/*
 * LP5521 LED chip driver.
 *
 * Copyright (C) 2010 Nokia Corporation
 * Copyright (C) 2012 Texas Instruments
 *
 * Contact: Samu Onkalo <samu.p.onkalo@nokia.com>
 *          Milo(Woogyom) Kim <milo.kim@ti.com>
 *
 * 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.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
 * 02110-1301 USA
 */

#include <linux/delay.h>
#include <linux/firmware.h>
#include <linux/i2c.h>
#include <linux/leds.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/platform_data/leds-lp55xx.h>
#include <linux/slab.h>
#include <linux/of.h>

#include "leds-lp55xx-common.h"

#define LP5521_PROGRAM_LENGTH           32
#define LP5521_MAX_LEDS                 3
#define LP5521_CMD_DIRECT               0x3F

/* Registers */
#define LP5521_REG_ENABLE               0x00
#define LP5521_REG_OP_MODE              0x01
#define LP5521_REG_R_PWM                0x02
#define LP5521_REG_G_PWM                0x03
#define LP5521_REG_B_PWM                0x04
#define LP5521_REG_R_CURRENT            0x05
#define LP5521_REG_G_CURRENT            0x06
#define LP5521_REG_B_CURRENT            0x07
#define LP5521_REG_CONFIG               0x08
#define LP5521_REG_STATUS               0x0C
#define LP5521_REG_RESET                0x0D
#define LP5521_REG_R_PROG_MEM           0x10
#define LP5521_REG_G_PROG_MEM           0x30
#define LP5521_REG_B_PROG_MEM           0x50

/* Base register to set LED current */
#define LP5521_REG_LED_CURRENT_BASE     LP5521_REG_R_CURRENT
/* Base register to set the brightness */
#define LP5521_REG_LED_PWM_BASE         LP5521_REG_R_PWM

/* Bits in ENABLE register */
#define LP5521_MASTER_ENABLE            0x40    /* Chip master enable */
#define LP5521_LOGARITHMIC_PWM          0x80    /* Logarithmic PWM adjustment */
#define LP5521_EXEC_RUN                 0x2A
#define LP5521_ENABLE_DEFAULT   \
        (LP5521_MASTER_ENABLE | LP5521_LOGARITHMIC_PWM)
#define LP5521_ENABLE_RUN_PROGRAM       \
        (LP5521_ENABLE_DEFAULT | LP5521_EXEC_RUN)

/* CONFIG register */
#define LP5521_PWM_HF                   0x40    /* PWM: 0 = 256Hz, 1 = 558Hz */
#define LP5521_PWRSAVE_EN               0x20    /* 1 = Power save mode */
#define LP5521_CP_MODE_OFF              0       /* Charge pump (CP) off */
#define LP5521_CP_MODE_BYPASS           8       /* CP forced to bypass mode */
#define LP5521_CP_MODE_1X5              0x10    /* CP forced to 1.5x mode */
#define LP5521_CP_MODE_AUTO             0x18    /* Automatic mode selection */
#define LP5521_R_TO_BATT                0x04    /* R out: 0 = CP, 1 = Vbat */
#define LP5521_CLK_INT                  0x01    /* Internal clock */
#define LP5521_DEFAULT_CFG              \
        (LP5521_PWM_HF | LP5521_PWRSAVE_EN | LP5521_CP_MODE_AUTO)

/* Status */
#define LP5521_EXT_CLK_USED             0x08

/* default R channel current register value */
#define LP5521_REG_R_CURR_DEFAULT       0xAF

/* Reset register value */
#define LP5521_RESET                    0xFF

/* Program Memory Operations */
#define LP5521_MODE_R_M                 0x30    /* Operation Mode Register */
#define LP5521_MODE_G_M                 0x0C
#define LP5521_MODE_B_M                 0x03
#define LP5521_LOAD_R                   0x10
#define LP5521_LOAD_G                   0x04
#define LP5521_LOAD_B                   0x01

#define LP5521_R_IS_LOADING(mode)       \
        ((mode & LP5521_MODE_R_M) == LP5521_LOAD_R)
#define LP5521_G_IS_LOADING(mode)       \
        ((mode & LP5521_MODE_G_M) == LP5521_LOAD_G)
#define LP5521_B_IS_LOADING(mode)       \
        ((mode & LP5521_MODE_B_M) == LP5521_LOAD_B)

