leds: add BCM6358 LED driver

This adds support for the LED controller on Broadcom's BCM6358.

Signed-off-by: Álvaro Fernández Rojas <noltari@gmail.com>
Acked-by: Jacek Anaszewski <j.anaszewski@samsung.com>
Signed-off-by: Bryan Wu <cooloney@gmail.com>

1 files changed, 243 insertions, 0 deletions

diff --git a/drivers/leds/leds-bcm6358.c b/drivers/leds/leds-bcm6358.c
new file mode 100644
index 0000000..21f9693
--- /dev/null
+++ b/drivers/leds/leds-bcm6358.c
@@ -0,0 +1,243 @@
+/*
+ * 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)
+{
+	iowrite32be(data, reg);
+}
+
+static unsigned long bcm6358_led_read(void __iomem *reg)
+{
+	return ioread32be(reg);
+}
+
+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_mode(struct bcm6358_led *led, unsigned long value)
+{
+	unsigned long val;
+
+	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);
+}
+
+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;
+
+	spin_lock_irqsave(led->lock, flags);
+	bcm6358_led_mode(led, value);
+	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;
+	unsigned long flags;
+	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);
+
+	spin_lock_irqsave(lock, flags);
+	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;
+
+			bcm6358_led_busy(led->mem);
+
+			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_mode(led, led->cdev.brightness);
+	spin_unlock_irqrestore(lock, flags);
+
+	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", &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", },
+	{ },
+};
+
+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");