// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * leds-netxbig.c - Driver for the 2Big and 5Big Network series LEDs
 *
 * Copyright (C) 2010 LaCie
 *
 * Author: Simon Guinot <sguinot@lacie.com>
 */

#include <linux/module.h>
#include <linux/irq.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/platform_device.h>
#include <linux/gpio/consumer.h>
#include <linux/leds.h>
#include <linux/of.h>
#include <linux/of_platform.h>

struct netxbig_gpio_ext {
        struct gpio_desc **addr;
        int             num_addr;
        struct gpio_desc **data;
        int             num_data;
        struct gpio_desc *enable;
};

enum netxbig_led_mode {
        NETXBIG_LED_OFF,
        NETXBIG_LED_ON,
        NETXBIG_LED_SATA,
        NETXBIG_LED_TIMER1,
        NETXBIG_LED_TIMER2,
        NETXBIG_LED_MODE_NUM,
};

#define NETXBIG_LED_INVALID_MODE NETXBIG_LED_MODE_NUM

struct netxbig_led_timer {
        unsigned long           delay_on;
        unsigned long           delay_off;
        enum netxbig_led_mode   mode;
};

struct netxbig_led {
        const char      *name;
        const char      *default_trigger;
        int             mode_addr;
        int             *mode_val;
        int             bright_addr;
        int             bright_max;
};

struct netxbig_led_platform_data {
        struct netxbig_gpio_ext *gpio_ext;
        struct netxbig_led_timer *timer;
        int                     num_timer;
        struct netxbig_led      *leds;
        int                     num_leds;
};

/*
 * GPIO extension bus.
 */

static DEFINE_SPINLOCK(gpio_ext_lock);

static void gpio_ext_set_addr(struct netxbig_gpio_ext *gpio_ext, int addr)
{
        int pin;

        for (pin = 0; pin < gpio_ext->num_addr; pin++)
                gpiod_set_value(gpio_ext->addr[pin], (addr >> pin) & 1);
}

static void gpio_ext_set_data(struct netxbig_gpio_ext *gpio_ext, int data)
{
        int pin;

        for (pin = 0; pin < gpio_ext->num_data; pin++)
                gpiod_set_value(gpio_ext->data[pin], (data >> pin) & 1);
}

static void gpio_ext_enable_select(struct netxbig_gpio_ext *gpio_ext)
{
        /* Enable select is done on the raising edge. */
        gpiod_set_value(gpio_ext->enable, 0);
        gpiod_set_value(gpio_ext->enable, 1);
}

static void gpio_ext_set_value(struct netxbig_gpio_ext *gpio_ext,
                               int addr, int value)
{
        unsigned long flags;

        spin_lock_irqsave(&gpio_ext_lock, flags);
        gpio_ext_set_addr(gpio_ext, addr);
        gpio_ext_set_data(gpio_ext, value);
        gpio_ext_enable_select(gpio_ext);
        spin_unlock_irqrestore(&gpio_ext_lock, flags);
}

/*
 * Class LED driver.
 */

struct netxbig_led_data {
        struct netxbig_gpio_ext *gpio_ext;
        struct led_classdev     cdev;
        int                     mode_addr;
        int                     *mode_val;
        int                     bright_addr;
        struct                  netxbig_led_timer *timer;
        int                     num_timer;
        enum netxbig_led_mode   mode;
        int                     sata;
        spinlock_t              lock;
};

static int netxbig_led_get_timer_mode(enum netxbig_led_mode *mode,
                                      unsigned long delay_on,
                                      unsigned long delay_off,
                                      struct netxbig_led_timer *timer,
                                      int num_timer)
{
        int i;

        for (i = 0; i < num_timer; i++) {
                if (timer[i].delay_on == delay_on &&
                    timer[i].delay_off == delay_off) {
                        *mode = timer[i].mode;
                        return 0;
                }
        }
        return -EINVAL;
}

static int netxbig_led_blink_set(struct led_classdev *led_cdev,
                                 unsigned long *delay_on,
                                 unsigned long *delay_off)
{
        struct netxbig_led_data *led_dat =
                container_of(led_cdev, struct netxbig_led_data, cdev);
        enum netxbig_led_mode mode;
        int mode_val;
        int ret;

