leds: Add WM8350 LED driver

The voltage and current regulators on the WM8350 AudioPlus PMIC can be
used in concert to provide a power efficient LED driver.  This driver
implements support for this within the standard LED class.

Platform initialisation code should configure the LED hardware in the
init callback provided by the WM8350 core driver.  The callback should
use wm8350_isink_set_flash(), wm8350_dcdc25_set_mode() and
wm8350_dcdc_set_slot() to configure the operating parameters of the
regulators for their hardware and then then use wm8350_register_led() to
instantiate the LED driver.

This driver was originally written by Liam Girdwood, though it has been
extensively modified since then.

Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Richard Purdie <rpurdie@linux.intel.com>

3 files changed, 341 insertions, 0 deletions

diff --git a/drivers/leds/Kconfig b/drivers/leds/Kconfig
index 3d0d2625f6ab..a4a1ae214630 100644
--- a/drivers/leds/Kconfig
+++ b/drivers/leds/Kconfig
@@ -164,6 +164,13 @@ config LEDS_PCA955X
           LED driver chips accessed via the I2C bus.  Supported
           devices include PCA9550, PCA9551, PCA9552, and PCA9553.
 
+config LEDS_WM8350
+        tristate "LED Support for WM8350 AudioPlus PMIC"
+        depends on LEDS_CLASS && MFD_WM8350
+        help
+          This option enables support for LEDs driven by the Wolfson
+          Microelectronics WM8350 AudioPlus PMIC.
+
 config LEDS_DA903X
         tristate "LED Support for DA9030/DA9034 PMIC"
         depends on LEDS_CLASS && PMIC_DA903X
diff --git a/drivers/leds/Makefile b/drivers/leds/Makefile
index ff4616a49043..bc247cb02e82 100644
--- a/drivers/leds/Makefile
+++ b/drivers/leds/Makefile
@@ -24,6 +24,7 @@ obj-$(CONFIG_LEDS_FSG)			+= leds-fsg.o
 obj-$(CONFIG_LEDS_PCA955X)              += leds-pca955x.o
 obj-$(CONFIG_LEDS_DA903X)               += leds-da903x.o
 obj-$(CONFIG_LEDS_HP_DISK)              += leds-hp-disk.o
+obj-$(CONFIG_LEDS_WM8350)               += leds-wm8350.o
 
