// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Driver for BCM6358 memory-mapped LEDs, based on leds-syscon.c
 *
 * Copyright 2015 Álvaro Fernández Rojas <noltari@gmail.com>
 */
#include <linux/delay.h>
#include <linux/io.h>
#include <linux/leds.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/spinlock.h>

#define BCM6358_REG_MODE                0x0
#define BCM6358_REG_CTRL                0x4

#define BCM6358_SLED_CLKDIV_MASK        3
#define BCM6358_SLED_CLKDIV_1           0
#define BCM6358_SLED_CLKDIV_2           1
#define BCM6358_SLED_CLKDIV_4           2
#define BCM6358_SLED_CLKDIV_8           3

#define BCM6358_SLED_POLARITY           BIT(2)
#define BCM6358_SLED_BUSY               BIT(3)

#define BCM6358_SLED_MAX_COUNT          32
#define BCM6358_SLED_WAIT               100

/**
 * struct bcm6358_led - state container for bcm6358 based LEDs
 * @cdev: LED class device for this LED
 * @mem: memory resource
 * @lock: memory lock
 * @pin: LED pin number
 * @active_low: LED is active low
 */
struct bcm6358_led {
        struct led_classdev cdev;
        void __iomem *mem;
        spinlock_t *lock;
        unsigned long pin;
        bool active_low;
};

static void bcm6358_led_write(void __iomem *reg, unsigned long data)
{
#ifdef CONFIG_CPU_BIG_ENDIAN
        iowrite32be(data, reg);
#else
        writel(data, reg);
#endif
}

static unsigned long bcm6358_led_read(void __iomem *reg)
{
#ifdef CONFIG_CPU_BIG_ENDIAN
        return ioread32be(reg);
#else
        return readl(reg);
#endif
}

static unsigned long bcm6358_led_busy(void __iomem *mem)
{
        unsigned long val;

        while ((val = bcm6358_led_read(mem + BCM6358_REG_CTRL)) &
                BCM6358_SLED_BUSY)
                udelay(BCM6358_SLED_WAIT);

        return val;
}

static void bcm6358_led_set(struct led_classdev *led_cdev,
                            enum led_brightness value)
{
        struct bcm6358_led *led =
                container_of(led_cdev, struct bcm6358_led, cdev);
        unsigned long flags, val;

        spin_lock_irqsave(led->lock, flags);
        bcm6358_led_busy(led->mem);
        val = bcm6358_led_read(led->mem + BCM6358_REG_MODE);
        if ((led->active_low && value == LED_OFF) ||
            (!led->active_low && value != LED_OFF))
                val |= BIT(led->pin);
        else
                val &= ~(BIT(led->pin));
        bcm6358_led_write(led->mem + BCM6358_REG_MODE, val);
        spin_unlock_irqrestore(led->lock, flags);
}

static int bcm6358_led(struct device *dev, struct device_node *nc, u32 reg,
                       void __iomem *mem, spinlock_t *lock)
{
        struct led_init_data init_data = {};
        struct bcm6358_led *led;
        enum led_default_state state;
        unsigned long val;
        int rc;

        led = devm_kzalloc(dev, sizeof(*led), GFP_KERNEL);
        if (!led)
                return -ENOMEM;

        led->pin = reg;
        led->mem = mem;
        led->lock = lock;

        if (of_property_read_bool(nc, "active-low"))
                led->active_low = true;

        init_data.fwnode = of_fwnode_handle(nc);

        state = led_init_default_state_get(init_data.fwnode);
        switch (state) {
        case LEDS_DEFSTATE_ON:
                led->cdev.brightness = LED_FULL;
                break;
        case LEDS_DEFSTATE_KEEP:
                val = bcm6358_led_read(led->mem + BCM6358_REG_MODE);
                val &= BIT(led->pin);
                if ((led->active_low && !val) || (!led->active_low && val))
                        led->cdev.brightness = LED_FULL;
                else
                        led->cdev.brightness = LED_OFF;
                break;
        default:
                led->cdev.brightness = LED_OFF;
        }

        bcm6358_led_set(&led->cdev, led->cdev.brightness);

        led->cdev.brightness_set = bcm6358_led_set;

        rc = devm_led_classdev_register_ext(dev, &led->cdev, &init_data);
        if (rc < 0)
                return rc;

        dev_dbg(dev, "registered LED %s\n", led->cdev.name);

        return 0;
}

static int bcm6358_leds_probe(struct platform_device *pdev)
{
        struct device *dev = &pdev->dev;
        struct device_node *np = dev_of_node(&pdev->dev);
        void __iomem *mem;
        spinlock_t *lock; /* memory lock */
        unsigned long val;
        u32 clk_div;

        mem = devm_platform_ioremap_resource(pdev, 0);
        if (IS_ERR(mem))
                return PTR_ERR(mem);

        lock = devm_kzalloc(dev, sizeof(*lock), GFP_KERNEL);
        if (!lock)
                return -ENOMEM;

        spin_lock_init(lock);

        val = bcm6358_led_busy(mem);
        val &= ~(BCM6358_SLED_POLARITY | BCM6358_SLED_CLKDIV_MASK);
        if (of_property_read_bool(np, "brcm,clk-dat-low"))
                val |= BCM6358_SLED_POLARITY;
        of_property_read_u32(np, "brcm,clk-div", &clk_div);
        switch (clk_div) {
        case 8:
                val |= BCM6358_SLED_CLKDIV_8;
                break;
        case 4:
                val |= BCM6358_SLED_CLKDIV_4;
                break;
        case 2:
                val |= BCM6358_SLED_CLKDIV_2;
                break;
        default:
                val |= BCM6358_SLED_CLKDIV_1;
                break;
        }
        bcm6358_led_write(mem + BCM6358_REG_CTRL, val);

        for_each_available_child_of_node_scoped(np, child) {
                int rc;
                u32 reg;

                if (of_property_read_u32(child, "reg", &reg))
                        continue;

                if (reg >= BCM6358_SLED_MAX_COUNT) {
                        dev_err(dev, "invalid LED (%u >= %d)\n", reg,
                                BCM6358_SLED_MAX_COUNT);
                        continue;
                }

                rc = bcm6358_led(dev, child, reg, mem, lock);
                if (rc < 0)
                        return rc;
        }

        return 0;
}

static const struct of_device_id bcm6358_leds_of_match[] = {
        { .compatible = "brcm,bcm6358-leds", },
        { },
};
MODULE_DEVICE_TABLE(of, bcm6358_leds_of_match);

static struct platform_driver bcm6358_leds_driver = {
        .probe = bcm6358_leds_probe,
        .driver = {
                .name = "leds-bcm6358",
                .of_match_table = bcm6358_leds_of_match,
        },
};

module_platform_driver(bcm6358_leds_driver);

MODULE_AUTHOR("Álvaro Fernández Rojas <noltari@gmail.com>");
MODULE_DESCRIPTION("LED driver for BCM6358 controllers");
MODULE_LICENSE("GPL v2");
MODULE_ALIAS("platform:leds-bcm6358");