296 lines
7.8 KiB
Diff
296 lines
7.8 KiB
Diff
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From c541b4c80043848ff19e4906ecfc49c6f6818198 Mon Sep 17 00:00:00 2001
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From: Potato <nikko@faint.day>
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Date: Mon, 2 Oct 2023 15:14:09 +0800
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Subject: [PATCH 1/6] video: backlight: Add OCP8178 backlight driver
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This driver is taken from
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https://github.com/clockworkpi/DevTerm/blob/main/Code/patch/armbian_build_a06/patch/kernel-005-backlight.patch
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and optimized for v6.5.
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---
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drivers/video/backlight/Kconfig | 6 +
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drivers/video/backlight/Makefile | 1 +
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drivers/video/backlight/ocp8178_bl.c | 245 +++++++++++++++++++++++++++
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3 files changed, 252 insertions(+)
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create mode 100644 drivers/video/backlight/ocp8178_bl.c
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diff --git a/drivers/video/backlight/Kconfig b/drivers/video/backlight/Kconfig
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index 0e66152b02e6..efb66e7abb85 100644
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--- a/drivers/video/backlight/Kconfig
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+++ b/drivers/video/backlight/Kconfig
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@@ -484,6 +484,12 @@ config BACKLIGHT_LED
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If you have a LCD backlight adjustable by LED class driver, say Y
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to enable this driver.
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+config BACKLIGHT_OCP8178
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+ tristate "OCP8178 Backlight Driver"
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+ depends on GPIOLIB || COMPILE_TEST
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+ help
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+ If you have an OCP8178, say Y to enable the backlight driver.
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+
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endif # BACKLIGHT_CLASS_DEVICE
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endmenu
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diff --git a/drivers/video/backlight/Makefile b/drivers/video/backlight/Makefile
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index ac878b4fb0ee..4d431321f1f2 100644
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--- a/drivers/video/backlight/Makefile
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+++ b/drivers/video/backlight/Makefile
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@@ -60,3 +60,4 @@ obj-$(CONFIG_BACKLIGHT_WM831X) += wm831x_bl.o
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obj-$(CONFIG_BACKLIGHT_ARCXCNN) += arcxcnn_bl.o
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obj-$(CONFIG_BACKLIGHT_RAVE_SP) += rave-sp-backlight.o
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obj-$(CONFIG_BACKLIGHT_LED) += led_bl.o
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+obj-$(CONFIG_BACKLIGHT_OCP8178) += ocp8178_bl.o
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diff --git a/drivers/video/backlight/ocp8178_bl.c b/drivers/video/backlight/ocp8178_bl.c
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new file mode 100644
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index 000000000000..2b0d1b159500
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--- /dev/null
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+++ b/drivers/video/backlight/ocp8178_bl.c
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@@ -0,0 +1,245 @@
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+/*
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+ * ocp8178_bl.c - ocp8178 backlight driver
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+ *
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+ * This program is free software; you can redistribute it and/or modify
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+ * it under the terms of the GNU General Public License version 2 as
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+ * published by the Free Software Foundation.