 # LED Triggers
 obj-$(CONFIG_LEDS_TRIGGER_TIMER)        += ledtrig-timer.o
diff --git a/drivers/leds/leds-wm8350.c b/drivers/leds/leds-wm8350.c
new file mode 100644
index 000000000000..846ed978103f
--- /dev/null
+++ b/drivers/leds/leds-wm8350.c
@@ -0,0 +1,333 @@
+/*
+ * LED driver for WM8350 driven LEDS.
+ *
+ * Copyright(C) 2007, 2008 Wolfson Microelectronics PLC.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ */
+
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/platform_device.h>
+#include <linux/leds.h>
+#include <linux/err.h>
+#include <linux/mfd/wm8350/pmic.h>
+#include <linux/regulator/consumer.h>
+
+/* Microamps */
+static const int isink_cur[] = {
+        4,
+        5,
+        6,
+        7,
+        8,
+        10,
+        11,
+        14,
+        16,
+        19,
+        23,
+        27,
+        32,
+        39,
+        46,
+        54,
+        65,
+        77,
+        92,
+        109,
+        130,
+        154,
+        183,
+        218,
+        259,
+        308,
+        367,
+        436,
+        518,
+        616,
+        733,
+        872,
+        1037,
+        1233,
+        1466,
+        1744,
+        2073,
+        2466,
+        2933,
+        3487,
+        4147,
+        4932,
+        5865,
+        6975,
+        8294,
+        9864,
+        11730,
+        13949,
+        16589,
+        19728,
+        23460,
+        27899,
+        33178,
+        39455,
+        46920,
+        55798,
+        66355,
+        78910,
+        93840,
+        111596,
+        132710,
+        157820,
+        187681,
+        223191
+};
+
+#define to_wm8350_led(led_cdev) \
+        container_of(led_cdev, struct wm8350_led, cdev)
+
+static void wm8350_led_enable(struct wm8350_led *led)
+{
+        int ret;
+
+        if (led->enabled)
+                return;
+
+        ret = regulator_enable(led->isink);
+        if (ret != 0) {
+                dev_err(led->cdev.dev, "Failed to enable ISINK: %d\n", ret);
+                return;
+        }
+
+        ret = regulator_enable(led->dcdc);
+        if (ret != 0) {
+                dev_err(led->cdev.dev, "Failed to enable DCDC: %d\n", ret);
+                regulator_disable(led->isink);
+                return;
+        }
+
+        led->enabled = 1;
+}
+
+static void wm8350_led_disable(struct wm8350_led *led)
+{
+        int ret;
+
+        if (!led->enabled)
+                return;
+
+        ret = regulator_disable(led->dcdc);
+        if (ret != 0) {
+                dev_err(led->cdev.dev, "Failed to disable DCDC: %d\n", ret);
+                return;
+        }
+
+        ret = regulator_disable(led->isink);
+        if (ret != 0) {
+                dev_err(led->cdev.dev, "Failed to disable ISINK: %d\n", ret);
+                regulator_enable(led->dcdc);
+                return;
+        }
+
+        led->enabled = 0;
+}
+
+static void led_work(struct work_struct *work)
+{
+        struct wm8350_led *led = container_of(work, struct wm8350_led, work);
+        int ret;
+        int uA;
+        unsigned long flags;
+
+        mutex_lock(&led->mutex);
+
+        spin_lock_irqsave(&led->value_lock, flags);
+
+        if (led->value == LED_OFF) {
+                spin_unlock_irqrestore(&led->value_lock, flags);
+                wm8350_led_disable(led);
+                goto out;
+        }
+
+        /* This scales linearly into the index of valid current
+         * settings which results in a linear scaling of perceived
+         * brightness due to the non-linear current settings provided
+         * by the hardware.
+         */
+        uA = (led->max_uA_index * led->value) / LED_FULL;
+        spin_unlock_irqrestore(&led->value_lock, flags);
+        BUG_ON(uA >= ARRAY_SIZE(isink_cur));
+
+        ret = regulator_set_current_limit(led->isink, isink_cur[uA],
+                                          isink_cur[uA]);
+        if (ret != 0)
+                dev_err(led->cdev.dev, "Failed to set %duA: %d\n",
+                        isink_cur[uA], ret);
+
+        wm8350_led_enable(led);
+
+out:
+        mutex_unlock(&led->mutex);
+}
+
+static void wm8350_led_set(struct led_classdev *led_cdev,
+                           enum led_brightness value)
+{
+        struct wm8350_led *led = to_wm8350_led(led_cdev);
+        unsigned long flags;
+
+        spin_lock_irqsave(&led->value_lock, flags);
