233 строки
5.3 KiB
C
233 строки
5.3 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* Driver for BCM6358 memory-mapped LEDs, based on leds-syscon.c
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*
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* Copyright 2015 Álvaro Fernández Rojas <noltari@gmail.com>
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*/
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#include <linux/delay.h>
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#include <linux/io.h>
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#include <linux/leds.h>
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#include <linux/module.h>
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#include <linux/of.h>
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#include <linux/platform_device.h>
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#include <linux/spinlock.h>
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#define BCM6358_REG_MODE 0x0
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#define BCM6358_REG_CTRL 0x4
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#define BCM6358_SLED_CLKDIV_MASK 3
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#define BCM6358_SLED_CLKDIV_1 0
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#define BCM6358_SLED_CLKDIV_2 1
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#define BCM6358_SLED_CLKDIV_4 2
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#define BCM6358_SLED_CLKDIV_8 3
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#define BCM6358_SLED_POLARITY BIT(2)
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#define BCM6358_SLED_BUSY BIT(3)
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#define BCM6358_SLED_MAX_COUNT 32
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#define BCM6358_SLED_WAIT 100
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/**
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* struct bcm6358_led - state container for bcm6358 based LEDs
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* @cdev: LED class device for this LED
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* @mem: memory resource
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* @lock: memory lock
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* @pin: LED pin number
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* @active_low: LED is active low
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*/
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struct bcm6358_led {
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struct led_classdev cdev;
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void __iomem *mem;
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spinlock_t *lock;
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unsigned long pin;
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bool active_low;
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};
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static void bcm6358_led_write(void __iomem *reg, unsigned long data)
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{
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#ifdef CONFIG_CPU_BIG_ENDIAN
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iowrite32be(data, reg);
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#else
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writel(data, reg);
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#endif
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}
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static unsigned long bcm6358_led_read(void __iomem *reg)
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{
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#ifdef CONFIG_CPU_BIG_ENDIAN
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return ioread32be(reg);
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#else
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return readl(reg);
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#endif
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}
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static unsigned long bcm6358_led_busy(void __iomem *mem)
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{
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unsigned long val;
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while ((val = bcm6358_led_read(mem + BCM6358_REG_CTRL)) &
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BCM6358_SLED_BUSY)
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udelay(BCM6358_SLED_WAIT);
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return val;
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}
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static void bcm6358_led_set(struct led_classdev *led_cdev,
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enum led_brightness value)
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{
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struct bcm6358_led *led =
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container_of(led_cdev, struct bcm6358_led, cdev);
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unsigned long flags, val;
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spin_lock_irqsave(led->lock, flags);
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bcm6358_led_busy(led->mem);
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val = bcm6358_led_read(led->mem + BCM6358_REG_MODE);
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if ((led->active_low && value == LED_OFF) ||
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(!led->active_low && value != LED_OFF))
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val |= BIT(led->pin);
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else
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val &= ~(BIT(led->pin));
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bcm6358_led_write(led->mem + BCM6358_REG_MODE, val);
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spin_unlock_irqrestore(led->lock, flags);
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}
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static int bcm6358_led(struct device *dev, struct device_node *nc, u32 reg,
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void __iomem *mem, spinlock_t *lock)
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{
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struct bcm6358_led *led;
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const char *state;
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int rc;
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led = devm_kzalloc(dev, sizeof(*led), GFP_KERNEL);
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if (!led)
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return -ENOMEM;
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led->pin = reg;
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led->mem = mem;
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led->lock = lock;
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if (of_property_read_bool(nc, "active-low"))
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led->active_low = true;
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led->cdev.name = of_get_property(nc, "label", NULL) ? : nc->name;
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led->cdev.default_trigger = of_get_property(nc,
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"linux,default-trigger",
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NULL);
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if (!of_property_read_string(nc, "default-state", &state)) {
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if (!strcmp(state, "on")) {
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led->cdev.brightness = LED_FULL;
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} else if (!strcmp(state, "keep")) {
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unsigned long val;
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val = bcm6358_led_read(led->mem + BCM6358_REG_MODE);
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val &= BIT(led->pin);
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if ((led->active_low && !val) ||
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(!led->active_low && val))
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led->cdev.brightness = LED_FULL;
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else
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led->cdev.brightness = LED_OFF;
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} else {
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led->cdev.brightness = LED_OFF;
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}
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} else {
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led->cdev.brightness = LED_OFF;
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}
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bcm6358_led_set(&led->cdev, led->cdev.brightness);
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led->cdev.brightness_set = bcm6358_led_set;
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rc = devm_led_classdev_register(dev, &led->cdev);
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if (rc < 0)
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return rc;
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dev_dbg(dev, "registered LED %s\n", led->cdev.name);
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return 0;
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}
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static int bcm6358_leds_probe(struct platform_device *pdev)
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{
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struct device *dev = &pdev->dev;
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struct device_node *np = dev_of_node(&pdev->dev);
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struct device_node *child;
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void __iomem *mem;
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spinlock_t *lock; /* memory lock */
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unsigned long val;
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u32 clk_div;
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mem = devm_platform_ioremap_resource(pdev, 0);
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if (IS_ERR(mem))
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return PTR_ERR(mem);
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lock = devm_kzalloc(dev, sizeof(*lock), GFP_KERNEL);
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if (!lock)
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return -ENOMEM;
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spin_lock_init(lock);
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val = bcm6358_led_busy(mem);
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val &= ~(BCM6358_SLED_POLARITY | BCM6358_SLED_CLKDIV_MASK);
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if (of_property_read_bool(np, "brcm,clk-dat-low"))
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val |= BCM6358_SLED_POLARITY;
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of_property_read_u32(np, "brcm,clk-div", &clk_div);
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switch (clk_div) {
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case 8:
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val |= BCM6358_SLED_CLKDIV_8;
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break;
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case 4:
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val |= BCM6358_SLED_CLKDIV_4;
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break;
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case 2:
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val |= BCM6358_SLED_CLKDIV_2;
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break;
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default:
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val |= BCM6358_SLED_CLKDIV_1;
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break;
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}
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bcm6358_led_write(mem + BCM6358_REG_CTRL, val);
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for_each_available_child_of_node(np, child) {
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int rc;
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u32 reg;
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if (of_property_read_u32(child, "reg", ®))
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continue;
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if (reg >= BCM6358_SLED_MAX_COUNT) {
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dev_err(dev, "invalid LED (%u >= %d)\n", reg,
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BCM6358_SLED_MAX_COUNT);
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continue;
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}
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rc = bcm6358_led(dev, child, reg, mem, lock);
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if (rc < 0) {
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of_node_put(child);
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return rc;
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}
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}
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return 0;
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}
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static const struct of_device_id bcm6358_leds_of_match[] = {
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{ .compatible = "brcm,bcm6358-leds", },
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{ },
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};
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MODULE_DEVICE_TABLE(of, bcm6358_leds_of_match);
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static struct platform_driver bcm6358_leds_driver = {
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.probe = bcm6358_leds_probe,
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.driver = {
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.name = "leds-bcm6358",
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.of_match_table = bcm6358_leds_of_match,
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},
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};
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module_platform_driver(bcm6358_leds_driver);
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MODULE_AUTHOR("Álvaro Fernández Rojas <noltari@gmail.com>");
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MODULE_DESCRIPTION("LED driver for BCM6358 controllers");
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MODULE_LICENSE("GPL v2");
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MODULE_ALIAS("platform:leds-bcm6358");
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