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
18#include <asm/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, r->end - r->start + 1, "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, r->end - r->start + 1);
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->algo = i2c_versatile_algo;
103	i2c->algo.data = i2c;
104
105	ret = i2c_bit_add_bus(&i2c->adap);
106	if (ret >= 0) {
107		platform_set_drvdata(dev, i2c);
108		return 0;
109	}
110
111	iounmap(i2c->base);
112 err_free:
113	kfree(i2c);
114 err_release:
115	release_mem_region(r->start, r->end - r->start + 1);
116 err_out:
117	return ret;
118}
119
120static int i2c_versatile_remove(struct platform_device *dev)
121{
122	struct i2c_versatile *i2c = platform_get_drvdata(dev);
123
124	platform_set_drvdata(dev, NULL);
125
126	i2c_del_adapter(&i2c->adap);
127	return 0;
128}
129
130static struct platform_driver i2c_versatile_driver = {
131	.probe		= i2c_versatile_probe,
132	.remove		= i2c_versatile_remove,
133	.driver		= {
134		.name	= "versatile-i2c",
135		.owner	= THIS_MODULE,
136	},
137};
138
139static int __init i2c_versatile_init(void)
140{
141	return platform_driver_register(&i2c_versatile_driver);
142}
143
144static void __exit i2c_versatile_exit(void)
145{
146	platform_driver_unregister(&i2c_versatile_driver);
147}
148
149module_init(i2c_versatile_init);
150module_exit(i2c_versatile_exit);
151
152MODULE_DESCRIPTION("ARM Versatile I2C bus driver");
153MODULE_LICENSE("GPL");
154