stmpe-spi.c

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/*
 * ST Microelectronics MFD: stmpe's spi client specific driver
 *
 * Copyright (C) ST Microelectronics SA 2011
 *
 * License Terms: GNU General Public License, version 2
 * Author: Viresh Kumar <[email protected]> for ST Microelectronics
 */

#include <linux/spi/spi.h>
#include <linux/interrupt.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/types.h>
#include "stmpe.h"

#define READ_CMD    (1 << 7)

static int spi_reg_read(struct stmpe *stmpe, u8 reg)
{
    struct spi_device *spi = stmpe->client;
    int status = spi_w8r16(spi, reg | READ_CMD);

    return (status < 0) ? status : status >> 8;
}

static int spi_reg_write(struct stmpe *stmpe, u8 reg, u8 val)
{
    struct spi_device *spi = stmpe->client;
    u16 cmd = (val << 8) | reg;

    return spi_write(spi, (const u8 *)&cmd, 2);
}

static int spi_block_read(struct stmpe *stmpe, u8 reg, u8 length, u8 *values)
{
    int ret, i;

    for (i = 0; i < length; i++) {
        ret = spi_reg_read(stmpe, reg + i);
        if (ret < 0)
            return ret;
        *(values + i) = ret;
    }

    return 0;
}

static int spi_block_write(struct stmpe *stmpe, u8 reg, u8 length,
        const u8 *values)
{
    int ret = 0, i;

    for (i = length; i > 0; i--, reg++) {
        ret = spi_reg_write(stmpe, reg, *(values + i - 1));
        if (ret < 0)
            return ret;
    }

    return ret;
}

static void spi_init(struct stmpe *stmpe)
{
    struct spi_device *spi = stmpe->client;

    spi->bits_per_word = 8;

    /* This register is only present for stmpe811 */
    if (stmpe->variant->id_val == 0x0811)
        spi_reg_write(stmpe, STMPE811_REG_SPI_CFG, spi->mode);

    if (spi_setup(spi) < 0)
        dev_dbg(&spi->dev, "spi_setup failed\n");
}

static struct stmpe_client_info spi_ci = {
    .read_byte = spi_reg_read,
    .write_byte = spi_reg_write,
    .read_block = spi_block_read,
    .write_block = spi_block_write,
    .init = spi_init,
};

static int __devinit
stmpe_spi_probe(struct spi_device *spi)
{
    const struct spi_device_id *id = spi_get_device_id(spi);

    /* don't exceed max specified rate - 1MHz - Limitation of STMPE */
    if (spi->max_speed_hz > 1000000) {
        dev_dbg(&spi->dev, "f(sample) %d KHz?\n",
                (spi->max_speed_hz/1000));
        return -EINVAL;
    }

    spi_ci.irq = spi->irq;
    spi_ci.client = spi;
    spi_ci.dev = &spi->dev;

    return stmpe_probe(&spi_ci, id->driver_data);
}

static int __devexit stmpe_spi_remove(struct spi_device *spi)
{
    struct stmpe *stmpe = dev_get_drvdata(&spi->dev);

    return stmpe_remove(stmpe);
}

static const struct spi_device_id stmpe_spi_id[] = {
    { "stmpe610", STMPE610 },
    { "stmpe801", STMPE801 },
    { "stmpe811", STMPE811 },
    { "stmpe1601", STMPE1601 },
    { "stmpe2401", STMPE2401 },
    { "stmpe2403", STMPE2403 },
    { }
};
MODULE_DEVICE_TABLE(spi, stmpe_id);

static struct spi_driver stmpe_spi_driver = {
    .driver = {
        .name   = "stmpe-spi",
        .owner  = THIS_MODULE,
#ifdef CONFIG_PM
        .pm = &stmpe_dev_pm_ops,
#endif
    },
    .probe      = stmpe_spi_probe,
    .remove     = __devexit_p(stmpe_spi_remove),
    .id_table   = stmpe_spi_id,
};

static int __init stmpe_init(void)
{
    return spi_register_driver(&stmpe_spi_driver);
}
subsys_initcall(stmpe_init);

static void __exit stmpe_exit(void)
{
    spi_unregister_driver(&stmpe_spi_driver);
}
module_exit(stmpe_exit);

MODULE_LICENSE("GPL v2");
MODULE_DESCRIPTION("STMPE MFD SPI Interface Driver");
MODULE_AUTHOR("Viresh Kumar <[email protected]>");