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 
26 struct i2c_versatile {
27 	struct i2c_adapter	 adap;
28 	struct i2c_algo_bit_data algo;
29 	void __iomem		 *base;
30 };
31 
32 static 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 
39 static 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 
46 static int i2c_versatile_getsda(void *data)
47 {
48 	struct i2c_versatile *i2c = data;
49 	return !!(readl(i2c->base + I2C_CONTROL) & SDA);
50 }
51 
52 static int i2c_versatile_getscl(void *data)
53 {
54 	struct i2c_versatile *i2c = data;
55 	return !!(readl(i2c->base + I2C_CONTROL) & SCL);
56 }
57 
58 static 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 
67 static int i2c_versatile_probe(struct platform_device *dev)
68 {
69 	struct i2c_versatile *i2c;
70 	struct resource *r;
71 	int ret;
72 
73 	i2c = devm_kzalloc(&dev->dev, sizeof(struct i2c_versatile), GFP_KERNEL);
74 	if (!i2c)
75 		return -ENOMEM;
76 
77 	r = platform_get_resource(dev, IORESOURCE_MEM, 0);
78 	i2c->base = devm_ioremap_resource(&dev->dev, r);
79 	if (IS_ERR(i2c->base))
80 		return PTR_ERR(i2c->base);
81 
82 	writel(SCL | SDA, i2c->base + I2C_CONTROLS);
83 
84 	i2c->adap.owner = THIS_MODULE;
85 	strlcpy(i2c->adap.name, "Versatile I2C adapter", sizeof(i2c->adap.name));
86 	i2c->adap.algo_data = &i2c->algo;
87 	i2c->adap.dev.parent = &dev->dev;
88 	i2c->adap.dev.of_node = dev->dev.of_node;
89 	i2c->algo = i2c_versatile_algo;
90 	i2c->algo.data = i2c;
91 
92 	i2c->adap.nr = dev->id;
93 	ret = i2c_bit_add_numbered_bus(&i2c->adap);
94 	if (ret < 0)
95 		return ret;
96 
97 	platform_set_drvdata(dev, i2c);
98 
99 	return 0;
100 }
101 
102 static int i2c_versatile_remove(struct platform_device *dev)
103 {
104 	struct i2c_versatile *i2c = platform_get_drvdata(dev);
105 
106 	i2c_del_adapter(&i2c->adap);
107 	return 0;
108 }
109 
110 static const struct of_device_id i2c_versatile_match[] = {
111 	{ .compatible = "arm,versatile-i2c", },
112 	{},
113 };
114 MODULE_DEVICE_TABLE(of, i2c_versatile_match);
115 
116 static struct platform_driver i2c_versatile_driver = {
117 	.probe		= i2c_versatile_probe,
118 	.remove		= i2c_versatile_remove,
119 	.driver		= {
120 		.name	= "versatile-i2c",
121 		.of_match_table = i2c_versatile_match,
122 	},
123 };
124 
125 static int __init i2c_versatile_init(void)
126 {
127 	return platform_driver_register(&i2c_versatile_driver);
128 }
129 
130 static void __exit i2c_versatile_exit(void)
131 {
132 	platform_driver_unregister(&i2c_versatile_driver);
133 }
134 
135 subsys_initcall(i2c_versatile_init);
136 module_exit(i2c_versatile_exit);
137 
138 MODULE_DESCRIPTION("ARM Versatile I2C bus driver");
139 MODULE_LICENSE("GPL");
140 MODULE_ALIAS("platform:versatile-i2c");
141