3 files changed, 388 insertions, 0 deletions

diff --git a/drivers/video/backlight/Kconfig b/drivers/video/backlight/Kconfig
index 4615aca2cee2..a942a2488480 100644
--- a/drivers/video/backlight/Kconfig
+++ b/drivers/video/backlight/Kconfig
@@ -405,6 +405,13 @@ config BACKLIGHT_TPS65217
           If you have a Texas Instruments TPS65217 say Y to enable the
           backlight driver.
 
+config BACKLIGHT_AS3711
+        tristate "AS3711 Backlight"
+        depends on BACKLIGHT_CLASS_DEVICE && MFD_AS3711
+        help
+          If you have an Austrian Microsystems AS3711 say Y to enable the
+          backlight driver.
+
 endif # BACKLIGHT_CLASS_DEVICE
 
 endif # BACKLIGHT_LCD_SUPPORT
diff --git a/drivers/video/backlight/Makefile b/drivers/video/backlight/Makefile
index 6c53e5b4707d..4606c218e8e4 100644
--- a/drivers/video/backlight/Makefile
+++ b/drivers/video/backlight/Makefile
@@ -23,6 +23,7 @@ obj-$(CONFIG_BACKLIGHT_ADP5520)		+= adp5520_bl.o
 obj-$(CONFIG_BACKLIGHT_ADP8860)         += adp8860_bl.o
 obj-$(CONFIG_BACKLIGHT_ADP8870)         += adp8870_bl.o
 obj-$(CONFIG_BACKLIGHT_APPLE)           += apple_bl.o
+obj-$(CONFIG_BACKLIGHT_AS3711)          += as3711_bl.o
 obj-$(CONFIG_BACKLIGHT_ATMEL_PWM)       += atmel-pwm-bl.o
 obj-$(CONFIG_BACKLIGHT_CARILLO_RANCH)   += cr_bllcd.o
 obj-$(CONFIG_BACKLIGHT_CLASS_DEVICE)    += backlight.o
diff --git a/drivers/video/backlight/as3711_bl.c b/drivers/video/backlight/as3711_bl.c
new file mode 100644
index 000000000000..41d52fe52543
--- /dev/null
+++ b/drivers/video/backlight/as3711_bl.c
@@ -0,0 +1,380 @@
+/*
+ * AS3711 PMIC backlight driver, using DCDC Step Up Converters
+ *
+ * Copyright (C) 2012 Renesas Electronics Corporation
+ * Author: Guennadi Liakhovetski, <g.liakhovetski@gmx.de>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the version 2 of the GNU General Public License as
+ * published by the Free Software Foundation
+ */
+
+#include <linux/backlight.h>
+#include <linux/delay.h>
+#include <linux/device.h>
+#include <linux/err.h>
+#include <linux/fb.h>
+#include <linux/kernel.h>
+#include <linux/mfd/as3711.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+#include <linux/slab.h>
+
+enum as3711_bl_type {
+        AS3711_BL_SU1,
+        AS3711_BL_SU2,
+};
+
+struct as3711_bl_data {
+        bool powered;
+        const char *fb_name;
+        struct device *fb_dev;
+        enum as3711_bl_type type;
+        int brightness;
+        struct backlight_device *bl;
+};
+
+struct as3711_bl_supply {
+        struct as3711_bl_data su1;
+        struct as3711_bl_data su2;
+        const struct as3711_bl_pdata *pdata;
+        struct as3711 *as3711;
+};
+
+static struct as3711_bl_supply *to_supply(struct as3711_bl_data *su)
+{
+        switch (su->type) {
+        case AS3711_BL_SU1:
+                return container_of(su, struct as3711_bl_supply, su1);
+        case AS3711_BL_SU2:
+                return container_of(su, struct as3711_bl_supply, su2);
+        }
+        return NULL;
+}
+
+static int as3711_set_brightness_auto_i(struct as3711_bl_data *data,
+                                        unsigned int brightness)
+{
+        struct as3711_bl_supply *supply = to_supply(data);
+        struct as3711 *as3711 = supply->as3711;
+        const struct as3711_bl_pdata *pdata = supply->pdata;
+        int ret = 0;
+
+        /* Only all equal current values are supported */
+        if (pdata->su2_auto_curr1)
+                ret = regmap_write(as3711->regmap, AS3711_CURR1_VALUE,
+                                   brightness);
+        if (!ret && pdata->su2_auto_curr2)
+                ret = regmap_write(as3711->regmap, AS3711_CURR2_VALUE,
+                                   brightness);
+        if (!ret && pdata->su2_auto_curr3)
+                ret = regmap_write(as3711->regmap, AS3711_CURR3_VALUE,
+                                   brightness);
+
