[PATCH 3/3] leds: Add ktd2692 flash LED driver
From: Ingi Kim
Date: Thu Feb 26 2015 - 20:01:53 EST
This patch adds a driver to support the ktd2692 flash LEDs.
ktd2692 can control flash current by ExpressWire interface.
Signed-off-by: Ingi Kim <ingi2.kim@xxxxxxxxxxx>
---
drivers/leds/Kconfig | 8 ++
drivers/leds/Makefile | 1 +
drivers/leds/leds-ktd2692.c | 245 +++++++++++++++++++++++++++++++++++++++++++
3 files changed, 254 insertions(+)
create mode 100644 drivers/leds/leds-ktd2692.c
diff --git a/drivers/leds/Kconfig b/drivers/leds/Kconfig
index 25b320d..f8870db 100644
--- a/drivers/leds/Kconfig
+++ b/drivers/leds/Kconfig
@@ -526,6 +526,14 @@ config LEDS_VERSATILE
This option enabled support for the LEDs on the ARM Versatile
and RealView boards. Say Y to enabled these.
+config LEDS_KTD2692
+ tristate "LED support for the KTD2692 Driver"
+ depends on LEDS_CLASS
+ depends on GPIOLIB
+ help
+ This option enables support for the KTD2692 connected through
+ ExpressWire Interface. Say Y to enable these.
+
comment "LED Triggers"
source "drivers/leds/trigger/Kconfig"
diff --git a/drivers/leds/Makefile b/drivers/leds/Makefile
index cbba921..289513b 100644
--- a/drivers/leds/Makefile
+++ b/drivers/leds/Makefile
@@ -58,6 +58,7 @@ obj-$(CONFIG_LEDS_BLINKM) += leds-blinkm.o
obj-$(CONFIG_LEDS_SYSCON) += leds-syscon.o
obj-$(CONFIG_LEDS_VERSATILE) += leds-versatile.o
obj-$(CONFIG_LEDS_MENF21BMC) += leds-menf21bmc.o
+obj-$(CONFIG_LEDS_KTD2692) += leds-ktd2692.o
# LED SPI Drivers
obj-$(CONFIG_LEDS_DAC124S085) += leds-dac124s085.o
diff --git a/drivers/leds/leds-ktd2692.c b/drivers/leds/leds-ktd2692.c
new file mode 100644
index 0000000..9c98689
--- /dev/null
+++ b/drivers/leds/leds-ktd2692.c
@@ -0,0 +1,245 @@
+/*
+ * Kinetic Technologies KTD2692 Flash LED Driver
+ *
+ * Copyright (C) 2015 Samsung Electronics
+ * Ingi Kim <ingi2.kim@xxxxxxxxxxx>
+ *
+ * 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/module.h>
+#include <linux/err.h>
+#include <linux/leds.h>
+#include <linux/of_gpio.h>
+#include <linux/platform_device.h>
+#include <linux/delay.h>
+
+#define GET_BIT(bit, val) (((val) >> (bit)) & 0x01)
+
+/* Adjust a multiple of brightness */
+#define KTD2692_BRIGHTNESS_RANGE_255_TO_16(x) (((x) >> 4) & 0x0F)
+#define KTD2692_BRIGHTNESS_RANGE_255_TO_8(x) (((x) >> 5) & 0x0F)
+#define KTD2692_BRIGHTNESS_RANGE_255_TO_4(x) (((x) >> 6) & 0x0F)
+
+/* Base register address */
+#define KTD2692_REG_LVP_BASE 0x00
+#define KTD2692_REG_FLASH_TIMEOUT_BASE 0x20
+#define KTD2692_REG_MIN_CURRENT_SET_BASE 0x40
+#define KTD2692_REG_MOVIE_CURRENT_BASE 0x60
+#define KTD2692_REG_FLASH_CURRENT_BASE 0x80
+#define KTD2692_REG_MODE_BASE 0xA0
+
+/* Set bit coding time for expresswire interface */
+#define KTD2692_TIME_RESET_US 700
+#define KTD2692_TIME_DATA_START_TIME_US 10
+#define KTD2692_TIME_HIGH_END_OF_DATA_US 350
+#define KTD2692_TIME_LOW_END_OF_DATA_US 10
+#define KTD2692_TIME_SHORT_BITSET_US 4
+#define KTD2692_TIME_LONG_BITSET_US 12
+
+/* KTD2692 default length of name */
+#define KTD2692_NAME_LENGTH 20
+
+/* KTD2692 default name */
+#define KTD2692_DEFAULT_NAME "ktd2692"
+
+enum ktd2692_mode {
+ KTD2692_MODE_DISABLE = 0,
+ KTD2692_MODE_MOVIE,
+ KTD2692_MODE_FLASH,
+};
+
+enum ktd2692_bitset {
+ KTD2692_LOW = 0,
+ KTD2692_HIGH,
+};
+
+struct ktd2692_context {
+ struct led_classdev cdev;
+ u8 mode;
+ int strobe_gpio;
+};
+
+static int ktd2692_brightness_set_gpio(struct ktd2692_context *led)
+{
+ int ret;
+
+ ret = devm_gpio_request_one(led->cdev.dev,
