backlight: pm8941-wled: Move PM8941 WLED driver to backlight
authorBjorn Andersson <bjorn.andersson@sonymobile.com>
Wed, 22 Jul 2015 00:44:49 +0000 (17:44 -0700)
committerLee Jones <lee.jones@linaro.org>
Tue, 25 Aug 2015 07:41:56 +0000 (08:41 +0100)
The Qualcomm PM8941 WLED block is used for backlight and should therefor
be in the backlight framework and not in the LED framework. This moves
the driver and adapts to the backlight api instead.

Signed-off-by: Bjorn Andersson <bjorn.andersson@sonymobile.com>
Tested-by: Rob Clark <robdclark@gmail.com>
Acked-by: Jacek Anaszewski <j.anaszewski@samsung.com>
Acked-by: Jingoo Han <jingoohan1@gmail.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Documentation/devicetree/bindings/leds/leds-pm8941-wled.txt [deleted file]
Documentation/devicetree/bindings/video/backlight/pm8941-wled.txt [new file with mode: 0644]
drivers/leds/Kconfig
drivers/leds/Makefile
drivers/leds/leds-pm8941-wled.c [deleted file]
drivers/video/backlight/Kconfig
drivers/video/backlight/Makefile
drivers/video/backlight/pm8941-wled.c [new file with mode: 0644]

diff --git a/Documentation/devicetree/bindings/leds/leds-pm8941-wled.txt b/Documentation/devicetree/bindings/leds/leds-pm8941-wled.txt
deleted file mode 100644 (file)
index a85a964..0000000
+++ /dev/null
@@ -1,43 +0,0 @@
-Binding for Qualcomm PM8941 WLED driver
-
-Required properties:
-- compatible: should be "qcom,pm8941-wled"
-- reg: slave address
-
-Optional properties:
-- label: The label for this led
-  See Documentation/devicetree/bindings/leds/common.txt
-- linux,default-trigger: Default trigger assigned to the LED
-  See Documentation/devicetree/bindings/leds/common.txt
-- qcom,cs-out: bool; enable current sink output
-- qcom,cabc: bool; enable content adaptive backlight control
-- qcom,ext-gen: bool; use externally generated modulator signal to dim
-- qcom,current-limit: mA; per-string current limit; value from 0 to 25
-       default: 20mA
-- qcom,current-boost-limit: mA; boost current limit; one of:
-       105, 385, 525, 805, 980, 1260, 1400, 1680
-       default: 805mA
-- qcom,switching-freq: kHz; switching frequency; one of:
-       600, 640, 685, 738, 800, 872, 960, 1066, 1200, 1371,
-       1600, 1920, 2400, 3200, 4800, 9600,
-       default: 1600kHz
-- qcom,ovp: V; Over-voltage protection limit; one of:
-       27, 29, 32, 35
-       default: 29V
-- qcom,num-strings: #; number of led strings attached; value from 1 to 3
-       default: 2
-
-Example:
-
-pm8941-wled@d800 {
-       compatible = "qcom,pm8941-wled";
-       reg = <0xd800>;
-       label = "backlight";
-
-       qcom,cs-out;
-       qcom,current-limit = <20>;
-       qcom,current-boost-limit = <805>;
-       qcom,switching-freq = <1600>;
-       qcom,ovp = <29>;
-       qcom,num-strings = <2>;
-};
diff --git a/Documentation/devicetree/bindings/video/backlight/pm8941-wled.txt b/Documentation/devicetree/bindings/video/backlight/pm8941-wled.txt
new file mode 100644 (file)
index 0000000..424f844
--- /dev/null
@@ -0,0 +1,40 @@
+Binding for Qualcomm PM8941 WLED driver
+
+Required properties:
+- compatible: should be "qcom,pm8941-wled"
+- reg: slave address
+
+Optional properties:
+- label: The name of the backlight device
+- qcom,cs-out: bool; enable current sink output
+- qcom,cabc: bool; enable content adaptive backlight control
+- qcom,ext-gen: bool; use externally generated modulator signal to dim
+- qcom,current-limit: mA; per-string current limit; value from 0 to 25
+       default: 20mA
+- qcom,current-boost-limit: mA; boost current limit; one of:
+       105, 385, 525, 805, 980, 1260, 1400, 1680
+       default: 805mA
+- qcom,switching-freq: kHz; switching frequency; one of:
+       600, 640, 685, 738, 800, 872, 960, 1066, 1200, 1371,
+       1600, 1920, 2400, 3200, 4800, 9600,
+       default: 1600kHz
+- qcom,ovp: V; Over-voltage protection limit; one of:
+       27, 29, 32, 35
+       default: 29V
+- qcom,num-strings: #; number of led strings attached; value from 1 to 3
+       default: 2
+
+Example:
+
+pm8941-wled@d800 {
+       compatible = "qcom,pm8941-wled";
+       reg = <0xd800>;
+       label = "backlight";
+
+       qcom,cs-out;
+       qcom,current-limit = <20>;
+       qcom,current-boost-limit = <805>;
+       qcom,switching-freq = <1600>;
+       qcom,ovp = <29>;
+       qcom,num-strings = <2>;
+};
index 9ad35f72ab4c077791cf7942cceb36301325872d..b8d4b965ca2a305ae24695298d6f84852a86dad5 100644 (file)
@@ -578,14 +578,6 @@ config LEDS_VERSATILE
          This option enabled support for the LEDs on the ARM Versatile
          and RealView boards. Say Y to enabled these.
