1/*
2 *  i2c-versatile.c
3 *
4 *  Copyright (C) 2006 ARM Ltd.
5 *  written by Russell King, Deep Blue Solutions Ltd.
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 version 2 as
9 * published by the Free Software Foundation.
10 */
11#include <linux/kernel.h>
12#include <linux/module.h>
13#include <linux/i2c.h>
14#include <linux/i2c-algo-bit.h>
15#include <linux/init.h>
16#include <linux/platform_device.h>
17#include <linux/slab.h>
18#include <linux/io.h>
19
20#define I2C_CONTROL	0x00
21#define I2C_CONTROLS	0x00
22#define I2C_CONTROLC	0x04
23#define SCL		(1 << 0)
24#define SDA		(1 << 1)
25
26struct i2c_versatile {
27	struct i2c_adapter	 adap;
28	struct i2c_algo_bit_data algo;
29	void __iomem		 *base;
30};
31
32static void i2c_versatile_setsda(void *data, int state)
33{
34	struct i2c_versatile *i2c = data;
35
36	writel(SDA, i2c->base + (state ? I2C_CONTROLS : I2C_CONTROLC));
37}
38
39static void i2c_versatile_setscl(void *data, int state)
40{
41	struct i2c_versatile *i2c = data;
42
43	writel(SCL, i2c->base + (state ? I2C_CONTROLS : I2C_CONTROLC));
44}
45
46static int i2c_versatile_getsda(void *data)
47{
48	struct i2c_versatile *i2c = data;
49	return !!(readl(i2c->base + I2C_CONTROL) & SDA);
50}
51
52static int i2c_versatile_getscl(void *data)
53{
54	struct i2c_versatile *i2c = data;
55	return !!(readl(i2c->base + I2C_CONTROL) & SCL);
56}
57
58static struct i2c_algo_bit_data i2c_versatile_algo = {
59	.setsda	= i2c_versatile_setsda,
60	.setscl = i2c_versatile_setscl,
61	.getsda	= i2c_versatile_getsda,
62	.getscl = i2c_versatile_getscl,
63	.udelay	= 30,
64	.timeout = HZ,
65};
66
67static int i2c_versatile_probe(struct platform_device *dev)
68{
69	struct i2c_versatile *i2c;
70	struct resource *r;
71	int ret;
72
73	r = platform_get_resource(dev, IORESOURCE_MEM, 0);
74	if (!r) {
75		ret = -EINVAL;
76		goto err_out;
77	}
78
79	if (!request_mem_region(r->start, resource_size(r), "versatile-i2c")) {
80		ret = -EBUSY;
81		goto err_out;
82	}
83
84	i2c = kzalloc(sizeof(struct i2c_versatile), GFP_KERNEL);
85	if (!i2c) {
86		ret = -ENOMEM;
87		goto err_release;
88	}
89
90	i2c->base = ioremap(r->start, resource_size(r));
91	if (!i2c->base) {
92		ret = -ENOMEM;
93		goto err_free;
94	}
95
96	writel(SCL | SDA, i2c->base + I2C_CONTROLS);
97
98	i2c->adap.owner = THIS_MODULE;
99	strlcpy(i2c->adap.name, "Versatile I2C adapter", sizeof(i2c->adap.name));
100	i2c->adap.algo_data = &i2c->algo;
101	i2c->adap.dev.parent = &dev->dev;
102	i2c->adap.dev.of_node = dev->dev.of_node;
103	i2c->algo = i2c_versatile_algo;
104	i2c->algo.data = i2c;
105
106	i2c->adap.nr = dev->id;
107	ret = i2c_bit_add_numbered_bus(&i2c->adap);
108	if (ret >= 0) {
109		platform_set_drvdata(dev, i2c);
110		return 0;
111	}
112
113	iounmap(i2c->base);
114 err_free:
115	kfree(i2c);
116 err_release:
117	release_mem_region(r->start, resource_size(r));
118 err_out:
119	return ret;
120}
121
122static int i2c_versatile_remove(struct platform_device *dev)
123{
124	struct i2c_versatile *i2c = platform_get_drvdata(dev);
125
126	i2c_del_adapter(&i2c->adap);
127	return 0;
128}
129
130static const struct of_device_id i2c_versatile_match[] = {
131	{ .compatible = "arm,versatile-i2c", },
132	{},
133};
134MODULE_DEVICE_TABLE(of, i2c_versatile_match);
135
136static struct platform_driver i2c_versatile_driver = {
137	.probe		= i2c_versatile_probe,
138	.remove		= i2c_versatile_remove,
139	.driver		= {
140		.name	= "versatile-i2c",
141		.of_match_table = i2c_versatile_match,
142	},
143};
144
145static int __init i2c_versatile_init(void)
146{
147	return platform_driver_register(&i2c_versatile_driver);
148}
149
150static void __exit i2c_versatile_exit(void)
151{
152	platform_driver_unregister(&i2c_versatile_driver);
153}
154
155subsys_initcall(i2c_versatile_init);
156module_exit(i2c_versatile_exit);
157
158MODULE_DESCRIPTION("ARM Versatile I2C bus driver");
159MODULE_LICENSE("GPL");
160MODULE_ALIAS("platform:versatile-i2c");
161