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        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
 102static 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
 110static const struct of_device_id i2c_versatile_match[] = {
 111        { .compatible = "arm,versatile-i2c", },
 112        {},
 113};
 114MODULE_DEVICE_TABLE(of, i2c_versatile_match);
 115
 116static 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
 125static int __init i2c_versatile_init(void)
 126{
 127        return platform_driver_register(&i2c_versatile_driver);
 128}
 129
 130static void __exit i2c_versatile_exit(void)
 131{
 132        platform_driver_unregister(&i2c_versatile_driver);
 133}
 134
 135subsys_initcall(i2c_versatile_init);
 136module_exit(i2c_versatile_exit);
 137
 138MODULE_DESCRIPTION("ARM Versatile I2C bus driver");
 139MODULE_LICENSE("GPL");
 140MODULE_ALIAS("platform:versatile-i2c");
 141