 
-config LEDS_PM8941_WLED
-       tristate "LED support for the Qualcomm PM8941 WLED block"
-       depends on LEDS_CLASS
-       select REGMAP
-       help
-         This option enables support for the 'White' LED block
-         on Qualcomm PM8941 PMICs.
-
 comment "LED Triggers"
 source "drivers/leds/trigger/Kconfig"
 
index 8d6a24a2f51376fb9a6aaa704cc1d1908dc51d5a..abe96d960ebed5812322bc6332f7b13329ea9c07 100644 (file)
@@ -63,7 +63,6 @@ obj-$(CONFIG_LEDS_BLINKM)             += leds-blinkm.o
 obj-$(CONFIG_LEDS_SYSCON)              += leds-syscon.o
 obj-$(CONFIG_LEDS_VERSATILE)           += leds-versatile.o
 obj-$(CONFIG_LEDS_MENF21BMC)           += leds-menf21bmc.o
-obj-$(CONFIG_LEDS_PM8941_WLED)         += leds-pm8941-wled.o
 obj-$(CONFIG_LEDS_KTD2692)             += leds-ktd2692.o
 
 # LED SPI Drivers
diff --git a/drivers/leds/leds-pm8941-wled.c b/drivers/leds/leds-pm8941-wled.c
deleted file mode 100644 (file)
index bf64a59..0000000
+++ /dev/null
@@ -1,435 +0,0 @@
-/* Copyright (c) 2015, Sony Mobile Communications, AB.
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 and
- * only version 2 as published by the Free Software Foundation.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- */
-
-#include <linux/kernel.h>
-#include <linux/leds.h>
-#include <linux/module.h>
-#include <linux/of.h>
-#include <linux/of_device.h>
-#include <linux/regmap.h>
-
-#define PM8941_WLED_REG_VAL_BASE               0x40
-#define  PM8941_WLED_REG_VAL_MAX               0xFFF
-
-#define PM8941_WLED_REG_MOD_EN                 0x46
-#define  PM8941_WLED_REG_MOD_EN_BIT            BIT(7)
-#define  PM8941_WLED_REG_MOD_EN_MASK           BIT(7)
-
-#define PM8941_WLED_REG_SYNC                   0x47
-#define  PM8941_WLED_REG_SYNC_MASK             0x07
-#define  PM8941_WLED_REG_SYNC_LED1             BIT(0)
-#define  PM8941_WLED_REG_SYNC_LED2             BIT(1)
-#define  PM8941_WLED_REG_SYNC_LED3             BIT(2)
-#define  PM8941_WLED_REG_SYNC_ALL              0x07
-#define  PM8941_WLED_REG_SYNC_CLEAR            0x00
-
-#define PM8941_WLED_REG_FREQ                   0x4c
-#define  PM8941_WLED_REG_FREQ_MASK             0x0f
-
-#define PM8941_WLED_REG_OVP                    0x4d
-#define  PM8941_WLED_REG_OVP_MASK              0x03
-
-#define PM8941_WLED_REG_BOOST                  0x4e
-#define  PM8941_WLED_REG_BOOST_MASK            0x07
-
-#define PM8941_WLED_REG_SINK                   0x4f
-#define  PM8941_WLED_REG_SINK_MASK             0xe0
-#define  PM8941_WLED_REG_SINK_SHFT             0x05
-
-/* Per-'string' registers below */
-#define PM8941_WLED_REG_STR_OFFSET             0x10
-
-#define PM8941_WLED_REG_STR_MOD_EN_BASE                0x60
-#define  PM8941_WLED_REG_STR_MOD_MASK          BIT(7)
-#define  PM8941_WLED_REG_STR_MOD_EN            BIT(7)
-
-#define PM8941_WLED_REG_STR_SCALE_BASE         0x62
-#define  PM8941_WLED_REG_STR_SCALE_MASK                0x1f
-
-#define PM8941_WLED_REG_STR_MOD_SRC_BASE       0x63
-#define  PM8941_WLED_REG_STR_MOD_SRC_MASK      0x01
-#define  PM8941_WLED_REG_STR_MOD_SRC_INT       0x00
-#define  PM8941_WLED_REG_STR_MOD_SRC_EXT       0x01
-
-#define PM8941_WLED_REG_STR_CABC_BASE          0x66
-#define  PM8941_WLED_REG_STR_CABC_MASK         BIT(7)
-#define  PM8941_WLED_REG_STR_CABC_EN           BIT(7)
-
-struct pm8941_wled_config {
-       u32 i_boost_limit;
-       u32 ovp;
-       u32 switch_freq;
-       u32 num_strings;
-       u32 i_limit;
-       bool cs_out_en;
-       bool ext_gen;
-       bool cabc_en;
-};
-
-struct pm8941_wled {
-       struct regmap *regmap;
-       u16 addr;
-
-       struct led_classdev cdev;
-
-       struct pm8941_wled_config cfg;
-};
-
-static int pm8941_wled_set(struct led_classdev *cdev,
-                          enum led_brightness value)
-{
-       struct pm8941_wled *wled;
-       u8 ctrl = 0;
-       u16 val;
-       int rc;
-       int i;
-
-       wled = container_of(cdev, struct pm8941_wled, cdev);
-
-       if (value != 0)
-               ctrl = PM8941_WLED_REG_MOD_EN_BIT;
