i2c: iMX/MXC support
[linux-2.6.git] / drivers / i2c / busses / i2c-imx.c
1 /*
2  *      Copyright (C) 2002 Motorola GSG-China
3  *
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.
8  *
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.
13  *
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,
17  *      USA.
18  *
19  * Author:
20  *      Darius Augulis, Teltonika Inc.
21  *
22  * Desc.:
23  *      Implementation of I2C Adapter/Algorithm Driver
24  *      for I2C Bus integrated in Freescale i.MX/MXC processors
25  *
26  *      Derived from Motorola GSG China I2C example driver
27  *
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>
32  *
33  */
34
35 /** Includes *******************************************************************
36 *******************************************************************************/
37
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>
46 #include <linux/io.h>
47 #include <linux/sched.h>
48 #include <linux/platform_device.h>
49 #include <linux/clk.h>
50
51 #include <mach/irqs.h>
52 #include <mach/hardware.h>
53 #include <mach/i2c.h>
54
55 /** Defines ********************************************************************
56 *******************************************************************************/
57
58 /* This will be the driver name the kernel reports */
59 #define DRIVER_NAME "imx-i2c"
60
61 /* Default value */
62 #define IMX_I2C_BIT_RATE        100000  /* 100kHz */
63
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 */
70
71 /* Bits of IMX I2C registers */
72 #define I2SR_RXAK       0x01
73 #define I2SR_IIF        0x02
74 #define I2SR_SRW        0x04
75 #define I2SR_IAL        0x10
76 #define I2SR_IBB        0x20
77 #define I2SR_IAAS       0x40
78 #define I2SR_ICF        0x80
79 #define I2CR_RSTA       0x04
80 #define I2CR_TXAK       0x08
81 #define I2CR_MTX        0x10
82 #define I2CR_MSTA       0x20
83 #define I2CR_IIEN       0x40
84 #define I2CR_IEN        0x80
85
86 /** Variables ******************************************************************
87 *******************************************************************************/
88
89 static unsigned int disable_delay;      /* Dummy delay */
90
91 /*
92  * sorted list of clock divider, register value pairs
93  * taken from table 26-5, p.26-9, Freescale i.MX
94  * Integrated Portable System Processor Reference Manual
95  * Document Number: MC9328MXLRM, Rev. 5.1, 06/2007
96  *
97  * Duplicated divider values removed from list
98  */
99
100 static u16 __initdata i2c_clk_div[50][2] = {
101         { 22,   0x20 }, { 24,   0x21 }, { 26,   0x22 }, { 28,   0x23 },
102         { 30,   0x00 }, { 32,   0x24 }, { 36,   0x25 }, { 40,   0x26 },
103         { 42,   0x03 }, { 44,   0x27 }, { 48,   0x28 }, { 52,   0x05 },
104         { 56,   0x29 }, { 60,   0x06 }, { 64,   0x2A }, { 72,   0x2B },
105         { 80,   0x2C }, { 88,   0x09 }, { 96,   0x2D }, { 104,  0x0A },
106         { 112,  0x2E }, { 128,  0x2F }, { 144,  0x0C }, { 160,  0x30 },
107         { 192,  0x31 }, { 224,  0x32 }, { 240,  0x0F }, { 256,  0x33 },
108         { 288,  0x10 }, { 320,  0x34 }, { 384,  0x35 }, { 448,  0x36 },
109         { 480,  0x13 }, { 512,  0x37 }, { 576,  0x14 }, { 640,  0x38 },
110         { 768,  0x39 }, { 896,  0x3A }, { 960,  0x17 }, { 1024, 0x3B },
111         { 1152, 0x18 }, { 1280, 0x3C }, { 1536, 0x3D }, { 1792, 0x3E },
112         { 1920, 0x1B }, { 2048, 0x3F }, { 2304, 0x1C }, { 2560, 0x1D },
113         { 3072, 0x1E }, { 3840, 0x1F }
114 };
115
116 struct imx_i2c_struct {
117         struct i2c_adapter      adapter;
118         struct resource         *res;
