/*
 * 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 IS_ENABLED(CONFIG_INPUT_DM355EVM)
#define msp_has_keyboard()      true
#else
#define msp_has_keyboard()      false
#endif

#if IS_ENABLED(CONFIG_LEDS_GPIO)
#define msp_has_leds()          true
#else
#define msp_has_leds()          false
#endif

#if IS_ENABLED(CONFIG_RTC_DRV_DM355EVM)
#define msp_has_rtc()           true
#else
#define msp_has_rtc()           false
#endif

#if IS_ENABLED(CONFIG_VIDEO_TVP514X)
#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;

/**
 * dm355evm_msp_write - Writes a register in dm355evm_msp
 * @value: the value to be written
 * @reg: register address
 *
 * Returns result of operation - 0 is success, else negative errno
 */
int dm355evm_msp_write(u8 value, u8 reg)
{
        return i2c_smbus_write_byte_data(msp430, reg, value);
}
EXPORT_SYMBOL(dm355evm_msp_write);

/**
 * dm355evm_msp_read - Reads a register from dm355evm_msp
 * @reg: register address
 *
 * Returns result of operation - value, or negative errno
 */
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)
                return ERR_PTR(-ENOMEM);

        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 put_device;
                }
        }

        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 put_device;
                }
        }

        status = platform_device_add(pdev);
        if (status)
                goto put_device;

        return &pdev->dev;

put_device:
        platform_device_put(pdev);
        dev_err(&client->dev, "failed to add device %s\n", name);
        return ERR_PTR(status);
}

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.parent = &client->dev;
        status = gpiochip_add_data(&dm355evm_msp_gpio, NULL);
        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 (dev_get_platdata(&client->dev)) {
                void (*mmcsd_setup)(unsigned) = dev_get_platdata(&client->dev);

                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");