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>
50 #include <linux/slab.h>
52 #include <linux/of_device.h>
53 #include <linux/of_i2c.h>
55 #include <mach/irqs.h>
56 #include <mach/hardware.h>
59 /** Defines ********************************************************************
60 *******************************************************************************/
62 /* This will be the driver name the kernel reports */
63 #define DRIVER_NAME "imx-i2c"
66 #define IMX_I2C_BIT_RATE 100000 /* 100kHz */
68 /* IMX I2C registers */
69 #define IMX_I2C_IADR 0x00 /* i2c slave address */
70 #define IMX_I2C_IFDR 0x04 /* i2c frequency divider */
71 #define IMX_I2C_I2CR 0x08 /* i2c control */
72 #define IMX_I2C_I2SR 0x0C /* i2c status */
73 #define IMX_I2C_I2DR 0x10 /* i2c transfer data */
75 /* Bits of IMX I2C registers */
76 #define I2SR_RXAK 0x01
81 #define I2SR_IAAS 0x40
83 #define I2CR_RSTA 0x04
84 #define I2CR_TXAK 0x08
86 #define I2CR_MSTA 0x20
87 #define I2CR_IIEN 0x40
90 /** Variables ******************************************************************
91 *******************************************************************************/
94 * sorted list of clock divider, register value pairs
95 * taken from table 26-5, p.26-9, Freescale i.MX
96 * Integrated Portable System Processor Reference Manual
97 * Document Number: MC9328MXLRM, Rev. 5.1, 06/2007
99 * Duplicated divider values removed from list
102 static u16 __initdata i2c_clk_div[50][2] = {
103 { 22, 0x20 }, { 24, 0x21 }, { 26, 0x22 }, { 28, 0x23 },
104 { 30, 0x00 }, { 32, 0x24 }, { 36, 0x25 }, { 40, 0x26 },
105 { 42, 0x03 }, { 44, 0x27 }, { 48, 0x28 }, { 52, 0x05 },
106 { 56, 0x29 }, { 60, 0x06 }, { 64, 0x2A }, { 72, 0x2B },
107 { 80, 0x2C }, { 88, 0x09 }, { 96, 0x2D }, { 104, 0x0A },
108 { 112, 0x2E }, { 128, 0x2F }, { 144, 0x0C }, { 160, 0x30 },
109 { 192, 0x31 }, { 224, 0x32 }, { 240, 0x0F }, { 256, 0x33 },
110 { 288, 0x10 }, { 320, 0x34 }, { 384, 0x35 }, { 448, 0x36 },
111 { 480, 0x13 }, { 512, 0x37 }, { 576, 0x14 }, { 640, 0x38 },
112 { 768, 0x39 }, { 896, 0x3A }, { 960, 0x17 }, { 1024, 0x3B },
113 { 1152, 0x18 }, { 1280, 0x3C }, { 1536, 0x3D }, { 1792, 0x3E },
114 { 1920, 0x1B }, { 2048, 0x3F }, { 2304, 0x1C }, { 2560, 0x1D },
115 { 3072, 0x1E }, { 3840, 0x1F }
118 struct imx_i2c_struct {
119 struct i2c_adapter adapter;
120 struct resource *res;
124 wait_queue_head_t queue;
126 unsigned int disable_delay;
128 unsigned int ifdr; /* IMX_I2C_IFDR */
131 static const struct of_device_id i2c_imx_dt_ids[] = {
132 { .compatible = "fsl,imx1-i2c", },
136 /** Functions for IMX I2C adapter driver ***************************************
137 *******************************************************************************/
139 static int i2c_imx_bus_busy(struct imx_i2c_struct *i2c_imx, int for_busy)
141 unsigned long orig_jiffies = jiffies;
144 dev_dbg(&i2c_imx->adapter.dev, "<%s>\n", __func__);