119         struct clk              *clk;
120         void __iomem            *base;
121         int                     irq;
122         wait_queue_head_t       queue;
123         unsigned long           i2csr;
124 };
125
126 /** Functions for IMX I2C adapter driver ***************************************
127 *******************************************************************************/
128
129 static int i2c_imx_bus_busy(struct imx_i2c_struct *i2c_imx)
130 {
131         unsigned long orig_jiffies = jiffies;
132
133         dev_dbg(&i2c_imx->adapter.dev, "<%s>\n", __func__);
134
135         /* wait for bus not busy */
136         while (readb(i2c_imx->base + IMX_I2C_I2SR) & I2SR_IBB) {
137                 if (signal_pending(current)) {
138                         dev_dbg(&i2c_imx->adapter.dev,
139                                 "<%s> I2C Interrupted\n", __func__);
140                         return -EINTR;
141                 }
142                 if (time_after(jiffies, orig_jiffies + HZ / 1000)) {
143                         dev_dbg(&i2c_imx->adapter.dev,
144                                 "<%s> I2C bus is busy\n", __func__);
145                         return -EIO;
146                 }
147                 schedule();
148         }
149
150         return 0;
151 }
152
153 static int i2c_imx_trx_complete(struct imx_i2c_struct *i2c_imx)
154 {
155         int result;
156
157         result = wait_event_interruptible_timeout(i2c_imx->queue,
158                 i2c_imx->i2csr & I2SR_IIF, HZ / 10);
159
160         if (unlikely(result < 0)) {
161                 dev_dbg(&i2c_imx->adapter.dev, "<%s> result < 0\n", __func__);
162                 return result;
163         } else if (unlikely(!(i2c_imx->i2csr & I2SR_IIF))) {
164                 dev_dbg(&i2c_imx->adapter.dev, "<%s> Timeout\n", __func__);
165                 return -ETIMEDOUT;
166         }
167         dev_dbg(&i2c_imx->adapter.dev, "<%s> TRX complete\n", __func__);
168         i2c_imx->i2csr = 0;
169         return 0;
170 }
171
172 static int i2c_imx_acked(struct imx_i2c_struct *i2c_imx)
173 {
174         if (readb(i2c_imx->base + IMX_I2C_I2SR) & I2SR_RXAK) {
175                 dev_dbg(&i2c_imx->adapter.dev, "<%s> No ACK\n", __func__);
176                 return -EIO;  /* No ACK */
177         }
178
179         dev_dbg(&i2c_imx->adapter.dev, "<%s> ACK received\n", __func__);
180         return 0;
181 }
182
183 static void i2c_imx_start(struct imx_i2c_struct *i2c_imx)
184 {
185         unsigned int temp = 0;
186
187         dev_dbg(&i2c_imx->adapter.dev, "<%s>\n", __func__);
188
189         /* Enable I2C controller */
190         writeb(I2CR_IEN, i2c_imx->base + IMX_I2C_I2CR);
191         /* Start I2C transaction */
192         temp = readb(i2c_imx->base + IMX_I2C_I2CR);
193         temp |= I2CR_MSTA;
194         writeb(temp, i2c_imx->base + IMX_I2C_I2CR);
195         temp |= I2CR_IIEN | I2CR_MTX | I2CR_TXAK;
196         writeb(temp, i2c_imx->base + IMX_I2C_I2CR);
197 }
198
199 static void i2c_imx_stop(struct imx_i2c_struct *i2c_imx)
200 {
201         unsigned int temp = 0;
202
203         /* Stop I2C transaction */
204         dev_dbg(&i2c_imx->adapter.dev, "<%s>\n", __func__);
205         temp = readb(i2c_imx->base + IMX_I2C_I2CR);
206         temp &= ~I2CR_MSTA;
207         writeb(temp, i2c_imx->base + IMX_I2C_I2CR);
208         /* setup chip registers to defaults */
209         writeb(I2CR_IEN, i2c_imx->base + IMX_I2C_I2CR);
210         writeb(0, i2c_imx->base + IMX_I2C_I2SR);
211         /*
212          * This delay caused by an i.MXL hardware bug.
213          * If no (or too short) delay, no "STOP" bit will be generated.
