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authorDuje Mihanović <duje.mihanovic@skole.hr>2024-01-25 18:30:56 +0300
committerLee Jones <lee@kernel.org>2024-03-07 11:45:16 +0300
commita5554f1b5bc3be5d01f41b7550aa5b05b7c88c09 (patch)
treed3ad9cf3576f06b64e57b2a95803d9a0b498d778 /drivers/video
parent922235a9b89417e4c355ca813a1049c755b89570 (diff)
downloadlinux-a5554f1b5bc3be5d01f41b7550aa5b05b7c88c09.tar.xz
backlight: Add Kinetic KTD2801 Backlight support
KTD2801 is a LED backlight driver IC found in samsung,coreprimevelte. The brightness can be set using PWM or the ExpressWire protocol. Add support for the KTD2801. Reviewed-by: Linus Walleij <linus.walleij@linaro.org> Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org> Signed-off-by: Duje Mihanović <duje.mihanovic@skole.hr> Link: https://lore.kernel.org/r/20240125-ktd2801-v5-4-e22da232a825@skole.hr Signed-off-by: Lee Jones <lee@kernel.org>
Diffstat (limited to 'drivers/video')
-rw-r--r--drivers/video/backlight/Kconfig7
-rw-r--r--drivers/video/backlight/Makefile1
-rw-r--r--drivers/video/backlight/ktd2801-backlight.c128
3 files changed, 136 insertions, 0 deletions
diff --git a/drivers/video/backlight/Kconfig b/drivers/video/backlight/Kconfig
index ea2d0d69bd8c..230bca07b09d 100644
--- a/drivers/video/backlight/Kconfig
+++ b/drivers/video/backlight/Kconfig
@@ -183,6 +183,13 @@ config BACKLIGHT_KTD253
which is a 1-wire GPIO-controlled backlight found in some mobile
phones.
+config BACKLIGHT_KTD2801
+ tristate "Backlight Driver for Kinetic KTD2801"
+ select LEDS_EXPRESSWIRE
+ help
+ Say Y to enable the backlight driver for the Kinetic KTD2801 1-wire
+ GPIO-controlled backlight found in Samsung Galaxy Core Prime VE LTE.
+
config BACKLIGHT_KTZ8866
tristate "Backlight Driver for Kinetic KTZ8866"
depends on I2C
diff --git a/drivers/video/backlight/Makefile b/drivers/video/backlight/Makefile
index 06966cb20459..8d2cb252042d 100644
--- a/drivers/video/backlight/Makefile
+++ b/drivers/video/backlight/Makefile
@@ -34,6 +34,7 @@ obj-$(CONFIG_BACKLIGHT_HP680) += hp680_bl.o
obj-$(CONFIG_BACKLIGHT_HP700) += jornada720_bl.o
obj-$(CONFIG_BACKLIGHT_IPAQ_MICRO) += ipaq_micro_bl.o
obj-$(CONFIG_BACKLIGHT_KTD253) += ktd253-backlight.o
+obj-$(CONFIG_BACKLIGHT_KTD2801) += ktd2801-backlight.o
obj-$(CONFIG_BACKLIGHT_KTZ8866) += ktz8866.o
obj-$(CONFIG_BACKLIGHT_LM3533) += lm3533_bl.o
obj-$(CONFIG_BACKLIGHT_LM3630A) += lm3630a_bl.o
diff --git a/drivers/video/backlight/ktd2801-backlight.c b/drivers/video/backlight/ktd2801-backlight.c
new file mode 100644
index 000000000000..c020acff40f1
--- /dev/null
+++ b/drivers/video/backlight/ktd2801-backlight.c
@@ -0,0 +1,128 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Datasheet:
+ * https://www.kinet-ic.com/uploads/web/KTD2801/KTD2801-04b.pdf
+ */
+#include <linux/backlight.h>
+#include <linux/gpio/consumer.h>
+#include <linux/leds-expresswire.h>
+#include <linux/platform_device.h>
+#include <linux/property.h>
+
+#define KTD2801_DEFAULT_BRIGHTNESS 100
+#define KTD2801_MAX_BRIGHTNESS 255
+
+/* These values have been extracted from Samsung's driver. */
