2C bus disable function
243 * to fix chip hardware bug.
245 i2c_imx
->disable_delay
= (500000U * i2c_clk_div
[i
][0]
246 + (i2c_clk_rate
/ 2) - 1) / (i2c_clk_rate
/ 2);
248 /* dev_dbg() can't be used, because adapter is not yet registered */
249 #ifdef CONFIG_I2C_DEBUG_BUS
250 printk(KERN_DEBUG
"I2C: <%s> I2C_CLK=%d, REQ DIV=%d\n",
251 __func__
, i2c_clk_rate
, div
);
252 printk(KERN_DEBUG
"I2C: <%s> IFDR[IC]=0x%x, REAL DIV=%d\n",
253 __func__
, i2c_clk_div
[i
][1], i2c_clk_div
[i
][0]);
257 static irqreturn_t
i2c_imx_isr(int irq
, void *dev_id
)
259 struct imx_i2c_struct
*i2c_imx
= dev_id
;
262 temp
= readb(i2c_imx
->base
+ IMX_I2C_I2SR
);
263 if (temp
& I2SR_IIF
) {
264 /* save status register */
265 i2c_imx
->i2csr
= temp
;
267 writeb(temp
, i2c_imx
->base
+ IMX_I2C_I2SR
);
268 wake_up_interruptible(&i2c_imx
->queue
);
275 static int i2c_imx_write(struct imx_i2c_struct
*i2c_imx
, struct i2c_msg
*msgs
)
279 dev_dbg(&i2c_imx
->adapter
.dev
, "<%s> write slave address: addr=0x%x\n",
280 __func__
, msgs
->addr
<< 1);
282 /* write slave address */
283 writeb(msgs
->addr
<< 1, i2c_imx
->base
+ IMX_I2C_I2DR
);
284 result
= i2c_imx_trx_complete(i2c_imx
);
287 result
= i2c_imx_acked(i2c_imx
);
290 dev_dbg(&i2c_imx
->adapter
.dev
, "<%s> write data\n", __func__
);
293 for (i
= 0; i
< msgs
->len
; i
++) {
294 dev_dbg(&i2c_imx
->adapter
.dev
,
295 "<%s> write byte: B%d=0x%X\n",
296 __func__
, i
, msgs
->buf
[i
]);
297 writeb(msgs
->buf
[i
], i2c_imx
->base
+ IMX_I2C_I2DR
);
298 result
= i2c_imx_trx_complete(i2c_imx
);
301 result
= i2c_imx_acked(i2c_imx
);
308 static int i2c_imx_read(struct imx_i2c_struct
*i2c_imx
, struct i2c_msg
*msgs
)
313 dev_dbg(&i2c_imx
->adapter
.dev
,
314 "<%s> write slave address: addr=0x%x\n",
315 __func__
, (msgs
->addr
<< 1) | 0x01);
317 /* write slave address */
318 writeb((msgs
->addr
<< 1) | 0x01, i2c_imx
->base
+ IMX_I2C_I2DR
);
319 result
= i2c_imx_trx_complete(i2c_imx
);
322 result
= i2c_imx_acked(i2c_imx
);
326 dev_dbg(&i2c_imx
->adapter
.dev
, "<%s> setup bus\n", __func__
);
328 /* setup bus to read data */
329 temp
= readb(i2c_imx
->base
+ IMX_I2C_I2CR
);
333 writeb(temp
, i2c_imx
->base
+ IMX_I2C_I2CR
);
334 readb(i2c_imx
->base
+ IMX_I2C_I2DR
); /* dummy read */
336 dev_dbg(&i2c_imx
->adapter
.dev
, "<%s> read data\n", __func__
);
339 for (i
= 0; i
< msgs
->len
; i
++) {
340 result
= i2c_imx_trx_complete(i2c_imx
);
343 if (i
== (msgs
->len
- 1)) {
344 dev_dbg(&i2c_imx
->adapter
.dev
,
345 "<%s> clear MSTA\n", __func__
);
346 temp
= readb(i2c_imx
->base
+ IMX_I2C_I2CR
);
348 writeb(temp
, i2c_imx
->base
+ IMX_I2C_I2CR
);
349 } else if (i
== (msgs
->len
- 2)) {
350 dev_dbg(&i2c_imx
->adapter
.dev
,
351 "<%s> set TXAK\n", __func__
);
352 temp
= readb(i2c_imx
->base
+ IMX_I2C_I2CR
);
354 writeb(temp
, i2c_imx
->base
+ IMX_I2C_I2CR
);
356 msgs
->buf
[i
] = readb(i2c_imx
->base
+ IMX_I2C_I2DR
);
357 dev_dbg(&i2c_imx
->adapter
.dev
,
358 "<%s> read byte: B%d=0x%X\n",
359 __func__
, i
, msgs
->buf
[i
]);
364 static int i2c_imx_xfer(struct i2c_adapter
*adapter
,
365 struct i2c_msg
*msgs
, int num
)
367 unsigned int i
, temp
;
369 struct imx_i2c_struct
*i2c_imx
= i2c_get_adapdata(adapter
);
371 dev_dbg(&i2c_imx
->adapter
.dev
