[PATCH 2/3] tegra: pwm-backlight: add tegra pwm-bl driver

[Alexandre Courbot <acourbot@nvidia.com>]

Add a PWM-backlight subdriver for Tegra boards, with support for
Ventana.

Signed-off-by: Alexandre Courbot <acourbot@nvidia.com>
---
 arch/arm/boot/dts/tegra20-ventana.dts  |  18 +++-
 arch/arm/configs/tegra_defconfig       |   1 +
 drivers/video/backlight/Kconfig        |   7 ++
 drivers/video/backlight/pwm_bl.c       |   3 +
 drivers/video/backlight/pwm_bl_tegra.c | 159 +++++++++++++++++++++++++++++++++
 5 files changed, 186 insertions(+), 2 deletions(-)
 create mode 100644 drivers/video/backlight/pwm_bl_tegra.c

diff --git a/arch/arm/boot/dts/tegra20-ventana.dts b/arch/arm/boot/dts/tegra20-ventana.dts
index adc4754..a77b529 100644
--- a/arch/arm/boot/dts/tegra20-ventana.dts
+++ b/arch/arm/boot/dts/tegra20-ventana.dts
@@ -516,6 +516,20 @@
 		bus-width = <8>;
 	};
 
+	backlight {
+		compatible = "pwm-backlight-ventana";
+		brightness-levels = <0 16 32 48 64 80 96 112 128 144 160 176 192 208 224 240 255>;
+		default-brightness-level = <12>;
+
+		pwms = <&pwm 2 5000000>;
+		pwm-names = "backlight";
+
+		power-supply = <&vdd_bl_reg>;
+		panel-supply = <&vdd_pnl_reg>;
+		bl-gpio = <&gpio 28 0>;
+		bl-panel = <&gpio 10 0>;
+	};
+
 	regulators {
 		compatible = "simple-bus";
 		#address-cells = <1>;
@@ -549,7 +563,7 @@
 			enable-active-high;
 		};
 
-		regulator@3 {
+		vdd_pnl_reg: regulator@3 {
 			compatible = "regulator-fixed";
 			reg = <3>;
 			regulator-name = "vdd_pnl";
@@ -559,7 +573,7 @@
 			enable-active-high;
 		};
 
-		regulator@4 {
+		vdd_bl_reg: regulator@4 {
 			compatible = "regulator-fixed";
 			reg = <4>;
 			regulator-name = "vdd_bl";
diff --git a/arch/arm/configs/tegra_defconfig b/arch/arm/configs/tegra_defconfig
index a7827fd..1c46602 100644
--- a/arch/arm/configs/tegra_defconfig
+++ b/arch/arm/configs/tegra_defconfig
@@ -150,6 +150,7 @@ CONFIG_BACKLIGHT_LCD_SUPPORT=y
 CONFIG_BACKLIGHT_CLASS_DEVICE=y
 # CONFIG_BACKLIGHT_GENERIC is not set
 CONFIG_BACKLIGHT_PWM=y
+CONFIG_BACKLIGHT_PWM_TEGRA=y
 CONFIG_FRAMEBUFFER_CONSOLE=y
 CONFIG_LOGO=y
 CONFIG_SOUND=y
diff --git a/drivers/video/backlight/Kconfig b/drivers/video/backlight/Kconfig
index 765a945..377a409 100644
--- a/drivers/video/backlight/Kconfig
+++ b/drivers/video/backlight/Kconfig
@@ -244,6 +244,13 @@ config BACKLIGHT_PWM
 	  If you have a LCD backlight adjustable by PWM, say Y to enable
 	  this driver.
 
+config BACKLIGHT_PWM_TEGRA
+	bool "PWM Backlight Driver for Tegra boards"
+	depends on BACKLIGHT_PWM && ARCH_TEGRA
+	help
+	  Support backlight power sequencing for Tegra boards.
+	  Supported boards: Ventana.
+
 config BACKLIGHT_DA903X
 	tristate "Backlight Driver for DA9030/DA9034 using WLED"
 	depends on PMIC_DA903X
diff --git a/drivers/video/backlight/pwm_bl.c b/drivers/video/backlight/pwm_bl.c
index b65a797..1a4a9a3 100644
--- a/drivers/video/backlight/pwm_bl.c
+++ b/drivers/video/backlight/pwm_bl.c
@@ -217,6 +217,9 @@ static int pwm_backlight_parse_dt(struct device *dev,
 
 static struct of_device_id pwm_backlight_of_match[] = {
 	{ .compatible = "pwm-backlight" },
+#ifdef CONFIG_BACKLIGHT_PWM_TEGRA
+	{ .compatible = "pwm-backlight-ventana" },
+#endif
 	{ }
 };
 