214          */
215         udelay(disable_delay);
216         /* Disable I2C controller */
217         writeb(0, i2c_imx->base + IMX_I2C_I2CR);
218 }
219
220 static void __init i2c_imx_set_clk(struct imx_i2c_struct *i2c_imx,
221                                                         unsigned int rate)
222 {
223         unsigned int i2c_clk_rate;
224         unsigned int div;
225         int i;
226
227         /* Divider value calculation */
228         i2c_clk_rate = clk_get_rate(i2c_imx->clk);
229         div = (i2c_clk_rate + rate - 1) / rate;
230         if (div < i2c_clk_div[0][0])
231                 i = 0;
232         else if (div > i2c_clk_div[ARRAY_SIZE(i2c_clk_div) - 1][0])
233                 i = ARRAY_SIZE(i2c_clk_div) - 1;
234         else
235                 for (i = 0; i2c_clk_div[i][0] < div; i++);
236
237         /* Write divider value to register */
238         writeb(i2c_clk_div[i][1], i2c_imx->base + IMX_I2C_IFDR);
239
240         /*
241          * There dummy delay is calculated.
242          * It should be about one I2C clock period long.
243          * This delay is used in I2C bus disable function
244          * to fix chip hardware bug.
245          */
246         disable_delay = (500000U * i2c_clk_div[i][0]
247                 + (i2c_clk_rate / 2) - 1) / (i2c_clk_rate / 2);
248
249         /* dev_dbg() can't be used, because adapter is not yet registered */
250 #ifdef CONFIG_I2C_DEBUG_BUS
251         printk(KERN_DEBUG "I2C: <%s> I2C_CLK=%d, REQ DIV=%d\n",
252                 __func__, i2c_clk_rate, div);
253         printk(KERN_DEBUG "I2C: <%s> IFDR[IC]=0x%x, REAL DIV=%d\n",
254                 __func__, i2c_clk_div[i][1], i2c_clk_div[i][0]);
255 #endif
256 }
257
258 static irqreturn_t i2c_imx_isr(int irq, void *dev_id)
259 {
260         struct imx_i2c_struct *i2c_imx = dev_id;
261         unsigned int temp;
262
263         temp = readb(i2c_imx->base + IMX_I2C_I2SR);
264         if (temp & I2SR_IIF) {
265                 /* save status register */
266                 i2c_imx->i2csr = temp;
267                 temp &= ~I2SR_IIF;
268                 writeb(temp, i2c_imx->base + IMX_I2C_I2SR);
269                 wake_up_interruptible(&i2c_imx->queue);
270                 return IRQ_HANDLED;
271         }
272
273         return IRQ_NONE;
274 }
275
276 static int i2c_imx_write(struct imx_i2c_struct *i2c_imx, struct i2c_msg *msgs)
277 {
278         int i, result;
279
280         dev_dbg(&i2c_imx->adapter.dev, "<%s> write slave address: addr=0x%x\n",
281                 __func__, msgs->addr << 1);
282
283         /* write slave address */
284         writeb(msgs->addr << 1, i2c_imx->base + IMX_I2C_I2DR);
285         result = i2c_imx_trx_complete(i2c_imx);
286         if (result)
287                 return result;
288         result = i2c_imx_acked(i2c_imx);
289         if (result)
290                 return result;
291         dev_dbg(&i2c_imx->adapter.dev, "<%s> write data\n", __func__);
292
293         /* write data */
294         for (i = 0; i < msgs->len; i++) {
295                 dev_dbg(&i2c_imx->adapter.dev,
296                         "<%s> write byte: B%d=0x%X\n",
297                         __func__, i, msgs->buf[i]);
298                 writeb(msgs->buf[i], i2c_imx->base + IMX_I2C_I2DR);
299                 result = i2c_imx_trx_complete(i2c_imx);
300                 if (result)
301                         return result;
302                 result = i2c_imx_acked(i2c_imx);
303                 if (result)
304                         return result;
305         }
306         return 0;
307 }
308
309 static int i2c_imx_read(struct imx_i2c_struct *i2c_imx, struct i2c_msg *msgs)
310 {
311         int i, result;
312         unsigned int temp;
313
314         dev_dbg(&i2c_imx->adapter.dev,
315                 "<%s> write slave address: addr=0x%x\n",
316                 __func__, (msgs->addr << 1) | 0x01);
