dm355evm_msp.c

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/*
 * dm355evm_msp.c - driver for MSP430 firmware on DM355EVM board
 *
 * Copyright (C) 2008 David Brownell
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 */

#include <linux/init.h>
#include <linux/mutex.h>
#include <linux/platform_device.h>
#include <linux/clk.h>
#include <linux/module.h>
#include <linux/err.h>
#include <linux/gpio.h>
#include <linux/leds.h>
#include <linux/i2c.h>
#include <linux/i2c/dm355evm_msp.h>


/*
 * The DM355 is a DaVinci chip with video support but no C64+ DSP.  Its
 * EVM board has an MSP430 programmed with firmware for various board
 * support functions.  This driver exposes some of them directly, and
 * supports other drivers (e.g. RTC, input) for more complex access.
 *
 * Because this firmware is entirely board-specific, this file embeds
 * knowledge that would be passed as platform_data in a generic driver.
 *
 * This driver was tested with firmware revision A4.
 */

#if defined(CONFIG_INPUT_DM355EVM) || defined(CONFIG_INPUT_DM355EVM_MODULE)
#define msp_has_keyboard()  true
#else
#define msp_has_keyboard()  false
#endif

#if defined(CONFIG_LEDS_GPIO) || defined(CONFIG_LEDS_GPIO_MODULE)
#define msp_has_leds()      true
#else
#define msp_has_leds()      false
#endif

#if defined(CONFIG_RTC_DRV_DM355EVM) || defined(CONFIG_RTC_DRV_DM355EVM_MODULE)
#define msp_has_rtc()       true
#else
#define msp_has_rtc()       false
#endif

#if defined(CONFIG_VIDEO_TVP514X) || defined(CONFIG_VIDEO_TVP514X_MODULE)
#define msp_has_tvp()       true
#else
#define msp_has_tvp()       false
#endif


/*----------------------------------------------------------------------*/

/* REVISIT for paranoia's sake, retry reads/writes on error */

static struct i2c_client *msp430;

int dm355evm_msp_write(u8 value, u8 reg)
{
    return i2c_smbus_write_byte_data(msp430, reg, value);
}
EXPORT_SYMBOL(dm355evm_msp_write);

int dm355evm_msp_read(u8 reg)
{
    return i2c_smbus_read_byte_data(msp430, reg);
}
EXPORT_SYMBOL(dm355evm_msp_read);

/*----------------------------------------------------------------------*/

/*
 * Many of the msp430 pins are just used as fixed-direction GPIOs.
 * We could export a few more of them this way, if we wanted.
 */
#define MSP_GPIO(bit,reg)   ((DM355EVM_MSP_ ## reg) << 3 | (bit))

static const u8 msp_gpios[] = {
    /* eight leds */
    MSP_GPIO(0, LED), MSP_GPIO(1, LED),
    MSP_GPIO(2, LED), MSP_GPIO(3, LED),
    MSP_GPIO(4, LED), MSP_GPIO(5, LED),
    MSP_GPIO(6, LED), MSP_GPIO(7, LED),
    /* SW6 and the NTSC/nPAL jumper */
    MSP_GPIO(0, SWITCH1), MSP_GPIO(1, SWITCH1),
    MSP_GPIO(2, SWITCH1), MSP_GPIO(3, SWITCH1),
    MSP_GPIO(4, SWITCH1),
    /* switches on MMC/SD sockets */
    /*
     * Note: EVMDM355_ECP_VA4.pdf suggests that Bit 2 and 4 should be
     * checked for card detection. However on the EVM bit 1 and 3 gives
     * this status, for 0 and 1 instance respectively. The pdf also
     * suggests that Bit 1 and 3 should be checked for write protection.
     * However on the EVM bit 2 and 4 gives this status,for 0 and 1
     * instance respectively.
     */
    MSP_GPIO(2, SDMMC), MSP_GPIO(1, SDMMC), /* mmc0 WP, nCD */
    MSP_GPIO(4, SDMMC), MSP_GPIO(3, SDMMC), /* mmc1 WP, nCD */
};

#define MSP_GPIO_REG(offset)    (msp_gpios[(offset)] >> 3)
#define MSP_GPIO_MASK(offset)   BIT(msp_gpios[(offset)] & 0x07)

static int msp_gpio_in(struct gpio_chip *chip, unsigned offset)
{
    switch (MSP_GPIO_REG(offset)) {
    case DM355EVM_MSP_SWITCH1:
    case DM355EVM_MSP_SWITCH2:
    case DM355EVM_MSP_SDMMC:
        return 0;
    default:
        return -EINVAL;
    }
}

static u8 msp_led_cache;

static int msp_gpio_get(struct gpio_chip *chip, unsigned offset)
{
    int reg, status;

    reg = MSP_GPIO_REG(offset);
    status = dm355evm_msp_read(reg);
    if (status < 0)
        return status;
    if (reg == DM355EVM_MSP_LED)
        msp_led_cache = status;
    return status & MSP_GPIO_MASK(offset);
}

static int msp_gpio_out(struct gpio_chip *chip, unsigned offset, int value)
{
    int mask, bits;

