LXR 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
  26struct i2c_versatile {
  27        struct i2c_adapter       adap;
  28        struct i2c_algo_bit_data algo;
  29        void __iomem             *base;
  30};
  31
  32static 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
  39static 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
  46static int i2c_versatile_getsda(void *data)
  47{
  48        struct i2c_versatile *i2c = data;
  49        return !!(readl(i2c->base + I2C_CONTROL) & SDA);
  50}
  51
  52static int i2c_versatile_getscl(void *data)
  53{
  54        struct i2c_versatile *i2c = data;
  55        return !!(readl(i2c->base + I2C_CONTROL) & SCL);
  56}
  57
  58static 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
  67static 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
 122static 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
 130static const struct of_device_id i2c_versatile_match[] = {
 131        { .compatible = "arm,versatile-i2c", },
 132        {},
 133};
 134MODULE_DEVICE_TABLE(of, i2c_versatile_match);
 135
 136static struct platform_driver i2c_versatile_driver = {
 137        .probe          = i2c_versatile_probe,
 138        .remove         = i2c_versatile_remove,
 139        .driver         = {
 140                .name   = "versatile-i2c",
 141                .of_match_table = i2c_versatile_match,
 142        },
 143};
 144
 145static int __init i2c_versatile_init(void)
 146{
 147        return platform_driver_register(&i2c_versatile_driver);
 148}
 149
 150static void __exit i2c_versatile_exit(void)
 151{
 152        platform_driver_unregister(&i2c_versatile_driver);
 153}
 154
 155subsys_initcall(i2c_versatile_init);
 156module_exit(i2c_versatile_exit);
 157
 158MODULE_DESCRIPTION("ARM Versatile I2C bus driver");
 159MODULE_LICENSE("GPL");
 160MODULE_ALIAS("platform:versatile-i2c");
 161