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i2c-versatile.c

/*
 *  i2c-versatile.c
 *
 *  Copyright (C) 2006 ARM Ltd.
 *  written by Russell King, Deep Blue Solutions Ltd.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/i2c.h>
#include <linux/i2c-algo-bit.h>
#include <linux/init.h>
#include <linux/platform_device.h>

#include <asm/io.h>

#define I2C_CONTROL     0x00
#define I2C_CONTROLS    0x00
#define I2C_CONTROLC    0x04
#define SCL       (1 << 0)
#define SDA       (1 << 1)

struct i2c_versatile {
      struct i2c_adapter       adap;
      struct i2c_algo_bit_data algo;
      void __iomem             *base;
};

static void i2c_versatile_setsda(void *data, int state)
{
      struct i2c_versatile *i2c = data;

      writel(SDA, i2c->base + (state ? I2C_CONTROLS : I2C_CONTROLC));
}

static void i2c_versatile_setscl(void *data, int state)
{
      struct i2c_versatile *i2c = data;

      writel(SCL, i2c->base + (state ? I2C_CONTROLS : I2C_CONTROLC));
}

static int i2c_versatile_getsda(void *data)
{
      struct i2c_versatile *i2c = data;
      return !!(readl(i2c->base + I2C_CONTROL) & SDA);
}

static int i2c_versatile_getscl(void *data)
{
      struct i2c_versatile *i2c = data;
      return !!(readl(i2c->base + I2C_CONTROL) & SCL);
}

static struct i2c_algo_bit_data i2c_versatile_algo = {
      .setsda     = i2c_versatile_setsda,
      .setscl = i2c_versatile_setscl,
      .getsda     = i2c_versatile_getsda,
      .getscl = i2c_versatile_getscl,
      .udelay     = 30,
      .timeout = HZ,
};

static int i2c_versatile_probe(struct platform_device *dev)
{
      struct i2c_versatile *i2c;
      struct resource *r;
      int ret;

      r = platform_get_resource(dev, IORESOURCE_MEM, 0);
      if (!r) {
            ret = -EINVAL;
            goto err_out;
      }

      if (!request_mem_region(r->start, r->end - r->start + 1, "versatile-i2c")) {
            ret = -EBUSY;
            goto err_out;
      }

      i2c = kzalloc(sizeof(struct i2c_versatile), GFP_KERNEL);
      if (!i2c) {
            ret = -ENOMEM;
            goto err_release;
      }

      i2c->base = ioremap(r->start, r->end - r->start + 1);
      if (!i2c->base) {
            ret = -ENOMEM;
            goto err_free;
      }

      writel(SCL | SDA, i2c->base + I2C_CONTROLS);

      i2c->adap.owner = THIS_MODULE;
      strlcpy(i2c->adap.name, "Versatile I2C adapter", sizeof(i2c->adap.name));
      i2c->adap.algo_data = &i2c->algo;
      i2c->adap.dev.parent = &dev->dev;
      i2c->algo = i2c_versatile_algo;
      i2c->algo.data = i2c;

      ret = i2c_bit_add_bus(&i2c->adap);
      if (ret >= 0) {
            platform_set_drvdata(dev, i2c);
            return 0;
      }

      iounmap(i2c->base);
 err_free:
      kfree(i2c);
 err_release:
      release_mem_region(r->start, r->end - r->start + 1);
 err_out:
      return ret;
}

static int i2c_versatile_remove(struct platform_device *dev)
{
      struct i2c_versatile *i2c = platform_get_drvdata(dev);

      platform_set_drvdata(dev, NULL);

      i2c_del_adapter(&i2c->adap);
      return 0;
}

static struct platform_driver i2c_versatile_driver = {
      .probe            = i2c_versatile_probe,
      .remove           = i2c_versatile_remove,
      .driver           = {
            .name = "versatile-i2c",
            .owner      = THIS_MODULE,
      },
};

static int __init i2c_versatile_init(void)
{
      return platform_driver_register(&i2c_versatile_driver);
}

static void __exit i2c_versatile_exit(void)
{
      platform_driver_unregister(&i2c_versatile_driver);
}

module_init(i2c_versatile_init);
module_exit(i2c_versatile_exit);

MODULE_DESCRIPTION("ARM Versatile I2C bus driver");
MODULE_LICENSE("GPL");

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