    /* NOTE:  there are some other signals that could be
     * packaged as output GPIOs, but they aren't as useful
     * as the LEDs ... so for now we don't.
     */
    if (MSP_GPIO_REG(offset) != DM355EVM_MSP_LED)
        return -EINVAL;

    mask = MSP_GPIO_MASK(offset);
    bits = msp_led_cache;

    bits &= ~mask;
    if (value)
        bits |= mask;
    msp_led_cache = bits;

    return dm355evm_msp_write(bits, DM355EVM_MSP_LED);
}

static void msp_gpio_set(struct gpio_chip *chip, unsigned offset, int value)
{
    msp_gpio_out(chip, offset, value);
}

static struct gpio_chip dm355evm_msp_gpio = {
    .label          = "dm355evm_msp",
    .owner          = THIS_MODULE,
    .direction_input    = msp_gpio_in,
    .get            = msp_gpio_get,
    .direction_output   = msp_gpio_out,
    .set            = msp_gpio_set,
    .base           = -EINVAL,      /* dynamic assignment */
    .ngpio          = ARRAY_SIZE(msp_gpios),
    .can_sleep      = true,
};

/*----------------------------------------------------------------------*/

static struct device *add_child(struct i2c_client *client, const char *name,
        void *pdata, unsigned pdata_len,
        bool can_wakeup, int irq)
{
    struct platform_device  *pdev;
    int         status;

    pdev = platform_device_alloc(name, -1);
    if (!pdev) {
        dev_dbg(&client->dev, "can't alloc dev\n");
        status = -ENOMEM;
        goto err;
    }

    device_init_wakeup(&pdev->dev, can_wakeup);
    pdev->dev.parent = &client->dev;

    if (pdata) {
        status = platform_device_add_data(pdev, pdata, pdata_len);
        if (status < 0) {
            dev_dbg(&pdev->dev, "can't add platform_data\n");
            goto err;
        }
    }

    if (irq) {
        struct resource r = {
            .start = irq,
            .flags = IORESOURCE_IRQ,
        };

        status = platform_device_add_resources(pdev, &r, 1);
        if (status < 0) {
            dev_dbg(&pdev->dev, "can't add irq\n");
            goto err;
        }
    }

    status = platform_device_add(pdev);

err:
    if (status < 0) {
        platform_device_put(pdev);
        dev_err(&client->dev, "can't add %s dev\n", name);
        return ERR_PTR(status);
    }
    return &pdev->dev;
}

static int add_children(struct i2c_client *client)
{
    static const struct {
        int offset;
        char *label;
    } config_inputs[] = {
        /* 8 == right after the LEDs */
        { 8 + 0, "sw6_1", },
        { 8 + 1, "sw6_2", },
        { 8 + 2, "sw6_3", },
        { 8 + 3, "sw6_4", },
        { 8 + 4, "NTSC/nPAL", },
    };

    struct device   *child;
    int     status;
    int     i;

    /* GPIO-ish stuff */
    dm355evm_msp_gpio.dev = &client->dev;
    status = gpiochip_add(&dm355evm_msp_gpio);
    if (status < 0)
        return status;

    /* LED output */
    if (msp_has_leds()) {
#define GPIO_LED(l) .name = l, .active_low = true
        static struct gpio_led evm_leds[] = {
            { GPIO_LED("dm355evm::ds14"),
                .default_trigger = "heartbeat", },
            { GPIO_LED("dm355evm::ds15"),
                .default_trigger = "mmc0", },
            { GPIO_LED("dm355evm::ds16"),
                /* could also be a CE-ATA drive */
                .default_trigger = "mmc1", },
            { GPIO_LED("dm355evm::ds17"),
                .default_trigger = "nand-disk", },
            { GPIO_LED("dm355evm::ds18"), },
            { GPIO_LED("dm355evm::ds19"), },
            { GPIO_LED("dm355evm::ds20"), },
            { GPIO_LED("dm355evm::ds21"), },
        };
#undef GPIO_LED

        struct gpio_led_platform_data evm_led_data = {
            .num_leds   = ARRAY_SIZE(evm_leds),
            .leds       = evm_leds,
        };

        for (i = 0; i < ARRAY_SIZE(evm_leds); i++)
            evm_leds[i].gpio = i + dm355evm_msp_gpio.base;

