// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * leds-ns2.c - Driver for the Network Space v2 (and parents) dual-GPIO LED
 *
 * Copyright (C) 2010 LaCie
 *
 * Author: Simon Guinot <sguinot@lacie.com>
 *
 * Based on leds-gpio.c by Raphael Assenat <raph@8d.com>
 */

#include <linux/kernel.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
#include <linux/gpio/consumer.h>
#include <linux/leds.h>
#include <linux/module.h>
#include <linux/of.h>
#include "leds.h"

enum ns2_led_modes {
        NS_V2_LED_OFF,
        NS_V2_LED_ON,
        NS_V2_LED_SATA,
};

/*
 * If the size of this structure or types of its members is changed,
 * the filling of array modval in function ns2_led_register must be changed
 * accordingly.
 */
struct ns2_led_modval {
        u32                     mode;
        u32                     cmd_level;
        u32                     slow_level;
} __packed;

/*
 * The Network Space v2 dual-GPIO LED is wired to a CPLD. Three different LED
 * modes are available: off, on and SATA activity blinking. The LED modes are
 * controlled through two GPIOs (command and slow): each combination of values
 * for the command/slow GPIOs corresponds to a LED mode.
 */

struct ns2_led {
        struct led_classdev     cdev;
        struct gpio_desc        *cmd;
        struct gpio_desc        *slow;
        bool                    can_sleep;
        unsigned char           sata; /* True when SATA mode active. */
        rwlock_t                rw_lock; /* Lock GPIOs. */
        int                     num_modes;
        struct ns2_led_modval   *modval;
};

static int ns2_led_get_mode(struct ns2_led *led, enum ns2_led_modes *mode)
{
        int i;
        int cmd_level;
        int slow_level;

        cmd_level = gpiod_get_value_cansleep(led->cmd);
        slow_level = gpiod_get_value_cansleep(led->slow);

        for (i = 0; i < led->num_modes; i++) {
                if (cmd_level == led->modval[i].cmd_level &&
                    slow_level == led->modval[i].slow_level) {
                        *mode = led->modval[i].mode;
                        return 0;
                }
        }

        return -EINVAL;
}

static void ns2_led_set_mode(struct ns2_led *led, enum ns2_led_modes mode)
{
        int i;
        unsigned long flags;

        for (i = 0; i < led->num_modes; i++)
                if (mode == led->modval[i].mode)
                        break;

        if (i == led->num_modes)
                return;

        write_lock_irqsave(&led->rw_lock, flags);

        if (!led->can_sleep) {
                gpiod_set_value(led->cmd, led->modval[i].cmd_level);
                gpiod_set_value(led->slow, led->modval[i].slow_level);
                goto exit_unlock;
        }

        gpiod_set_value_cansleep(led->cmd, led->modval[i].cmd_level);
        gpiod_set_value_cansleep(led->slow, led->modval[i].slow_level);

exit_unlock:
        write_unlock_irqrestore(&led->rw_lock, flags);
}

static void ns2_led_set(struct led_classdev *led_cdev,
                        enum led_brightness value)
{
        struct ns2_led *led = container_of(led_cdev, struct ns2_led, cdev);
        enum ns2_led_modes mode;

        if (value == LED_OFF)
                mode = NS_V2_LED_OFF;
        else if (led->sata)
                mode = NS_V2_LED_SATA;
        else
                mode = NS_V2_LED_ON;

        ns2_led_set_mode(led, mode);
}

static int ns2_led_set_blocking(struct led_classdev *led_cdev,
                        enum led_brightness value)
{
        ns2_led_set(led_cdev, value);
        return 0;
}

static ssize_t ns2_led_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 ns2_led *led = container_of(led_cdev, struct ns2_led, cdev);
        int ret;
        unsigned long enable;

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

        enable = !!enable;

        if (led->sata == enable)
                goto exit;

        led->sata = enable;

        if (!led_get_brightness(led_cdev))
                goto exit;

        if (enable)
                ns2_led_set_mode(led, NS_V2_LED_SATA);
        else
                ns2_led_set_mode(led, NS_V2_LED_ON);

exit:
        return count;
}

static ssize_t ns2_led_sata_show(struct device *dev,
                                 struct device_attribute *attr, char *buf)
{
        struct led_classdev *led_cdev = dev_get_drvdata(dev);
        struct ns2_led *led = container_of(led_cdev, struct ns2_led, cdev);

