i2c-pca-platform.c

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/*
 *  i2c_pca_platform.c
 *
 *  Platform driver for the PCA9564 I2C controller.
 *
 *  Copyright (C) 2008 Pengutronix
 *
 *  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/init.h>
#include <linux/slab.h>
#include <linux/delay.h>
#include <linux/jiffies.h>
#include <linux/errno.h>
#include <linux/i2c.h>
#include <linux/interrupt.h>
#include <linux/platform_device.h>
#include <linux/i2c-algo-pca.h>
#include <linux/i2c-pca-platform.h>
#include <linux/gpio.h>
#include <linux/io.h>

#include <asm/irq.h>

struct i2c_pca_pf_data {
    void __iomem            *reg_base;
    int             irq;    /* if 0, use polling */
    int             gpio;
    wait_queue_head_t       wait;
    struct i2c_adapter      adap;
    struct i2c_algo_pca_data    algo_data;
    unsigned long           io_base;
    unsigned long           io_size;
};

/* Read/Write functions for different register alignments */

static int i2c_pca_pf_readbyte8(void *pd, int reg)
{
    struct i2c_pca_pf_data *i2c = pd;
    return ioread8(i2c->reg_base + reg);
}

static int i2c_pca_pf_readbyte16(void *pd, int reg)
{
    struct i2c_pca_pf_data *i2c = pd;
    return ioread8(i2c->reg_base + reg * 2);
}

static int i2c_pca_pf_readbyte32(void *pd, int reg)
{
    struct i2c_pca_pf_data *i2c = pd;
    return ioread8(i2c->reg_base + reg * 4);
}

static void i2c_pca_pf_writebyte8(void *pd, int reg, int val)
{
    struct i2c_pca_pf_data *i2c = pd;
    iowrite8(val, i2c->reg_base + reg);
}

static void i2c_pca_pf_writebyte16(void *pd, int reg, int val)
{
    struct i2c_pca_pf_data *i2c = pd;
    iowrite8(val, i2c->reg_base + reg * 2);
}

static void i2c_pca_pf_writebyte32(void *pd, int reg, int val)
{
    struct i2c_pca_pf_data *i2c = pd;
    iowrite8(val, i2c->reg_base + reg * 4);
}


static int i2c_pca_pf_waitforcompletion(void *pd)
{
    struct i2c_pca_pf_data *i2c = pd;
    unsigned long timeout;
    long ret;

    if (i2c->irq) {
        ret = wait_event_timeout(i2c->wait,
            i2c->algo_data.read_byte(i2c, I2C_PCA_CON)
            & I2C_PCA_CON_SI, i2c->adap.timeout);
    } else {
        /* Do polling */
        timeout = jiffies + i2c->adap.timeout;
        do {
            ret = time_before(jiffies, timeout);
            if (i2c->algo_data.read_byte(i2c, I2C_PCA_CON)
                    & I2C_PCA_CON_SI)
                break;
            udelay(100);
        } while (ret);
    }

    return ret > 0;
}

static void i2c_pca_pf_dummyreset(void *pd)
{
    struct i2c_pca_pf_data *i2c = pd;
    printk(KERN_WARNING "%s: No reset-pin found. Chip may get stuck!\n",
        i2c->adap.name);
}

static void i2c_pca_pf_resetchip(void *pd)
{
    struct i2c_pca_pf_data *i2c = pd;

    gpio_set_value(i2c->gpio, 0);
    ndelay(100);
    gpio_set_value(i2c->gpio, 1);
}

static irqreturn_t i2c_pca_pf_handler(int this_irq, void *dev_id)
{
    struct i2c_pca_pf_data *i2c = dev_id;

    if ((i2c->algo_data.read_byte(i2c, I2C_PCA_CON) & I2C_PCA_CON_SI) == 0)
        return IRQ_NONE;

    wake_up(&i2c->wait);

    return IRQ_HANDLED;
}


static int __devinit i2c_pca_pf_probe(struct platform_device *pdev)
{
    struct i2c_pca_pf_data *i2c;
    struct resource *res;
    struct i2c_pca9564_pf_platform_data *platform_data =
                pdev->dev.platform_data;
    int ret = 0;
    int irq;

    res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
    irq = platform_get_irq(pdev, 0);
    /* If irq is 0, we do polling. */

    if (res == NULL) {
        ret = -ENODEV;
        goto e_print;
    }

    if (!request_mem_region(res->start, resource_size(res), res->name)) {
        ret = -ENOMEM;
        goto e_print;
    }

    i2c = kzalloc(sizeof(struct i2c_pca_pf_data), GFP_KERNEL);
    if (!i2c) {
        ret = -ENOMEM;
        goto e_alloc;
    }

