/*
 * Copyright 2007-2008 Extreme Engineering Solutions, Inc.
 *
 * Author: Nate Case <ncase@xes-inc.com>
 *
 * This file is subject to the terms and conditions of version 2 of
 * the GNU General Public License.  See the file COPYING in the main
 * directory of this archive for more details.
 *
 * LED driver for various PCA955x I2C LED drivers
 *
 * Supported devices:
 *
 *      Device          Description             7-bit slave address
 *      ------          -----------             -------------------
 *      PCA9550         2-bit driver            0x60 .. 0x61
 *      PCA9551         8-bit driver            0x60 .. 0x67
 *      PCA9552         16-bit driver           0x60 .. 0x67
 *      PCA9553/01      4-bit driver            0x62
 *      PCA9553/02      4-bit driver            0x63
 *
 * Philips PCA955x LED driver chips follow a register map as shown below:
 *
 *      Control Register                Description
 *      ----------------                -----------
 *      0x0                             Input register 0
 *                                      ..
 *      NUM_INPUT_REGS - 1              Last Input register X
 *
 *      NUM_INPUT_REGS                  Frequency prescaler 0
 *      NUM_INPUT_REGS + 1              PWM register 0
 *      NUM_INPUT_REGS + 2              Frequency prescaler 1
 *      NUM_INPUT_REGS + 3              PWM register 1
 *
 *      NUM_INPUT_REGS + 4              LED selector 0
 *      NUM_INPUT_REGS + 4
 *          + NUM_LED_REGS - 1          Last LED selector
 *
 *  where NUM_INPUT_REGS and NUM_LED_REGS vary depending on how many
 *  bits the chip supports.
 */

#include <linux/acpi.h>
#include <linux/ctype.h>
#include <linux/delay.h>
#include <linux/err.h>
#include <linux/gpio.h>
#include <linux/i2c.h>
#include <linux/leds.h>
#include <linux/module.h>
#include <linux/of_device.h>
#include <linux/of.h>
#include <linux/slab.h>
#include <linux/string.h>

#include <dt-bindings/leds/leds-pca955x.h>

/* LED select registers determine the source that drives LED outputs */
#define PCA955X_LS_LED_ON       0x0     /* Output LOW */
#define PCA955X_LS_LED_OFF      0x1     /* Output HI-Z */
#define PCA955X_LS_BLINK0       0x2     /* Blink at PWM0 rate */
#define PCA955X_LS_BLINK1       0x3     /* Blink at PWM1 rate */

#define PCA955X_GPIO_INPUT      LED_OFF
#define PCA955X_GPIO_HIGH       LED_OFF
#define PCA955X_GPIO_LOW        LED_FULL

enum pca955x_type {
        pca9550,
        pca9551,
        pca9552,
        pca9553,
};

struct pca955x_chipdef {
        int                     bits;
        u8                      slv_addr;       /* 7-bit slave address mask */
        int                     slv_addr_shift; /* Number of bits to ignore */
};

static struct pca955x_chipdef pca955x_chipdefs[] = {
        [pca9550] = {
                .bits           = 2,
                .slv_addr       = /* 110000x */ 0x60,
                .slv_addr_shift = 1,
        },
        [pca9551] = {
                .bits           = 8,
                .slv_addr       = /* 1100xxx */ 0x60,
                .slv_addr_shift = 3,
        },
        [pca9552] = {
                .bits           = 16,
                .slv_addr       = /* 1100xxx */ 0x60,
                .slv_addr_shift = 3,
        },
        [pca9553] = {
                .bits           = 4,
                .slv_addr       = /* 110001x */ 0x62,
                .slv_addr_shift = 1,
        },
};

static const struct i2c_device_id pca955x_id[] = {
        { "pca9550", pca9550 },
        { "pca9551", pca9551 },
        { "pca9552", pca9552 },
        { "pca9553", pca9553 },
        { }
};
MODULE_DEVICE_TABLE(i2c, pca955x_id);

static const struct acpi_device_id pca955x_acpi_ids[] = {
        { "PCA9550",  pca9550 },
        { "PCA9551",  pca9551 },
        { "PCA9552",  pca9552 },
        { "PCA9553",  pca9553 },
        { }
};
MODULE_DEVICE_TABLE(acpi, pca955x_acpi_ids);

