/* * Driver for BCM6358 memory-mapped LEDs, based on leds-syscon.c * * Copyright 2015 Álvaro Fernández Rojas <noltari@gmail.com> * * This program is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License as published by the * Free Software Foundation; either version 2 of the License, or (at your * option) any later version. */ #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 bcm6358_led *led; const char *state; 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; led->cdev.name = of_get_property(nc, "label", NULL) ? : nc->name; led->cdev.default_trigger = of_get_property(nc, "linux,default-trigger", NULL); if (!of_property_read_string(nc, "default-state", &state)) { if (!strcmp(state, "on")) { led->cdev.brightness = LED_FULL; } else if (!strcmp(state, "keep")) { unsigned long val; 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; } else { led->cdev.brightness = LED_OFF; } } else { led->cdev.brightness = LED_OFF; } bcm6358_led_set(&led->cdev, led->cdev.brightness); led->cdev.brightness_set = bcm6358_led_set; rc = led_classdev_register(dev, &led->cdev); 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 = pdev->dev.of_node; struct device_node *child; struct resource *mem_r; void __iomem *mem; spinlock_t *lock; /* memory lock */ unsigned long val; u32 clk_div; mem_r = platform_get_resource(pdev, IORESOURCE_MEM, 0); if (!mem_r) return -EINVAL; mem = devm_ioremap_resource(dev, mem_r); 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(np, child) { int rc; u32 reg; if (of_property_read_u32(child, "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) { of_node_put(child); 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");