    init_waitqueue_head(&i2c->wait);

    i2c->reg_base = ioremap(res->start, resource_size(res));
    if (!i2c->reg_base) {
        ret = -ENOMEM;
        goto e_remap;
    }
    i2c->io_base = res->start;
    i2c->io_size = resource_size(res);
    i2c->irq = irq;

    i2c->adap.nr = pdev->id;
    i2c->adap.owner = THIS_MODULE;
    snprintf(i2c->adap.name, sizeof(i2c->adap.name),
         "PCA9564/PCA9665 at 0x%08lx",
         (unsigned long) res->start);
    i2c->adap.algo_data = &i2c->algo_data;
    i2c->adap.dev.parent = &pdev->dev;

    if (platform_data) {
        i2c->adap.timeout = platform_data->timeout;
        i2c->algo_data.i2c_clock = platform_data->i2c_clock_speed;
        i2c->gpio = platform_data->gpio;
    } else {
        i2c->adap.timeout = HZ;
        i2c->algo_data.i2c_clock = 59000;
        i2c->gpio = -1;
    }

    i2c->algo_data.data = i2c;
    i2c->algo_data.wait_for_completion = i2c_pca_pf_waitforcompletion;
    i2c->algo_data.reset_chip = i2c_pca_pf_dummyreset;

    switch (res->flags & IORESOURCE_MEM_TYPE_MASK) {
    case IORESOURCE_MEM_32BIT:
        i2c->algo_data.write_byte = i2c_pca_pf_writebyte32;
        i2c->algo_data.read_byte = i2c_pca_pf_readbyte32;
        break;
    case IORESOURCE_MEM_16BIT:
        i2c->algo_data.write_byte = i2c_pca_pf_writebyte16;
        i2c->algo_data.read_byte = i2c_pca_pf_readbyte16;
        break;
    case IORESOURCE_MEM_8BIT:
    default:
        i2c->algo_data.write_byte = i2c_pca_pf_writebyte8;
        i2c->algo_data.read_byte = i2c_pca_pf_readbyte8;
        break;
    }

    /* Use gpio_is_valid() when in mainline */
    if (i2c->gpio > -1) {
        ret = gpio_request(i2c->gpio, i2c->adap.name);
        if (ret == 0) {
            gpio_direction_output(i2c->gpio, 1);
            i2c->algo_data.reset_chip = i2c_pca_pf_resetchip;
        } else {
            printk(KERN_WARNING "%s: Registering gpio failed!\n",
                i2c->adap.name);
            i2c->gpio = ret;
        }
    }

    if (irq) {
        ret = request_irq(irq, i2c_pca_pf_handler,
            IRQF_TRIGGER_FALLING, pdev->name, i2c);
        if (ret)
            goto e_reqirq;
    }

    if (i2c_pca_add_numbered_bus(&i2c->adap) < 0) {
        ret = -ENODEV;
        goto e_adapt;
    }

    platform_set_drvdata(pdev, i2c);

    printk(KERN_INFO "%s registered.\n", i2c->adap.name);

    return 0;

e_adapt:
    if (irq)
        free_irq(irq, i2c);
e_reqirq:
    if (i2c->gpio > -1)
        gpio_free(i2c->gpio);

    iounmap(i2c->reg_base);
e_remap:
    kfree(i2c);
e_alloc:
    release_mem_region(res->start, resource_size(res));
e_print:
    printk(KERN_ERR "Registering PCA9564/PCA9665 FAILED! (%d)\n", ret);
    return ret;
}

static int __devexit i2c_pca_pf_remove(struct platform_device *pdev)
{
    struct i2c_pca_pf_data *i2c = platform_get_drvdata(pdev);
    platform_set_drvdata(pdev, NULL);

    i2c_del_adapter(&i2c->adap);

    if (i2c->irq)
        free_irq(i2c->irq, i2c);

    if (i2c->gpio > -1)
        gpio_free(i2c->gpio);

    iounmap(i2c->reg_base);
    release_mem_region(i2c->io_base, i2c->io_size);
    kfree(i2c);

    return 0;
}

static struct platform_driver i2c_pca_pf_driver = {
    .probe = i2c_pca_pf_probe,
    .remove = __devexit_p(i2c_pca_pf_remove),
    .driver = {
        .name = "i2c-pca-platform",
        .owner = THIS_MODULE,
    },
};

module_platform_driver(i2c_pca_pf_driver);

MODULE_AUTHOR("Wolfram Sang <[email protected]>");
MODULE_DESCRIPTION("I2C-PCA9564/PCA9665 platform driver");
MODULE_LICENSE("GPL");