i2c-puv3.c revision c6a88fa60c7cd500f8368345ee98e472daf4ed04 
1/*
2 * I2C driver for PKUnity-v3 SoC
3 * Code specific to PKUnity SoC and UniCore ISA
4 *
5 *	Maintained by GUAN Xue-tao <gxt@mprc.pku.edu.cn>
6 *	Copyright (C) 2001-2010 Guan Xuetao
7 *
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License version 2 as
10 * published by the Free Software Foundation.
11 */
12
13#include <linux/module.h>
14#include <linux/kernel.h>
15#include <linux/err.h>
16#include <linux/slab.h>
17#include <linux/types.h>
18#include <linux/delay.h>
19#include <linux/i2c.h>
20#include <linux/init.h>
21#include <linux/clk.h>
22#include <linux/platform_device.h>
23#include <linux/io.h>
24#include <mach/hardware.h>
25
26/*
27 * Poll the i2c status register until the specified bit is set.
28 * Returns 0 if timed out (100 msec).
29 */
30static short poll_status(unsigned long bit)
31{
32	int loop_cntr = 1000;
33
34	if (bit & I2C_STATUS_TFNF) {
35		do {
36			udelay(10);
37		} while (!(readl(I2C_STATUS) & bit) && (--loop_cntr > 0));
38	} else {
39		/* RXRDY handler */
40		do {
41			if (readl(I2C_TAR) == I2C_TAR_EEPROM)
42				msleep(20);
43			else
44				udelay(10);
45		} while (!(readl(I2C_RXFLR) & 0xf) && (--loop_cntr > 0));
46	}
47
48	return (loop_cntr > 0);
49}
50
51static int xfer_read(struct i2c_adapter *adap, unsigned char *buf, int length)
52{
53	int i2c_reg = *buf;
54
55	/* Read data */
56	while (length--) {
57		if (!poll_status(I2C_STATUS_TFNF)) {
58			dev_dbg(&adap->dev, "Tx FIFO Not Full timeout\n");
59			return -ETIMEDOUT;
60		}
61
62		/* send addr */
63		writel(i2c_reg | I2C_DATACMD_WRITE, I2C_DATACMD);
64
65		/* get ready to next write */
66		i2c_reg++;
67
68		/* send read CMD */
69		writel(I2C_DATACMD_READ, I2C_DATACMD);
70
71		/* wait until the Rx FIFO have available */
72		if (!poll_status(I2C_STATUS_RFNE)) {
73			dev_dbg(&adap->dev, "RXRDY timeout\n");
74			return -ETIMEDOUT;
75		}
76
77		/* read the data to buf */
78		*buf = (readl(I2C_DATACMD) & I2C_DATACMD_DAT_MASK);
79		buf++;
80	}
81
82	return 0;
83}
84
85static int xfer_write(struct i2c_adapter *adap, unsigned char *buf, int length)
86{
87	int i2c_reg = *buf;
88
89	/* Do nothing but storing the reg_num to a static variable */
90	if (i2c_reg == -1) {
91		printk(KERN_WARNING "Error i2c reg\n");
92		return -ETIMEDOUT;
93	}
94
95	if (length == 1)
96		return 0;
97
98	buf++;
99	length--;
100	while (length--) {
101		/* send addr */
102		writel(i2c_reg | I2C_DATACMD_WRITE, I2C_DATACMD);
103
104		/* send write CMD */
105		writel(*buf | I2C_DATACMD_WRITE, I2C_DATACMD);
106
107		/* wait until the Rx FIFO have available */
108		msleep(20);
109
110		/* read the data to buf */
111		i2c_reg++;
112		buf++;
113	}
114
115	return 0;
116}
117
118/*
119 * Generic i2c master transfer entrypoint.
