dm: backlight: Add a driver for GPIO backlight

Add a driver for GPIO backlights.
It understands the standard device tree binding.
It can be used with simple-panel when PWM is not necessary.

Signed-off-by: Patrick Delaunay <patrick.delaunay@st.com>

diff --git a/drivers/video/Kconfig b/drivers/video/Kconfig
index fe34da073bbbaeb899134b8f5d8e497d468237b1..40a656ee0a89f896d3ac5640518763951f7c243b 100644 (file)
--- a/drivers/video/Kconfig
+++ b/drivers/video/Kconfig
@@ -25,6 +25,16 @@ config BACKLIGHT_PWM
          it understands the standard device tree
          (leds/backlight/pwm-backlight.txt)
 
+config BACKLIGHT_GPIO
+       bool "Generic GPIO based Backlight Driver"
+       depends on DM_VIDEO
+       help
+         If you have a LCD backlight adjustable by GPIO, say Y to enable
+         this driver.
+         This driver can be used with "simple-panel" and
+         it understands the standard device tree
+         (leds/backlight/gpio-backlight.txt)
+
 config VIDEO_BPP8
        bool "Support 8-bit-per-pixel displays"
        depends on DM_VIDEO

diff --git a/drivers/video/Makefile b/drivers/video/Makefile
index fc1cd14a51eb02f843630f5b6da11aca23d39629..e73bc93b1682e6eb44a5eb8a3539de46175fc94e 100644 (file)
--- a/drivers/video/Makefile
+++ b/drivers/video/Makefile
@@ -12,6 +12,7 @@ obj-$(CONFIG_DM_VIDEO) += panel-uclass.o simple_panel.o
 obj-$(CONFIG_DM_VIDEO) += video-uclass.o vidconsole-uclass.o
 obj-$(CONFIG_DM_VIDEO) += video_bmp.o
 obj-$(CONFIG_BACKLIGHT_PWM) += pwm_backlight.o
+obj-$(CONFIG_BACKLIGHT_GPIO) += backlight_gpio.o
 obj-$(CONFIG_CONSOLE_NORMAL) += console_normal.o
 obj-$(CONFIG_CONSOLE_ROTATION) += console_rotate.o
 obj-$(CONFIG_CONSOLE_TRUETYPE) += console_truetype.o fonts/

diff --git a/drivers/video/backlight_gpio.c b/drivers/video/backlight_gpio.c
new file mode 100644 (file)
index 0000000..772df5d
--- /dev/null
+++ b/drivers/video/backlight_gpio.c
@@ -0,0 +1,74 @@
+/*
+ * Copyright (C) 2017, STMicroelectronics - All Rights Reserved
+ * Author: Patrick Delaunay <patrick.delaunay@st.com>
+ *
+ * SPDX-License-Identifier:    GPL-2.0+
+ */
+
+#include <common.h>
+#include <dm.h>
+#include <backlight.h>
+#include <asm/gpio.h>
+
+DECLARE_GLOBAL_DATA_PTR;
+
+struct gpio_backlight_priv {
+       struct gpio_desc gpio;
+       bool def_value;
+};
+
+static int gpio_backlight_enable(struct udevice *dev)
+{
+       struct gpio_backlight_priv *priv = dev_get_priv(dev);
+
+       dm_gpio_set_value(&priv->gpio, 1);
+
+       return 0;
+}
+
+static int gpio_backlight_ofdata_to_platdata(struct udevice *dev)
+{
+       struct gpio_backlight_priv *priv = dev_get_priv(dev);
+       int ret;
+
+       ret = gpio_request_by_name(dev, "gpios", 0, &priv->gpio,
+                                  GPIOD_IS_OUT);
+       if (ret) {
+               debug("%s: Warning: cannot get GPIO: ret=%d\n",
+                     __func__, ret);
+               return ret;
+       }
+
+       priv->def_value = dev_read_bool(dev, "default-on");
+
+       return 0;
+}
+
+static int gpio_backlight_probe(struct udevice *dev)
+{
+       struct gpio_backlight_priv *priv = dev_get_priv(dev);
+
+       if (priv->def_value)
+               gpio_backlight_enable(dev);
+
+       return 0;
+}
+
+static const struct backlight_ops gpio_backlight_ops = {
+       .enable = gpio_backlight_enable,
+};
+
+static const struct udevice_id gpio_backlight_ids[] = {
+       { .compatible = "gpio-backlight" },
+       { }
+};
+
+U_BOOT_DRIVER(gpio_backlight) = {
+       .name   = "gpio_backlight",
+       .id     = UCLASS_PANEL_BACKLIGHT,
+       .of_match = gpio_backlight_ids,
+       .ops    = &gpio_backlight_ops,
+       .ofdata_to_platdata     = gpio_backlight_ofdata_to_platdata,
+       .probe          = gpio_backlight_probe,
+       .priv_auto_alloc_size   = sizeof(struct gpio_backlight_priv),
+};