        /* Look for a LED mode with the requested timer frequency. */
        ret = netxbig_led_get_timer_mode(&mode, *delay_on, *delay_off,
                                         led_dat->timer, led_dat->num_timer);
        if (ret < 0)
                return ret;

        mode_val = led_dat->mode_val[mode];
        if (mode_val == NETXBIG_LED_INVALID_MODE)
                return -EINVAL;

        spin_lock_irq(&led_dat->lock);

        gpio_ext_set_value(led_dat->gpio_ext, led_dat->mode_addr, mode_val);
        led_dat->mode = mode;

        spin_unlock_irq(&led_dat->lock);

        return 0;
}

static void netxbig_led_set(struct led_classdev *led_cdev,
                            enum led_brightness value)
{
        struct netxbig_led_data *led_dat =
                container_of(led_cdev, struct netxbig_led_data, cdev);
        enum netxbig_led_mode mode;
        int mode_val;
        int set_brightness = 1;
        unsigned long flags;

        spin_lock_irqsave(&led_dat->lock, flags);

        if (value == LED_OFF) {
                mode = NETXBIG_LED_OFF;
                set_brightness = 0;
        } else {
                if (led_dat->sata)
                        mode = NETXBIG_LED_SATA;
                else if (led_dat->mode == NETXBIG_LED_OFF)
                        mode = NETXBIG_LED_ON;
                else /* Keep 'timer' mode. */
                        mode = led_dat->mode;
        }
        mode_val = led_dat->mode_val[mode];

        gpio_ext_set_value(led_dat->gpio_ext, led_dat->mode_addr, mode_val);
        led_dat->mode = mode;
        /*
         * Note that the brightness register is shared between all the
         * SATA LEDs. So, change the brightness setting for a single
         * SATA LED will affect all the others.
         */
        if (set_brightness)
                gpio_ext_set_value(led_dat->gpio_ext,
                                   led_dat->bright_addr, value);

        spin_unlock_irqrestore(&led_dat->lock, flags);
}

static ssize_t sata_store(struct device *dev,
                          struct device_attribute *attr,
                          const char *buff, size_t count)
{
        struct led_classdev *led_cdev = dev_get_drvdata(dev);
        struct netxbig_led_data *led_dat =
                container_of(led_cdev, struct netxbig_led_data, cdev);
        unsigned long enable;
        enum netxbig_led_mode mode;
        int mode_val;
        int ret;

        ret = kstrtoul(buff, 10, &enable);
        if (ret < 0)
                return ret;

        enable = !!enable;

        spin_lock_irq(&led_dat->lock);

        if (led_dat->sata == enable) {
                ret = count;
                goto exit_unlock;
        }

        if (led_dat->mode != NETXBIG_LED_ON &&
            led_dat->mode != NETXBIG_LED_SATA)
                mode = led_dat->mode; /* Keep modes 'off' and 'timer'. */
        else if (enable)
                mode = NETXBIG_LED_SATA;
        else
                mode = NETXBIG_LED_ON;

        mode_val = led_dat->mode_val[mode];
        if (mode_val == NETXBIG_LED_INVALID_MODE) {
                ret = -EINVAL;
                goto exit_unlock;
        }

        gpio_ext_set_value(led_dat->gpio_ext, led_dat->mode_addr, mode_val);
        led_dat->mode = mode;
        led_dat->sata = enable;

        ret = count;

exit_unlock:
        spin_unlock_irq(&led_dat->lock);

        return ret;
}

static ssize_t sata_show(struct device *dev,
                         struct device_attribute *attr, char *buf)
{
        struct led_classdev *led_cdev = dev_get_drvdata(dev);
        struct netxbig_led_data *led_dat =
                container_of(led_cdev, struct netxbig_led_data, cdev);

        return sprintf(buf, "%d\n", led_dat->sata);
}

static DEVICE_ATTR_RW(sata);

static struct attribute *netxbig_led_attrs[] = {
        &dev_attr_sata.attr,
        NULL
};
ATTRIBUTE_GROUPS(netxbig_led);