147 temp = readb(i2c_imx->base + IMX_I2C_I2SR);
148 if (for_busy && (temp & I2SR_IBB))
150 if (!for_busy && !(temp & I2SR_IBB))
152 if (time_after(jiffies, orig_jiffies + msecs_to_jiffies(500))) {
153 dev_dbg(&i2c_imx->adapter.dev,
154 "<%s> I2C bus is busy\n", __func__);
163 static int i2c_imx_trx_complete(struct imx_i2c_struct *i2c_imx)
165 wait_event_timeout(i2c_imx->queue, i2c_imx->i2csr & I2SR_IIF, HZ / 10);
167 if (unlikely(!(i2c_imx->i2csr & I2SR_IIF))) {
168 dev_dbg(&i2c_imx->adapter.dev, "<%s> Timeout\n", __func__);
171 dev_dbg(&i2c_imx->adapter.dev, "<%s> TRX complete\n", __func__);
176 static int i2c_imx_acked(struct imx_i2c_struct *i2c_imx)
178 if (readb(i2c_imx->base + IMX_I2C_I2SR) & I2SR_RXAK) {
179 dev_dbg(&i2c_imx->adapter.dev, "<%s> No ACK\n", __func__);
180 return -EIO; /* No ACK */
183 dev_dbg(&i2c_imx->adapter.dev, "<%s> ACK received\n", __func__);
187 static int i2c_imx_start(struct imx_i2c_struct *i2c_imx)
189 unsigned int temp = 0;
192 dev_dbg(&i2c_imx->adapter.dev, "<%s>\n", __func__);
194 clk_prepare_enable(i2c_imx->clk);
195 writeb(i2c_imx->ifdr, i2c_imx->base + IMX_I2C_IFDR);
196 /* Enable I2C controller */
197 writeb(0, i2c_imx->base + IMX_I2C_I2SR);
198 writeb(I2CR_IEN, i2c_imx->base + IMX_I2C_I2CR);
200 /* Wait controller to be stable */
203 /* Start I2C transaction */
204 temp = readb(i2c_imx->base + IMX_I2C_I2CR);
206 writeb(temp, i2c_imx->base + IMX_I2C_I2CR);
207 result = i2c_imx_bus_busy(i2c_imx, 1);
210 i2c_imx->stopped = 0;
212 temp |= I2CR_IIEN | I2CR_MTX | I2CR_TXAK;
213 writeb(temp, i2c_imx->base + IMX_I2C_I2CR);
217 static void i2c_imx_stop(struct imx_i2c_struct *i2c_imx)
219 unsigned int temp = 0;
221 if (!i2c_imx->stopped) {
222 /* Stop I2C transaction */
223 dev_dbg(&i2c_imx->adapter.dev, "<%s>\n", __func__);
224 temp = readb(i2c_imx->base + IMX_I2C_I2CR);
225 temp &= ~(I2CR_MSTA | I2CR_MTX);
226 writeb(temp, i2c_imx->base + IMX_I2C_I2CR);
230 * This delay caused by an i.MXL hardware bug.
231 * If no (or too short) delay, no "STOP" bit will be generated.
233 udelay(i2c_imx->disable_delay);
236 if (!i2c_imx->stopped) {
237 i2c_imx_bus_busy(i2c_imx, 0);
238 i2c_imx->stopped = 1;
241 /* Disable I2C controller */
242 writeb(0, i2c_imx->base + IMX_I2C_I2CR);
243 clk_disable_unprepare(i2c_imx->clk);
246 static void __init i2c_imx_set_clk(struct imx_i2c_struct *i2c_imx,
249 unsigned int i2c_clk_rate;
253 /* Divider value calculation */
254 i2c_clk_rate = clk_get_rate(i2c_imx->clk);
255 div = (i2c_clk_rate + rate - 1) / rate;
256 if (div < i2c_clk_div[0][0])
258 else if (div > i2c_clk_div[ARRAY_SIZE(i2c_clk_div) - 1][0])
259 i = ARRAY_SIZE(i2c_clk_div) - 1;
261 for (i = 0; i2c_clk_div[i][0] < div; i++);
263 /* Store divider value */
264 i2c_imx->ifdr = i2c_clk_div[i][1];
267 * There dummy delay is calculated.
268 * It should be about one I2C clock period long.
269 * This delay is used in I2C bus disable function
270 * to fix chip hardware bug.
