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->algo = i2c_versatile_algo;
 103         i2c->algo.data = i2c;
 104
 105         if (dev->id >= 0) {
 106                 /* static bus numbering */
 107                 i2c->adap.nr = dev->id;
 108                 ret = i2c_bit_add_numbered_bus(&i2c->adap);
 109         } else
 110                 /* dynamic bus numbering */
 111                 ret = i2c_bit_add_bus(&i2c->adap);
 112         if (ret >= 0) {
 113                 platform_set_drvdata(dev, i2c);
 114                 return 0;
 115         }
 116
 117         iounmap(i2c->base);
 118  err_free:
 119         kfree(i2c);
 120  err_release:
 121         release_mem_region(r->start, resource_size(r));
 122  err_out:
 123         return ret;
 124 }
 125
 126 static int i2c_versatile_remove(struct platform_device *dev)
 127 {
 128         struct i2c_versatile *i2c = platform_get_drvdata(dev);
 129
 130         platform_set_drvdata(dev, NULL);
 131
 132         i2c_del_adapter(&i2c->adap);
 133         return 0;
 134 }
 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         },
 143 };
 144
 145 static int __init i2c_versatile_init(void)
 146 {
 147         return platform_driver_register(&i2c_versatile_driver);
 148 }
 149
 150 static void __exit i2c_versatile_exit(void)
 151 {
 152         platform_driver_unregister(&i2c_versatile_driver);
 153 }
 154
 155 subsys_initcall(i2c_versatile_init);
 156 module_exit(i2c_versatile_exit);
 157
 158 MODULE_DESCRIPTION("ARM Versatile I2C bus driver");
 159 MODULE_LICENSE("GPL");
 160 MODULE_ALIAS("platform:versatile-i2c");