, "<%s>\n", __func__
);
373 /* Check if i2c bus is not busy */
374 result
= i2c_imx_bus_busy(i2c_imx
);
378 /* Start I2C transfer */
379 i2c_imx_start(i2c_imx
);
381 /* read/write data */
382 for (i
= 0; i
< num
; i
++) {
384 dev_dbg(&i2c_imx
->adapter
.dev
,
385 "<%s> repeated start\n", __func__
);
386 temp
= readb(i2c_imx
->base
+ IMX_I2C_I2CR
);
388 writeb(temp
, i2c_imx
->base
+ IMX_I2C_I2CR
);
390 dev_dbg(&i2c_imx
->adapter
.dev
,
391 "<%s> transfer message: %d\n", __func__
, i
);
392 /* write/read data */
393 #ifdef CONFIG_I2C_DEBUG_BUS
394 temp
= readb(i2c_imx
->base
+ IMX_I2C_I2CR
);
395 dev_dbg(&i2c_imx
->adapter
.dev
, "<%s> CONTROL: IEN=%d, IIEN=%d, "
396 "MSTA=%d, MTX=%d, TXAK=%d, RSTA=%d\n", __func__
,
397 (temp
& I2CR_IEN
? 1 : 0), (temp
& I2CR_IIEN
? 1 : 0),
398 (temp
& I2CR_MSTA
? 1 : 0), (temp
& I2CR_MTX
? 1 : 0),
399 (temp
& I2CR_TXAK
? 1 : 0), (temp
& I2CR_RSTA
? 1 : 0));
400 temp
= readb(i2c_imx
->base
+ IMX_I2C_I2SR
);
401 dev_dbg(&i2c_imx
->adapter
.dev
,
402 "<%s> STATUS: ICF=%d, IAAS=%d, IBB=%d, "
403 "IAL=%d, SRW=%d, IIF=%d, RXAK=%d\n", __func__
,
404 (temp
& I2SR_ICF
? 1 : 0), (temp
& I2SR_IAAS
? 1 : 0),
405 (temp
& I2SR_IBB
? 1 : 0), (temp
& I2SR_IAL
? 1 : 0),
406 (temp
& I2SR_SRW
? 1 : 0), (temp
& I2SR_IIF
? 1 : 0),
407 (temp
& I2SR_RXAK
? 1 : 0));
409 if (msgs
[i
].flags
& I2C_M_RD
)
410 result
= i2c_imx_read(i2c_imx
, &msgs
[i
]);
412 result
= i2c_imx_write(i2c_imx
, &msgs
[i
]);
416 /* Stop I2C transfer */
417 i2c_imx_stop(i2c_imx
);
419 dev_dbg(&i2c_imx
->adapter
.dev
, "<%s> exit with: %s: %d\n", __func__
,
420 (result
< 0) ? "error" : "success msg",
421 (result
< 0) ? result
: num
);
422 return (result
< 0) ? result
: num
;
425 static u32
i2c_imx_func(struct i2c_adapter
*adapter
)
427 return I2C_FUNC_I2C
| I2C_FUNC_SMBUS_EMUL
;
430 static struct i2c_algorithm i2c_imx_algo
= {
431 .master_xfer
= i2c_imx_xfer
,
432 .functionality
= i2c_imx_func
,
435 static int __init
i2c_imx_probe(struct platform_device
*pdev
)
437 struct imx_i2c_struct
*i2c_imx
;
438 struct resource
*res
;
439 struct imxi2c_platform_data
*pdata
;
441 resource_size_t res_size
;
445 dev_dbg(&pdev
->dev
, "<%s>\n", __func__
);
447 res
= platform_get_resource(pdev
, IORESOURCE_MEM
, 0);
449 dev_err(&pdev
->dev
, "can't get device resources\n");
452 irq
= platform_get_irq(pdev
, 0);
454 dev_err(&pdev
->dev
, "can't get irq number\n");
458 pdata
= pdev
->dev
.platform_data
;
460 if (pdata
&& pdata
->init
) {
461 ret
= pdata
->init(&pdev
->dev
);
466 res_size
= resource_size(res
);
467 base
= ioremap(res
->start
, res_size
);
469 dev_err(&pdev
->dev
, "ioremap failed\n");
474 i2c_imx
= kzalloc(sizeof(struct imx_i2c_struct
), GFP_KERNEL
);
476 dev_err(&pdev
->dev
, "can't allocate interface\n");
481 if (!request_mem_region(res
->start
, res_size
, DRIVER_NAME
)) {
486 /* Setup i2c_imx driver structure */
487 strcpy(i2c_imx
->adapter
.name
, pdev
->name
);
488 i2c_imx
->adapter
.owner
= THIS_MODULE
;
489 i2c_imx
->adapter
.algo
= &i2c_imx_algo
;
490 i2c_imx
->adapter
.dev
.parent
= &pdev
->dev
;
491 i2c_imx
->adapter
.nr
= pdev
->id
;
493 i2c_imx
->base
= base
;
497 i2c_imx
->clk
= clk_get(&pdev
->dev
, "i2c_clk");
498 if (IS_ERR(i2c_imx
->clk
)) {
499 ret