-
-       val = value * PM8941_WLED_REG_VAL_MAX / LED_FULL;
-
-       rc = regmap_update_bits(wled->regmap,
-                       wled->addr + PM8941_WLED_REG_MOD_EN,
-                       PM8941_WLED_REG_MOD_EN_MASK, ctrl);
-       if (rc)
-               return rc;
-
-       for (i = 0; i < wled->cfg.num_strings; ++i) {
-               u8 v[2] = { val & 0xff, (val >> 8) & 0xf };
-
-               rc = regmap_bulk_write(wled->regmap,
-                               wled->addr + PM8941_WLED_REG_VAL_BASE + 2 * i,
-                               v, 2);
-               if (rc)
-                       return rc;
-       }
-
-       rc = regmap_update_bits(wled->regmap,
-                       wled->addr + PM8941_WLED_REG_SYNC,
-                       PM8941_WLED_REG_SYNC_MASK, PM8941_WLED_REG_SYNC_ALL);
-       if (rc)
-               return rc;
-
-       rc = regmap_update_bits(wled->regmap,
-                       wled->addr + PM8941_WLED_REG_SYNC,
-                       PM8941_WLED_REG_SYNC_MASK, PM8941_WLED_REG_SYNC_CLEAR);
-       return rc;
-}
-
-static void pm8941_wled_set_brightness(struct led_classdev *cdev,
-                                      enum led_brightness value)
-{
-       if (pm8941_wled_set(cdev, value)) {
-               dev_err(cdev->dev, "Unable to set brightness\n");
-               return;
-       }
-       cdev->brightness = value;
-}
-
-static int pm8941_wled_setup(struct pm8941_wled *wled)
-{
-       int rc;
-       int i;
-
-       rc = regmap_update_bits(wled->regmap,
-                       wled->addr + PM8941_WLED_REG_OVP,
-                       PM8941_WLED_REG_OVP_MASK, wled->cfg.ovp);
-       if (rc)
-               return rc;
-
-       rc = regmap_update_bits(wled->regmap,
-                       wled->addr + PM8941_WLED_REG_BOOST,
-                       PM8941_WLED_REG_BOOST_MASK, wled->cfg.i_boost_limit);
-       if (rc)
-               return rc;
-
-       rc = regmap_update_bits(wled->regmap,
-                       wled->addr + PM8941_WLED_REG_FREQ,
-                       PM8941_WLED_REG_FREQ_MASK, wled->cfg.switch_freq);
-       if (rc)
-               return rc;
-
-       if (wled->cfg.cs_out_en) {
-               u8 all = (BIT(wled->cfg.num_strings) - 1)
-                               << PM8941_WLED_REG_SINK_SHFT;
-
-               rc = regmap_update_bits(wled->regmap,
-                               wled->addr + PM8941_WLED_REG_SINK,
-                               PM8941_WLED_REG_SINK_MASK, all);
-               if (rc)
-                       return rc;
-       }
-
-       for (i = 0; i < wled->cfg.num_strings; ++i) {
-               u16 addr = wled->addr + PM8941_WLED_REG_STR_OFFSET * i;
-
-               rc = regmap_update_bits(wled->regmap,
-                               addr + PM8941_WLED_REG_STR_MOD_EN_BASE,
-                               PM8941_WLED_REG_STR_MOD_MASK,
-                               PM8941_WLED_REG_STR_MOD_EN);
-               if (rc)
-                       return rc;
-
-               if (wled->cfg.ext_gen) {
-                       rc = regmap_update_bits(wled->regmap,
-                                       addr + PM8941_WLED_REG_STR_MOD_SRC_BASE,
-                                       PM8941_WLED_REG_STR_MOD_SRC_MASK,
-                                       PM8941_WLED_REG_STR_MOD_SRC_EXT);
-                       if (rc)
-                               return rc;
-               }
-
-               rc = regmap_update_bits(wled->regmap,
-                               addr + PM8941_WLED_REG_STR_SCALE_BASE,
-                               PM8941_WLED_REG_STR_SCALE_MASK,
-                               wled->cfg.i_limit);
-               if (rc)
-                       return rc;
-
-               rc = regmap_update_bits(wled->regmap,
-                               addr + PM8941_WLED_REG_STR_CABC_BASE,
-                               PM8941_WLED_REG_STR_CABC_MASK,
-                               wled->cfg.cabc_en ?