        /* NOTE:  these are the only fully programmable LEDs
         * on the board, since GPIO-61/ds22 (and many signals
         * going to DC7) must be used for AEMIF address lines
         * unless the top 1 GB of NAND is unused...
         */
        child = add_child(client, "leds-gpio",
                &evm_led_data, sizeof(evm_led_data),
                false, 0);
        if (IS_ERR(child))
            return PTR_ERR(child);
    }

    /* configuration inputs */
    for (i = 0; i < ARRAY_SIZE(config_inputs); i++) {
        int gpio = dm355evm_msp_gpio.base + config_inputs[i].offset;

        gpio_request_one(gpio, GPIOF_IN, config_inputs[i].label);

        /* make it easy for userspace to see these */
        gpio_export(gpio, false);
    }

    /* MMC/SD inputs -- right after the last config input */
    if (client->dev.platform_data) {
        void (*mmcsd_setup)(unsigned) = client->dev.platform_data;

        mmcsd_setup(dm355evm_msp_gpio.base + 8 + 5);
    }

    /* RTC is a 32 bit counter, no alarm */
    if (msp_has_rtc()) {
        child = add_child(client, "rtc-dm355evm",
                NULL, 0, false, 0);
        if (IS_ERR(child))
            return PTR_ERR(child);
    }

    /* input from buttons and IR remote (uses the IRQ) */
    if (msp_has_keyboard()) {
        child = add_child(client, "dm355evm_keys",
                NULL, 0, true, client->irq);
        if (IS_ERR(child))
            return PTR_ERR(child);
    }

    return 0;
}

/*----------------------------------------------------------------------*/

static void dm355evm_command(unsigned command)
{
    int status;

    status = dm355evm_msp_write(command, DM355EVM_MSP_COMMAND);
    if (status < 0)
        dev_err(&msp430->dev, "command %d failure %d\n",
                command, status);
}

static void dm355evm_power_off(void)
{
    dm355evm_command(MSP_COMMAND_POWEROFF);
}

static int dm355evm_msp_remove(struct i2c_client *client)
{
    pm_power_off = NULL;
    msp430 = NULL;
    return 0;
}

static int
dm355evm_msp_probe(struct i2c_client *client, const struct i2c_device_id *id)
{
    int     status;
    const char  *video = msp_has_tvp() ? "TVP5146" : "imager";

    if (msp430)
        return -EBUSY;
    msp430 = client;

    /* display revision status; doubles as sanity check */
    status = dm355evm_msp_read(DM355EVM_MSP_FIRMREV);
    if (status < 0)
        goto fail;
    dev_info(&client->dev, "firmware v.%02X, %s as video-in\n",
            status, video);

    /* mux video input:  either tvp5146 or some external imager */
    status = dm355evm_msp_write(msp_has_tvp() ? 0 : MSP_VIDEO_IMAGER,
            DM355EVM_MSP_VIDEO_IN);
    if (status < 0)
        dev_warn(&client->dev, "error %d muxing %s as video-in\n",
            status, video);

    /* init LED cache, and turn off the LEDs */
    msp_led_cache = 0xff;
    dm355evm_msp_write(msp_led_cache, DM355EVM_MSP_LED);

    /* export capabilities we support */
    status = add_children(client);
    if (status < 0)
        goto fail;

    /* PM hookup */
    pm_power_off = dm355evm_power_off;

    return 0;

fail:
    /* FIXME remove children ... */
    dm355evm_msp_remove(client);
    return status;
}

static const struct i2c_device_id dm355evm_msp_ids[] = {
    { "dm355evm_msp", 0 },
    { /* end of list */ },
};
MODULE_DEVICE_TABLE(i2c, dm355evm_msp_ids);

static struct i2c_driver dm355evm_msp_driver = {
    .driver.name    = "dm355evm_msp",
    .id_table   = dm355evm_msp_ids,
    .probe      = dm355evm_msp_probe,
    .remove     = dm355evm_msp_remove,
};

static int __init dm355evm_msp_init(void)
{
    return i2c_add_driver(&dm355evm_msp_driver);
}
subsys_initcall(dm355evm_msp_init);

static void __exit dm355evm_msp_exit(void)
{
    i2c_del_driver(&dm355evm_msp_driver);
}
module_exit(dm355evm_msp_exit);

MODULE_DESCRIPTION("Interface to MSP430 firmware on DM355EVM");
MODULE_LICENSE("GPL");