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/backlight_gpio.c b/drivers/video/backlight_gpio.c
new file mode 100644
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),
+};