= PTR_ERR(i2c_imx
->clk
);
500 dev_err(&pdev
->dev
, "can't get I2C clock\n");
503 clk_enable(i2c_imx
->clk
);
506 ret
= request_irq(i2c_imx
->irq
, i2c_imx_isr
, 0, pdev
->name
, i2c_imx
);
508 dev_err(&pdev
->dev
, "can't claim irq %d\n", i2c_imx
->irq
);
513 init_waitqueue_head(&i2c_imx
->queue
);
515 /* Set up adapter data */
516 i2c_set_adapdata(&i2c_imx
->adapter
, i2c_imx
);
518 /* Set up clock divider */
519 if (pdata
&& pdata
->bitrate
)
520 i2c_imx_set_clk(i2c_imx
, pdata
->bitrate
);
522 i2c_imx_set_clk(i2c_imx
, IMX_I2C_BIT_RATE
);
524 /* Set up chip registers to defaults */
525 writeb(0, i2c_imx
->base
+ IMX_I2C_I2CR
);
526 writeb(0, i2c_imx
->base
+ IMX_I2C_I2SR
);
528 /* Add I2C adapter */
529 ret
= i2c_add_numbered_adapter(&i2c_imx
->adapter
);
531 dev_err(&pdev
->dev
, "registration failed\n");
535 /* Set up platform driver data */
536 platform_set_drvdata(pdev
, i2c_imx
);
538 dev_dbg(&i2c_imx
->adapter
.dev
, "claimed irq %d\n", i2c_imx
->irq
);
539 dev_dbg(&i2c_imx
->adapter
.dev
, "device resources from 0x%x to 0x%x\n",
540 i2c_imx
->res
->start
, i2c_imx
->res
->end
);
541 dev_dbg(&i2c_imx
->adapter
.dev
, "allocated %d bytes at 0x%x \n",
542 res_size
, i2c_imx
->res
->start
);
543 dev_dbg(&i2c_imx
->adapter
.dev
, "adapter name: \"%s\"\n",
544 i2c_imx
->adapter
.name
);
545 dev_dbg(&i2c_imx
->adapter
.dev
, "IMX I2C adapter registered\n");
547 return 0; /* Return OK */
550 free_irq(i2c_imx
->irq
, i2c_imx
);
552 clk_disable(i2c_imx
->clk
);
553 clk_put(i2c_imx
->clk
);
555 release_mem_region(i2c_imx
->res
->start
, resource_size(res
));
561 if (pdata
&& pdata
->exit
)
562 pdata
->exit(&pdev
->dev
);
563 return ret
; /* Return error number */
566 static int __exit
i2c_imx_remove(struct platform_device
*pdev
)
568 struct imx_i2c_struct
*i2c_imx
= platform_get_drvdata(pdev
);
569 struct imxi2c_platform_data
*pdata
= pdev
->dev
.platform_data
;
572 dev_dbg(&i2c_imx
->adapter
.dev
, "adapter removed\n");
573 i2c_del_adapter(&i2c_imx
->adapter
);
574 platform_set_drvdata(pdev
, NULL
);
577 free_irq(i2c_imx
->irq
, i2c_imx
);
579 /* setup chip registers to defaults */
580 writeb(0, i2c_imx
->base
+ IMX_I2C_IADR
);
581 writeb(0, i2c_imx
->base
+ IMX_I2C_IFDR
);
582 writeb(0, i2c_imx
->base
+ IMX_I2C_I2CR
);
583 writeb(0, i2c_imx
->base
+ IMX_I2C_I2SR
);
585 /* Shut down hardware */
586 if (pdata
&& pdata
->exit
)
587 pdata
->exit(&pdev
->dev
);
589 /* Disable I2C clock */
590 clk_disable(i2c_imx
->clk
);
591 clk_put(i2c_imx
->clk
);
593 release_mem_region(i2c_imx
->res
->start
, resource_size(i2c_imx
->res
));
594 iounmap(i2c_imx
->base
);
599 static struct platform_driver i2c_imx_driver
= {
600 .probe
= i2c_imx_probe
,
601 .remove
= __exit_p(i2c_imx_remove
),
604 .owner
= THIS_MODULE
,
608 static int __init
i2c_adap_imx_init(void)
610 return platform_driver_probe(&i2c_imx_driver
, i2c_imx_probe
);
613 static void __exit
i2c_adap_imx_exit(void)
615 platform_driver_unregister(&i2c_imx_driver
);
618 module_init(i2c_adap_imx_init
);
619 module_exit(i2c_adap_imx_exit
);
621 MODULE_LICENSE("GPL");
622 MODULE_AUTHOR("Darius Augulis");
623 MODULE_DESCRIPTION("I2C adapter driver for IMX I2C bus");
624 MODULE_ALIAS("platform:" DRIVER_NAME
);