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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         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 
122 static 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 
130 static const struct of_device_id i2c_versatile_match[] = {
131         { .compatible = "arm,versatile-i2c", },
132         {},
133 };
134 MODULE_DEVICE_TABLE(of, i2c_versatile_match);
135 
136 static struct platform_driver i2c_versatile_driver = {
137         .probe          = i2c_versatile_probe,
138         .remove         = i2c_versatile_remove,
139         .driver         = {
140                 .name   = "versatile-i2c",
141                 .owner  = THIS_MODULE,
142                 .of_match_table = i2c_versatile_match,
143         },
144 };
145 
146 static int __init i2c_versatile_init(void)
147 {
148         return platform_driver_register(&i2c_versatile_driver);
149 }
150 
151 static void __exit i2c_versatile_exit(void)
152 {
153         platform_driver_unregister(&i2c_versatile_driver);
154 }
155 
156 subsys_initcall(i2c_versatile_init);
157 module_exit(i2c_versatile_exit);
158 
159 MODULE_DESCRIPTION("ARM Versatile I2C bus driver");
160 MODULE_LICENSE("GPL");
161 MODULE_ALIAS("platform:versatile-i2c");
162 

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