#define LP5521_EXEC_R_M                 0x30    /* Enable Register */
#define LP5521_EXEC_G_M                 0x0C
#define LP5521_EXEC_B_M                 0x03
#define LP5521_EXEC_M                   0x3F
#define LP5521_RUN_R                    0x20
#define LP5521_RUN_G                    0x08
#define LP5521_RUN_B                    0x02

static inline void lp5521_wait_opmode_done(void)
{
        /* operation mode change needs to be longer than 153 us */
        usleep_range(200, 300);
}

static inline void lp5521_wait_enable_done(void)
{
        /* it takes more 488 us to update ENABLE register */
        usleep_range(500, 600);
}

static void lp5521_set_led_current(struct lp55xx_led *led, u8 led_current)
{
        led->led_current = led_current;
        lp55xx_write(led->chip, LP5521_REG_LED_CURRENT_BASE + led->chan_nr,
                led_current);
}

static void lp5521_load_engine(struct lp55xx_chip *chip)
{
        enum lp55xx_engine_index idx = chip->engine_idx;
        static const u8 mask[] = {
                [LP55XX_ENGINE_1] = LP5521_MODE_R_M,
                [LP55XX_ENGINE_2] = LP5521_MODE_G_M,
                [LP55XX_ENGINE_3] = LP5521_MODE_B_M,
        };

        static const u8 val[] = {
                [LP55XX_ENGINE_1] = LP5521_LOAD_R,
                [LP55XX_ENGINE_2] = LP5521_LOAD_G,
                [LP55XX_ENGINE_3] = LP5521_LOAD_B,
        };

        lp55xx_update_bits(chip, LP5521_REG_OP_MODE, mask[idx], val[idx]);

        lp5521_wait_opmode_done();
}

static void lp5521_stop_all_engines(struct lp55xx_chip *chip)
{
        lp55xx_write(chip, LP5521_REG_OP_MODE, 0);
        lp5521_wait_opmode_done();
}

static void lp5521_stop_engine(struct lp55xx_chip *chip)
{
        enum lp55xx_engine_index idx = chip->engine_idx;
        static const u8 mask[] = {
                [LP55XX_ENGINE_1] = LP5521_MODE_R_M,
                [LP55XX_ENGINE_2] = LP5521_MODE_G_M,
                [LP55XX_ENGINE_3] = LP5521_MODE_B_M,
        };

        lp55xx_update_bits(chip, LP5521_REG_OP_MODE, mask[idx], 0);

        lp5521_wait_opmode_done();
}

static void lp5521_run_engine(struct lp55xx_chip *chip, bool start)
{
        int ret;
        u8 mode;
        u8 exec;

        /* stop engine */
        if (!start) {
                lp5521_stop_engine(chip);
                lp55xx_write(chip, LP5521_REG_OP_MODE, LP5521_CMD_DIRECT);
                lp5521_wait_opmode_done();
                return;
        }

        /*
         * To run the engine,
         * operation mode and enable register should updated at the same time
         */

        ret = lp55xx_read(chip, LP5521_REG_OP_MODE, &mode);
        if (ret)
                return;

        ret = lp55xx_read(chip, LP5521_REG_ENABLE, &exec);
        if (ret)
                return;

        /* change operation mode to RUN only when each engine is loading */
        if (LP5521_R_IS_LOADING(mode)) {
                mode = (mode & ~LP5521_MODE_R_M) | LP5521_RUN_R;
                exec = (exec & ~LP5521_EXEC_R_M) | LP5521_RUN_R;
        }

        if (LP5521_G_IS_LOADING(mode)) {
                mode = (mode & ~LP5521_MODE_G_M) | LP5521_RUN_G;
                exec = (exec & ~LP5521_EXEC_G_M) | LP5521_RUN_G;
        }

        if (LP5521_B_IS_LOADING(mode)) {
                mode = (mode & ~LP5521_MODE_B_M) | LP5521_RUN_B;
                exec = (exec & ~LP5521_EXEC_B_M) | LP5521_RUN_B;
        }

        lp55xx_write(chip, LP5521_REG_OP_MODE, mode);
        lp5521_wait_opmode_done();

        lp55xx_update_bits(chip, LP5521_REG_ENABLE, LP5521_EXEC_M, exec);
        lp5521_wait_enable_done();
}