-                                       PM8941_WLED_REG_STR_CABC_EN : 0);
-               if (rc)
-                       return rc;
-       }
-
-       return 0;
-}
-
-static const struct pm8941_wled_config pm8941_wled_config_defaults = {
-       .i_boost_limit = 3,
-       .i_limit = 20,
-       .ovp = 2,
-       .switch_freq = 5,
-       .num_strings = 0,
-       .cs_out_en = false,
-       .ext_gen = false,
-       .cabc_en = false,
-};
-
-struct pm8941_wled_var_cfg {
-       const u32 *values;
-       u32 (*fn)(u32);
-       int size;
-};
-
-static const u32 pm8941_wled_i_boost_limit_values[] = {
-       105, 385, 525, 805, 980, 1260, 1400, 1680,
-};
-
-static const struct pm8941_wled_var_cfg pm8941_wled_i_boost_limit_cfg = {
-       .values = pm8941_wled_i_boost_limit_values,
-       .size = ARRAY_SIZE(pm8941_wled_i_boost_limit_values),
-};
-
-static const u32 pm8941_wled_ovp_values[] = {
-       35, 32, 29, 27,
-};
-
-static const struct pm8941_wled_var_cfg pm8941_wled_ovp_cfg = {
-       .values = pm8941_wled_ovp_values,
-       .size = ARRAY_SIZE(pm8941_wled_ovp_values),
-};
-
-static u32 pm8941_wled_num_strings_values_fn(u32 idx)
-{
-       return idx + 1;
-}
-
-static const struct pm8941_wled_var_cfg pm8941_wled_num_strings_cfg = {
-       .fn = pm8941_wled_num_strings_values_fn,
-       .size = 3,
-};
-
-static u32 pm8941_wled_switch_freq_values_fn(u32 idx)
-{
-       return 19200 / (2 * (1 + idx));
-}
-
-static const struct pm8941_wled_var_cfg pm8941_wled_switch_freq_cfg = {
-       .fn = pm8941_wled_switch_freq_values_fn,
-       .size = 16,
-};
-
-static const struct pm8941_wled_var_cfg pm8941_wled_i_limit_cfg = {
-       .size = 26,
-};
-
-static u32 pm8941_wled_values(const struct pm8941_wled_var_cfg *cfg, u32 idx)
-{
-       if (idx >= cfg->size)
-               return UINT_MAX;
-       if (cfg->fn)
-               return cfg->fn(idx);
-       if (cfg->values)
-               return cfg->values[idx];
-       return idx;
-}
-
-static int pm8941_wled_configure(struct pm8941_wled *wled, struct device *dev)
-{
-       struct pm8941_wled_config *cfg = &wled->cfg;
-       u32 val;
-       int rc;
-       u32 c;
-       int i;
-       int j;
-
-       const struct {
-               const char *name;
-               u32 *val_ptr;
-               const struct pm8941_wled_var_cfg *cfg;
-       } u32_opts[] = {
-               {
-                       "qcom,current-boost-limit",
-                       &cfg->i_boost_limit,
-                       .cfg = &pm8941_wled_i_boost_limit_cfg,
-               },
-               {
-                       "qcom,current-limit",
-                       &cfg->i_limit,
-                       .cfg = &pm8941_wled_i_limit_cfg,
-               },
-               {
-                       "qcom,ovp",
-                       &cfg->ovp,
-                       .cfg = &pm8941_wled_ovp_cfg,
-               },
-               {
-                       "qcom,switching-freq",
-                       &cfg->switch_freq,
-                       .cfg = &pm8941_wled_switch_freq_cfg,
-               },
-               {
-                       "qcom,num-strings",
-                       &cfg->num_strings,
-                       .cfg = &pm8941_wled_num_strings_cfg,
-               },
-       };
-       const struct {
-               const char *name;
-               bool *val_ptr;
-       } bool_opts[] = {
-               { "qcom,cs-out", &cfg->cs_out_en, },
-               { "qcom,ext-gen", &cfg->ext_gen, },
-               { "qcom,cabc", &cfg->cabc_en, },
-       };
-
-       rc = of_property_read_u32(dev->of_node, "reg", &val);
-       if (rc || val > 0xffff) {
-               dev_err(dev, "invalid IO resources\n");
-               return rc ? rc : -EINVAL;
-       }
-       wled->addr = val;
-
-       rc = of_property_read_string(dev->of_node, "label", &wled->cdev.name);
-       if (rc)
-               wled->cdev.name = dev->of_node->name;
-
-       wled->cdev.default_trigger = of_get_property(dev->of_node,
-                       "linux,default-trigger", NULL);
-
-       *cfg = pm8941_wled_config_defaults;
-       for (i = 0; i < ARRAY_SIZE(u32_opts); ++i) {
-               rc = of_property_read_u32(dev->of_node, u32_opts[i].name, &val);
-               if (rc == -EINVAL) {
-                       continue;