static int create_netxbig_led(struct platform_device *pdev,
                              struct netxbig_led_platform_data *pdata,
                              struct netxbig_led_data *led_dat,
                              const struct netxbig_led *template)
{
        spin_lock_init(&led_dat->lock);
        led_dat->gpio_ext = pdata->gpio_ext;
        led_dat->cdev.name = template->name;
        led_dat->cdev.default_trigger = template->default_trigger;
        led_dat->cdev.blink_set = netxbig_led_blink_set;
        led_dat->cdev.brightness_set = netxbig_led_set;
        /*
         * Because the GPIO extension bus don't allow to read registers
         * value, there is no way to probe the LED initial state.
         * So, the initial sysfs LED value for the "brightness" and "sata"
         * attributes are inconsistent.
         *
         * Note that the initial LED state can't be reconfigured.
         * The reason is that the LED behaviour must stay uniform during
         * the whole boot process (bootloader+linux).
         */
        led_dat->sata = 0;
        led_dat->cdev.brightness = LED_OFF;
        led_dat->cdev.max_brightness = template->bright_max;
        led_dat->cdev.flags |= LED_CORE_SUSPENDRESUME;
        led_dat->mode_addr = template->mode_addr;
        led_dat->mode_val = template->mode_val;
        led_dat->bright_addr = template->bright_addr;
        led_dat->timer = pdata->timer;
        led_dat->num_timer = pdata->num_timer;
        /*
         * If available, expose the SATA activity blink capability through
         * a "sata" sysfs attribute.
         */
        if (led_dat->mode_val[NETXBIG_LED_SATA] != NETXBIG_LED_INVALID_MODE)
                led_dat->cdev.groups = netxbig_led_groups;

        return devm_led_classdev_register(&pdev->dev, &led_dat->cdev);
}

/**
 * netxbig_gpio_ext_remove() - Clean up GPIO extension data
 * @data: managed resource data to clean up
 *
 * Since we pick GPIO descriptors from another device than the device our
 * driver is probing to, we need to register a specific callback to free
 * these up using managed resources.
 */
static void netxbig_gpio_ext_remove(void *data)
{
        struct netxbig_gpio_ext *gpio_ext = data;
        int i;

        for (i = 0; i < gpio_ext->num_addr; i++)
                gpiod_put(gpio_ext->addr[i]);
        for (i = 0; i < gpio_ext->num_data; i++)
                gpiod_put(gpio_ext->data[i]);
        gpiod_put(gpio_ext->enable);
}

/**
 * netxbig_gpio_ext_get() - Obtain GPIO extension device data
 * @dev: main LED device
 * @gpio_ext_dev: the GPIO extension device
 * @gpio_ext: the data structure holding the GPIO extension data
 *
 * This function walks the subdevice that only contain GPIO line
 * handles in the device tree and obtains the GPIO descriptors from that
 * device.
 */
static int netxbig_gpio_ext_get(struct device *dev,
                                struct device *gpio_ext_dev,
                                struct netxbig_gpio_ext *gpio_ext)
{
        struct gpio_desc **addr, **data;
        int num_addr, num_data;
        struct gpio_desc *gpiod;
        int ret;
        int i;

        ret = gpiod_count(gpio_ext_dev, "addr");
        if (ret < 0) {
                dev_err(dev,
                        "Failed to count GPIOs in DT property addr-gpios\n");
                return ret;
        }
        num_addr = ret;
        addr = devm_kcalloc(dev, num_addr, sizeof(*addr), GFP_KERNEL);
        if (!addr)
                return -ENOMEM;

