--- a/drivers/video/backlight/Kconfig
+++ b/drivers/video/backlight/Kconfig
@@ -479,6 +479,12 @@ config BACKLIGHT_LED
If you have a LCD backlight adjustable by LED class driver, say Y
to enable this driver.
+config BACKLIGHT_OCP8178
+ tristate "OCP8178 Backlight Driver"
+ depends on GPIOLIB
+ help
+ If you have an OCP8178, say Y to enable the backlight driver.
+
endif # BACKLIGHT_CLASS_DEVICE
endmenu
--- a/drivers/video/backlight/Makefile
+++ b/drivers/video/backlight/Makefile
@@ -59,3 +59,4 @@ obj-$(CONFIG_BACKLIGHT_WM831X) += wm831x_bl.o
obj-$(CONFIG_BACKLIGHT_ARCXCNN) += arcxcnn_bl.o
obj-$(CONFIG_BACKLIGHT_RAVE_SP) += rave-sp-backlight.o
obj-$(CONFIG_BACKLIGHT_LED) += led_bl.o
+obj-$(CONFIG_BACKLIGHT_OCP8178) += ocp8178_bl.o
--- /dev/null
+++ b/drivers/video/backlight/ocp8178_bl.c
@@ -0,0 +1,277 @@
+/*
+ * ocp8178_bl.c - ocp8178 backlight driver
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/backlight.h>
+#include <linux/err.h>
+#include <linux/fb.h>
+#include <linux/gpio.h> /* Only for legacy support */
+#include <linux/gpio/consumer.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_gpio.h>
+#include <linux/platform_data/gpio_backlight.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+#include <linux/delay.h>
+#include <linux/timer.h>
+#include <linux/poll.h>
+#include <linux/proc_fs.h>
+#include <linux/seq_file.h>
+#include <linux/sched.h>
+#include <linux/interrupt.h>
+#include <linux/irq.h>
+#include <linux/io.h>
+#include <linux/clk.h>
+
+struct ocp8178_backlight {
+ struct device *dev;
+ struct device *fbdev;
+
+ struct gpio_desc *gpiod;
+ int def_value;
+ int current_value;
+};
+
+#define DETECT_DELAY 200
+#define DETECT_TIME 500
+#define DETECT_WINDOW_TIME 1000
+#define START_TIME 10
+#define END_TIME 10
+#define SHUTDOWN_TIME 3000
+#define LOW_BIT_HIGH_TIME 10
+#define LOW_BIT_LOW_TIME 50
+#define HIGH_BIT_HIGH_TIME 50
+#define HIGH_BIT_LOW_TIME 10
+#define MAX_BRIGHTNESS_VALUE 9
+
+static void entry_1wire_mode(struct ocp8178_backlight *gbl)
+{
+ unsigned long flags = 0;
+ local_irq_save(flags);
+ gpiod_set_value(gbl->gpiod, 0);
+ mdelay(SHUTDOWN_TIME/1000);
+ gpiod_set_value(gbl->gpiod, 1);
+ udelay(DETECT_DELAY);
+ gpiod_set_value(gbl->gpiod, 0);
+ udelay(DETECT_TIME);
+ gpiod_set_value(gbl->gpiod, 1);
+ udelay(DETECT_WINDOW_TIME);
+ local_irq_restore(flags);
+}
+
+static inline void write_bit(struct ocp8178_backlight *gbl, int bit)
+{
+ if (bit) {
+ gpiod_set_value(gbl->gpiod, 0);
+ udelay(HIGH_BIT_LOW_TIME);
+ gpiod_set_value(gbl->gpiod, 1);
+ udelay(HIGH_BIT_HIGH_TIME);
+ } else {
+ gpiod_set_value(gbl->gpiod, 0);
+ udelay(LOW_BIT_LOW_TIME);
+ gpiod_set_value(gbl->gpiod, 1);
+ udelay(LOW_BIT_HIGH_TIME);
+ }
+}
+
+static void write_byte(struct ocp8178_backlight *gbl, int byte)
+{
+ unsigned long flags = 0;
+ unsigned char data = 0x72;
+ int i;
+
+ local_irq_save(flags);
+
+ gpiod_set_value(gbl->gpiod, 1);
+ udelay(START_TIME);
+ for(i = 0; i < 8; i++) {
+ if(data & 0x80) {
+ write_bit(gbl, 1);
+ } else {
+ write_bit(gbl, 0);
+ }
+ data <<= 1;
+ }
+ gpiod_set_value(gbl->gpiod, 0);
+ udelay(END_TIME);
+
+ data = byte & 0x1f;
+
+ gpiod_set_value(gbl->gpiod, 1);
+ udelay(START_TIME);
+ for(i = 0; i < 8; i++) {
+ if(data & 0x80) {
+ write_bit(gbl, 1);
+ } else {
+ write_bit(gbl, 0);
+ }
+ data <<= 1;
+ }
+ gpiod_set_value(gbl->gpiod, 0);
+ udelay(END_TIME);
+ gpiod_set_value(gbl->gpiod, 1);
+
+ local_irq_restore(flags);
+}
+
+unsigned char ocp8178_bl_table[MAX_BRIGHTNESS_VALUE+1] = {0, 1, 4, 8, 12, 16, 20, 24, 28, 31};
+