+        return ret;
+}
+
+static int as3711_set_brightness_v(struct as3711 *as3711,
+                                   unsigned int brightness,
+                                   unsigned int reg)
+{
+        if (brightness > 31)
+                return -EINVAL;
+
+        return regmap_update_bits(as3711->regmap, reg, 0xf0,
+                                  brightness << 4);
+}
+
+static int as3711_bl_su2_reset(struct as3711_bl_supply *supply)
+{
+        struct as3711 *as3711 = supply->as3711;
+        int ret = regmap_update_bits(as3711->regmap, AS3711_STEPUP_CONTROL_5,
+                                     3, supply->pdata->su2_fbprot);
+        if (!ret)
+                ret = regmap_update_bits(as3711->regmap,
+                                         AS3711_STEPUP_CONTROL_2, 1, 0);
+        if (!ret)
+                ret = regmap_update_bits(as3711->regmap,
+                                         AS3711_STEPUP_CONTROL_2, 1, 1);
+        return ret;
+}
+
+/*
+ * Someone with less fragile or less expensive hardware could try to simplify
+ * the brightness adjustment procedure.
+ */
+static int as3711_bl_update_status(struct backlight_device *bl)
+{
+        struct as3711_bl_data *data = bl_get_data(bl);
+        struct as3711_bl_supply *supply = to_supply(data);
+        struct as3711 *as3711 = supply->as3711;
+        int brightness = bl->props.brightness;
+        int ret = 0;
+
+        dev_dbg(&bl->dev, "%s(): brightness %u, pwr %x, blank %x, state %x\n",
+                __func__, bl->props.brightness, bl->props.power,
+                bl->props.fb_blank, bl->props.state);
+
+        if (bl->props.power != FB_BLANK_UNBLANK ||
+            bl->props.fb_blank != FB_BLANK_UNBLANK ||
+            bl->props.state & (BL_CORE_SUSPENDED | BL_CORE_FBBLANK))
+                brightness = 0;
+
+        if (data->type == AS3711_BL_SU1) {
+                ret = as3711_set_brightness_v(as3711, brightness,
+                                              AS3711_STEPUP_CONTROL_1);
+        } else {
+                const struct as3711_bl_pdata *pdata = supply->pdata;
+
+                switch (pdata->su2_feedback) {
+                case AS3711_SU2_VOLTAGE:
+                        ret = as3711_set_brightness_v(as3711, brightness,
+                                                      AS3711_STEPUP_CONTROL_2);
+                        break;
+                case AS3711_SU2_CURR_AUTO:
+                        ret = as3711_set_brightness_auto_i(data, brightness / 4);
+                        if (ret < 0)
+                                return ret;
+                        if (brightness) {
+                                ret = as3711_bl_su2_reset(supply);
+                                if (ret < 0)
+                                        return ret;
+                                udelay(500);
+                                ret = as3711_set_brightness_auto_i(data, brightness);
+                        } else {
+                                ret = regmap_update_bits(as3711->regmap,
+                                                AS3711_STEPUP_CONTROL_2, 1, 0);
+                        }
+                        break;
+                /* Manual one current feedback pin below */
+                case AS3711_SU2_CURR1:
+                        ret = regmap_write(as3711->regmap, AS3711_CURR1_VALUE,
+                                           brightness);
+                        break;
+                case AS3711_SU2_CURR2:
+                        ret = regmap_write(as3711->regmap, AS3711_CURR2_VALUE,
+                                           brightness);
+                        break;
+                case AS3711_SU2_CURR3:
+                        ret = regmap_write(as3711->regmap, AS3711_CURR3_VALUE,
+                                           brightness);
+                        break;
+                default:
+                        ret = -EINVAL;
+                }
+        }
+        if (!ret)
+                data->brightness = brightness;
+
+        return ret;
+}
+
+static int as3711_bl_get_brightness(struct backlight_device *bl)
+{
+        struct as3711_bl_data *data = bl_get_data(bl);
+
+        return data->brightness;
+}
+
+static const struct backlight_ops as3711_bl_ops = {
+        .update_status  = as3711_bl_update_status,
+        .get_brightness = as3711_bl_get_brightness,
+};
+
+static int as3711_bl_init_su2(struct as3711_bl_supply *supply)
+{
+        struct as3711 *as3711 = supply->as3711;
+        const struct as3711_bl_pdata *pdata = supply->pdata;
+        u8 ctl = 0;
+        int ret;
+
+        dev_dbg(as3711->dev, "%s(): use %u\n", __func__, pdata->su2_feedback);
+
+        /* Turn SU2 off */
+        ret = regmap_write(as3711->regmap, AS3711_STEPUP_CONTROL_2, 0);
+        if (ret < 0)
+                return ret;
+
+        switch (pdata->su2_feedback) {
+        case AS3711_SU2_VOLTAGE:
+                ret = regmap_update_bits(as3711->regmap, AS3711_STEPUP_CONTROL_4, 3, 0);
+                break;
+        case AS3711_SU2_CURR1:
+                ctl = 1;
+                ret = regmap_update_bits(as3711->regmap, AS3711_STEPUP_CONTROL_4, 3, 1);
+                break;
+        case AS3711_SU2_CURR2:
+                ctl = 4;
+                ret = regmap_update_bits(as3711->regmap, AS3711_STEPUP_CONTROL_4, 3, 2);
+                break;
+        case AS3711_SU2_CURR3:
+                ctl = 0x10;
+                ret = regmap_update_bits(as3711->regmap, AS3711_STEPUP_CONTROL_4, 3, 3);
+                break;
+        case AS3711_SU2_CURR_AUTO:
+                if (pdata->su2_auto_curr1)
+                        ctl = 2;
+                if (pdata->su2_auto_curr2)
+                        ctl |= 8;
+                if (pdata->su2_auto_curr3)
+                        ctl |= 0x20;
+                ret = 0;
+                break;
+        default:
+                return -EINVAL;
+        }
+
+        if (!ret)
+                ret = regmap_write(as3711->regmap, AS3711_CURR_CONTROL, ctl);
+
+        return ret;
+}
+
+static int as3711_bl_register(struct platform_device *pdev,
+                              unsigned int max_brightness, struct as3711_bl_data *su)
+{
+        struct backlight_properties props = {.type = BACKLIGHT_RAW,};
+        struct backlight_device *bl;
+
+        /* max tuning I = 31uA for voltage- and 38250uA for current-feedback */
+        props.max_brightness = max_brightness;
+
+        bl = backlight_device_register(su->type == AS3711_BL_SU1 ?
+                                       "as3711-su1" : "as3711-su2",
+                                       &pdev->dev, su,
+                                       &as3711_bl_ops, &props);
+        if (IS_ERR(bl)) {
+                dev_err(&pdev->dev, "failed to register backlight\n");
+                return PTR_ERR(bl);
+        }
+
+        bl->props.brightness = props.max_brightness;
+
+        backlight_update_status(bl);
+
+        su->bl = bl;
+
+        return 0;
+}
+
+static int as3711_backlight_probe(struct platform_device *pdev)
+{
+        struct as3711_bl_pdata *pdata = dev_get_platdata(&pdev->dev);
+        struct as3711 *as3711 = dev_get_drvdata(pdev->dev.parent);
+        struct as3711_bl_supply *supply;
+        struct as3711_bl_data *su;
+        unsigned int max_brightness;
+        int ret;
+
+        if (!pdata || (!pdata->su1_fb && !pdata->su2_fb)) {
+                dev_err(&pdev->dev, "No platform data, exiting...\n");
+                return -ENODEV;
+        }
+
+        /*
+         * Due to possible hardware damage I chose to block all modes,
+         * unsupported on my hardware. Anyone, wishing to use any of those modes
+         * will have to first review the code, then activate and test it.
