3 files changed, 258 insertions, 0 deletions

diff --git a/drivers/video/backlight/Kconfig b/drivers/video/backlight/Kconfig
index f9d19be05540..f86dbfd209ad 100644
--- a/drivers/video/backlight/Kconfig
+++ b/drivers/video/backlight/Kconfig
@@ -229,3 +229,10 @@ config BACKLIGHT_SAHARA
         help
           If you have a Tabletkiosk Sahara Touch-iT, say y to enable the
           backlight driver.
+
+config BACKLIGHT_WM831X
+        tristate "WM831x PMIC Backlight Driver"
+        depends on BACKLIGHT_CLASS_DEVICE && MFD_WM831X
+        help
+          If you have a backlight driven by the ISINK and DCDC of a
+          WM831x PMIC say y to enable the backlight driver for it.
diff --git a/drivers/video/backlight/Makefile b/drivers/video/backlight/Makefile
index 4eb178c1d684..df0b67ce88b6 100644
--- a/drivers/video/backlight/Makefile
+++ b/drivers/video/backlight/Makefile
@@ -24,4 +24,5 @@ obj-$(CONFIG_BACKLIGHT_DA903X)	+= da903x_bl.o
 obj-$(CONFIG_BACKLIGHT_MBP_NVIDIA) += mbp_nvidia_bl.o
 obj-$(CONFIG_BACKLIGHT_TOSA)    += tosa_bl.o
 obj-$(CONFIG_BACKLIGHT_SAHARA)  += kb3886_bl.o
+obj-$(CONFIG_BACKLIGHT_WM831X)  += wm831x_bl.o
 
diff --git a/drivers/video/backlight/wm831x_bl.c b/drivers/video/backlight/wm831x_bl.c
new file mode 100644
index 000000000000..467bdb7efb23
--- /dev/null
+++ b/drivers/video/backlight/wm831x_bl.c
@@ -0,0 +1,250 @@
+/*
+ * Backlight driver for Wolfson Microelectronics WM831x PMICs
+ *
+ * Copyright 2009 Wolfson Microelectonics 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/fb.h>
+#include <linux/backlight.h>
+
+#include <linux/mfd/wm831x/core.h>
+#include <linux/mfd/wm831x/pdata.h>
+#include <linux/mfd/wm831x/regulator.h>
+
+struct wm831x_backlight_data {
+        struct wm831x *wm831x;
+        int isink_reg;
+        int current_brightness;
+};
+
+static int wm831x_backlight_set(struct backlight_device *bl, int brightness)
+{
+        struct wm831x_backlight_data *data = bl_get_data(bl);
+        struct wm831x *wm831x = data->wm831x;
+        int power_up = !data->current_brightness && brightness;
+        int power_down = data->current_brightness && !brightness;
+        int ret;
+
+        if (power_up) {
+                /* Enable the ISINK */
+                ret = wm831x_set_bits(wm831x, data->isink_reg,
+                                      WM831X_CS1_ENA, WM831X_CS1_ENA);
+                if (ret < 0)
+                        goto err;
+
+                /* Enable the DC-DC */
+                ret = wm831x_set_bits(wm831x, WM831X_DCDC_ENABLE,
+                                      WM831X_DC4_ENA, WM831X_DC4_ENA);
+                if (ret < 0)
+                        goto err;
+        }
+
+        if (power_down) {
+                /* DCDC first */
+                ret = wm831x_set_bits(wm831x, WM831X_DCDC_ENABLE,
+                                      WM831X_DC4_ENA, 0);
+                if (ret < 0)
+                        goto err;
+
+                /* ISINK */
+                ret = wm831x_set_bits(wm831x, data->isink_reg,
+                                      WM831X_CS1_DRIVE | WM831X_CS1_ENA, 0);
+                if (ret < 0)
+                        goto err;
+        }
+
+        /* Set the new brightness */
+        ret = wm831x_set_bits(wm831x, data->isink_reg,
+                              WM831X_CS1_ISEL_MASK, brightness);
+        if (ret < 0)
+                goto err;
+
+        if (power_up) {
+                /* Drive current through the ISINK */
+                ret = wm831x_set_bits(wm831x, data->isink_reg,
+                                      WM831X_CS1_DRIVE, WM831X_CS1_DRIVE);
+                if (ret < 0)
+                        return ret;
+        }
+
+        data->current_brightness = brightness;
+
+        return 0;
+
+err:
+        /* If we were in the middle of a power transition always shut down
+         * for safety.