272 i2c_imx->disable_delay = (500000U * i2c_clk_div[i][0]
273 + (i2c_clk_rate / 2) - 1) / (i2c_clk_rate / 2);
275 /* dev_dbg() can't be used, because adapter is not yet registered */
276 #ifdef CONFIG_I2C_DEBUG_BUS
277 printk(KERN_DEBUG "I2C: <%s> I2C_CLK=%d, REQ DIV=%d\n",
278 __func__, i2c_clk_rate, div);
279 printk(KERN_DEBUG "I2C: <%s> IFDR[IC]=0x%x, REAL DIV=%d\n",
280 __func__, i2c_clk_div[i][1], i2c_clk_div[i][0]);
284 static irqreturn_t i2c_imx_isr(int irq, void *dev_id)
286 struct imx_i2c_struct *i2c_imx = dev_id;
289 temp = readb(i2c_imx->base + IMX_I2C_I2SR);
290 if (temp & I2SR_IIF) {
291 /* save status register */
292 i2c_imx->i2csr = temp;
294 writeb(temp, i2c_imx->base + IMX_I2C_I2SR);
295 wake_up(&i2c_imx->queue);
302 static int i2c_imx_write(struct imx_i2c_struct *i2c_imx, struct i2c_msg *msgs)
306 dev_dbg(&i2c_imx->adapter.dev, "<%s> write slave address: addr=0x%x\n",
307 __func__, msgs->addr << 1);
309 /* write slave address */
310 writeb(msgs->addr << 1, i2c_imx->base + IMX_I2C_I2DR);
311 result = i2c_imx_trx_complete(i2c_imx);
314 result = i2c_imx_acked(i2c_imx);
317 dev_dbg(&i2c_imx->adapter.dev, "<%s> write data\n", __func__);
320 for (i = 0; i < msgs->len; i++) {
321 dev_dbg(&i2c_imx->adapter.dev,
322 "<%s> write byte: B%d=0x%X\n",
323 __func__, i, msgs->buf[i]);
324 writeb(msgs->buf[i], i2c_imx->base + IMX_I2C_I2DR);
325 result = i2c_imx_trx_complete(i2c_imx);
328 result = i2c_imx_acked(i2c_imx);
335 static int i2c_imx_read(struct imx_i2c_struct *i2c_imx, struct i2c_msg *msgs)
340 dev_dbg(&i2c_imx->adapter.dev,
341 "<%s> write slave address: addr=0x%x\n",
342 __func__, (msgs->addr << 1) | 0x01);
344 /* write slave address */
345 writeb((msgs->addr << 1) | 0x01, i2c_imx->base + IMX_I2C_I2DR);
346 result = i2c_imx_trx_complete(i2c_imx);
349 result = i2c_imx_acked(i2c_imx);
353 dev_dbg(&i2c_imx->adapter.dev, "<%s> setup bus\n", __func__);
355 /* setup bus to read data */
356 temp = readb(i2c_imx->base + IMX_I2C_I2CR);
360 writeb(temp, i2c_imx->base + IMX_I2C_I2CR);
361 readb(i2c_imx->base + IMX_I2C_I2DR); /* dummy read */
363 dev_dbg(&i2c_imx->adapter.dev, "<%s> read data\n", __func__);
366 for (i = 0; i < msgs->len; i++) {
367 result = i2c_imx_trx_complete(i2c_imx);
370 if (i == (msgs->len - 1)) {
371 /* It must generate STOP before read I2DR to prevent
372 controller from generating another clock cycle */
373 dev_dbg(&i2c_imx->adapter.dev,
374 "<%s> clear MSTA\n", __func__);
375 temp = readb(i2c_imx->base + IMX_I2C_I2CR);
376 temp &= ~(I2CR_MSTA | I2CR_MTX);
377 writeb(temp, i2c_imx->base + IMX_I2C_I2CR);
378 i2c_imx_bus_busy(i2c_imx, 0);
379 i2c_imx->stopped = 1;
380 } else if (i == (msgs->len - 2)) {
381 dev_dbg(&i2c_imx->adapter.dev,
382 "<%s> set TXAK\n", __func__);
383 temp = readb(i2c_imx->base + IMX_I2C_I2CR);
385 writeb(temp, i2c_imx->base + IMX_I2C_I2CR);
387 msgs->buf[i] = readb(i2c_imx->base + IMX_I2C_I2DR);
388 dev_dbg(&i2c_imx->adapter.dev,
389 "<%s> read byte: B%d=0x%X\n",
390 __func__, i, msgs->buf[i]);
395 static int i2c_imx_xfer(struct i2c_adapter *adapter,
396 struct i2c_msg *msgs, int num)
