i2c-versatile.c

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/*
 *  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 <linux/slab.h>
#include <linux/io.h>
#include <linux/of_i2c.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, resource_size(r), "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, resource_size(r));
    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->adap.dev.of_node = dev->dev.of_node;
    i2c->algo = i2c_versatile_algo;
    i2c->algo.data = i2c;

    i2c->adap.nr = dev->id;
    ret = i2c_bit_add_numbered_bus(&i2c->adap);
    if (ret >= 0) {
        platform_set_drvdata(dev, i2c);
        of_i2c_register_devices(&i2c->adap);
        return 0;
    }

    iounmap(i2c->base);
 err_free:
    kfree(i2c);
 err_release:
    release_mem_region(r->start, resource_size(r));
 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 const struct of_device_id i2c_versatile_match[] = {
    { .compatible = "arm,versatile-i2c", },
    {},
};
MODULE_DEVICE_TABLE(of, i2c_versatile_match);

static struct platform_driver i2c_versatile_driver = {
    .probe      = i2c_versatile_probe,
    .remove     = i2c_versatile_remove,
    .driver     = {
        .name   = "versatile-i2c",
        .owner  = THIS_MODULE,
        .of_match_table = i2c_versatile_match,
    },
};

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);
}

subsys_initcall(i2c_versatile_init);
module_exit(i2c_versatile_exit);

MODULE_DESCRIPTION("ARM Versatile I2C bus driver");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:versatile-i2c");