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+ */
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+
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+#include <linux/backlight.h>
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+#include <linux/err.h>
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+#include <linux/fb.h>
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+#include <linux/gpio/consumer.h>
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+#include <linux/init.h>
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+#include <linux/kernel.h>
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+#include <linux/module.h>
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+#include <linux/of.h>
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+#include <linux/platform_device.h>
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+#include <linux/slab.h>
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+#include <linux/delay.h>
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+
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+struct ocp8178_backlight {
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+ struct device *dev;
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+ struct device *fbdev;
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+
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+ struct gpio_desc *gpiod;
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+ int def_value;
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+ int current_value;
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+};
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+
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+#define DETECT_DELAY 200
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+#define DETECT_TIME 500
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+#define DETECT_WINDOW_TIME 1000
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+#define START_TIME 10
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+#define END_TIME 10
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+#define SHUTDOWN_TIME 3000
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+#define LOW_BIT_HIGH_TIME 10
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+#define LOW_BIT_LOW_TIME 50
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+#define HIGH_BIT_HIGH_TIME 50
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+#define HIGH_BIT_LOW_TIME 10
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+#define MAX_BRIGHTNESS_VALUE 9
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+
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+static void entry_1wire_mode(struct ocp8178_backlight *gbl)
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+{
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+ unsigned long flags = 0;
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+ local_irq_save(flags);
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+ gpiod_set_value(gbl->gpiod, 0);
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+ mdelay(SHUTDOWN_TIME/1000);
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+ gpiod_set_value(gbl->gpiod, 1);
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+ udelay(DETECT_DELAY);
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+ gpiod_set_value(gbl->gpiod, 0);
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+ udelay(DETECT_TIME);
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+ gpiod_set_value(gbl->gpiod, 1);
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+ udelay(DETECT_WINDOW_TIME);
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+ local_irq_restore(flags);
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+}
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+
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+static inline void write_bit(struct ocp8178_backlight *gbl, int bit)
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+{
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+ if (bit) {
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+ gpiod_set_value(gbl->gpiod, 0);
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+ udelay(HIGH_BIT_LOW_TIME);
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+ gpiod_set_value(gbl->gpiod, 1);
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+ udelay(HIGH_BIT_HIGH_TIME);
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+ } else {
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+ gpiod_set_value(gbl->gpiod, 0);
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+ udelay(LOW_BIT_LOW_TIME);
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+ gpiod_set_value(gbl->gpiod, 1);
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+ udelay(LOW_BIT_HIGH_TIME);
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+ }
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+}
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+
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+static void write_byte(struct ocp8178_backlight *gbl, int byte)
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+{
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+ unsigned long flags = 0;
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+ unsigned char data = 0x72;
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+ int i;
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+
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+ local_irq_save(flags);
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+
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+ gpiod_set_value(gbl->gpiod, 1);
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+ udelay(START_TIME);
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+ for(i = 0; i < 8; i++) {
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+ if(data & 0x80) {
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+ write_bit(gbl, 1);
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+ } else {
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+ write_bit(gbl, 0);
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+ }
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+ data <<= 1;
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+ }
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+ gpiod_set_value(gbl->gpiod, 0);
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+ udelay(END_TIME);
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+
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+ data = byte & 0x1f;
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+
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+ gpiod_set_value(gbl->gpiod, 1);
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+ udelay(START_TIME);
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+ for(i = 0; i < 8; i++) {
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+ if(data & 0x80) {
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+ write_bit(gbl, 1);
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+ } else {
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+ write_bit(gbl, 0);
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+ }
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+ data <<= 1;
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+ }
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+ gpiod_set_value(gbl->gpiod, 0);
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+ udelay(END_TIME);
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+ gpiod_set_value(gbl->gpiod, 1);
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+
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+ local_irq_restore(flags);
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+}
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+
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+unsigned char ocp8178_bl_table[MAX_BRIGHTNESS_VALUE+1] = {0, 1, 4, 8, 12, 16, 20, 24, 28, 31};
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+
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+static int ocp8178_update_status(struct backlight_device *bl)
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+{
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+ struct ocp8178_backlight *gbl = bl_get_data(bl);
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+ int brightness = bl->props.brightness, i;
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+
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+ if (bl->props.power != FB_BLANK_UNBLANK ||
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+ bl->props.fb_blank != FB_BLANK_UNBLANK ||
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+ bl->props.state & (BL_CORE_SUSPENDED | BL_CORE_FBBLANK))
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+ brightness = 0;
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+
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+ if(brightness > MAX_BRIGHTNESS_VALUE)
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+ brightness = MAX_BRIGHTNESS_VALUE;
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+
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+ for(i = 0; i < 2; i++) {
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+ entry_1wire_mode(gbl);