317
318         /* write slave address */
319         writeb((msgs->addr << 1) | 0x01, i2c_imx->base + IMX_I2C_I2DR);
320         result = i2c_imx_trx_complete(i2c_imx);
321         if (result)
322                 return result;
323         result = i2c_imx_acked(i2c_imx);
324         if (result)
325                 return result;
326
327         dev_dbg(&i2c_imx->adapter.dev, "<%s> setup bus\n", __func__);
328
329         /* setup bus to read data */
330         temp = readb(i2c_imx->base + IMX_I2C_I2CR);
331         temp &= ~I2CR_MTX;
332         if (msgs->len - 1)
333                 temp &= ~I2CR_TXAK;
334         writeb(temp, i2c_imx->base + IMX_I2C_I2CR);
335         readb(i2c_imx->base + IMX_I2C_I2DR); /* dummy read */
336
337         dev_dbg(&i2c_imx->adapter.dev, "<%s> read data\n", __func__);
338
339         /* read data */
340         for (i = 0; i < msgs->len; i++) {
341                 result = i2c_imx_trx_complete(i2c_imx);
342                 if (result)
343                         return result;
344                 if (i == (msgs->len - 1)) {
345                         dev_dbg(&i2c_imx->adapter.dev,
346                                 "<%s> clear MSTA\n", __func__);
347                         temp = readb(i2c_imx->base + IMX_I2C_I2CR);
348                         temp &= ~I2CR_MSTA;
349                         writeb(temp, i2c_imx->base + IMX_I2C_I2CR);
350                 } else if (i == (msgs->len - 2)) {
351                         dev_dbg(&i2c_imx->adapter.dev,
352                                 "<%s> set TXAK\n", __func__);
353                         temp = readb(i2c_imx->base + IMX_I2C_I2CR);
354                         temp |= I2CR_TXAK;
355                         writeb(temp, i2c_imx->base + IMX_I2C_I2CR);
356                 }
357                 msgs->buf[i] = readb(i2c_imx->base + IMX_I2C_I2DR);
358                 dev_dbg(&i2c_imx->adapter.dev,
359                         "<%s> read byte: B%d=0x%X\n",
360                         __func__, i, msgs->buf[i]);
361         }
362         return 0;
363 }
364
365 static int i2c_imx_xfer(struct i2c_adapter *adapter,
366                                                 struct i2c_msg *msgs, int num)
367 {
368         unsigned int i, temp;
369         int result;
370         struct imx_i2c_struct *i2c_imx = i2c_get_adapdata(adapter);
371
372         dev_dbg(&i2c_imx->adapter.dev, "<%s>\n", __func__);
373
374         /* Check if i2c bus is not busy */
375         result = i2c_imx_bus_busy(i2c_imx);
376         if (result)
377                 goto fail0;
378
379         /* Start I2C transfer */
380         i2c_imx_start(i2c_imx);
381
382         /* read/write data */
383         for (i = 0; i < num; i++) {
384                 if (i) {
385                         dev_dbg(&i2c_imx->adapter.dev,
386                                 "<%s> repeated start\n", __func__);
387                         temp = readb(i2c_imx->base + IMX_I2C_I2CR);
388                         temp |= I2CR_RSTA;
389                         writeb(temp, i2c_imx->base + IMX_I2C_I2CR);
390                 }
391                 dev_dbg(&i2c_imx->adapter.dev,
392                         "<%s> transfer message: %d\n", __func__, i);
393                 /* write/read data */
394 #ifdef CONFIG_I2C_DEBUG_BUS
395                 temp = readb(i2c_imx->base + IMX_I2C_I2CR);
396                 dev_dbg(&i2c_imx->adapter.dev, "<%s> CONTROL: IEN=%d, IIEN=%d, "
397                         "MSTA=%d, MTX=%d, TXAK=%d, RSTA=%d\n", __func__,
398                         (temp & I2CR_IEN ? 1 : 0), (temp & I2CR_IIEN ? 1 : 0),
399                         (temp & I2CR_MSTA ? 1 : 0), (temp & I2CR_MTX ? 1 : 0),
400                         (temp & I2CR_TXAK ? 1 : 0), (temp & I2CR_RSTA ? 1 : 0));
401                 temp = readb(i2c_imx->base + IMX_I2C_I2SR);