-               } else if (rc) {
-                       dev_err(dev, "error reading '%s'\n", u32_opts[i].name);
-                       return rc;
-               }
-
-               c = UINT_MAX;
-               for (j = 0; c != val; j++) {
-                       c = pm8941_wled_values(u32_opts[i].cfg, j);
-                       if (c == UINT_MAX) {
-                               dev_err(dev, "invalid value for '%s'\n",
-                                       u32_opts[i].name);
-                               return -EINVAL;
-                       }
-               }
-
-               dev_dbg(dev, "'%s' = %u\n", u32_opts[i].name, c);
-               *u32_opts[i].val_ptr = j;
-       }
-
-       for (i = 0; i < ARRAY_SIZE(bool_opts); ++i) {
-               if (of_property_read_bool(dev->of_node, bool_opts[i].name))
-                       *bool_opts[i].val_ptr = true;
-       }
-
-       cfg->num_strings = cfg->num_strings + 1;
-
-       return 0;
-}
-
-static int pm8941_wled_probe(struct platform_device *pdev)
-{
-       struct pm8941_wled *wled;
-       struct regmap *regmap;
-       int rc;
-
-       regmap = dev_get_regmap(pdev->dev.parent, NULL);
-       if (!regmap) {
-               dev_err(&pdev->dev, "Unable to get regmap\n");
-               return -EINVAL;
-       }
-
-       wled = devm_kzalloc(&pdev->dev, sizeof(*wled), GFP_KERNEL);
-       if (!wled)
-               return -ENOMEM;
-
-       wled->regmap = regmap;
-
-       rc = pm8941_wled_configure(wled, &pdev->dev);
-       if (rc)
-               return rc;
-
-       rc = pm8941_wled_setup(wled);
-       if (rc)
-               return rc;
-
-       wled->cdev.brightness_set = pm8941_wled_set_brightness;
-
-       rc = devm_led_classdev_register(&pdev->dev, &wled->cdev);
-       if (rc)
-               return rc;
-
-       platform_set_drvdata(pdev, wled);
-
-       return 0;
-};
-
-static const struct of_device_id pm8941_wled_match_table[] = {
-       { .compatible = "qcom,pm8941-wled" },
-       {}
-};
-MODULE_DEVICE_TABLE(of, pm8941_wled_match_table);
-
-static struct platform_driver pm8941_wled_driver = {
-       .probe = pm8941_wled_probe,
-       .driver = {
-               .name = "pm8941-wled",
-               .of_match_table = pm8941_wled_match_table,
-       },
-};
-
-module_platform_driver(pm8941_wled_driver);
-
-MODULE_DESCRIPTION("pm8941 wled driver");
-MODULE_LICENSE("GPL v2");
-MODULE_ALIAS("platform:pm8941-wled");
index 0505b796d743250e9e314b5a34747ff05033574e..5ffa4b4e26c0e874d3f63068456b3d72d8b4beb5 100644 (file)
@@ -299,6 +299,13 @@ config BACKLIGHT_TOSA
          If you have an Sharp SL-6000 Zaurus say Y to enable a driver
          for its backlight
 
+config BACKLIGHT_PM8941_WLED
+       tristate "Qualcomm PM8941 WLED Driver"
+       select REGMAP
+       help
+         If you have the Qualcomm PM8941, say Y to enable a driver for the
+         WLED block.
+
 config BACKLIGHT_SAHARA
        tristate "Tabletkiosk Sahara Touch-iT Backlight Driver"
        depends on X86
index d67073f9d421f91a6689c1d971235b2c18c4789f..16ec534cff3044209adbae3495c19d97fee3ef73 100644 (file)
@@ -48,6 +48,7 @@ obj-$(CONFIG_BACKLIGHT_OMAP1)         += omap1_bl.o
 obj-$(CONFIG_BACKLIGHT_OT200)          += ot200_bl.o
 obj-$(CONFIG_BACKLIGHT_PANDORA)                += pandora_bl.o
 obj-$(CONFIG_BACKLIGHT_PCF50633)       += pcf50633-backlight.o
+obj-$(CONFIG_BACKLIGHT_PM8941_WLED)    += pm8941-wled.o
 obj-$(CONFIG_BACKLIGHT_PWM)            += pwm_bl.o
 obj-$(CONFIG_BACKLIGHT_SAHARA)         += kb3886_bl.o
 obj-$(CONFIG_BACKLIGHT_SKY81452)       += sky81452-backlight.o
diff --git a/drivers/video/backlight/pm8941-wled.c b/drivers/video/backlight/pm8941-wled.c
new file mode 100644 (file)
index 0000000..c704c32
--- /dev/null
@@ -0,0 +1,427 @@
+/* Copyright (c) 2015, Sony Mobile Communications, AB.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 and
+ * only version 2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/kernel.h>
+#include <linux/backlight.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/regmap.h>
+
+#define PM8941_WLED_REG_VAL_BASE               0x40
+#define  PM8941_WLED_REG_VAL_MAX               0xFFF
+
+#define PM8941_WLED_REG_MOD_EN                 0x46
+#define  PM8941_WLED_REG_MOD_EN_BIT            BIT(7)
+#define  PM8941_WLED_REG_MOD_EN_MASK           BIT(7)
+