static int lp5521_update_program_memory(struct lp55xx_chip *chip,
                                        const u8 *data, size_t size)
{
        enum lp55xx_engine_index idx = chip->engine_idx;
        u8 pattern[LP5521_PROGRAM_LENGTH] = {0};
        static const u8 addr[] = {
                [LP55XX_ENGINE_1] = LP5521_REG_R_PROG_MEM,
                [LP55XX_ENGINE_2] = LP5521_REG_G_PROG_MEM,
                [LP55XX_ENGINE_3] = LP5521_REG_B_PROG_MEM,
        };
        unsigned cmd;
        char c[3];
        int nrchars;
        int ret;
        int offset = 0;
        int i = 0;

        while ((offset < size - 1) && (i < LP5521_PROGRAM_LENGTH)) {
                /* separate sscanfs because length is working only for %s */
                ret = sscanf(data + offset, "%2s%n ", c, &nrchars);
                if (ret != 1)
                        goto err;

                ret = sscanf(c, "%2x", &cmd);
                if (ret != 1)
                        goto err;

                pattern[i] = (u8)cmd;
                offset += nrchars;
                i++;
        }

        /* Each instruction is 16bit long. Check that length is even */
        if (i % 2)
                goto err;

        for (i = 0; i < LP5521_PROGRAM_LENGTH; i++) {
                ret = lp55xx_write(chip, addr[idx] + i, pattern[i]);
                if (ret)
                        return -EINVAL;
        }

        return size;

err:
        dev_err(&chip->cl->dev, "wrong pattern format\n");
        return -EINVAL;
}

static void lp5521_firmware_loaded(struct lp55xx_chip *chip)
{
        const struct firmware *fw = chip->fw;

        if (fw->size > LP5521_PROGRAM_LENGTH) {
                dev_err(&chip->cl->dev, "firmware data size overflow: %zu\n",
                        fw->size);
                return;
        }

        /*
         * Program memory sequence
         *  1) set engine mode to "LOAD"
         *  2) write firmware data into program memory
         */

        lp5521_load_engine(chip);
        lp5521_update_program_memory(chip, fw->data, fw->size);
}

static int lp5521_post_init_device(struct lp55xx_chip *chip)
{
        int ret;
        u8 val;

        /*
         * Make sure that the chip is reset by reading back the r channel
         * current reg. This is dummy read is required on some platforms -
         * otherwise further access to the R G B channels in the
         * LP5521_REG_ENABLE register will not have any effect - strange!
         */
        ret = lp55xx_read(chip, LP5521_REG_R_CURRENT, &val);
        if (ret) {
                dev_err(&chip->cl->dev, "error in resetting chip\n");
                return ret;
        }
        if (val != LP5521_REG_R_CURR_DEFAULT) {
                dev_err(&chip->cl->dev,
                        "unexpected data in register (expected 0x%x got 0x%x)\n",
                        LP5521_REG_R_CURR_DEFAULT, val);
                ret = -EINVAL;
                return ret;
        }
        usleep_range(10000, 20000);

        /* Set all PWMs to direct control mode */
        ret = lp55xx_write(chip, LP5521_REG_OP_MODE, LP5521_CMD_DIRECT);

        /* Update configuration for the clock setting */
        val = LP5521_DEFAULT_CFG;
        if (!lp55xx_is_extclk_used(chip))
                val |= LP5521_CLK_INT;

        ret = lp55xx_write(chip, LP5521_REG_CONFIG, val);
        if (ret)
                return ret;

        /* Initialize all channels PWM to zero -> leds off */
        lp55xx_write(chip, LP5521_REG_R_PWM, 0);
        lp55xx_write(chip, LP5521_REG_G_PWM, 0);
        lp55xx_write(chip, LP5521_REG_B_PWM, 0);

        /* Set engines are set to run state when OP_MODE enables engines */
        ret = lp55xx_write(chip, LP5521_REG_ENABLE, LP5521_ENABLE_RUN_PROGRAM);
        if (ret)
                return ret;

        lp5521_wait_enable_done();

        return 0;
}

static int lp5521_run_selftest(struct lp55xx_chip *chip, char *buf)
{
        struct lp55xx_platform_data *pdata = chip->pdata;
        int ret;
        u8 status;

        ret = lp55xx_read(chip, LP5521_REG_STATUS, &status);
        if (ret < 0)
                return ret;

        if (pdata->clock_mode != LP55XX_CLOCK_EXT)
                return 0;

