2 * TI DAVINCI I2C adapter driver.
4 * Copyright (C) 2006 Texas Instruments.
5 * Copyright (C) 2007 MontaVista Software Inc.
7 * Updated by Vinod & Sudhakar Feb 2005
9 * ----------------------------------------------------------------------------
11 * This program is free software; you can redistribute it and/or modify
12 * it under the terms of the GNU General Public License as published by
13 * the Free Software Foundation; either version 2 of the License, or
14 * (at your option) any later version.
16 * This program is distributed in the hope that it will be useful,
17 * but WITHOUT ANY WARRANTY; without even the implied warranty of
18 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
19 * GNU General Public License for more details.
21 * You should have received a copy of the GNU General Public License
22 * along with this program; if not, write to the Free Software
23 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
24 * ----------------------------------------------------------------------------
27 #include <linux/kernel.h>
28 #include <linux/module.h>
29 #include <linux/delay.h>
30 #include <linux/i2c.h>
31 #include <linux/clk.h>
32 #include <linux/errno.h>
33 #include <linux/sched.h>
34 #include <linux/err.h>
35 #include <linux/interrupt.h>
36 #include <linux/platform_device.h>
39 #include <asm/hardware.h>
40 #include <asm/mach-types.h>
42 #include <asm/arch/i2c.h>
44 /* ----- global defines ----------------------------------------------- */
46 #define DAVINCI_I2C_TIMEOUT (1*HZ)
47 #define I2C_DAVINCI_INTR_ALL (DAVINCI_I2C_IMR_AAS | \
48 DAVINCI_I2C_IMR_SCD | \
49 DAVINCI_I2C_IMR_ARDY | \
50 DAVINCI_I2C_IMR_NACK | \
53 #define DAVINCI_I2C_OAR_REG 0x00
54 #define DAVINCI_I2C_IMR_REG 0x04
55 #define DAVINCI_I2C_STR_REG 0x08
56 #define DAVINCI_I2C_CLKL_REG 0x0c
57 #define DAVINCI_I2C_CLKH_REG 0x10
58 #define DAVINCI_I2C_CNT_REG 0x14
59 #define DAVINCI_I2C_DRR_REG 0x18
60 #define DAVINCI_I2C_SAR_REG 0x1c
61 #define DAVINCI_I2C_DXR_REG 0x20
62 #define DAVINCI_I2C_MDR_REG 0x24
63 #define DAVINCI_I2C_IVR_REG 0x28
64 #define DAVINCI_I2C_EMDR_REG 0x2c
65 #define DAVINCI_I2C_PSC_REG 0x30
67 #define DAVINCI_I2C_IVR_AAS 0x07
68 #define DAVINCI_I2C_IVR_SCD 0x06
69 #define DAVINCI_I2C_IVR_XRDY 0x05
70 #define DAVINCI_I2C_IVR_RDR 0x04
71 #define DAVINCI_I2C_IVR_ARDY 0x03
72 #define DAVINCI_I2C_IVR_NACK 0x02
73 #define DAVINCI_I2C_IVR_AL 0x01
75 #define DAVINCI_I2C_STR_BB (1 << 12)
76 #define DAVINCI_I2C_STR_RSFULL (1 << 11)
77 #define DAVINCI_I2C_STR_SCD (1 << 5)
78 #define DAVINCI_I2C_STR_ARDY (1 << 2)
79 #define DAVINCI_I2C_STR_NACK (1 << 1)
80 #define DAVINCI_I2C_STR_AL (1 << 0)
82 #define DAVINCI_I2C_MDR_NACK (1 << 15)
83 #define DAVINCI_I2C_MDR_STT (1 << 13)
84 #define DAVINCI_I2C_MDR_STP (1 << 11)
85 #define DAVINCI_I2C_MDR_MST (1 << 10)
86 #define DAVINCI_I2C_MDR_TRX (1 << 9)
87 #define DAVINCI_I2C_MDR_XA (1 << 8)
88 #define DAVINCI_I2C_MDR_IRS (1 << 5)
90 #define DAVINCI_I2C_IMR_AAS (1 << 6)
91 #define DAVINCI_I2C_IMR_SCD (1 << 5)
92 #define DAVINCI_I2C_IMR_XRDY (1 << 4)
93 #define DAVINCI_I2C_IMR_RRDY (1 << 3)
94 #define DAVINCI_I2C_IMR_ARDY (1 << 2)
95 #define DAVINCI_I2C_IMR_NACK (1 << 1)
96 #define DAVINCI_I2C_IMR_AL (1 << 0)
98 #define MOD_REG_BIT(val, mask, set) do { \
106 struct davinci_i2c_dev {
109 struct completion cmd_complete;
115 struct i2c_adapter adapter;
118 /* default platform data to use if not supplied in the platform_device */
119 static struct davinci_i2c_platform_data davinci_i2c_platform_data_default = {
124 static inline void davinci_i2c_write_reg(struct davinci_i2c_dev *i2c_dev,
127 __raw_writew(val, i2c_dev->base + reg);
130 static inline u16 davinci_i2c_read_reg(struct davinci_i2c_dev *i2c_dev, int reg)
132 return __raw_readw(i2c_dev->base + reg);
136 * This functions configures I2C and brings I2C out of reset.