+const struct expresswire_timing ktd2801_timing = {
+ .poweroff_us = 2600,
+ .detect_delay_us = 150,
+ .detect_us = 270,
+ .data_start_us = 5,
+ .short_bitset_us = 5,
+ .long_bitset_us = 15,
+ .end_of_data_low_us = 10,
+ .end_of_data_high_us = 350
+};
+
+struct ktd2801_backlight {
+ struct expresswire_common_props props;
+ struct backlight_device *bd;
+ bool was_on;
+};
+
+static int ktd2801_update_status(struct backlight_device *bd)
+{
+ struct ktd2801_backlight *ktd2801 = bl_get_data(bd);
+ u8 brightness = (u8) backlight_get_brightness(bd);
+
+ if (backlight_is_blank(bd)) {
+ expresswire_power_off(&ktd2801->props);
+ ktd2801->was_on = false;
+ return 0;
+ }
+
+ if (!ktd2801->was_on) {
+ expresswire_enable(&ktd2801->props);
+ ktd2801->was_on = true;
+ }
+
+ expresswire_write_u8(&ktd2801->props, brightness);
+
+ return 0;
+}
+
+static const struct backlight_ops ktd2801_backlight_ops = {
+ .update_status = ktd2801_update_status,
+};
+
+static int ktd2801_backlight_probe(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ struct backlight_device *bd;
+ struct ktd2801_backlight *ktd2801;
+ u32 brightness, max_brightness;
+ int ret;
+
+ ktd2801 = devm_kzalloc(dev, sizeof(*ktd2801), GFP_KERNEL);
+ if (!ktd2801)
+ return -ENOMEM;
+ ktd2801->was_on = true;
+ ktd2801->props.timing = ktd2801_timing;
+
+ ret = device_property_read_u32(dev, "max-brightness", &max_brightness);
+ if (ret)
+ max_brightness = KTD2801_MAX_BRIGHTNESS;
+ if (max_brightness > KTD2801_MAX_BRIGHTNESS) {
+ dev_err(dev, "illegal max brightness specified\n");
+ max_brightness = KTD2801_MAX_BRIGHTNESS;
+ }
+
+ ret = device_property_read_u32(dev, "default-brightness", &brightness);
+ if (ret)
+ brightness = KTD2801_DEFAULT_BRIGHTNESS;
+ if (brightness > max_brightness) {
+ dev_err(dev, "default brightness exceeds max\n");
+ brightness = max_brightness;
+ }
+
+ ktd2801->props.ctrl_gpio = devm_gpiod_get(dev, "ctrl", GPIOD_OUT_HIGH);
+ if (IS_ERR(ktd2801->props.ctrl_gpio))
+ return dev_err_probe(dev, PTR_ERR(ktd2801->props.ctrl_gpio),
+ "failed to get backlight GPIO");
+ gpiod_set_consumer_name(ktd2801->props.ctrl_gpio, dev_name(dev));
+
+ bd = devm_backlight_device_register(dev, dev_name(dev), dev, ktd2801,
+ &ktd2801_backlight_ops, NULL);
+ if (IS_ERR(bd))
+ return dev_err_probe(dev, PTR_ERR(bd),
+ "failed to register backlight");
+
+ bd->props.max_brightness = max_brightness;
+ bd->props.brightness = brightness;
+
+ ktd2801->bd = bd;
+ platform_set_drvdata(pdev, bd);
+ backlight_update_status(bd);
+
+ return 0;
+}
+
+static const struct of_device_id ktd2801_of_match[] = {
+ { .compatible = "kinetic,ktd2801" },
+ { }
+};
+MODULE_DEVICE_TABLE(of, ktd2801_of_match);
+
+static struct platform_driver ktd2801_backlight_driver = {
+ .driver = {
+ .name = "ktd2801-backlight",
+ .of_match_table = ktd2801_of_match,
+ },
+ .probe = ktd2801_backlight_probe,
+};
+module_platform_driver(ktd2801_backlight_driver);
+
+MODULE_IMPORT_NS(EXPRESSWIRE);
+MODULE_AUTHOR("Duje Mihanović <duje.mihanovic@skole.hr>");
+MODULE_DESCRIPTION("Kinetic KTD2801 Backlight Driver");
+MODULE_LICENSE("GPL");