/drivers/i2c/busses/i2c-simtec.c

  1/*
  2 * Copyright (C) 2005 Simtec Electronics
  3 *	Ben Dooks <ben@simtec.co.uk>
  4 *
  5 * Simtec Generic I2C Controller
  6 *
  7 * This program is free software; you can redistribute it and/or modify
  8 * it under the terms of the GNU General Public License as published by
  9 * the Free Software Foundation; either version 2 of the License
 10 *
 11 * This program is distributed in the hope that it will be useful,
 12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 14 * GNU General Public License for more details.
 15 *
 16 * You should have received a copy of the GNU General Public License
 17 * along with this program; if not, write to the Free Software
 18 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 19*/
 20
 21#include <linux/kernel.h>
 22#include <linux/module.h>
 23#include <linux/init.h>
 24#include <linux/delay.h>
 25#include <linux/platform_device.h>
 26#include <linux/slab.h>
 27#include <linux/io.h>
 28
 29#include <linux/i2c.h>
 30#include <linux/i2c-algo-bit.h>
 31
 32struct simtec_i2c_data {
 33	struct resource		*ioarea;
 34	void __iomem		*reg;
 35	struct i2c_adapter	 adap;
 36	struct i2c_algo_bit_data bit;
 37};
 38
 39#define CMD_SET_SDA	(1<<2)
 40#define CMD_SET_SCL	(1<<3)
 41
 42#define STATE_SDA	(1<<0)
 43#define STATE_SCL	(1<<1)
 44
 45/* i2c bit-bus functions */
 46
 47static void simtec_i2c_setsda(void *pw, int state)
 48{
 49	struct simtec_i2c_data *pd = pw;
 50	writeb(CMD_SET_SDA | (state ? STATE_SDA : 0), pd->reg);
 51}
 52
 53static void simtec_i2c_setscl(void *pw, int state)
 54{
 55	struct simtec_i2c_data *pd = pw;
 56	writeb(CMD_SET_SCL | (state ? STATE_SCL : 0), pd->reg);
 57}
 58
 59static int simtec_i2c_getsda(void *pw)
 60{
 61	struct simtec_i2c_data *pd = pw;
 62	return readb(pd->reg) & STATE_SDA ? 1 : 0;
 63}
 64
 65static int simtec_i2c_getscl(void *pw)
 66{
 67	struct simtec_i2c_data *pd = pw;
 68	return readb(pd->reg) & STATE_SCL ? 1 : 0;
 69}
 70
 71/* device registration */
 72
 73static int simtec_i2c_probe(struct platform_device *dev)
 74{
 75	struct simtec_i2c_data *pd;
 76	struct resource *res;
 77	int size;
 78	int ret;
 79
 80	pd = kzalloc(sizeof(struct simtec_i2c_data), GFP_KERNEL);
 81	if (pd == NULL) {
 82		dev_err(&dev->dev, "cannot allocate private data\n");
 83		return -ENOMEM;
 84	}
 85
 86	platform_set_drvdata(dev, pd);
 87
 88	res = platform_get_resource(dev, IORESOURCE_MEM, 0);
 89	if (res == NULL) {
 90		dev_err(&dev->dev, "cannot find IO resource\n");
 91		ret = -ENOENT;
 92		goto err;
 93	}
 94
 95	size = resource_size(res);
 96
 97	pd->ioarea = request_mem_region(res->start, size, dev->name);
 98	if (pd->ioarea == NULL) {
 99		dev_err(&dev->dev, "cannot request IO\n");
100		ret = -ENXIO;
101		goto err;
102	}
103
104	pd->reg = ioremap(res->start, size);
105	if (pd->reg == NULL) {
106		dev_err(&dev->dev, "cannot map IO\n");
107		ret = -ENXIO;
108		goto err_res;
109	}
110
111	/* setup the private data */
112
113	pd->adap.owner = THIS_MODULE;
114	pd->adap.algo_data = &pd->bit;
115	pd->adap.dev.parent = &dev->dev;
116
117	strlcpy(pd->adap.name, "Simtec I2C", sizeof(pd->adap.name));
118
119	pd->bit.data = pd;
120	pd->bit.setsda = simtec_i2c_setsda;
121	pd->bit.setscl = simtec_i2c_setscl;
122	pd->bit.getsda = simtec_i2c_getsda;
123	pd->bit.getscl = simtec_i2c_getscl;
124	pd->bit.timeout = HZ;
125	pd->bit.udelay = 20;
126
127	ret = i2c_bit_add_bus(&pd->adap);
128	if (ret)
129		goto err_all;
130
131	return 0;
132
133 err_all:
134	iounmap(pd->reg);
135
136 err_res:
137	release_resource(pd->ioarea);
138	kfree(pd->ioarea);
139
140 err:
141	kfree(pd);
142	return ret;
143}
144
145static int simtec_i2c_remove(struct platform_device *dev)
146{
147	struct simtec_i2c_data *pd = platform_get_drvdata(dev);
148
149	i2c_del_adapter(&pd->adap);
150
151	iounmap(pd->reg);
152	release_resource(pd->ioarea);
153	kfree(pd->ioarea);
154	kfree(pd);
155
156	return 0;
157}
158
159
160/* device driver */
161
162/* work with hotplug and coldplug */
163MODULE_ALIAS("platform:simtec-i2c");
164
165static struct platform_driver simtec_i2c_driver = {
166	.driver		= {
167		.name		= "simtec-i2c",
168		.owner		= THIS_MODULE,
169	},
170	.probe		= simtec_i2c_probe,
171	.remove		= simtec_i2c_remove,
172};
173
174static int __init i2c_adap_simtec_init(void)
175{
176	return platform_driver_register(&simtec_i2c_driver);
177}
178
179static void __exit i2c_adap_simtec_exit(void)
180{
181	platform_driver_unregister(&simtec_i2c_driver);
182}
183
184module_init(i2c_adap_simtec_init);
185module_exit(i2c_adap_simtec_exit);
186
187MODULE_DESCRIPTION("Simtec Generic I2C Bus driver");
188MODULE_AUTHOR("Ben Dooks <ben@simtec.co.uk>");
189MODULE_LICENSE("GPL");