        /* Check that ext clock is really in use if requested */
        if  ((status & LP5521_EXT_CLK_USED) == 0)
                return -EIO;

        return 0;
}

static int lp5521_led_brightness(struct lp55xx_led *led)
{
        struct lp55xx_chip *chip = led->chip;
        int ret;

        mutex_lock(&chip->lock);
        ret = lp55xx_write(chip, LP5521_REG_LED_PWM_BASE + led->chan_nr,
                led->brightness);
        mutex_unlock(&chip->lock);

        return ret;
}

static ssize_t show_engine_mode(struct device *dev,
                                struct device_attribute *attr,
                                char *buf, int nr)
{
        struct lp55xx_led *led = i2c_get_clientdata(to_i2c_client(dev));
        struct lp55xx_chip *chip = led->chip;
        enum lp55xx_engine_mode mode = chip->engines[nr - 1].mode;

        switch (mode) {
        case LP55XX_ENGINE_RUN:
                return sprintf(buf, "run\n");
        case LP55XX_ENGINE_LOAD:
                return sprintf(buf, "load\n");
        case LP55XX_ENGINE_DISABLED:
        default:
                return sprintf(buf, "disabled\n");
        }
}
show_mode(1)
show_mode(2)
show_mode(3)

static ssize_t store_engine_mode(struct device *dev,
                                 struct device_attribute *attr,
                                 const char *buf, size_t len, int nr)
{
        struct lp55xx_led *led = i2c_get_clientdata(to_i2c_client(dev));
        struct lp55xx_chip *chip = led->chip;
        struct lp55xx_engine *engine = &chip->engines[nr - 1];

        mutex_lock(&chip->lock);

        chip->engine_idx = nr;

        if (!strncmp(buf, "run", 3)) {
                lp5521_run_engine(chip, true);
                engine->mode = LP55XX_ENGINE_RUN;
        } else if (!strncmp(buf, "load", 4)) {
                lp5521_stop_engine(chip);
                lp5521_load_engine(chip);
                engine->mode = LP55XX_ENGINE_LOAD;
        } else if (!strncmp(buf, "disabled", 8)) {
                lp5521_stop_engine(chip);
                engine->mode = LP55XX_ENGINE_DISABLED;
        }

        mutex_unlock(&chip->lock);

        return len;
}
store_mode(1)
store_mode(2)
store_mode(3)

static ssize_t store_engine_load(struct device *dev,
                             struct device_attribute *attr,
                             const char *buf, size_t len, int nr)
{
        struct lp55xx_led *led = i2c_get_clientdata(to_i2c_client(dev));
        struct lp55xx_chip *chip = led->chip;
        int ret;

        mutex_lock(&chip->lock);

        chip->engine_idx = nr;
        lp5521_load_engine(chip);
        ret = lp5521_update_program_memory(chip, buf, len);

        mutex_unlock(&chip->lock);

        return ret;
}
store_load(1)
store_load(2)
store_load(3)

static ssize_t lp5521_selftest(struct device *dev,
                               struct device_attribute *attr,
                               char *buf)
{
        struct lp55xx_led *led = i2c_get_clientdata(to_i2c_client(dev));
        struct lp55xx_chip *chip = led->chip;
        int ret;

        mutex_lock(&chip->lock);
        ret = lp5521_run_selftest(chip, buf);
        mutex_unlock(&chip->lock);

        return scnprintf(buf, PAGE_SIZE, "%s\n", ret ? "FAIL" : "OK");
}

/* device attributes */
static LP55XX_DEV_ATTR_RW(engine1_mode, show_engine1_mode, store_engine1_mode);
static LP55XX_DEV_ATTR_RW(engine2_mode, show_engine2_mode, store_engine2_mode);
static LP55XX_DEV_ATTR_RW(engine3_mode, show_engine3_mode, store_engine3_mode);
static LP55XX_DEV_ATTR_WO(engine1_load, store_engine1_load);
static LP55XX_DEV_ATTR_WO(engine2_load, store_engine2_load);
static LP55XX_DEV_ATTR_WO(engine3_load, store_engine3_load);
static LP55XX_DEV_ATTR_RO(selftest, lp5521_selftest);

static struct attribute *lp5521_attributes[] = {
        &dev_attr_engine1_mode.attr,
        &dev_attr_engine2_mode.attr,
        &dev_attr_engine3_mode.attr,
        &dev_attr_engine1_load.attr,
        &dev_attr_engine2_load.attr,
        &dev_attr_engine3_load.attr,
        &dev_attr_selftest.attr,
        NULL
};

static const struct attribute_group lp5521_group = {
        .attrs = lp5521_attributes,
};

