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Linux/drivers/i2c/busses/i2c-versatile.c

  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 

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