spi-tle62x0.c

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/*
 * Support Infineon TLE62x0 driver chips
 *
 * Copyright (c) 2007 Simtec Electronics
 *  Ben Dooks, <[email protected]>
 *
 * 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/device.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/slab.h>

#include <linux/spi/spi.h>
#include <linux/spi/tle62x0.h>


#define CMD_READ    0x00
#define CMD_SET     0xff

#define DIAG_NORMAL 0x03
#define DIAG_OVERLOAD   0x02
#define DIAG_OPEN   0x01
#define DIAG_SHORTGND   0x00

struct tle62x0_state {
    struct spi_device   *us;
    struct mutex        lock;
    unsigned int        nr_gpio;
    unsigned int        gpio_state;

    unsigned char       tx_buff[4];
    unsigned char       rx_buff[4];
};

static int to_gpio_num(struct device_attribute *attr);

static inline int tle62x0_write(struct tle62x0_state *st)
{
    unsigned char *buff = st->tx_buff;
    unsigned int gpio_state = st->gpio_state;

    buff[0] = CMD_SET;

    if (st->nr_gpio == 16) {
        buff[1] = gpio_state >> 8;
        buff[2] = gpio_state;
    } else {
        buff[1] = gpio_state;
    }

    dev_dbg(&st->us->dev, "buff %02x,%02x,%02x\n",
        buff[0], buff[1], buff[2]);

    return spi_write(st->us, buff, (st->nr_gpio == 16) ? 3 : 2);
}

static inline int tle62x0_read(struct tle62x0_state *st)
{
    unsigned char *txbuff = st->tx_buff;
    struct spi_transfer xfer = {
        .tx_buf     = txbuff,
        .rx_buf     = st->rx_buff,
        .len        = (st->nr_gpio * 2) / 8,
    };
    struct spi_message msg;

    txbuff[0] = CMD_READ;
    txbuff[1] = 0x00;
    txbuff[2] = 0x00;
    txbuff[3] = 0x00;

    spi_message_init(&msg);
    spi_message_add_tail(&xfer, &msg);

    return spi_sync(st->us, &msg);
}

static unsigned char *decode_fault(unsigned int fault_code)
{
    fault_code &= 3;

    switch (fault_code) {
    case DIAG_NORMAL:
        return "N";
    case DIAG_OVERLOAD:
        return "V";
    case DIAG_OPEN:
        return "O";
    case DIAG_SHORTGND:
        return "G";
    }

    return "?";
}

static ssize_t tle62x0_status_show(struct device *dev,
        struct device_attribute *attr, char *buf)
{
    struct tle62x0_state *st = dev_get_drvdata(dev);
    char *bp = buf;
    unsigned char *buff = st->rx_buff;
    unsigned long fault = 0;
    int ptr;
    int ret;

    mutex_lock(&st->lock);
    ret = tle62x0_read(st);
    dev_dbg(dev, "tle62x0_read() returned %d\n", ret);
    if (ret < 0) {
        mutex_unlock(&st->lock);
        return ret;
    }

    for (ptr = 0; ptr < (st->nr_gpio * 2)/8; ptr += 1) {
        fault <<= 8;
        fault  |= ((unsigned long)buff[ptr]);

        dev_dbg(dev, "byte %d is %02x\n", ptr, buff[ptr]);
    }

    for (ptr = 0; ptr < st->nr_gpio; ptr++) {
        bp += sprintf(bp, "%s ", decode_fault(fault >> (ptr * 2)));
    }

    *bp++ = '\n';

    mutex_unlock(&st->lock);
    return bp - buf;
}

static DEVICE_ATTR(status_show, S_IRUGO, tle62x0_status_show, NULL);

static ssize_t tle62x0_gpio_show(struct device *dev,
        struct device_attribute *attr, char *buf)
{
    struct tle62x0_state *st = dev_get_drvdata(dev);
    int gpio_num = to_gpio_num(attr);
    int value;

    mutex_lock(&st->lock);
    value = (st->gpio_state >> gpio_num) & 1;
    mutex_unlock(&st->lock);

    return snprintf(buf, PAGE_SIZE, "%d", value);
}

static ssize_t tle62x0_gpio_store(struct device *dev,
        struct device_attribute *attr,
        const char *buf, size_t len)
{
    struct tle62x0_state *st = dev_get_drvdata(dev);
    int gpio_num = to_gpio_num(attr);
    unsigned long val;
    char *endp;

    val = simple_strtoul(buf, &endp, 0);
    if (buf == endp)
        return -EINVAL;

    dev_dbg(dev, "setting gpio %d to %ld\n", gpio_num, val);

    mutex_lock(&st->lock);

    if (val)
        st->gpio_state |= 1 << gpio_num;
    else
        st->gpio_state &= ~(1 << gpio_num);

    tle62x0_write(st);
    mutex_unlock(&st->lock);