/* Chip specific configurations */
static struct lp55xx_device_config lp5521_cfg = {
        .reset = {
                .addr = LP5521_REG_RESET,
                .val  = LP5521_RESET,
        },
        .enable = {
                .addr = LP5521_REG_ENABLE,
                .val  = LP5521_ENABLE_DEFAULT,
        },
        .max_channel  = LP5521_MAX_LEDS,
        .post_init_device   = lp5521_post_init_device,
        .brightness_fn      = lp5521_led_brightness,
        .set_led_current    = lp5521_set_led_current,
        .firmware_cb        = lp5521_firmware_loaded,
        .run_engine         = lp5521_run_engine,
        .dev_attr_group     = &lp5521_group,
};

static int lp5521_probe(struct i2c_client *client,
                        const struct i2c_device_id *id)
{
        int ret;
        struct lp55xx_chip *chip;
        struct lp55xx_led *led;
        struct lp55xx_platform_data *pdata = dev_get_platdata(&client->dev);
        struct device_node *np = client->dev.of_node;

        if (!pdata) {
                if (np) {
                        pdata = lp55xx_of_populate_pdata(&client->dev, np);
                        if (IS_ERR(pdata))
                                return PTR_ERR(pdata);
                } else {
                        dev_err(&client->dev, "no platform data\n");
                        return -EINVAL;
                }
        }

        chip = devm_kzalloc(&client->dev, sizeof(*chip), GFP_KERNEL);
        if (!chip)
                return -ENOMEM;

        led = devm_kcalloc(&client->dev,
                        pdata->num_channels, sizeof(*led), GFP_KERNEL);
        if (!led)
                return -ENOMEM;

        chip->cl = client;
        chip->pdata = pdata;
        chip->cfg = &lp5521_cfg;

        mutex_init(&chip->lock);

        i2c_set_clientdata(client, led);

        ret = lp55xx_init_device(chip);
        if (ret)
                goto err_init;

        dev_info(&client->dev, "%s programmable led chip found\n", id->name);

        ret = lp55xx_register_leds(led, chip);
        if (ret)
                goto err_register_leds;

        ret = lp55xx_register_sysfs(chip);
        if (ret) {
                dev_err(&client->dev, "registering sysfs failed\n");
                goto err_register_sysfs;
        }

        return 0;

err_register_sysfs:
        lp55xx_unregister_leds(led, chip);
err_register_leds:
        lp55xx_deinit_device(chip);
err_init:
        return ret;
}

static int lp5521_remove(struct i2c_client *client)
{
        struct lp55xx_led *led = i2c_get_clientdata(client);
        struct lp55xx_chip *chip = led->chip;

        lp5521_stop_all_engines(chip);
        lp55xx_unregister_sysfs(chip);
        lp55xx_unregister_leds(led, chip);
        lp55xx_deinit_device(chip);

        return 0;
}

static const struct i2c_device_id lp5521_id[] = {
        { "lp5521", 0 }, /* Three channel chip */
        { }
};
MODULE_DEVICE_TABLE(i2c, lp5521_id);

#ifdef CONFIG_OF
static const struct of_device_id of_lp5521_leds_match[] = {
        { .compatible = "national,lp5521", },
        {},
};

MODULE_DEVICE_TABLE(of, of_lp5521_leds_match);
#endif
static struct i2c_driver lp5521_driver = {
        .driver = {
                .name   = "lp5521",
                .of_match_table = of_match_ptr(of_lp5521_leds_match),
        },
        .probe          = lp5521_probe,
        .remove         = lp5521_remove,
        .id_table       = lp5521_id,
};

module_i2c_driver(lp5521_driver);

MODULE_AUTHOR("Mathias Nyman, Yuri Zaporozhets, Samu Onkalo");
MODULE_AUTHOR("Milo Kim <milo.kim@ti.com>");
MODULE_DESCRIPTION("LP5521 LED engine");
MODULE_LICENSE("GPL v2");