+        led->value = value;
+        schedule_work(&led->work);
+        spin_unlock_irqrestore(&led->value_lock, flags);
+}
+
+#ifdef CONFIG_PM
+static int wm8350_led_suspend(struct platform_device *pdev, pm_message_t state)
+{
+        struct wm8350_led *led = platform_get_drvdata(pdev);
+
+        led_classdev_suspend(&led->cdev);
+        return 0;
+}
+
+static int wm8350_led_resume(struct platform_device *pdev)
+{
+        struct wm8350_led *led = platform_get_drvdata(pdev);
+
+        led_classdev_resume(&led->cdev);
+        return 0;
+}
+#else
+#define wm8350_led_suspend NULL
+#define wm8350_led_resume NULL
+#endif
+
+static void wm8350_led_shutdown(struct platform_device *pdev)
+{
+        struct wm8350_led *led = platform_get_drvdata(pdev);
+
+        mutex_lock(&led->mutex);
+        led->value = LED_OFF;
+        wm8350_led_disable(led);
+        mutex_unlock(&led->mutex);
+}
+
+static int wm8350_led_probe(struct platform_device *pdev)
+{
+        struct regulator *isink, *dcdc;
+        struct wm8350_led *led;
+        struct wm8350_led_platform_data *pdata = pdev->dev.platform_data;
+        int ret, i;
+
+        if (pdata == NULL) {
+                dev_err(&pdev->dev, "no platform data\n");
+                return -ENODEV;
+        }
+
+        if (pdata->max_uA < isink_cur[0]) {
+                dev_err(&pdev->dev, "Invalid maximum current %duA\n",
+                        pdata->max_uA);
+                return -EINVAL;
+        }
+
+        isink = regulator_get(&pdev->dev, "led_isink");
+        if (IS_ERR(isink)) {
+                printk(KERN_ERR "%s: cant get ISINK\n", __func__);
+                return PTR_ERR(isink);
+        }
+
+        dcdc = regulator_get(&pdev->dev, "led_vcc");
+        if (IS_ERR(dcdc)) {
+                printk(KERN_ERR "%s: cant get DCDC\n", __func__);
+                ret = PTR_ERR(dcdc);
+                goto err_isink;
+        }
+
+        led = kzalloc(sizeof(*led), GFP_KERNEL);
+        if (led == NULL) {
+                ret = -ENOMEM;
+                goto err_dcdc;
+        }
+
+        led->cdev.brightness_set = wm8350_led_set;
+        led->cdev.default_trigger = pdata->default_trigger;
+        led->cdev.name = pdata->name;
+        led->enabled = regulator_is_enabled(isink);
+        led->isink = isink;
+        led->dcdc = dcdc;
+
+        for (i = 0; i < ARRAY_SIZE(isink_cur) - 1; i++)
+                if (isink_cur[i] >= pdata->max_uA)
+                        break;
+        led->max_uA_index = i;
+        if (pdata->max_uA != isink_cur[i])
+                dev_warn(&pdev->dev,
+                         "Maximum current %duA is not directly supported,"
+                         " check platform data\n",
+                         pdata->max_uA);
+
+        spin_lock_init(&led->value_lock);
+        mutex_init(&led->mutex);
+        INIT_WORK(&led->work, led_work);
+        led->value = LED_OFF;
+        platform_set_drvdata(pdev, led);
+
+        ret = led_classdev_register(&pdev->dev, &led->cdev);
+        if (ret < 0)
+                goto err_led;
+
+        return 0;
+
+ err_led:
+        kfree(led);
+ err_dcdc:
+        regulator_put(dcdc);
+ err_isink:
+        regulator_put(isink);
+        return ret;
+}
+
+static int wm8350_led_remove(struct platform_device *pdev)
+{
+        struct wm8350_led *led = platform_get_drvdata(pdev);
+
+        led_classdev_unregister(&led->cdev);
+        flush_scheduled_work();
+        wm8350_led_disable(led);
+        regulator_put(led->dcdc);
+        regulator_put(led->isink);
+        kfree(led);
+        return 0;
+}
+
+static struct platform_driver wm8350_led_driver = {
+        .driver = {
+                   .name = "wm8350-led",
+                   .owner = THIS_MODULE,
+                   },
+        .probe = wm8350_led_probe,
+        .remove = wm8350_led_remove,
+        .shutdown = wm8350_led_shutdown,
+        .suspend = wm8350_led_suspend,
+        .resume = wm8350_led_resume,
+};
+
+static int __devinit wm8350_led_init(void)
+{
+        return platform_driver_register(&wm8350_led_driver);
+}
+module_init(wm8350_led_init);
+
+static void wm8350_led_exit(void)
+{
+        platform_driver_unregister(&wm8350_led_driver);
+}
+module_exit(wm8350_led_exit);
+
+MODULE_AUTHOR("Mark Brown");
+MODULE_DESCRIPTION("WM8350 LED driver");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:wm8350-led");