120 *
121 */
122static int puv3_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg *pmsg,
123		int num)
124{
125	int i, ret;
126	unsigned char swap;
127
128	/* Disable i2c */
129	writel(I2C_ENABLE_DISABLE, I2C_ENABLE);
130
131	/* Set the work mode and speed*/
132	writel(I2C_CON_MASTER | I2C_CON_SPEED_STD | I2C_CON_SLAVEDISABLE, I2C_CON);
133
134	writel(pmsg->addr, I2C_TAR);
135
136	/* Enable i2c */
137	writel(I2C_ENABLE_ENABLE, I2C_ENABLE);
138
139	dev_dbg(&adap->dev, "puv3_i2c_xfer: processing %d messages:\n", num);
140
141	for (i = 0; i < num; i++) {
142		dev_dbg(&adap->dev, " #%d: %sing %d byte%s %s 0x%02x\n", i,
143			pmsg->flags & I2C_M_RD ? "read" : "writ",
144			pmsg->len, pmsg->len > 1 ? "s" : "",
145			pmsg->flags & I2C_M_RD ? "from" : "to",	pmsg->addr);
146
147		if (pmsg->len && pmsg->buf) {	/* sanity check */
148			if (pmsg->flags & I2C_M_RD)
149				ret = xfer_read(adap, pmsg->buf, pmsg->len);
150			else
151				ret = xfer_write(adap, pmsg->buf, pmsg->len);
152
153			if (ret)
154				return ret;
155
156		}
157		dev_dbg(&adap->dev, "transfer complete\n");
158		pmsg++;		/* next message */
159	}
160
161	/* XXX: fixup be16_to_cpu in bq27x00_battery.c */
162	if (pmsg->addr == I2C_TAR_PWIC) {
163		swap = pmsg->buf[0];
164		pmsg->buf[0] = pmsg->buf[1];
165		pmsg->buf[1] = swap;
166	}
167
168	return i;
169}
170
171/*
172 * Return list of supported functionality.
173 */
174static u32 puv3_i2c_func(struct i2c_adapter *adapter)
175{
176	return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
177}
178
179static struct i2c_algorithm puv3_i2c_algorithm = {
180	.master_xfer	= puv3_i2c_xfer,
181	.functionality	= puv3_i2c_func,
182};
183
184/*
185 * Main initialization routine.
186 */
187static int puv3_i2c_probe(struct platform_device *pdev)
188{
189	struct i2c_adapter *adapter;
190	struct resource *mem;
191	int rc;
192
193	mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
194	if (!mem)
195		return -ENODEV;
196
197	if (!request_mem_region(mem->start, resource_size(mem), "puv3_i2c"))
198		return -EBUSY;
199
200	adapter = kzalloc(sizeof(struct i2c_adapter), GFP_KERNEL);
201	if (adapter == NULL) {
202		dev_err(&pdev->dev, "can't allocate interface!\n");
203		rc = -ENOMEM;
204		goto fail_nomem;
205	}
206	snprintf(adapter->name, sizeof(adapter->name), "PUV3-I2C at 0x%08x",
207			mem->start);
208	adapter->algo = &puv3_i2c_algorithm;
209	adapter->class = I2C_CLASS_HWMON;
210	adapter->dev.parent = &pdev->dev;
211
212	platform_set_drvdata(pdev, adapter);
213
214	adapter->nr = pdev->id;
215	rc = i2c_add_numbered_adapter(adapter);
216	if (rc) {
217		dev_err(&pdev->dev, "Adapter '%s' registration failed\n",
218				adapter->name);
219		goto fail_add_adapter;
220	}
221
222	dev_info(&pdev->dev, "PKUnity v3 i2c bus adapter.\n");
223	return 0;
224
225fail_add_adapter:
226	kfree(adapter);
227fail_nomem:
228	release_mem_region(mem->start, resource_size(mem));
229
230	return rc;
231}
232
233static int puv3_i2c_remove(struct platform_device *pdev)
234{
235	struct i2c_adapter *adapter = platform_get_drvdata(pdev);
236	struct resource *mem;
237
238	i2c_del_adapter(adapter);
239
240	put_device(&pdev->dev);
241
242	mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
243	release_mem_region(mem->start, resource_size(mem));
244
245	return 0;
246}
247
248#ifdef CONFIG_PM_SLEEP
249static int puv3_i2c_suspend(struct device *dev)
250{
251	int poll_count;
252	/* Disable the IIC */
253	writel(I2C_ENABLE_DISABLE, I2C_ENABLE);
254	for (poll_count = 0; poll_count < 50; poll_count++) {
255		if (readl(I2C_ENSTATUS) & I2C_ENSTATUS_ENABLE)
256			udelay(25);
257	}
258
259	return 0;
260}
261
262static SIMPLE_DEV_PM_OPS(puv3_i2c_pm, puv3_i2c_suspend, NULL);
263#define PUV3_I2C_PM	(&puv3_i2c_pm)
264
265#else
266#define PUV3_I2C_PM	NULL
267#endif
268
269static struct platform_driver puv3_i2c_driver = {
270	.probe		= puv3_i2c_probe,
271	.remove		= puv3_i2c_remove,
272	.driver		= {
273		.name	= "PKUnity-v3-I2C",
274		.owner	= THIS_MODULE,
275		.pm	= PUV3_I2C_PM,
276	}
277};
278
279module_platform_driver(puv3_i2c_driver);
280
281MODULE_DESCRIPTION("PKUnity v3 I2C driver");
282MODULE_LICENSE("GPL v2");
283MODULE_ALIAS("platform:puv3_i2c");
284