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>

3 files changed, 252 insertions, 0 deletions

diff --git a/drivers/leds/Kconfig b/drivers/leds/Kconfig
index ec26dd18b891..86de046d4281 100644
--- a/drivers/leds/Kconfig
+++ b/drivers/leds/Kconfig
@@ -58,6 +58,14 @@ config LEDS_BCM6328
           This option enables support for LEDs connected to the BCM6328
           LED HW controller accessed via MMIO registers.
 
+config LEDS_BCM6358
+        tristate "LED Support for Broadcom BCM6358"
+        depends on LEDS_CLASS
+        depends on OF
+        help
+          This option enables support for LEDs connected to the BCM6358
+          LED HW controller accessed via MMIO registers.
+
 config LEDS_LM3530
         tristate "LCD Backlight driver for LM3530"
         depends on LEDS_CLASS
diff --git a/drivers/leds/Makefile b/drivers/leds/Makefile
index edb3abf270ea..8d6a24a2f513 100644
--- a/drivers/leds/Makefile
+++ b/drivers/leds/Makefile
@@ -9,6 +9,7 @@ obj-$(CONFIG_LEDS_TRIGGERS)		+= led-triggers.o
 obj-$(CONFIG_LEDS_88PM860X)             += leds-88pm860x.o
 obj-$(CONFIG_LEDS_AAT1290)              += leds-aat1290.o
 obj-$(CONFIG_LEDS_BCM6328)              += leds-bcm6328.o
+obj-$(CONFIG_LEDS_BCM6358)              += leds-bcm6358.o
 obj-$(CONFIG_LEDS_BD2802)               += leds-bd2802.o
 obj-$(CONFIG_LEDS_LOCOMO)               += leds-locomo.o
 obj-$(CONFIG_LEDS_LM3530)               += leds-lm3530.o
diff --git a/drivers/leds/leds-bcm6358.c b/drivers/leds/leds-bcm6358.c
new file mode 100644
index 000000000000..21f96930b3be
--- /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");