struct pca955x {
        struct mutex lock;
        struct pca955x_led *leds;
        struct pca955x_chipdef  *chipdef;
        struct i2c_client       *client;
#ifdef CONFIG_LEDS_PCA955X_GPIO
        struct gpio_chip gpio;
#endif
};

struct pca955x_led {
        struct pca955x  *pca955x;
        struct led_classdev     led_cdev;
        int                     led_num;        /* 0 .. 15 potentially */
        char                    name[32];
        u32                     type;
        const char              *default_trigger;
};

struct pca955x_platform_data {
        struct pca955x_led      *leds;
        int                     num_leds;
};

/* 8 bits per input register */
static inline int pca95xx_num_input_regs(int bits)
{
        return (bits + 7) / 8;
}

/* 4 bits per LED selector register */
static inline int pca95xx_num_led_regs(int bits)
{
        return (bits + 3)  / 4;
}

/*
 * Return an LED selector register value based on an existing one, with
 * the appropriate 2-bit state value set for the given LED number (0-3).
 */
static inline u8 pca955x_ledsel(u8 oldval, int led_num, int state)
{
        return (oldval & (~(0x3 << (led_num << 1)))) |
                ((state & 0x3) << (led_num << 1));
}

/*
 * Write to frequency prescaler register, used to program the
 * period of the PWM output.  period = (PSCx + 1) / 38
 */
static int pca955x_write_psc(struct i2c_client *client, int n, u8 val)
{
        struct pca955x *pca955x = i2c_get_clientdata(client);
        int ret;

        ret = i2c_smbus_write_byte_data(client,
                pca95xx_num_input_regs(pca955x->chipdef->bits) + 2*n,
                val);
        if (ret < 0)
                dev_err(&client->dev, "%s: reg 0x%x, val 0x%x, err %d\n",
                        __func__, n, val, ret);
        return ret;
}

/*
 * Write to PWM register, which determines the duty cycle of the
 * output.  LED is OFF when the count is less than the value of this
 * register, and ON when it is greater.  If PWMx == 0, LED is always OFF.
 *
 * Duty cycle is (256 - PWMx) / 256
 */
static int pca955x_write_pwm(struct i2c_client *client, int n, u8 val)
{
        struct pca955x *pca955x = i2c_get_clientdata(client);
        int ret;

        ret = i2c_smbus_write_byte_data(client,
                pca95xx_num_input_regs(pca955x->chipdef->bits) + 1 + 2*n,
                val);
        if (ret < 0)
                dev_err(&client->dev, "%s: reg 0x%x, val 0x%x, err %d\n",
                        __func__, n, val, ret);
        return ret;
}

/*
 * Write to LED selector register, which determines the source that
 * drives the LED output.
 */
static int pca955x_write_ls(struct i2c_client *client, int n, u8 val)
{
        struct pca955x *pca955x = i2c_get_clientdata(client);
        int ret;

        ret = i2c_smbus_write_byte_data(client,
                pca95xx_num_input_regs(pca955x->chipdef->bits) + 4 + n,
                val);
        if (ret < 0)
                dev_err(&client->dev, "%s: reg 0x%x, val 0x%x, err %d\n",
                        __func__, n, val, ret);
        return ret;
}

/*
 * Read the LED selector register, which determines the source that
 * drives the LED output.
 */
static int pca955x_read_ls(struct i2c_client *client, int n, u8 *val)
{
        struct pca955x *pca955x = i2c_get_clientdata(client);
        int ret;

        ret = i2c_smbus_read_byte_data(client,
                pca95xx_num_input_regs(pca955x->chipdef->bits) + 4 + n);
        if (ret < 0) {
                dev_err(&client->dev, "%s: reg 0x%x, err %d\n",
                        __func__, n, ret);
                return ret;
        }
        *val = (u8)ret;
        return 0;
}