        /*
         * We cannot use devm_ managed resources with these GPIO descriptors
         * since they are associated with the "GPIO extension device" which
         * does not probe any driver. The device tree parser will however
         * populate a platform device for it so we can anyway obtain the
         * GPIO descriptors from the device.
         */
        for (i = 0; i < num_addr; i++) {
                gpiod = gpiod_get_index(gpio_ext_dev, "addr", i,
                                        GPIOD_OUT_LOW);
                if (IS_ERR(gpiod))
                        return PTR_ERR(gpiod);
                gpiod_set_consumer_name(gpiod, "GPIO extension addr");
                addr[i] = gpiod;
        }
        gpio_ext->addr = addr;
        gpio_ext->num_addr = num_addr;

        ret = gpiod_count(gpio_ext_dev, "data");
        if (ret < 0) {
                dev_err(dev,
                        "Failed to count GPIOs in DT property data-gpios\n");
                return ret;
        }
        num_data = ret;
        data = devm_kcalloc(dev, num_data, sizeof(*data), GFP_KERNEL);
        if (!data)
                return -ENOMEM;

        for (i = 0; i < num_data; i++) {
                gpiod = gpiod_get_index(gpio_ext_dev, "data", i,
                                        GPIOD_OUT_LOW);
                if (IS_ERR(gpiod))
                        return PTR_ERR(gpiod);
                gpiod_set_consumer_name(gpiod, "GPIO extension data");
                data[i] = gpiod;
        }
        gpio_ext->data = data;
        gpio_ext->num_data = num_data;

        gpiod = gpiod_get(gpio_ext_dev, "enable", GPIOD_OUT_LOW);
        if (IS_ERR(gpiod)) {
                dev_err(dev,
                        "Failed to get GPIO from DT property enable-gpio\n");
                return PTR_ERR(gpiod);
        }
        gpiod_set_consumer_name(gpiod, "GPIO extension enable");
        gpio_ext->enable = gpiod;

        return devm_add_action_or_reset(dev, netxbig_gpio_ext_remove, gpio_ext);
}

static int netxbig_leds_get_of_pdata(struct device *dev,
                                     struct netxbig_led_platform_data *pdata)
{
        struct device_node *np = dev_of_node(dev);
        struct device_node *gpio_ext_np;
        struct platform_device *gpio_ext_pdev;
        struct device *gpio_ext_dev;
        struct device_node *child;
        struct netxbig_gpio_ext *gpio_ext;
        struct netxbig_led_timer *timers;
        struct netxbig_led *leds, *led;
        int num_timers;
        int num_leds = 0;
        int ret;
        int i;

        /* GPIO extension */
        gpio_ext_np = of_parse_phandle(np, "gpio-ext", 0);
        if (!gpio_ext_np) {
                dev_err(dev, "Failed to get DT handle gpio-ext\n");
                return -EINVAL;
        }
        gpio_ext_pdev = of_find_device_by_node(gpio_ext_np);
        if (!gpio_ext_pdev) {
                dev_err(dev, "Failed to find platform device for gpio-ext\n");
                return -ENODEV;
        }
        gpio_ext_dev = &gpio_ext_pdev->dev;

        gpio_ext = devm_kzalloc(dev, sizeof(*gpio_ext), GFP_KERNEL);
        if (!gpio_ext) {
                of_node_put(gpio_ext_np);
                ret = -ENOMEM;
                goto put_device;
        }
        ret = netxbig_gpio_ext_get(dev, gpio_ext_dev, gpio_ext);
        of_node_put(gpio_ext_np);
        if (ret)
                goto put_device;
        pdata->gpio_ext = gpio_ext;

        /* Timers (optional) */
        ret = of_property_count_u32_elems(np, "timers");
        if (ret > 0) {
                if (ret % 3) {
                        ret = -EINVAL;
                        goto put_device;
                }

                num_timers = ret / 3;
                timers = devm_kcalloc(dev, num_timers, sizeof(*timers),
                                      GFP_KERNEL);
                if (!timers) {
                        ret = -ENOMEM;
                        goto put_device;
                }
                for (i = 0; i < num_timers; i++) {
                        u32 tmp;

                        of_property_read_u32_index(np, "timers", 3 * i,
                                                   &timers[i].mode);
                        if (timers[i].mode >= NETXBIG_LED_MODE_NUM) {
                                ret = -EINVAL;
                                goto put_device;
                        }
                        of_property_read_u32_index(np, "timers",
                                                   3 * i + 1, &tmp);
                        timers[i].delay_on = tmp;
                        of_property_read_u32_index(np, "timers",
                                                   3 * i + 2, &tmp);
                        timers[i].delay_off = tmp;
                }
                pdata->timer = timers;
                pdata->num_timer = num_timers;
        }