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+ write_byte(gbl, ocp8178_bl_table[brightness]);
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+ }
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+ gbl->current_value = brightness;
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+
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+ return 0;
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+}
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+
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+static int ocp8178_get_brightness(struct backlight_device *bl)
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+{
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+ struct ocp8178_backlight *gbl = bl_get_data(bl);
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+ return gbl->current_value;
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+}
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+
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+static int ocp8178_check_fb(struct backlight_device *bl,
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+ struct fb_info *info)
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+{
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+ struct ocp8178_backlight *gbl = bl_get_data(bl);
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+ return gbl->fbdev == NULL || gbl->fbdev == info->dev;
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+}
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+
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+static const struct backlight_ops ocp8178_backlight_ops = {
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+ .options = BL_CORE_SUSPENDRESUME,
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+ .update_status = ocp8178_update_status,
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+ .get_brightness = ocp8178_get_brightness,
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+ .check_fb = ocp8178_check_fb,
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+};
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+
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+static int ocp8178_probe_dt(struct platform_device *pdev,
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+ struct ocp8178_backlight *gbl)
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+{
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+ struct device *dev = &pdev->dev;
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+ struct device_node *of_node = dev->of_node;
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+ enum gpiod_flags flags;
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+ int ret = 0;
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+ u32 default_brightness;
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+
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+ of_property_read_u32(of_node, "default-brightness", &default_brightness);
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+ if(default_brightness > MAX_BRIGHTNESS_VALUE)
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+ gbl->def_value = MAX_BRIGHTNESS_VALUE;
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+ else
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+ gbl->def_value = default_brightness;
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+ flags = gbl->def_value ? GPIOD_OUT_HIGH : GPIOD_OUT_LOW;
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+
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+ gbl->gpiod = devm_gpiod_get(dev, "backlight-control", flags);
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+ if (IS_ERR(gbl->gpiod)) {
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+ ret = PTR_ERR(gbl->gpiod);
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+ return dev_err_probe(dev, ret,
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+ "Error: The backlight-control-gpios parameter is missing or invalid.\n");
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+ }
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+
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+ return ret;
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+}
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+
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+static int ocp8178_probe(struct platform_device *pdev)
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+{
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+ struct device *dev = &pdev->dev;
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+ struct backlight_properties props;
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+ struct backlight_device *bl;
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+ struct ocp8178_backlight *gbl;
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+ struct device_node *of_node = dev->of_node;
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+ int ret;
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+
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+ if (!of_node) {
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+ dev_err(&pdev->dev,
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+ "failed to find platform data or device tree node.\n");
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+ return -ENODEV;
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+ }
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+
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+ gbl = devm_kzalloc(dev, sizeof(*gbl), GFP_KERNEL);
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+ if (gbl == NULL)
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+ return -ENOMEM;
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+
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+ gbl->dev = dev;
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+
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+ ret = ocp8178_probe_dt(pdev, gbl);
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+ if (ret)
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+ return ret;
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+
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+ gbl->current_value = gbl->def_value;
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+
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+ memset(&props, 0, sizeof(props));
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+ props.type = BACKLIGHT_RAW;
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+ props.max_brightness = MAX_BRIGHTNESS_VALUE;
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+ bl = devm_backlight_device_register(&pdev->dev, dev_name(&pdev->dev),
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+ &pdev->dev, gbl, &ocp8178_backlight_ops,
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+ &props);
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+ if (IS_ERR(bl)) {
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+ dev_err(&pdev->dev, "failed to register backlight\n");
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+ return PTR_ERR(bl);
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+ }
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+
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+ bl->props.brightness = gbl->def_value;
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+ backlight_update_status(bl);
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+
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+ platform_set_drvdata(pdev, bl);
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+ return 0;
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+}
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+
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+static struct of_device_id ocp8178_of_match[] = {
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+ { .compatible = "ocp8178-backlight" },
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+ { /* sentinel */ }
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+};
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+
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+MODULE_DEVICE_TABLE(of, ocp8178_of_match);
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+
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+static struct platform_driver ocp8178_driver = {
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+ .driver = {
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+ .name = "ocp8178-backlight",
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+ .of_match_table = of_match_ptr(ocp8178_of_match),
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+ },
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+ .probe = ocp8178_probe,
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+};
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+
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+module_platform_driver(ocp8178_driver);
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+
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+MODULE_DESCRIPTION("OCP8178 Driver");
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+MODULE_LICENSE("GPL");
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--
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2.43.0
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