+static int ocp8178_update_status(struct backlight_device *bl)
+{
+ struct ocp8178_backlight *gbl = bl_get_data(bl);
+ int brightness = bl->props.brightness, i;
+
+ 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(brightness > MAX_BRIGHTNESS_VALUE)
+ brightness = MAX_BRIGHTNESS_VALUE;
+
+ for(i = 0; i < 2; i++) {
+ entry_1wire_mode(gbl);
+ write_byte(gbl, ocp8178_bl_table[brightness]);
+ }
+ gbl->current_value = brightness;
+
+ return 0;
+}
+
+static int ocp8178_get_brightness(struct backlight_device *bl)
+{
+ struct ocp8178_backlight *gbl = bl_get_data(bl);
+ return gbl->current_value;
+}
+
+static int ocp8178_check_fb(struct backlight_device *bl,
+ struct fb_info *info)
+{
+ struct ocp8178_backlight *gbl = bl_get_data(bl);
+ return gbl->fbdev == NULL || gbl->fbdev == info->dev;
+}
+
+static const struct backlight_ops ocp8178_backlight_ops = {
+ .options = BL_CORE_SUSPENDRESUME,
+ .update_status = ocp8178_update_status,
+ .get_brightness = ocp8178_get_brightness,
+ .check_fb = ocp8178_check_fb,
+};
+
+static int ocp8178_probe_dt(struct platform_device *pdev,
+ struct ocp8178_backlight *gbl)
+{
+ struct device *dev = &pdev->dev;
+ struct device_node *np = dev->of_node;
+ enum gpiod_flags flags;
+ int ret = 0;
+ u32 value32;
+
+ of_property_read_u32(np, "default-brightness", &value32);
+ if(value32 > MAX_BRIGHTNESS_VALUE)
+ gbl->def_value = MAX_BRIGHTNESS_VALUE;
+ else
+ gbl->def_value = value32;
+ flags = gbl->def_value ? GPIOD_OUT_HIGH : GPIOD_OUT_LOW;
+
+ gbl->gpiod = devm_gpiod_get(dev, "backlight-control", flags);
+ if (IS_ERR(gbl->gpiod)) {
+ ret = PTR_ERR(gbl->gpiod);
+
+ if (ret != -EPROBE_DEFER) {
+ dev_err(dev,
+ "Error: The gpios parameter is missing or invalid.\n");
+ }
+ }
+
+ return ret;
+}
+
+static struct backlight_device *backlight;
+
+static int ocp8178_probe(struct platform_device *pdev)
+{
+ struct backlight_properties props;
+ struct backlight_device *bl;
+ struct ocp8178_backlight *gbl;
+ struct device_node *np = pdev->dev.of_node;
+ int ret;
+
+ if ( !np) {
+ dev_err(&pdev->dev,
+ "failed to find platform data or device tree node.\n");
+ return -ENODEV;
+ }
+
+ gbl = devm_kzalloc(&pdev->dev, sizeof(*gbl), GFP_KERNEL);
+ if (gbl == NULL)
+ return -ENOMEM;
+
+ gbl->dev = &pdev->dev;
+
+ ret = ocp8178_probe_dt(pdev, gbl);
+ if (ret)
+ return ret;
+
+ gbl->current_value = gbl->def_value;
+
+ memset(&props, 0, sizeof(props));
+ props.type = BACKLIGHT_RAW;
+ props.max_brightness = MAX_BRIGHTNESS_VALUE;
+ bl = devm_backlight_device_register(&pdev->dev, dev_name(&pdev->dev),
+ &pdev->dev, gbl, &ocp8178_backlight_ops,
+ &props);
+ if (IS_ERR(bl)) {
+ dev_err(&pdev->dev, "failed to register backlight\n");
+ return PTR_ERR(bl);
+ }
+
+// entry_1wire_mode(gbl);
+
+ bl->props.brightness = gbl->def_value;
+ backlight_update_status(bl);
+
+ platform_set_drvdata(pdev, bl);
+
+ backlight = bl;
+ return 0;
+}
+
+static int ocp8178_suspend(struct platform_device *pdev, pm_message_t state)
+{
+ return 0;
+}
+
+static int ocp8178_resume(struct platform_device *pdev)
+{
+ return 0;
+}
+
+static struct of_device_id ocp8178_of_match[] = {
+ { .compatible = "ocp8178-backlight" },
+ { /* sentinel */ }
+};
+
+MODULE_DEVICE_TABLE(of, ocp8178_of_match);
+
+static struct platform_driver ocp8178_driver = {
+ .driver = {
+ .name = "ocp8178-backlight",
+ .of_match_table = of_match_ptr(ocp8178_of_match),
+ },
+ .probe = ocp8178_probe,
+ .suspend = ocp8178_suspend,
+ .resume = ocp8178_resume,
+};
+
+module_platform_driver(ocp8178_driver);
+
+MODULE_DESCRIPTION("OCP8178 Driver");
+MODULE_LICENSE("GPL");