        /* LEDs */
        num_leds = of_get_available_child_count(np);
        if (!num_leds) {
                dev_err(dev, "No LED subnodes found in DT\n");
                ret = -ENODEV;
                goto put_device;
        }

        leds = devm_kcalloc(dev, num_leds, sizeof(*leds), GFP_KERNEL);
        if (!leds) {
                ret = -ENOMEM;
                goto put_device;
        }

        led = leds;
        for_each_available_child_of_node(np, child) {
                const char *string;
                int *mode_val;
                int num_modes;

                ret = of_property_read_u32(child, "mode-addr",
                                           &led->mode_addr);
                if (ret)
                        goto err_node_put;

                ret = of_property_read_u32(child, "bright-addr",
                                           &led->bright_addr);
                if (ret)
                        goto err_node_put;

                ret = of_property_read_u32(child, "max-brightness",
                                           &led->bright_max);
                if (ret)
                        goto err_node_put;

                mode_val =
                        devm_kcalloc(dev,
                                     NETXBIG_LED_MODE_NUM, sizeof(*mode_val),
                                     GFP_KERNEL);
                if (!mode_val) {
                        ret = -ENOMEM;
                        goto err_node_put;
                }

                for (i = 0; i < NETXBIG_LED_MODE_NUM; i++)
                        mode_val[i] = NETXBIG_LED_INVALID_MODE;

                ret = of_property_count_u32_elems(child, "mode-val");
                if (ret < 0 || ret % 2) {
                        ret = -EINVAL;
                        goto err_node_put;
                }
                num_modes = ret / 2;
                if (num_modes > NETXBIG_LED_MODE_NUM) {
                        ret = -EINVAL;
                        goto err_node_put;
                }

                for (i = 0; i < num_modes; i++) {
                        int mode;
                        int val;

                        of_property_read_u32_index(child,
                                                   "mode-val", 2 * i, &mode);
                        of_property_read_u32_index(child,
                                                   "mode-val", 2 * i + 1, &val);
                        if (mode >= NETXBIG_LED_MODE_NUM) {
                                ret = -EINVAL;
                                goto err_node_put;
                        }
                        mode_val[mode] = val;
                }
                led->mode_val = mode_val;

                if (!of_property_read_string(child, "label", &string))
                        led->name = string;
                else
                        led->name = child->name;

                if (!of_property_read_string(child,
                                             "linux,default-trigger", &string))
                        led->default_trigger = string;

                led++;
        }

        pdata->leds = leds;
        pdata->num_leds = num_leds;

        return 0;

err_node_put:
        of_node_put(child);
put_device:
        put_device(gpio_ext_dev);
        return ret;
}

static const struct of_device_id of_netxbig_leds_match[] = {
        { .compatible = "lacie,netxbig-leds", },
        {},
};
MODULE_DEVICE_TABLE(of, of_netxbig_leds_match);

static int netxbig_led_probe(struct platform_device *pdev)
{
        struct netxbig_led_platform_data *pdata;
        struct netxbig_led_data *leds_data;
        int i;
        int ret;

        pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);
        if (!pdata)
                return -ENOMEM;
        ret = netxbig_leds_get_of_pdata(&pdev->dev, pdata);
        if (ret)
                return ret;

        leds_data = devm_kcalloc(&pdev->dev,
                                 pdata->num_leds, sizeof(*leds_data),
                                 GFP_KERNEL);
        if (!leds_data)
                return -ENOMEM;

        for (i = 0; i < pdata->num_leds; i++) {
                ret = create_netxbig_led(pdev, pdata,
                                         &leds_data[i], &pdata->leds[i]);
                if (ret < 0)
                        return ret;
        }

        return 0;
}

static struct platform_driver netxbig_led_driver = {
        .probe          = netxbig_led_probe,
        .driver         = {
                .name           = "leds-netxbig",
                .of_match_table = of_netxbig_leds_match,
        },
};

module_platform_driver(netxbig_led_driver);

MODULE_AUTHOR("Simon Guinot <sguinot@lacie.com>");
MODULE_DESCRIPTION("LED driver for LaCie xBig Network boards");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:leds-netxbig");