+#define PM8941_WLED_REG_SYNC                   0x47
+#define  PM8941_WLED_REG_SYNC_MASK             0x07
+#define  PM8941_WLED_REG_SYNC_LED1             BIT(0)
+#define  PM8941_WLED_REG_SYNC_LED2             BIT(1)
+#define  PM8941_WLED_REG_SYNC_LED3             BIT(2)
+#define  PM8941_WLED_REG_SYNC_ALL              0x07
+#define  PM8941_WLED_REG_SYNC_CLEAR            0x00
+
+#define PM8941_WLED_REG_FREQ                   0x4c
+#define  PM8941_WLED_REG_FREQ_MASK             0x0f
+
+#define PM8941_WLED_REG_OVP                    0x4d
+#define  PM8941_WLED_REG_OVP_MASK              0x03
+
+#define PM8941_WLED_REG_BOOST                  0x4e
+#define  PM8941_WLED_REG_BOOST_MASK            0x07
+
+#define PM8941_WLED_REG_SINK                   0x4f
+#define  PM8941_WLED_REG_SINK_MASK             0xe0
+#define  PM8941_WLED_REG_SINK_SHFT             0x05
+
+/* Per-'string' registers below */
+#define PM8941_WLED_REG_STR_OFFSET             0x10
+
+#define PM8941_WLED_REG_STR_MOD_EN_BASE                0x60
+#define  PM8941_WLED_REG_STR_MOD_MASK          BIT(7)
+#define  PM8941_WLED_REG_STR_MOD_EN            BIT(7)
+
+#define PM8941_WLED_REG_STR_SCALE_BASE         0x62
+#define  PM8941_WLED_REG_STR_SCALE_MASK                0x1f
+
+#define PM8941_WLED_REG_STR_MOD_SRC_BASE       0x63
+#define  PM8941_WLED_REG_STR_MOD_SRC_MASK      0x01
+#define  PM8941_WLED_REG_STR_MOD_SRC_INT       0x00
+#define  PM8941_WLED_REG_STR_MOD_SRC_EXT       0x01
+
+#define PM8941_WLED_REG_STR_CABC_BASE          0x66
+#define  PM8941_WLED_REG_STR_CABC_MASK         BIT(7)
+#define  PM8941_WLED_REG_STR_CABC_EN           BIT(7)
+
+struct pm8941_wled_config {
+       u32 i_boost_limit;
+       u32 ovp;
+       u32 switch_freq;
+       u32 num_strings;
+       u32 i_limit;
+       bool cs_out_en;
+       bool ext_gen;
+       bool cabc_en;
+};
+
+struct pm8941_wled {
+       const char *name;
+       struct regmap *regmap;
+       u16 addr;
+
+       struct pm8941_wled_config cfg;
+};
+
+static int pm8941_wled_update_status(struct backlight_device *bl)
+{
+       struct pm8941_wled *wled = bl_get_data(bl);
+       u16 val = bl->props.brightness;
+       u8 ctrl = 0;
+       int rc;
+       int i;
+
+       if (bl->props.power != FB_BLANK_UNBLANK ||
+           bl->props.fb_blank != FB_BLANK_UNBLANK ||
+           bl->props.state & BL_CORE_FBBLANK)
+               val = 0;
+
+       if (val != 0)
+               ctrl = PM8941_WLED_REG_MOD_EN_BIT;
+
+       rc = regmap_update_bits(wled->regmap,
+                       wled->addr + PM8941_WLED_REG_MOD_EN,
+                       PM8941_WLED_REG_MOD_EN_MASK, ctrl);
+       if (rc)
+               return rc;
+
+       for (i = 0; i < wled->cfg.num_strings; ++i) {
+               u8 v[2] = { val & 0xff, (val >> 8) & 0xf };
+
+               rc = regmap_bulk_write(wled->regmap,
+                               wled->addr + PM8941_WLED_REG_VAL_BASE + 2 * i,
+                               v, 2);
+               if (rc)
+                       return rc;
+       }
+
+       rc = regmap_update_bits(wled->regmap,
+                       wled->addr + PM8941_WLED_REG_SYNC,
+                       PM8941_WLED_REG_SYNC_MASK, PM8941_WLED_REG_SYNC_ALL);
+       if (rc)
+               return rc;
+
+       rc = regmap_update_bits(wled->regmap,
+                       wled->addr + PM8941_WLED_REG_SYNC,
+                       PM8941_WLED_REG_SYNC_MASK, PM8941_WLED_REG_SYNC_CLEAR);
+       return rc;
+}
+
+static int pm8941_wled_setup(struct pm8941_wled *wled)
+{
+       int rc;
+       int i;
+
+       rc = regmap_update_bits(wled->regmap,
+                       wled->addr + PM8941_WLED_REG_OVP,
+                       PM8941_WLED_REG_OVP_MASK, wled->cfg.ovp);
+       if (rc)
+               return rc;
+
+       rc = regmap_update_bits(wled->regmap,
+                       wled->addr + PM8941_WLED_REG_BOOST,
+                       PM8941_WLED_REG_BOOST_MASK, wled->cfg.i_boost_limit);
+       if (rc)
+               return rc;
+
+       rc = regmap_update_bits(wled->regmap,
+                       wled->addr + PM8941_WLED_REG_FREQ,
+                       PM8941_WLED_REG_FREQ_MASK, wled->cfg.switch_freq);
+       if (rc)
+               return rc;
+
+       if (wled->cfg.cs_out_en) {
+               u8 all = (BIT(wled->cfg.num_strings) - 1)
+                               << PM8941_WLED_REG_SINK_SHFT;
