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 
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 	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 
120 static 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 
130 static 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 
139 static int __init i2c_versatile_init(void)
140 {
141 	return platform_driver_register(&i2c_versatile_driver);
142 }
143 
144 static void __exit i2c_versatile_exit(void)
145 {
146 	platform_driver_unregister(&i2c_versatile_driver);
147 }
148 
149 module_init(i2c_versatile_init);
150 module_exit(i2c_versatile_exit);
151 
152 MODULE_DESCRIPTION("ARM Versatile I2C bus driver");
153 MODULE_LICENSE("GPL");
154 MODULE_ALIAS("platform:versatile-i2c");
155