static int pca955x_led_set(struct led_classdev *led_cdev,
                            enum led_brightness value)
{
        struct pca955x_led *pca955x_led;
        struct pca955x *pca955x;
        u8 ls;
        int chip_ls;    /* which LSx to use (0-3 potentially) */
        int ls_led;     /* which set of bits within LSx to use (0-3) */
        int ret;

        pca955x_led = container_of(led_cdev, struct pca955x_led, led_cdev);
        pca955x = pca955x_led->pca955x;

        chip_ls = pca955x_led->led_num / 4;
        ls_led = pca955x_led->led_num % 4;

        mutex_lock(&pca955x->lock);

        ret = pca955x_read_ls(pca955x->client, chip_ls, &ls);
        if (ret)
                goto out;

        switch (value) {
        case LED_FULL:
                ls = pca955x_ledsel(ls, ls_led, PCA955X_LS_LED_ON);
                break;
        case LED_OFF:
                ls = pca955x_ledsel(ls, ls_led, PCA955X_LS_LED_OFF);
                break;
        case LED_HALF:
                ls = pca955x_ledsel(ls, ls_led, PCA955X_LS_BLINK0);
                break;
        default:
                /*
                 * Use PWM1 for all other values.  This has the unwanted
                 * side effect of making all LEDs on the chip share the
                 * same brightness level if set to a value other than
                 * OFF, HALF, or FULL.  But, this is probably better than
                 * just turning off for all other values.
                 */
                ret = pca955x_write_pwm(pca955x->client, 1, 255 - value);
                if (ret)
                        goto out;
                ls = pca955x_ledsel(ls, ls_led, PCA955X_LS_BLINK1);
                break;
        }

        ret = pca955x_write_ls(pca955x->client, chip_ls, ls);

out:
        mutex_unlock(&pca955x->lock);

        return ret;
}

#ifdef CONFIG_LEDS_PCA955X_GPIO
/*
 * Read the INPUT register, which contains the state of LEDs.
 */
static int pca955x_read_input(struct i2c_client *client, int n, u8 *val)
{
        int ret = i2c_smbus_read_byte_data(client, n);

        if (ret < 0) {
                dev_err(&client->dev, "%s: reg 0x%x, err %d\n",
                        __func__, n, ret);
                return ret;
        }
        *val = (u8)ret;
        return 0;

}

static int pca955x_gpio_request_pin(struct gpio_chip *gc, unsigned int offset)
{
        struct pca955x *pca955x = gpiochip_get_data(gc);
        struct pca955x_led *led = &pca955x->leds[offset];

        if (led->type == PCA955X_TYPE_GPIO)
                return 0;

        return -EBUSY;
}

static int pca955x_set_value(struct gpio_chip *gc, unsigned int offset,
                             int val)
{
        struct pca955x *pca955x = gpiochip_get_data(gc);
        struct pca955x_led *led = &pca955x->leds[offset];

        if (val)
                return pca955x_led_set(&led->led_cdev, PCA955X_GPIO_HIGH);

        return pca955x_led_set(&led->led_cdev, PCA955X_GPIO_LOW);
}

static void pca955x_gpio_set_value(struct gpio_chip *gc, unsigned int offset,
                                   int val)
{
        pca955x_set_value(gc, offset, val);
}

static int pca955x_gpio_get_value(struct gpio_chip *gc, unsigned int offset)
{
        struct pca955x *pca955x = gpiochip_get_data(gc);
        struct pca955x_led *led = &pca955x->leds[offset];
        u8 reg = 0;

        /* There is nothing we can do about errors */
        pca955x_read_input(pca955x->client, led->led_num / 8, &reg);

        return !!(reg & (1 << (led->led_num % 8)));
}

static int pca955x_gpio_direction_input(struct gpio_chip *gc,
                                        unsigned int offset)
{
        struct pca955x *pca955x = gpiochip_get_data(gc);
        struct pca955x_led *led = &pca955x->leds[offset];

        /* To use as input ensure pin is not driven. */
        return pca955x_led_set(&led->led_cdev, PCA955X_GPIO_INPUT);
}

static int pca955x_gpio_direction_output(struct gpio_chip *gc,
                                         unsigned int offset, int val)
{
        return pca955x_set_value(gc, offset, val);
}
#endif /* CONFIG_LEDS_PCA955X_GPIO */