+
+               rc = regmap_update_bits(wled->regmap,
+                               wled->addr + PM8941_WLED_REG_SINK,
+                               PM8941_WLED_REG_SINK_MASK, all);
+               if (rc)
+                       return rc;
+       }
+
+       for (i = 0; i < wled->cfg.num_strings; ++i) {
+               u16 addr = wled->addr + PM8941_WLED_REG_STR_OFFSET * i;
+
+               rc = regmap_update_bits(wled->regmap,
+                               addr + PM8941_WLED_REG_STR_MOD_EN_BASE,
+                               PM8941_WLED_REG_STR_MOD_MASK,
+                               PM8941_WLED_REG_STR_MOD_EN);
+               if (rc)
+                       return rc;
+
+               if (wled->cfg.ext_gen) {
+                       rc = regmap_update_bits(wled->regmap,
+                                       addr + PM8941_WLED_REG_STR_MOD_SRC_BASE,
+                                       PM8941_WLED_REG_STR_MOD_SRC_MASK,
+                                       PM8941_WLED_REG_STR_MOD_SRC_EXT);
+                       if (rc)
+                               return rc;
+               }
+
+               rc = regmap_update_bits(wled->regmap,
+                               addr + PM8941_WLED_REG_STR_SCALE_BASE,
+                               PM8941_WLED_REG_STR_SCALE_MASK,
+                               wled->cfg.i_limit);
+               if (rc)
+                       return rc;
+
+               rc = regmap_update_bits(wled->regmap,
+                               addr + PM8941_WLED_REG_STR_CABC_BASE,
+                               PM8941_WLED_REG_STR_CABC_MASK,
+                               wled->cfg.cabc_en ?
+                                       PM8941_WLED_REG_STR_CABC_EN : 0);
+               if (rc)
+                       return rc;
+       }
+
+       return 0;
+}
+
+static const struct pm8941_wled_config pm8941_wled_config_defaults = {
+       .i_boost_limit = 3,
+       .i_limit = 20,
+       .ovp = 2,
+       .switch_freq = 5,
+       .num_strings = 0,
+       .cs_out_en = false,
+       .ext_gen = false,
+       .cabc_en = false,
+};
+
+struct pm8941_wled_var_cfg {
+       const u32 *values;
+       u32 (*fn)(u32);
+       int size;
+};
+
+static const u32 pm8941_wled_i_boost_limit_values[] = {
+       105, 385, 525, 805, 980, 1260, 1400, 1680,
+};
+
+static const struct pm8941_wled_var_cfg pm8941_wled_i_boost_limit_cfg = {
+       .values = pm8941_wled_i_boost_limit_values,
+       .size = ARRAY_SIZE(pm8941_wled_i_boost_limit_values),
+};
+
+static const u32 pm8941_wled_ovp_values[] = {
+       35, 32, 29, 27,
+};
+
+static const struct pm8941_wled_var_cfg pm8941_wled_ovp_cfg = {
+       .values = pm8941_wled_ovp_values,
+       .size = ARRAY_SIZE(pm8941_wled_ovp_values),
+};
+
+static u32 pm8941_wled_num_strings_values_fn(u32 idx)
+{
+       return idx + 1;
+}
+
+static const struct pm8941_wled_var_cfg pm8941_wled_num_strings_cfg = {
+       .fn = pm8941_wled_num_strings_values_fn,
+       .size = 3,
+};
+
+static u32 pm8941_wled_switch_freq_values_fn(u32 idx)
+{
+       return 19200 / (2 * (1 + idx));
+}
+
+static const struct pm8941_wled_var_cfg pm8941_wled_switch_freq_cfg = {
+       .fn = pm8941_wled_switch_freq_values_fn,
+       .size = 16,
+};
+
+static const struct pm8941_wled_var_cfg pm8941_wled_i_limit_cfg = {
+       .size = 26,
+};
+
+static u32 pm8941_wled_values(const struct pm8941_wled_var_cfg *cfg, u32 idx)
+{
+       if (idx >= cfg->size)
+               return UINT_MAX;
+       if (cfg->fn)
+               return cfg->fn(idx);
+       if (cfg->values)
+               return cfg->values[idx];
+       return idx;
+}
+
+static int pm8941_wled_configure(struct pm8941_wled *wled, struct device *dev)
+{
+       struct pm8941_wled_config *cfg = &wled->cfg;
+       u32 val;
+       int rc;
+       u32 c;
+       int i;
+       int j;
+
+       const struct {
+               const char *name;
+               u32 *val_ptr;
+               const struct pm8941_wled_var_cfg *cfg;
+       } u32_opts[] = {
+               {
+                       "qcom,current-boost-limit",
+                       &cfg->i_boost_limit,
+                       .cfg = &pm8941_wled_i_boost_limit_cfg,
+               },
+               {
+                       "qcom,current-limit",
+                       &cfg->i_limit,