402                 dev_dbg(&i2c_imx->adapter.dev,
403                         "<%s> STATUS: ICF=%d, IAAS=%d, IBB=%d, "
404                         "IAL=%d, SRW=%d, IIF=%d, RXAK=%d\n", __func__,
405                         (temp & I2SR_ICF ? 1 : 0), (temp & I2SR_IAAS ? 1 : 0),
406                         (temp & I2SR_IBB ? 1 : 0), (temp & I2SR_IAL ? 1 : 0),
407                         (temp & I2SR_SRW ? 1 : 0), (temp & I2SR_IIF ? 1 : 0),
408                         (temp & I2SR_RXAK ? 1 : 0));
409 #endif
410                 if (msgs[i].flags & I2C_M_RD)
411                         result = i2c_imx_read(i2c_imx, &msgs[i]);
412                 else
413                         result = i2c_imx_write(i2c_imx, &msgs[i]);
414         }
415
416 fail0:
417         /* Stop I2C transfer */
418         i2c_imx_stop(i2c_imx);
419
420         dev_dbg(&i2c_imx->adapter.dev, "<%s> exit with: %s: %d\n", __func__,
421                 (result < 0) ? "error" : "success msg",
422                         (result < 0) ? result : num);
423         return (result < 0) ? result : num;
424 }
425
426 static u32 i2c_imx_func(struct i2c_adapter *adapter)
427 {
428         return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
429 }
430
431 static struct i2c_algorithm i2c_imx_algo = {
432         .master_xfer    = i2c_imx_xfer,
433         .functionality  = i2c_imx_func,
434 };
435
436 static int __init i2c_imx_probe(struct platform_device *pdev)
437 {
438         struct imx_i2c_struct *i2c_imx;
439         struct resource *res;
440         struct imxi2c_platform_data *pdata;
441         void __iomem *base;
442         resource_size_t res_size;
443         int irq;
444         int ret;
445
446         dev_dbg(&pdev->dev, "<%s>\n", __func__);
447
448         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
449         if (!res) {
450                 dev_err(&pdev->dev, "can't get device resources\n");
451                 return -ENOENT;
452         }
453         irq = platform_get_irq(pdev, 0);
454         if (irq < 0) {
455                 dev_err(&pdev->dev, "can't get irq number\n");
456                 return -ENOENT;
457         }
458
459         pdata = pdev->dev.platform_data;
460
461         if (pdata && pdata->init) {
462                 ret = pdata->init(&pdev->dev);
463                 if (ret)
464                         return ret;
465         }
466
467         res_size = resource_size(res);
468         base = ioremap(res->start, res_size);
469         if (!base) {
470                 dev_err(&pdev->dev, "ioremap failed\n");
471                 ret = -EIO;
472                 goto fail0;
473         }
474
475         i2c_imx = kzalloc(sizeof(struct imx_i2c_struct), GFP_KERNEL);
476         if (!i2c_imx) {
477                 dev_err(&pdev->dev, "can't allocate interface\n");
478                 ret = -ENOMEM;
479                 goto fail1;
480         }
481
482         /* Setup i2c_imx driver structure */
483         strcpy(i2c_imx->adapter.name, pdev->name);
484         i2c_imx->adapter.owner          = THIS_MODULE;
485         i2c_imx->adapter.algo           = &i2c_imx_algo;
486         i2c_imx->adapter.dev.parent     = &pdev->dev;
487         i2c_imx->adapter.nr             = pdev->id;
488         i2c_imx->irq                    = irq;
489         i2c_imx->base                   = base;
490         i2c_imx->res                    = res;
491
492         /* Get I2C clock */
493         i2c_imx->clk = clk_get(&pdev->dev, "i2c_clk");
494         if (IS_ERR(i2c_imx->clk)) {
495                 ret = PTR_ERR(i2c_imx->clk);
496                 dev_err(&pdev->dev, "can't get I2C clock\n");
497                 goto fail2;
498         }
499         clk_enable(i2c_imx->clk);
500
501         /* Request IRQ */
502         ret = request_irq(i2c_imx->irq, i2c_imx_isr, 0, pdev->name, i2c_imx);
503         if (ret) {
