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