#if IS_ENABLED(CONFIG_OF)
static struct pca955x_platform_data *
pca955x_pdata_of_init(struct i2c_client *client, struct pca955x_chipdef *chip)
{
        struct device_node *np = client->dev.of_node;
        struct device_node *child;
        struct pca955x_platform_data *pdata;
        int count;

        count = of_get_child_count(np);
        if (!count || count > chip->bits)
                return ERR_PTR(-ENODEV);

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

        pdata->leds = devm_kzalloc(&client->dev,
                                   sizeof(struct pca955x_led) * chip->bits,
                                   GFP_KERNEL);
        if (!pdata->leds)
                return ERR_PTR(-ENOMEM);

        for_each_child_of_node(np, child) {
                const char *name;
                u32 reg;
                int res;

                res = of_property_read_u32(child, "reg", &reg);
                if ((res != 0) || (reg >= chip->bits))
                        continue;

                if (of_property_read_string(child, "label", &name))
                        name = child->name;

                snprintf(pdata->leds[reg].name, sizeof(pdata->leds[reg].name),
                         "%s", name);

                pdata->leds[reg].type = PCA955X_TYPE_LED;
                of_property_read_u32(child, "type", &pdata->leds[reg].type);
                of_property_read_string(child, "linux,default-trigger",
                                        &pdata->leds[reg].default_trigger);
        }

        pdata->num_leds = chip->bits;

        return pdata;
}

static const struct of_device_id of_pca955x_match[] = {
        { .compatible = "nxp,pca9550", .data = (void *)pca9550 },
        { .compatible = "nxp,pca9551", .data = (void *)pca9551 },
        { .compatible = "nxp,pca9552", .data = (void *)pca9552 },
        { .compatible = "nxp,pca9553", .data = (void *)pca9553 },
        {},
};

MODULE_DEVICE_TABLE(of, of_pca955x_match);
#else
static struct pca955x_platform_data *
pca955x_pdata_of_init(struct i2c_client *client, struct pca955x_chipdef *chip)
{
        return ERR_PTR(-ENODEV);
}
#endif

static int pca955x_probe(struct i2c_client *client,
                                        const struct i2c_device_id *id)
{
        struct pca955x *pca955x;
        struct pca955x_led *pca955x_led;
        struct pca955x_chipdef *chip;
        struct i2c_adapter *adapter;
        int i, err;
        struct pca955x_platform_data *pdata;
        int ngpios = 0;

        if (id) {
                chip = &pca955x_chipdefs[id->driver_data];
        } else {
                const struct acpi_device_id *acpi_id;

                acpi_id = acpi_match_device(pca955x_acpi_ids, &client->dev);
                if (!acpi_id)
                        return -ENODEV;
                chip = &pca955x_chipdefs[acpi_id->driver_data];
        }
        adapter = to_i2c_adapter(client->dev.parent);
        pdata = dev_get_platdata(&client->dev);
        if (!pdata) {
                pdata = pca955x_pdata_of_init(client, chip);
                if (IS_ERR(pdata))
                        return PTR_ERR(pdata);
        }

        /* Make sure the slave address / chip type combo given is possible */
        if ((client->addr & ~((1 << chip->slv_addr_shift) - 1)) !=
            chip->slv_addr) {
                dev_err(&client->dev, "invalid slave address %02x\n",
                                client->addr);
                return -ENODEV;
        }

        dev_info(&client->dev, "leds-pca955x: Using %s %d-bit LED driver at "
                        "slave address 0x%02x\n",
                        client->name, chip->bits, client->addr);

        if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA))
                return -EIO;

        if (pdata->num_leds != chip->bits) {
                dev_err(&client->dev,
                        "board info claims %d LEDs on a %d-bit chip\n",
                        pdata->num_leds, chip->bits);
                return -ENODEV;
        }

        pca955x = devm_kzalloc(&client->dev, sizeof(*pca955x), GFP_KERNEL);
        if (!pca955x)
                return -ENOMEM;

        pca955x->leds = devm_kzalloc(&client->dev,
                        sizeof(*pca955x_led) * chip->bits, GFP_KERNEL);
        if (!pca955x->leds)
                return -ENOMEM;

