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
17#include <linux/kernel.h>
18#include <linux/module.h>
19#include <linux/delay.h>
20#include <linux/platform_device.h>
21#include <linux/slab.h>
22#include <linux/io.h>
23
24#include <linux/i2c.h>
25#include <linux/i2c-algo-bit.h>
26
27struct simtec_i2c_data {
28	struct resource		*ioarea;
29	void __iomem		*reg;
30	struct i2c_adapter	 adap;
31	struct i2c_algo_bit_data bit;
32};
33
34#define CMD_SET_SDA	(1<<2)
35#define CMD_SET_SCL	(1<<3)
36
37#define STATE_SDA	(1<<0)
38#define STATE_SCL	(1<<1)
39
40/* i2c bit-bus functions */
41
42static void simtec_i2c_setsda(void *pw, int state)
43{
44	struct simtec_i2c_data *pd = pw;
45	writeb(CMD_SET_SDA | (state ? STATE_SDA : 0), pd->reg);
46}
47
48static void simtec_i2c_setscl(void *pw, int state)
49{
50	struct simtec_i2c_data *pd = pw;
51	writeb(CMD_SET_SCL | (state ? STATE_SCL : 0), pd->reg);
52}
53
54static int simtec_i2c_getsda(void *pw)
55{
56	struct simtec_i2c_data *pd = pw;
57	return readb(pd->reg) & STATE_SDA ? 1 : 0;
58}
59
60static int simtec_i2c_getscl(void *pw)
61{
62	struct simtec_i2c_data *pd = pw;
63	return readb(pd->reg) & STATE_SCL ? 1 : 0;
64}
65
66/* device registration */
67
68static int simtec_i2c_probe(struct platform_device *dev)
69{
70	struct simtec_i2c_data *pd;
71	struct resource *res;
72	int size;
73	int ret;
74
75	pd = kzalloc(sizeof(struct simtec_i2c_data), GFP_KERNEL);
76	if (pd == NULL)
77		return -ENOMEM;
78
79	platform_set_drvdata(dev, pd);
80
81	res = platform_get_resource(dev, IORESOURCE_MEM, 0);
82	if (res == NULL) {
83		dev_err(&dev->dev, "cannot find IO resource\n");
84		ret = -ENOENT;
85		goto err;
86	}
87
88	size = resource_size(res);
89
90	pd->ioarea = request_mem_region(res->start, size, dev->name);
91	if (pd->ioarea == NULL) {
92		dev_err(&dev->dev, "cannot request IO\n");
93		ret = -ENXIO;
94		goto err;
95	}
96
97	pd->reg = ioremap(res->start, size);
98	if (pd->reg == NULL) {
99		dev_err(&dev->dev, "cannot map IO\n");
100		ret = -ENXIO;
101		goto err_res;
102	}
103
104	/* setup the private data */
105
106	pd->adap.owner = THIS_MODULE;
107	pd->adap.algo_data = &pd->bit;
108	pd->adap.dev.parent = &dev->dev;
109
110	strlcpy(pd->adap.name, "Simtec I2C", sizeof(pd->adap.name));
111
112	pd->bit.data = pd;
113	pd->bit.setsda = simtec_i2c_setsda;
114	pd->bit.setscl = simtec_i2c_setscl;
115	pd->bit.getsda = simtec_i2c_getsda;
116	pd->bit.getscl = simtec_i2c_getscl;
117	pd->bit.timeout = HZ;
118	pd->bit.udelay = 20;
119
120	ret = i2c_bit_add_bus(&pd->adap);
121	if (ret)
122		goto err_all;
123
124	return 0;
125
126 err_all:
127	iounmap(pd->reg);
128
129 err_res:
130	release_resource(pd->ioarea);
131	kfree(pd->ioarea);
132
133 err:
134	kfree(pd);
135	return ret;
136}
137
138static int simtec_i2c_remove(struct platform_device *dev)
139{
140	struct simtec_i2c_data *pd = platform_get_drvdata(dev);
141
142	i2c_del_adapter(&pd->adap);
143
144	iounmap(pd->reg);
145	release_resource(pd->ioarea);
146	kfree(pd->ioarea);
147	kfree(pd);
148
149	return 0;
150}
151
152/* device driver */
153
154static struct platform_driver simtec_i2c_driver = {
155	.driver		= {
156		.name		= "simtec-i2c",
157	},
158	.probe		= simtec_i2c_probe,
159	.remove		= simtec_i2c_remove,
160};
161
162module_platform_driver(simtec_i2c_driver);
163
164MODULE_DESCRIPTION("Simtec Generic I2C Bus driver");
165MODULE_AUTHOR("Ben Dooks <ben@simtec.co.uk>");
166MODULE_LICENSE("GPL");
167MODULE_ALIAS("platform:simtec-i2c");
168