137 * This function is called during I2C init function. This function
138 * also gets called if I2C encounters any errors.
140 static int i2c_davinci_init(struct davinci_i2c_dev *dev)
142 struct davinci_i2c_platform_data *pdata = dev->dev->platform_data;
147 u32 input_clock = clk_get_rate(dev->clk);
151 pdata = &davinci_i2c_platform_data_default;
153 /* put I2C into reset */
154 w = davinci_i2c_read_reg(dev, DAVINCI_I2C_MDR_REG);
155 MOD_REG_BIT(w, DAVINCI_I2C_MDR_IRS, 0);
156 davinci_i2c_write_reg(dev, DAVINCI_I2C_MDR_REG, w);
158 /* NOTE: I2C Clock divider programming info
159 * As per I2C specs the following formulas provide prescaler
160 * and low/high divider values
161 * input clk --> PSC Div -----------> ICCL/H Div --> output clock
164 * output clk = module clk / (PSC + 1) [ (ICCL + d) + (ICCH + d) ]
167 * (ICCL + ICCH) = clk = (input clk / ((psc +1) * output clk)) - 2d;
169 * where if PSC == 0, d = 7,
174 psc = 26; /* To get 1MHz clock */
176 clk = ((input_clock / (psc + 1)) / (pdata->bus_freq * 1000)) - 10;
177 clkh = (50 * clk) / 100;
180 davinci_i2c_write_reg(dev, DAVINCI_I2C_PSC_REG, psc);
181 davinci_i2c_write_reg(dev, DAVINCI_I2C_CLKH_REG, clkh);
182 davinci_i2c_write_reg(dev, DAVINCI_I2C_CLKL_REG, clkl);
184 dev_dbg(dev->dev, "CLK = %d\n", clk);
185 dev_dbg(dev->dev, "PSC = %d\n",
186 davinci_i2c_read_reg(dev, DAVINCI_I2C_PSC_REG));
187 dev_dbg(dev->dev, "CLKL = %d\n",
188 davinci_i2c_read_reg(dev, DAVINCI_I2C_CLKL_REG));
189 dev_dbg(dev->dev, "CLKH = %d\n",
190 davinci_i2c_read_reg(dev, DAVINCI_I2C_CLKH_REG));
192 /* Take the I2C module out of reset: */
193 w = davinci_i2c_read_reg(dev, DAVINCI_I2C_MDR_REG);
194 MOD_REG_BIT(w, DAVINCI_I2C_MDR_IRS, 1);
195 davinci_i2c_write_reg(dev, DAVINCI_I2C_MDR_REG, w);
197 /* Enable interrupts */
198 davinci_i2c_write_reg(dev, DAVINCI_I2C_IMR_REG, I2C_DAVINCI_INTR_ALL);
204 * Waiting for bus not busy
206 static int i2c_davinci_wait_bus_not_busy(struct davinci_i2c_dev *dev,
209 unsigned long timeout;
211 timeout = jiffies + DAVINCI_I2C_TIMEOUT;
212 while (davinci_i2c_read_reg(dev, DAVINCI_I2C_STR_REG)
213 & DAVINCI_I2C_STR_BB) {
214 if (time_after(jiffies, timeout)) {
216 "timeout waiting for bus ready\n");
227 * Low level master read/write transaction. This function is called
228 * from i2c_davinci_xfer.