        i2c_set_clientdata(client, pca955x);

        mutex_init(&pca955x->lock);
        pca955x->client = client;
        pca955x->chipdef = chip;

        for (i = 0; i < chip->bits; i++) {
                pca955x_led = &pca955x->leds[i];
                pca955x_led->led_num = i;
                pca955x_led->pca955x = pca955x;
                pca955x_led->type = pdata->leds[i].type;

                switch (pca955x_led->type) {
                case PCA955X_TYPE_NONE:
                        break;
                case PCA955X_TYPE_GPIO:
                        ngpios++;
                        break;
                case PCA955X_TYPE_LED:
                        /*
                         * Platform data can specify LED names and
                         * default triggers
                         */
                        if (pdata->leds[i].name[0] == '\0')
                                snprintf(pdata->leds[i].name,
                                        sizeof(pdata->leds[i].name), "%d", i);

                        snprintf(pca955x_led->name,
                                sizeof(pca955x_led->name), "pca955x:%s",
                                pdata->leds[i].name);

                        if (pdata->leds[i].default_trigger)
                                pca955x_led->led_cdev.default_trigger =
                                        pdata->leds[i].default_trigger;

                        pca955x_led->led_cdev.name = pca955x_led->name;
                        pca955x_led->led_cdev.brightness_set_blocking =
                                pca955x_led_set;

                        err = devm_led_classdev_register(&client->dev,
                                                        &pca955x_led->led_cdev);
                        if (err)
                                return err;

                        /* Turn off LED */
                        err = pca955x_led_set(&pca955x_led->led_cdev, LED_OFF);
                        if (err)
                                return err;
                }
        }

        /* PWM0 is used for half brightness or 50% duty cycle */
        err = pca955x_write_pwm(client, 0, 255 - LED_HALF);
        if (err)
                return err;

        /* PWM1 is used for variable brightness, default to OFF */
        err = pca955x_write_pwm(client, 1, 0);
        if (err)
                return err;

        /* Set to fast frequency so we do not see flashing */
        err = pca955x_write_psc(client, 0, 0);
        if (err)
                return err;
        err = pca955x_write_psc(client, 1, 0);
        if (err)
                return err;

#ifdef CONFIG_LEDS_PCA955X_GPIO
        if (ngpios) {
                pca955x->gpio.label = "gpio-pca955x";
                pca955x->gpio.direction_input = pca955x_gpio_direction_input;
                pca955x->gpio.direction_output = pca955x_gpio_direction_output;
                pca955x->gpio.set = pca955x_gpio_set_value;
                pca955x->gpio.get = pca955x_gpio_get_value;
                pca955x->gpio.request = pca955x_gpio_request_pin;
                pca955x->gpio.can_sleep = 1;
                pca955x->gpio.base = -1;
                pca955x->gpio.ngpio = ngpios;
                pca955x->gpio.parent = &client->dev;
                pca955x->gpio.owner = THIS_MODULE;

                err = devm_gpiochip_add_data(&client->dev, &pca955x->gpio,
                                             pca955x);
                if (err) {
                        /* Use data->gpio.dev as a flag for freeing gpiochip */
                        pca955x->gpio.parent = NULL;
                        dev_warn(&client->dev, "could not add gpiochip\n");
                        return err;
                }
                dev_info(&client->dev, "gpios %i...%i\n",
                         pca955x->gpio.base, pca955x->gpio.base +
                         pca955x->gpio.ngpio - 1);
        }
#endif

        return 0;
}

static struct i2c_driver pca955x_driver = {
        .driver = {
                .name   = "leds-pca955x",
                .acpi_match_table = ACPI_PTR(pca955x_acpi_ids),
                .of_match_table = of_match_ptr(of_pca955x_match),
        },
        .probe  = pca955x_probe,
        .id_table = pca955x_id,
};

module_i2c_driver(pca955x_driver);

MODULE_AUTHOR("Nate Case <ncase@xes-inc.com>");
MODULE_DESCRIPTION("PCA955x LED driver");
MODULE_LICENSE("GPL v2");