+         */
+        if (power_up || power_down) {
+                wm831x_set_bits(wm831x, WM831X_DCDC_ENABLE, WM831X_DC4_ENA, 0);
+                wm831x_set_bits(wm831x, data->isink_reg, WM831X_CS1_ENA, 0);
+        }
+
+        return ret;
+}
+
+static int wm831x_backlight_update_status(struct backlight_device *bl)
+{
+        int brightness = bl->props.brightness;
+
+        if (bl->props.power != FB_BLANK_UNBLANK)
+                brightness = 0;
+
+        if (bl->props.fb_blank != FB_BLANK_UNBLANK)
+                brightness = 0;
+
+        if (bl->props.state & BL_CORE_SUSPENDED)
+                brightness = 0;
+
+        return wm831x_backlight_set(bl, brightness);
+}
+
+static int wm831x_backlight_get_brightness(struct backlight_device *bl)
+{
+        struct wm831x_backlight_data *data = bl_get_data(bl);
+        return data->current_brightness;
+}
+
+static struct backlight_ops wm831x_backlight_ops = {
+        .options = BL_CORE_SUSPENDRESUME,
+        .update_status  = wm831x_backlight_update_status,
+        .get_brightness = wm831x_backlight_get_brightness,
+};
+
+static int wm831x_backlight_probe(struct platform_device *pdev)
+{
+        struct wm831x *wm831x = dev_get_drvdata(pdev->dev.parent);
+        struct wm831x_pdata *wm831x_pdata;
+        struct wm831x_backlight_pdata *pdata;
+        struct wm831x_backlight_data *data;
+        struct backlight_device *bl;
+        int ret, i, max_isel, isink_reg, dcdc_cfg;
+
+        /* We need platform data */
+        if (pdev->dev.parent->platform_data) {
+                wm831x_pdata = pdev->dev.parent->platform_data;
+                pdata = wm831x_pdata->backlight;
+        } else {
+                pdata = NULL;
+        }
+
+        if (!pdata) {
+                dev_err(&pdev->dev, "No platform data supplied\n");
+                return -EINVAL;
+        }
+
+        /* Figure out the maximum current we can use */
+        for (i = 0; i < WM831X_ISINK_MAX_ISEL; i++) {
+                if (wm831x_isinkv_values[i] > pdata->max_uA)
+                        break;
+        }
+
+        if (i == 0) {
+                dev_err(&pdev->dev, "Invalid max_uA: %duA\n", pdata->max_uA);
+                return -EINVAL;
+        }
+        max_isel = i - 1;
+
+        if (pdata->max_uA != wm831x_isinkv_values[max_isel])
+                dev_warn(&pdev->dev,
+                         "Maximum current is %duA not %duA as requested\n",
+                         wm831x_isinkv_values[max_isel], pdata->max_uA);
+
+        switch (pdata->isink) {
+        case 1:
+                isink_reg = WM831X_CURRENT_SINK_1;
+                dcdc_cfg = 0;
+                break;
+        case 2:
+                isink_reg = WM831X_CURRENT_SINK_2;
+                dcdc_cfg = WM831X_DC4_FBSRC;
+                break;
+        default:
+                dev_err(&pdev->dev, "Invalid ISINK %d\n", pdata->isink);
+                return -EINVAL;
+        }
+
+        /* Configure the ISINK to use for feedback */
+        ret = wm831x_reg_unlock(wm831x);
+        if (ret < 0)
+                return ret;
+
+        ret = wm831x_set_bits(wm831x, WM831X_DC4_CONTROL, WM831X_DC4_FBSRC,
+                              dcdc_cfg);
+
+        wm831x_reg_lock(wm831x);
+        if (ret < 0)
+                return ret;
+
+        data = kzalloc(sizeof(*data), GFP_KERNEL);
+        if (data == NULL)
+                return -ENOMEM;
+
+        data->wm831x = wm831x;
+        data->current_brightness = 0;
+        data->isink_reg = isink_reg;
+
+        bl = backlight_device_register("wm831x", &pdev->dev,
+                        data, &wm831x_backlight_ops);
+        if (IS_ERR(bl)) {
+                dev_err(&pdev->dev, "failed to register backlight\n");
+                kfree(data);
+                return PTR_ERR(bl);
+        }
+
+        bl->props.max_brightness = max_isel;
+        bl->props.brightness = max_isel;
+
+        platform_set_drvdata(pdev, bl);
+
+        /* Disable the DCDC if it was started so we can bootstrap */
+        wm831x_set_bits(wm831x, WM831X_DCDC_ENABLE, WM831X_DC4_ENA, 0);
+
+
+        backlight_update_status(bl);
+
+        return 0;
+}
+
+static int wm831x_backlight_remove(struct platform_device *pdev)
+{
+        struct backlight_device *bl = platform_get_drvdata(pdev);
+        struct wm831x_backlight_data *data = bl_get_data(bl);
+
+        backlight_device_unregister(bl);
+        kfree(data);
+        return 0;
+}
+
+static struct platform_driver wm831x_backlight_driver = {
+        .driver         = {
+                .name   = "wm831x-backlight",
+                .owner  = THIS_MODULE,
+        },
+        .probe          = wm831x_backlight_probe,
+        .remove         = wm831x_backlight_remove,
+};
+
+static int __init wm831x_backlight_init(void)
+{
+        return platform_driver_register(&wm831x_backlight_driver);
+}
+module_init(wm831x_backlight_init);
+
+static void __exit wm831x_backlight_exit(void)
+{
+        platform_driver_unregister(&wm831x_backlight_driver);
+}
+module_exit(wm831x_backlight_exit);
+
+MODULE_DESCRIPTION("Backlight Driver for WM831x PMICs");
+MODULE_AUTHOR("Mark Brown <broonie@opensource.wolfsonmicro.com");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:wm831x-backlight");