231 i2c_davinci_xfer_msg(struct i2c_adapter *adap, struct i2c_msg *msg, int stop)
233 struct davinci_i2c_dev *dev = i2c_get_adapdata(adap);
234 struct davinci_i2c_platform_data *pdata = dev->dev->platform_data;
244 pdata = &davinci_i2c_platform_data_default;
245 /* Introduce a delay, required for some boards (e.g Davinci EVM) */
246 if (pdata->bus_delay)
247 udelay(pdata->bus_delay);
249 /* set the slave address */
250 davinci_i2c_write_reg(dev, DAVINCI_I2C_SAR_REG, msg->addr);
253 dev->buf_len = msg->len;
255 davinci_i2c_write_reg(dev, DAVINCI_I2C_CNT_REG, dev->buf_len);
257 init_completion(&dev->cmd_complete);
260 /* Clear any pending interrupts by reading the IVR */
261 stat = davinci_i2c_read_reg(dev, DAVINCI_I2C_IVR_REG);
263 /* Take I2C out of reset, configure it as master and set the
265 flag = DAVINCI_I2C_MDR_IRS | DAVINCI_I2C_MDR_MST | DAVINCI_I2C_MDR_STT;
267 /* if the slave address is ten bit address, enable XA bit */
268 if (msg->flags & I2C_M_TEN)
269 flag |= DAVINCI_I2C_MDR_XA;
270 if (!(msg->flags & I2C_M_RD))
271 flag |= DAVINCI_I2C_MDR_TRX;
273 flag |= DAVINCI_I2C_MDR_STP;
275 /* Enable receive or transmit interrupts */
276 w = davinci_i2c_read_reg(dev, DAVINCI_I2C_IMR_REG);
277 if (msg->flags & I2C_M_RD)
278 MOD_REG_BIT(w, DAVINCI_I2C_IMR_RRDY, 1);
280 MOD_REG_BIT(w, DAVINCI_I2C_IMR_XRDY, 1);
281 davinci_i2c_write_reg(dev, DAVINCI_I2C_IMR_REG, w);
283 /* write the data into mode register */
284 davinci_i2c_write_reg(dev, DAVINCI_I2C_MDR_REG, flag);
286 r = wait_for_completion_interruptible_timeout(&dev->cmd_complete,
287 DAVINCI_I2C_TIMEOUT);
293 dev_err(dev->dev, "controller timed out\n");
294 i2c_davinci_init(dev);
299 if (likely(!dev->cmd_err))
302 /* We have an error */
303 if (dev->cmd_err & DAVINCI_I2C_STR_AL) {
304 i2c_davinci_init(dev);
308 if (dev->cmd_err & DAVINCI_I2C_STR_NACK) {
309 if (msg->flags & I2C_M_IGNORE_NAK)
312 w = davinci_i2c_read_reg(dev, DAVINCI_I2C_MDR_REG);
313 MOD_REG_BIT(w, DAVINCI_I2C_MDR_STP, 1);
314 davinci_i2c_write_reg(dev, DAVINCI_I2C_MDR_REG, w);
322 * Prepare controller for a transaction and call i2c_davinci_xfer_msg
325 i2c_davinci_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num)
327 struct davinci_i2c_dev *dev = i2c_get_adapdata(adap);
331 dev_dbg(dev->dev, "%s: msgs: %d\n", __func__, num);
333 ret = i2c_davinci_wait_bus_not_busy(dev, 1);
335 dev_warn(dev->dev, "timeout waiting for bus ready\n");
339 for (i = 0; i < num; i++) {
340 ret = i2c_davinci_xfer_msg(adap, &msgs[i], (i == (num - 1)));
345 dev_dbg(dev->dev, "%s:%d ret: %d\n", __func__, __LINE__, ret);
350 static u32 i2c_davinci_func(struct i2c_adapter *adap)
352 return I2C_FUNC_I2C | (I2C_FUNC_SMBUS_EMUL & ~I2C_FUNC_SMBUS_QUICK);
356 * Interrupt service routine. This gets called whenever an I2C interrupt
359 static irqreturn_t i2c_davinci_isr(int this_irq, void *dev_id)
361 struct davinci_i2c_dev *dev = dev_id;
366 while ((stat = davinci_i2c_read_reg(dev, DAVINCI_I2C_IVR_REG))) {
367 dev_dbg(dev->dev, "%s: stat=0x%x\n", __func__, stat);
368 if (count++ == 100) {
369 dev_warn(dev->dev, "Too much work in one IRQ\n");
374 case DAVINCI_I2C_IVR_AL:
375 dev->cmd_err |= DAVINCI_I2C_STR_AL;
376 complete(&dev->cmd_complete);
379 case DAVINCI_I2C_IVR_NACK:
380 dev->cmd_err |= DAVINCI_I2C_STR_NACK;
381 complete(&dev->cmd_complete);
384 case DAVINCI_I2C_IVR_ARDY:
385 davinci_i2c_write_reg(dev,
386 DAVINCI_I2C_STR_REG, DAVINCI_I2C_STR_ARDY);
387 complete(&dev->cmd_complete);
390 case DAVINCI_I2C_IVR_RDR:
393 davinci_i2c_read_reg(dev,
394 DAVINCI_I2C_DRR_REG);
399 davinci_i2c_write_reg(dev,
401 DAVINCI_I2C_IMR_RRDY);