398 unsigned int i, temp;
400 struct imx_i2c_struct *i2c_imx = i2c_get_adapdata(adapter);
402 dev_dbg(&i2c_imx->adapter.dev, "<%s>\n", __func__);
404 /* Start I2C transfer */
405 result = i2c_imx_start(i2c_imx);
409 /* read/write data */
410 for (i = 0; i < num; i++) {
412 dev_dbg(&i2c_imx->adapter.dev,
413 "<%s> repeated start\n", __func__);
414 temp = readb(i2c_imx->base + IMX_I2C_I2CR);
416 writeb(temp, i2c_imx->base + IMX_I2C_I2CR);
417 result = i2c_imx_bus_busy(i2c_imx, 1);
421 dev_dbg(&i2c_imx->adapter.dev,
422 "<%s> transfer message: %d\n", __func__, i);
423 /* write/read data */
424 #ifdef CONFIG_I2C_DEBUG_BUS
425 temp = readb(i2c_imx->base + IMX_I2C_I2CR);
426 dev_dbg(&i2c_imx->adapter.dev, "<%s> CONTROL: IEN=%d, IIEN=%d, "
427 "MSTA=%d, MTX=%d, TXAK=%d, RSTA=%d\n", __func__,
428 (temp & I2CR_IEN ? 1 : 0), (temp & I2CR_IIEN ? 1 : 0),
429 (temp & I2CR_MSTA ? 1 : 0), (temp & I2CR_MTX ? 1 : 0),
430 (temp & I2CR_TXAK ? 1 : 0), (temp & I2CR_RSTA ? 1 : 0));
431 temp = readb(i2c_imx->base + IMX_I2C_I2SR);
432 dev_dbg(&i2c_imx->adapter.dev,
433 "<%s> STATUS: ICF=%d, IAAS=%d, IBB=%d, "
434 "IAL=%d, SRW=%d, IIF=%d, RXAK=%d\n", __func__,
435 (temp & I2SR_ICF ? 1 : 0), (temp & I2SR_IAAS ? 1 : 0),
436 (temp & I2SR_IBB ? 1 : 0), (temp & I2SR_IAL ? 1 : 0),
437 (temp & I2SR_SRW ? 1 : 0), (temp & I2SR_IIF ? 1 : 0),
438 (temp & I2SR_RXAK ? 1 : 0));
440 if (msgs[i].flags & I2C_M_RD)
441 result = i2c_imx_read(i2c_imx, &msgs[i]);
443 result = i2c_imx_write(i2c_imx, &msgs[i]);
449 /* Stop I2C transfer */
450 i2c_imx_stop(i2c_imx);
452 dev_dbg(&i2c_imx->adapter.dev, "<%s> exit with: %s: %d\n", __func__,
453 (result < 0) ? "error" : "success msg",
454 (result < 0) ? result : num);
455 return (result < 0) ? result : num;
458 static u32 i2c_imx_func(struct i2c_adapter *adapter)
460 return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
463 static struct i2c_algorithm i2c_imx_algo = {
464 .master_xfer = i2c_imx_xfer,
465 .functionality = i2c_imx_func,
468 static int __init i2c_imx_probe(struct platform_device *pdev)
470 struct imx_i2c_struct *i2c_imx;
471 struct resource *res;
472 struct imxi2c_platform_data *pdata = pdev->dev.platform_data;
474 resource_size_t res_size;
478 dev_dbg(&pdev->dev, "<%s>\n", __func__);
480 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
482 dev_err(&pdev->dev, "can't get device resources\n");
485 irq = platform_get_irq(pdev, 0);
487 dev_err(&pdev->dev, "can't get irq number\n");
491 res_size = resource_size(res);
493 if (!request_mem_region(res->start, res_size, DRIVER_NAME)) {
494 dev_err(&pdev->dev, "request_mem_region failed\n");
498 base = ioremap(res->start, res_size);
500 dev_err(&pdev->dev, "ioremap failed\n");
505 i2c_imx = kzalloc(sizeof(struct imx_i2c_struct), GFP_KERNEL);
507 dev_err(&pdev->dev, "can't allocate interface\n");
512 /* Setup i2c_imx driver structure */
513 strcpy(i2c_imx->adapter.name, pdev->name);
514 i2c_imx->adapter.owner = THIS_MODULE;
515 i2c_imx->adapter.algo = &i2c_imx_algo;
516 i2c_imx->adapter.dev.parent = &pdev->dev;
517 i2c_imx->adapter.nr = pdev->id;