504                 dev_err(&pdev->dev, "can't claim irq %d\n", i2c_imx->irq);
505                 goto fail3;
506         }
507
508         /* Init queue */
509         init_waitqueue_head(&i2c_imx->queue);
510
511         /* Set up adapter data */
512         i2c_set_adapdata(&i2c_imx->adapter, i2c_imx);
513
514         /* Set up clock divider */
515         if (pdata && pdata->bitrate)
516                 i2c_imx_set_clk(i2c_imx, pdata->bitrate);
517         else
518                 i2c_imx_set_clk(i2c_imx, IMX_I2C_BIT_RATE);
519
520         /* Set up chip registers to defaults */
521         writeb(0, i2c_imx->base + IMX_I2C_I2CR);
522         writeb(0, i2c_imx->base + IMX_I2C_I2SR);
523
524         /* Add I2C adapter */
525         ret = i2c_add_numbered_adapter(&i2c_imx->adapter);
526         if (ret < 0) {
527                 dev_err(&pdev->dev, "registration failed\n");
528                 goto fail4;
529         }
530
531         /* Set up platform driver data */
532         platform_set_drvdata(pdev, i2c_imx);
533
534         dev_dbg(&i2c_imx->adapter.dev, "claimed irq %d\n", i2c_imx->irq);
535         dev_dbg(&i2c_imx->adapter.dev, "device resources from 0x%x to 0x%x\n",
536                 i2c_imx->res->start, i2c_imx->res->end);
537         dev_dbg(&i2c_imx->adapter.dev, "allocated %d bytes at 0x%x \n",
538                 res_size, i2c_imx->res->start);
539         dev_dbg(&i2c_imx->adapter.dev, "adapter name: \"%s\"\n",
540                 i2c_imx->adapter.name);
541         dev_dbg(&i2c_imx->adapter.dev, "IMX I2C adapter registered\n");
542
543         return 0;   /* Return OK */
544
545 fail4:
546         free_irq(i2c_imx->irq, i2c_imx);
547 fail3:
548         clk_disable(i2c_imx->clk);
549         clk_put(i2c_imx->clk);
550 fail2:
551         kfree(i2c_imx);
552 fail1:
553         iounmap(base);
554 fail0:
555         if (pdata && pdata->exit)
556                 pdata->exit(&pdev->dev);
557         return ret; /* Return error number */
558 }
559
560 static int __exit i2c_imx_remove(struct platform_device *pdev)
561 {
562         struct imx_i2c_struct *i2c_imx = platform_get_drvdata(pdev);
563         struct imxi2c_platform_data *pdata = pdev->dev.platform_data;
564
565         /* remove adapter */
566         dev_dbg(&i2c_imx->adapter.dev, "adapter removed\n");
567         i2c_del_adapter(&i2c_imx->adapter);
568         platform_set_drvdata(pdev, NULL);
569
570         /* free interrupt */
571         free_irq(i2c_imx->irq, i2c_imx);
572
573         /* setup chip registers to defaults */
574         writeb(0, i2c_imx->base + IMX_I2C_IADR);
575         writeb(0, i2c_imx->base + IMX_I2C_IFDR);
576         writeb(0, i2c_imx->base + IMX_I2C_I2CR);
577         writeb(0, i2c_imx->base + IMX_I2C_I2SR);
578
579         /* Shut down hardware */
580         if (pdata && pdata->exit)
581                 pdata->exit(&pdev->dev);
582
583         /* Disable I2C clock */
584         clk_disable(i2c_imx->clk);
585         clk_put(i2c_imx->clk);
586
587         iounmap(i2c_imx->base);
588         kfree(i2c_imx);
589         return 0;
590 }
591
592 static struct platform_driver i2c_imx_driver = {
593         .probe          = i2c_imx_probe,
594         .remove         = __exit_p(i2c_imx_remove),
595         .driver = {
596                 .name   = DRIVER_NAME,
597                 .owner  = THIS_MODULE,
598         }
599 };
600
601 static int __init i2c_adap_imx_init(void)
602 {
603         return platform_driver_probe(&i2c_imx_driver, i2c_imx_probe);
604 }
605
606 static void __exit i2c_adap_imx_exit(void)
607 {
608         platform_driver_unregister(&i2c_imx_driver);
609 }
610
611 module_init(i2c_adap_imx_init);
612 module_exit(i2c_adap_imx_exit);
613
614 MODULE_LICENSE("GPL");
615 MODULE_AUTHOR("Darius Augulis");
616 MODULE_DESCRIPTION("I2C adapter driver for IMX I2C bus");
617 MODULE_ALIAS("platform:" DRIVER_NAME);