    return len;
}

static DEVICE_ATTR(gpio1, S_IWUSR|S_IRUGO,
        tle62x0_gpio_show, tle62x0_gpio_store);
static DEVICE_ATTR(gpio2, S_IWUSR|S_IRUGO,
        tle62x0_gpio_show, tle62x0_gpio_store);
static DEVICE_ATTR(gpio3, S_IWUSR|S_IRUGO,
        tle62x0_gpio_show, tle62x0_gpio_store);
static DEVICE_ATTR(gpio4, S_IWUSR|S_IRUGO,
        tle62x0_gpio_show, tle62x0_gpio_store);
static DEVICE_ATTR(gpio5, S_IWUSR|S_IRUGO,
        tle62x0_gpio_show, tle62x0_gpio_store);
static DEVICE_ATTR(gpio6, S_IWUSR|S_IRUGO,
        tle62x0_gpio_show, tle62x0_gpio_store);
static DEVICE_ATTR(gpio7, S_IWUSR|S_IRUGO,
        tle62x0_gpio_show, tle62x0_gpio_store);
static DEVICE_ATTR(gpio8, S_IWUSR|S_IRUGO,
        tle62x0_gpio_show, tle62x0_gpio_store);
static DEVICE_ATTR(gpio9, S_IWUSR|S_IRUGO,
        tle62x0_gpio_show, tle62x0_gpio_store);
static DEVICE_ATTR(gpio10, S_IWUSR|S_IRUGO,
        tle62x0_gpio_show, tle62x0_gpio_store);
static DEVICE_ATTR(gpio11, S_IWUSR|S_IRUGO,
        tle62x0_gpio_show, tle62x0_gpio_store);
static DEVICE_ATTR(gpio12, S_IWUSR|S_IRUGO,
        tle62x0_gpio_show, tle62x0_gpio_store);
static DEVICE_ATTR(gpio13, S_IWUSR|S_IRUGO,
        tle62x0_gpio_show, tle62x0_gpio_store);
static DEVICE_ATTR(gpio14, S_IWUSR|S_IRUGO,
        tle62x0_gpio_show, tle62x0_gpio_store);
static DEVICE_ATTR(gpio15, S_IWUSR|S_IRUGO,
        tle62x0_gpio_show, tle62x0_gpio_store);
static DEVICE_ATTR(gpio16, S_IWUSR|S_IRUGO,
        tle62x0_gpio_show, tle62x0_gpio_store);

static struct device_attribute *gpio_attrs[] = {
    [0]     = &dev_attr_gpio1,
    [1]     = &dev_attr_gpio2,
    [2]     = &dev_attr_gpio3,
    [3]     = &dev_attr_gpio4,
    [4]     = &dev_attr_gpio5,
    [5]     = &dev_attr_gpio6,
    [6]     = &dev_attr_gpio7,
    [7]     = &dev_attr_gpio8,
    [8]     = &dev_attr_gpio9,
    [9]     = &dev_attr_gpio10,
    [10]        = &dev_attr_gpio11,
    [11]        = &dev_attr_gpio12,
    [12]        = &dev_attr_gpio13,
    [13]        = &dev_attr_gpio14,
    [14]        = &dev_attr_gpio15,
    [15]        = &dev_attr_gpio16
};

static int to_gpio_num(struct device_attribute *attr)
{
    int ptr;

    for (ptr = 0; ptr < ARRAY_SIZE(gpio_attrs); ptr++) {
        if (gpio_attrs[ptr] == attr)
            return ptr;
    }

    return -1;
}

static int __devinit tle62x0_probe(struct spi_device *spi)
{
    struct tle62x0_state *st;
    struct tle62x0_pdata *pdata;
    int ptr;
    int ret;

    pdata = spi->dev.platform_data;
    if (pdata == NULL) {
        dev_err(&spi->dev, "no device data specified\n");
        return -EINVAL;
    }

    st = kzalloc(sizeof(struct tle62x0_state), GFP_KERNEL);
    if (st == NULL) {
        dev_err(&spi->dev, "no memory for device state\n");
        return -ENOMEM;
    }

    st->us = spi;
    st->nr_gpio = pdata->gpio_count;
    st->gpio_state = pdata->init_state;

    mutex_init(&st->lock);

    ret = device_create_file(&spi->dev, &dev_attr_status_show);
    if (ret) {
        dev_err(&spi->dev, "cannot create status attribute\n");
        goto err_status;
    }

    for (ptr = 0; ptr < pdata->gpio_count; ptr++) {
        ret = device_create_file(&spi->dev, gpio_attrs[ptr]);
        if (ret) {
            dev_err(&spi->dev, "cannot create gpio attribute\n");
            goto err_gpios;
        }
    }

    /* tle62x0_write(st); */
    spi_set_drvdata(spi, st);
    return 0;

 err_gpios:
    while (--ptr >= 0)
        device_remove_file(&spi->dev, gpio_attrs[ptr]);

    device_remove_file(&spi->dev, &dev_attr_status_show);

 err_status:
    kfree(st);
    return ret;
}

static int __devexit tle62x0_remove(struct spi_device *spi)
{
    struct tle62x0_state *st = spi_get_drvdata(spi);
    int ptr;

    for (ptr = 0; ptr < st->nr_gpio; ptr++)
        device_remove_file(&spi->dev, gpio_attrs[ptr]);

    device_remove_file(&spi->dev, &dev_attr_status_show);
    kfree(st);
    return 0;
}

static struct spi_driver tle62x0_driver = {
    .driver = {
        .name   = "tle62x0",
        .owner  = THIS_MODULE,
    },
    .probe      = tle62x0_probe,
    .remove     = __devexit_p(tle62x0_remove),
};

module_spi_driver(tle62x0_driver);

MODULE_AUTHOR("Ben Dooks <[email protected]>");
MODULE_DESCRIPTION("TLE62x0 SPI driver");
MODULE_LICENSE("GPL v2");
MODULE_ALIAS("spi:tle62x0");