518 i2c_imx->adapter.dev.of_node = pdev->dev.of_node;
520 i2c_imx->base = base;
524 i2c_imx->clk = clk_get(&pdev->dev, "i2c_clk");
525 if (IS_ERR(i2c_imx->clk)) {
526 ret = PTR_ERR(i2c_imx->clk);
527 dev_err(&pdev->dev, "can't get I2C clock\n");
532 ret = request_irq(i2c_imx->irq, i2c_imx_isr, 0, pdev->name, i2c_imx);
534 dev_err(&pdev->dev, "can't claim irq %d\n", i2c_imx->irq);
539 init_waitqueue_head(&i2c_imx->queue);
541 /* Set up adapter data */
542 i2c_set_adapdata(&i2c_imx->adapter, i2c_imx);
544 /* Set up clock divider */
545 bitrate = IMX_I2C_BIT_RATE;
546 ret = of_property_read_u32(pdev->dev.of_node,
547 "clock-frequency", &bitrate);
548 if (ret < 0 && pdata && pdata->bitrate)
549 bitrate = pdata->bitrate;
550 i2c_imx_set_clk(i2c_imx, bitrate);
552 /* Set up chip registers to defaults */
553 writeb(0, i2c_imx->base + IMX_I2C_I2CR);
554 writeb(0, i2c_imx->base + IMX_I2C_I2SR);
556 /* Add I2C adapter */
557 ret = i2c_add_numbered_adapter(&i2c_imx->adapter);
559 dev_err(&pdev->dev, "registration failed\n");
563 of_i2c_register_devices(&i2c_imx->adapter);
565 /* Set up platform driver data */
566 platform_set_drvdata(pdev, i2c_imx);
568 dev_dbg(&i2c_imx->adapter.dev, "claimed irq %d\n", i2c_imx->irq);
569 dev_dbg(&i2c_imx->adapter.dev, "device resources from 0x%x to 0x%x\n",
570 i2c_imx->res->start, i2c_imx->res->end);
571 dev_dbg(&i2c_imx->adapter.dev, "allocated %d bytes at 0x%x \n",
572 res_size, i2c_imx->res->start);
573 dev_dbg(&i2c_imx->adapter.dev, "adapter name: \"%s\"\n",
574 i2c_imx->adapter.name);
575 dev_dbg(&i2c_imx->adapter.dev, "IMX I2C adapter registered\n");
577 return 0; /* Return OK */
580 free_irq(i2c_imx->irq, i2c_imx);
582 clk_put(i2c_imx->clk);
588 release_mem_region(res->start, resource_size(res));
589 return ret; /* Return error number */
592 static int __exit i2c_imx_remove(struct platform_device *pdev)
594 struct imx_i2c_struct *i2c_imx = platform_get_drvdata(pdev);
597 dev_dbg(&i2c_imx->adapter.dev, "adapter removed\n");
598 i2c_del_adapter(&i2c_imx->adapter);
599 platform_set_drvdata(pdev, NULL);
602 free_irq(i2c_imx->irq, i2c_imx);
604 /* setup chip registers to defaults */
605 writeb(0, i2c_imx->base + IMX_I2C_IADR);
606 writeb(0, i2c_imx->base + IMX_I2C_IFDR);
607 writeb(0, i2c_imx->base + IMX_I2C_I2CR);
608 writeb(0, i2c_imx->base + IMX_I2C_I2SR);
610 clk_put(i2c_imx->clk);
612 iounmap(i2c_imx->base);
613 release_mem_region(i2c_imx->res->start, resource_size(i2c_imx->res));
618 static struct platform_driver i2c_imx_driver = {
619 .remove = __exit_p(i2c_imx_remove),
622 .owner = THIS_MODULE,
623 .of_match_table = i2c_imx_dt_ids,
627 static int __init i2c_adap_imx_init(void)
629 return platform_driver_probe(&i2c_imx_driver, i2c_imx_probe);
631 subsys_initcall(i2c_adap_imx_init);
633 static void __exit i2c_adap_imx_exit(void)
635 platform_driver_unregister(&i2c_imx_driver);
637 module_exit(i2c_adap_imx_exit);
639 MODULE_LICENSE("GPL");
640 MODULE_AUTHOR("Darius Augulis");
641 MODULE_DESCRIPTION("I2C adapter driver for IMX I2C bus");
642 MODULE_ALIAS("platform:" DRIVER_NAME);