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

static DEVICE_ATTR(sata, 0644, ns2_led_sata_show, ns2_led_sata_store);

static struct attribute *ns2_led_attrs[] = {
        &dev_attr_sata.attr,
        NULL
};
ATTRIBUTE_GROUPS(ns2_led);

static int ns2_led_register(struct device *dev, struct fwnode_handle *node,
                            struct ns2_led *led)
{
        struct led_init_data init_data = {};
        struct ns2_led_modval *modval;
        enum ns2_led_modes mode;
        int nmodes, ret;

        led->cmd = devm_fwnode_gpiod_get_index(dev, node, "cmd", 0, GPIOD_ASIS,
                                               fwnode_get_name(node));
        if (IS_ERR(led->cmd))
                return PTR_ERR(led->cmd);

        led->slow = devm_fwnode_gpiod_get_index(dev, node, "slow", 0,
                                                GPIOD_ASIS,
                                                fwnode_get_name(node));
        if (IS_ERR(led->slow))
                return PTR_ERR(led->slow);

        ret = fwnode_property_count_u32(node, "modes-map");
        if (ret < 0 || ret % 3) {
                dev_err(dev, "Missing or malformed modes-map for %pfw\n", node);
                return -EINVAL;
        }

        nmodes = ret / 3;
        modval = devm_kcalloc(dev, nmodes, sizeof(*modval), GFP_KERNEL);
        if (!modval)
                return -ENOMEM;

        fwnode_property_read_u32_array(node, "modes-map", (void *)modval,
                                       nmodes * 3);

        rwlock_init(&led->rw_lock);

        led->cdev.blink_set = NULL;
        led->cdev.flags |= LED_CORE_SUSPENDRESUME;
        led->cdev.groups = ns2_led_groups;
        led->can_sleep = gpiod_cansleep(led->cmd) || gpiod_cansleep(led->slow);
        if (led->can_sleep)
                led->cdev.brightness_set_blocking = ns2_led_set_blocking;
        else
                led->cdev.brightness_set = ns2_led_set;
        led->num_modes = nmodes;
        led->modval = modval;

        ret = ns2_led_get_mode(led, &mode);
        if (ret < 0)
                return ret;

        /* Set LED initial state. */
        led->sata = (mode == NS_V2_LED_SATA) ? 1 : 0;
        led->cdev.brightness = (mode == NS_V2_LED_OFF) ? LED_OFF : LED_FULL;

        init_data.fwnode = node;

        ret = devm_led_classdev_register_ext(dev, &led->cdev, &init_data);
        if (ret)
                dev_err(dev, "Failed to register LED for node %pfw\n", node);

        return ret;
}

static int ns2_led_probe(struct platform_device *pdev)
{
        struct device *dev = &pdev->dev;
        struct ns2_led *leds;
        int count;
        int ret;

        count = device_get_child_node_count(dev);
        if (!count)
                return -ENODEV;

        leds = devm_kcalloc(dev, count, sizeof(*leds), GFP_KERNEL);
        if (!leds)
                return -ENOMEM;

        device_for_each_child_node_scoped(dev, child) {
                ret = ns2_led_register(dev, child, leds++);
                if (ret)
                        return ret;
        }

        return 0;
}

static const struct of_device_id of_ns2_leds_match[] = {
        { .compatible = "lacie,ns2-leds", },
        {},
};
MODULE_DEVICE_TABLE(of, of_ns2_leds_match);

static struct platform_driver ns2_led_driver = {
        .probe          = ns2_led_probe,
        .driver         = {
                .name           = "leds-ns2",
                .of_match_table = of_ns2_leds_match,
        },
};

module_platform_driver(ns2_led_driver);

MODULE_AUTHOR("Simon Guinot <sguinot@lacie.com>");
MODULE_DESCRIPTION("Network Space v2 LED driver");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:leds-ns2");