+                       .cfg = &pm8941_wled_i_limit_cfg,
+               },
+               {
+                       "qcom,ovp",
+                       &cfg->ovp,
+                       .cfg = &pm8941_wled_ovp_cfg,
+               },
+               {
+                       "qcom,switching-freq",
+                       &cfg->switch_freq,
+                       .cfg = &pm8941_wled_switch_freq_cfg,
+               },
+               {
+                       "qcom,num-strings",
+                       &cfg->num_strings,
+                       .cfg = &pm8941_wled_num_strings_cfg,
+               },
+       };
+       const struct {
+               const char *name;
+               bool *val_ptr;
+       } bool_opts[] = {
+               { "qcom,cs-out", &cfg->cs_out_en, },
+               { "qcom,ext-gen", &cfg->ext_gen, },
+               { "qcom,cabc", &cfg->cabc_en, },
+       };
+
+       rc = of_property_read_u32(dev->of_node, "reg", &val);
+       if (rc || val > 0xffff) {
+               dev_err(dev, "invalid IO resources\n");
+               return rc ? rc : -EINVAL;
+       }
+       wled->addr = val;
+
+       rc = of_property_read_string(dev->of_node, "label", &wled->name);
+       if (rc)
+               wled->name = dev->of_node->name;
+
+       *cfg = pm8941_wled_config_defaults;
+       for (i = 0; i < ARRAY_SIZE(u32_opts); ++i) {
+               rc = of_property_read_u32(dev->of_node, u32_opts[i].name, &val);
+               if (rc == -EINVAL) {
+                       continue;
+               } else if (rc) {
+                       dev_err(dev, "error reading '%s'\n", u32_opts[i].name);
+                       return rc;
+               }
+
+               c = UINT_MAX;
+               for (j = 0; c != val; j++) {
+                       c = pm8941_wled_values(u32_opts[i].cfg, j);
+                       if (c == UINT_MAX) {
+                               dev_err(dev, "invalid value for '%s'\n",
+                                       u32_opts[i].name);
+                               return -EINVAL;
+                       }
+               }
+
+               dev_dbg(dev, "'%s' = %u\n", u32_opts[i].name, c);
+               *u32_opts[i].val_ptr = j;
+       }
+
+       for (i = 0; i < ARRAY_SIZE(bool_opts); ++i) {
+               if (of_property_read_bool(dev->of_node, bool_opts[i].name))
+                       *bool_opts[i].val_ptr = true;
+       }
+
+       cfg->num_strings = cfg->num_strings + 1;
+
+       return 0;
+}
+
+static const struct backlight_ops pm8941_wled_ops = {
+       .update_status = pm8941_wled_update_status,
+};
+
+static int pm8941_wled_probe(struct platform_device *pdev)
+{
+       struct backlight_properties props;
+       struct backlight_device *bl;
+       struct pm8941_wled *wled;
+       struct regmap *regmap;
+       int rc;
+
+       regmap = dev_get_regmap(pdev->dev.parent, NULL);
+       if (!regmap) {
+               dev_err(&pdev->dev, "Unable to get regmap\n");
+               return -EINVAL;
+       }
+
+       wled = devm_kzalloc(&pdev->dev, sizeof(*wled), GFP_KERNEL);
+       if (!wled)
+               return -ENOMEM;
+
+       wled->regmap = regmap;
+
+       rc = pm8941_wled_configure(wled, &pdev->dev);
+       if (rc)
+               return rc;
+
+       rc = pm8941_wled_setup(wled);
+       if (rc)
+               return rc;
+
+       memset(&props, 0, sizeof(struct backlight_properties));
+       props.type = BACKLIGHT_RAW;
+       props.max_brightness = PM8941_WLED_REG_VAL_MAX;
+       bl = devm_backlight_device_register(&pdev->dev, wled->name,
+                                           &pdev->dev, wled,
+                                           &pm8941_wled_ops, &props);
+       if (IS_ERR(bl))
+               return PTR_ERR(bl);
+
+       return 0;
+};
+
+static const struct of_device_id pm8941_wled_match_table[] = {
+       { .compatible = "qcom,pm8941-wled" },
+       {}
+};
+MODULE_DEVICE_TABLE(of, pm8941_wled_match_table);
+
+static struct platform_driver pm8941_wled_driver = {
+       .probe = pm8941_wled_probe,
+       .driver = {
+               .name = "pm8941-wled",
+               .of_match_table = pm8941_wled_match_table,
+       },
+};
+
+module_platform_driver(pm8941_wled_driver);
+
+MODULE_DESCRIPTION("pm8941 wled driver");
+MODULE_LICENSE("GPL v2");