403 dev_err(dev->dev, "RDR IRQ while no "
407 case DAVINCI_I2C_IVR_XRDY:
409 davinci_i2c_write_reg(dev, DAVINCI_I2C_DXR_REG,
415 w = davinci_i2c_read_reg(dev,
416 DAVINCI_I2C_IMR_REG);
417 MOD_REG_BIT(w, DAVINCI_I2C_IMR_XRDY, 0);
418 davinci_i2c_write_reg(dev,
422 dev_err(dev->dev, "TDR IRQ while no data to "
426 case DAVINCI_I2C_IVR_SCD:
427 davinci_i2c_write_reg(dev,
428 DAVINCI_I2C_STR_REG, DAVINCI_I2C_STR_SCD);
429 complete(&dev->cmd_complete);
432 case DAVINCI_I2C_IVR_AAS:
433 dev_warn(dev->dev, "Address as slave interrupt\n");
437 return count ? IRQ_HANDLED : IRQ_NONE;
440 static struct i2c_algorithm i2c_davinci_algo = {
441 .master_xfer = i2c_davinci_xfer,
442 .functionality = i2c_davinci_func,
445 static int davinci_i2c_probe(struct platform_device *pdev)
447 struct davinci_i2c_dev *dev;
448 struct i2c_adapter *adap;
449 struct resource *mem, *irq, *ioarea;
452 /* NOTE: driver uses the static register mapping */
453 mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
455 dev_err(&pdev->dev, "no mem resource?\n");
459 irq = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
461 dev_err(&pdev->dev, "no irq resource?\n");
465 ioarea = request_mem_region(mem->start, (mem->end - mem->start) + 1,
468 dev_err(&pdev->dev, "I2C region already claimed\n");
472 dev = kzalloc(sizeof(struct davinci_i2c_dev), GFP_KERNEL);
475 goto err_release_region;
478 dev->dev = get_device(&pdev->dev);
479 dev->irq = irq->start;
480 platform_set_drvdata(pdev, dev);
482 dev->clk = clk_get(&pdev->dev, "I2CCLK");
483 if (IS_ERR(dev->clk)) {
487 clk_enable(dev->clk);
489 dev->base = (void __iomem *)IO_ADDRESS(mem->start);
490 i2c_davinci_init(dev);
492 r = request_irq(dev->irq, i2c_davinci_isr, 0, pdev->name, dev);
494 dev_err(&pdev->dev, "failure requesting irq %i\n", dev->irq);
495 goto err_unuse_clocks;
498 adap = &dev->adapter;
499 i2c_set_adapdata(adap, dev);
500 adap->owner = THIS_MODULE;
501 adap->class = I2C_CLASS_HWMON;
502 strlcpy(adap->name, "DaVinci I2C adapter", sizeof(adap->name));
503 adap->algo = &i2c_davinci_algo;
504 adap->dev.parent = &pdev->dev;
510 r = i2c_add_numbered_adapter(adap);
512 dev_err(&pdev->dev, "failure adding adapter\n");
519 free_irq(dev->irq, dev);
521 clk_disable(dev->clk);
525 platform_set_drvdata(pdev, NULL);
526 put_device(&pdev->dev);
529 release_mem_region(mem->start, (mem->end - mem->start) + 1);
534 static int davinci_i2c_remove(struct platform_device *pdev)
536 struct davinci_i2c_dev *dev = platform_get_drvdata(pdev);
537 struct resource *mem;
539 platform_set_drvdata(pdev, NULL);
540 i2c_del_adapter(&dev->adapter);
541 put_device(&pdev->dev);
543 clk_disable(dev->clk);
547 davinci_i2c_write_reg(dev, DAVINCI_I2C_MDR_REG, 0);
548 free_irq(IRQ_I2C, dev);
551 mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
552 release_mem_region(mem->start, (mem->end - mem->start) + 1);
556 /* work with hotplug and coldplug */
557 MODULE_ALIAS("platform:i2c_davinci");
559 static struct platform_driver davinci_i2c_driver = {
560 .probe = davinci_i2c_probe,
561 .remove = davinci_i2c_remove,
563 .name = "i2c_davinci",
564 .owner = THIS_MODULE,
568 /* I2C may be needed to bring up other drivers */
569 static int __init davinci_i2c_init_driver(void)
571 return platform_driver_register(&davinci_i2c_driver);
573 subsys_initcall(davinci_i2c_init_driver);
575 static void __exit davinci_i2c_exit_driver(void)
577 platform_driver_unregister(&davinci_i2c_driver);
579 module_exit(davinci_i2c_exit_driver);
581 MODULE_AUTHOR("Texas Instruments India");
582 MODULE_DESCRIPTION("TI DaVinci I2C bus adapter");
583 MODULE_LICENSE("GPL");