+         */
+        if (pdata->su1_fb ||
+            pdata->su2_fbprot != AS3711_SU2_GPIO4 ||
+            pdata->su2_feedback != AS3711_SU2_CURR_AUTO) {
+                dev_warn(&pdev->dev,
+                         "Attention! An untested mode has been chosen!\n"
+                         "Please, review the code, enable, test, and report success:-)\n");
+                return -EINVAL;
+        }
+
+        supply = devm_kzalloc(&pdev->dev, sizeof(*supply), GFP_KERNEL);
+        if (!supply)
+                return -ENOMEM;
+
+        supply->as3711 = as3711;
+        supply->pdata = pdata;
+
+        if (pdata->su1_fb) {
+                su = &supply->su1;
+                su->fb_name = pdata->su1_fb;
+                su->type = AS3711_BL_SU1;
+
+                max_brightness = min(pdata->su1_max_uA, 31);
+                ret = as3711_bl_register(pdev, max_brightness, su);
+                if (ret < 0)
+                        return ret;
+        }
+
+        if (pdata->su2_fb) {
+                su = &supply->su2;
+                su->fb_name = pdata->su2_fb;
+                su->type = AS3711_BL_SU2;
+
+                switch (pdata->su2_fbprot) {
+                case AS3711_SU2_GPIO2:
+                case AS3711_SU2_GPIO3:
+                case AS3711_SU2_GPIO4:
+                case AS3711_SU2_LX_SD4:
+                        break;
+                default:
+                        ret = -EINVAL;
+                        goto esu2;
+                }
+
+                switch (pdata->su2_feedback) {
+                case AS3711_SU2_VOLTAGE:
+                        max_brightness = min(pdata->su2_max_uA, 31);
+                        break;
+                case AS3711_SU2_CURR1:
+                case AS3711_SU2_CURR2:
+                case AS3711_SU2_CURR3:
+                case AS3711_SU2_CURR_AUTO:
+                        max_brightness = min(pdata->su2_max_uA / 150, 255);
+                        break;
+                default:
+                        ret = -EINVAL;
+                        goto esu2;
+                }
+
+                ret = as3711_bl_init_su2(supply);
+                if (ret < 0)
+                        return ret;
+
+                ret = as3711_bl_register(pdev, max_brightness, su);
+                if (ret < 0)
+                        goto esu2;
+        }
+
+        platform_set_drvdata(pdev, supply);
+
+        return 0;
+
+esu2:
+        backlight_device_unregister(supply->su1.bl);
+        return ret;
+}
+
+static int as3711_backlight_remove(struct platform_device *pdev)
+{
+        struct as3711_bl_supply *supply = platform_get_drvdata(pdev);
+
+        backlight_device_unregister(supply->su1.bl);
+        backlight_device_unregister(supply->su2.bl);
+
+        return 0;
+}
+
+static struct platform_driver as3711_backlight_driver = {
+        .driver         = {
+                .name   = "as3711-backlight",
+                .owner  = THIS_MODULE,
+        },
+        .probe          = as3711_backlight_probe,
+        .remove         = as3711_backlight_remove,
+};
+
+module_platform_driver(as3711_backlight_driver);
+
+MODULE_DESCRIPTION("Backlight Driver for AS3711 PMICs");
+MODULE_AUTHOR("Guennadi Liakhovetski <g.liakhovetski@gmx.de");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:as3711-backlight");