diff --git a/drivers/video/backlight/pwm_bl_tegra.c b/drivers/video/backlight/pwm_bl_tegra.c
new file mode 100644
index 0000000..8f2195b
--- /dev/null
+++ b/drivers/video/backlight/pwm_bl_tegra.c
@@ -0,0 +1,159 @@
+/*
+ * pwm-backlight subdriver for Tegra.
+ *
+ * Copyright (c) 2013 NVIDIA CORPORATION.  All rights reserved.
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * 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/err.h>
+#include <linux/module.h>
+#include <linux/pwm_backlight.h>
+#include <linux/regulator/consumer.h>
+#include <linux/gpio.h>
+#include <linux/of_gpio.h>
+#include <linux/list.h>
+#include <linux/delay.h>
+#include <linux/slab.h>
+
+struct ventana_bl_data {
+	struct regulator *vdd_power;
+	struct regulator *vdd_panel;
+	int bl_gpio;
+	int panel_gpio;
+	bool is_on;
+};
+
+static int init_ventana(struct device *dev)
+{
+	struct ventana_bl_data *data;
+	int ret;
+
+	data = devm_kzalloc(dev, sizeof(struct ventana_bl_data), GFP_KERNEL);
+	if (!data)
+		return -ENOMEM;
+
+	data->vdd_power = devm_regulator_get(dev, "power");
+	if (IS_ERR(data->vdd_power)) {
+		dev_err(dev, "cannot get power regulator!\n");
+		return PTR_ERR(data->vdd_power);
+	}
+
+	data->vdd_panel = devm_regulator_get(dev, "panel");
+	if (IS_ERR(data->vdd_panel)) {
+		dev_err(dev, "cannot get panel regulator!\n");
+		return PTR_ERR(data->vdd_panel);
+	}
+
+	ret = of_get_named_gpio(dev->of_node, "bl-gpio", 0);
+	if (ret < 0) {
+		dev_err(dev, "cannot find backlight GPIO!\n");
+		return ret;
+	}
+	data->bl_gpio = ret;
+
+	ret = of_get_named_gpio(dev->of_node, "bl-panel", 0);
+	if (ret < 0) {
+		dev_err(dev, "cannot find panel GPIO!\n");
+		return ret;
+	}
+	data->panel_gpio = ret;
+
+	ret = devm_gpio_request_one(dev, data->bl_gpio,
+				    GPIOF_DIR_OUT | GPIOF_OUT_INIT_LOW,
+				    "backlight");
+	if (ret < 0) {
+		dev_err(dev, "cannot request backlight GPIO!\n");
+		return ret;
+	}
+
+	ret = devm_gpio_request_one(dev, data->panel_gpio,
+				    GPIOF_DIR_OUT | GPIOF_OUT_INIT_LOW,
+				    "panel");
+	if (ret < 0) {
+		dev_err(dev, "cannot request panel GPIO!\n");
+		return ret;
+	}
+
+	pwm_backlight_set_subdriver_data(dev, data);
+
+	return 0;
+}
+
+static void exit_ventana(struct device *dev)
+{
+	struct ventana_bl_data *data = pwm_backlight_get_subdriver_data(dev);
+
+	devm_gpio_free(dev, data->panel_gpio);
+	devm_gpio_free(dev, data->bl_gpio);
+	devm_regulator_put(data->vdd_panel);
+	devm_regulator_put(data->vdd_power);
+	devm_kfree(dev, data);
+}
+
+static int notify_ventana(struct device *dev, int brightness)
+{
+	struct ventana_bl_data *data = pwm_backlight_get_subdriver_data(dev);
+	if (brightness && !data->is_on) {
+		regulator_enable(data->vdd_panel);
+		gpio_set_value(data->panel_gpio, 1);
+		usleep_range(200000, 200000);
+		regulator_enable(data->vdd_power);
+		usleep_range(10000, 10000);
+	} else if (!brightness && data->is_on) {
+		gpio_set_value(data->bl_gpio, 0);
+	}
+
+	return brightness;
+}
+
+static void notify_after_ventana(struct device *dev, int brightness)
+{
+	struct ventana_bl_data *data = pwm_backlight_get_subdriver_data(dev);
+	if (brightness && !data->is_on) {
+		gpio_set_value(data->bl_gpio, 1);
+		data->is_on = true;
+	} else if (!brightness && data->is_on) {
+		usleep_range(10000, 10000);
+		regulator_disable(data->vdd_power);
+		usleep_range(200000, 200000);
+		gpio_set_value(data->panel_gpio, 0);
+		regulator_disable(data->vdd_panel);
+		data->is_on = false;
+	}
+}
+
+static struct pwm_backlight_subdriver pwm_backlight_ventana_subdriver = {
+	.name = "pwm-backlight-ventana",
+	.init = init_ventana,
+	.exit = exit_ventana,
+	.notify = notify_ventana,
+	.notify_after = notify_after_ventana,
+};
+
+static int __init pwm_backlight_tegra_init(void)
+{
+	pwm_backlight_add_subdriver(&pwm_backlight_ventana_subdriver);
+	return 0;
+}
+
+static void __exit pwm_backlight_tegra_exit(void)
+{
+	pwm_backlight_remove_subdriver(&pwm_backlight_ventana_subdriver);
+}
+
+module_init(pwm_backlight_tegra_init);
+module_exit(pwm_backlight_tegra_exit);
+
+MODULE_DESCRIPTION("Backlight Driver for Tegra boards");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:pwm-tegra-backlight");
+
+
-- 
1.8.1.1