+ led->strobe_gpio, GPIOF_INIT_LOW, "strobe-gpio");
+
+ if (ret)
+ dev_err(led->cdev.dev,
+ "failed to request strobe-gpio %d error %d\n",
+ led->strobe_gpio, ret);
+
+ return ret;
+}
+
+static void ktd2692_expresswire_start(struct ktd2692_context *led)
+{
+ gpio_set_value(led->strobe_gpio, KTD2692_HIGH);
+ udelay(KTD2692_TIME_DATA_START_TIME_US);
+}
+
+static void ktd2692_expresswire_reset(struct ktd2692_context *led)
+{
+ gpio_set_value(led->strobe_gpio, KTD2692_LOW);
+ udelay(KTD2692_TIME_RESET_US);
+}
+
+static void ktd2692_expresswire_end(struct ktd2692_context *led)
+{
+ gpio_set_value(led->strobe_gpio, KTD2692_LOW);
+ udelay(KTD2692_TIME_LOW_END_OF_DATA_US);
+ gpio_set_value(led->strobe_gpio, KTD2692_HIGH);
+ udelay(KTD2692_TIME_HIGH_END_OF_DATA_US);
+}
+
+static void ktd2692_expresswire_set_bit(struct ktd2692_context *led, bool bit)
+{
+ if (bit) {
+ gpio_set_value(led->strobe_gpio, KTD2692_LOW);
+ udelay(KTD2692_TIME_SHORT_BITSET_US);
+ gpio_set_value(led->strobe_gpio, KTD2692_HIGH);
+ udelay(KTD2692_TIME_LONG_BITSET_US);
+ } else {
+ gpio_set_value(led->strobe_gpio, KTD2692_LOW);
+ udelay(KTD2692_TIME_LONG_BITSET_US);
+ gpio_set_value(led->strobe_gpio, KTD2692_HIGH);
+ udelay(KTD2692_TIME_SHORT_BITSET_US);
+ }
+}
+
+static void ktd2692_expresswire_write(struct ktd2692_context *led, u8 value)
+{
+ int i;
+
+ ktd2692_expresswire_start(led);
+ for (i = 7; i >= 0; i--)
+ ktd2692_expresswire_set_bit(led, GET_BIT(i, value));
+ ktd2692_expresswire_end(led);
+}
+
+static void ktd2692_brightness_set(struct led_classdev *led_cdev,
+ enum led_brightness value)
+{
+ u8 mask;
+ int brightness = (int)value;
+ struct ktd2692_context *led =
+ container_of(led_cdev, struct ktd2692_context, cdev);
+
+ if (brightness == LED_OFF) {
+ gpio_set_value(led->strobe_gpio, 0);
+ led->cdev.brightness = brightness;
+ return;
+ }
+
+ if (brightness < 0 || brightness > led->cdev.max_brightness) {
+ dev_err(led_cdev->dev, "Invalid brightness %d\n", brightness);
+ } else {
+ mask = KTD2692_BRIGHTNESS_RANGE_255_TO_8(value);
+ mask |= KTD2692_REG_MOVIE_CURRENT_BASE;
+ ktd2692_expresswire_write(led, mask);
+
+ led->mode = KTD2692_REG_MODE_BASE | KTD2692_MODE_MOVIE;
+ ktd2692_expresswire_write(led, led->mode);
+ led->cdev.brightness = brightness;
+ }
+}
+
+static enum led_brightness ktd2692_brightness_get(struct led_classdev *led_cdev)
+{
+ struct ktd2692_context *led =
+ container_of(led_cdev, struct ktd2692_context, cdev);
+
+ return led->cdev.brightness;
+}
+
+static struct ktd2692_context *ktd2692_parse_dt(struct device *dev)
+{
+ struct device_node *np = dev->of_node;
+ struct ktd2692_context *led;
+
+ led = devm_kzalloc(dev, sizeof(struct ktd2692_context), GFP_KERNEL);
+ if (!led)
+ return ERR_PTR((long)led);
+
+ led->strobe_gpio = of_get_named_gpio(np, "strobe-gpio", 0);
+ if (!gpio_is_valid(led->strobe_gpio)) {
+ dev_err(dev, "no strobe_gpio property found\n");
+ return ERR_PTR(led->strobe_gpio);
+ }
+
+ return led;
+}
+
+static int ktd2692_probe(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ struct ktd2692_context *led;
+ int ret;
+
+ if (!dev->of_node)
+ return -ENODEV;
+
+ led = ktd2692_parse_dt(dev);
+ if (IS_ERR(led))
+ return PTR_ERR(led);
+
+ led->cdev.name = KTD2692_DEFAULT_NAME;
+ led->cdev.brightness = LED_OFF;
+ led->cdev.max_brightness = LED_FULL;
+ led->cdev.flags |= LED_CORE_SUSPENDRESUME;
+ led->cdev.brightness_set = ktd2692_brightness_set;
+ led->cdev.brightness_get = ktd2692_brightness_get;
+ led->mode = KTD2692_REG_MODE_BASE | KTD2692_MODE_DISABLE;
+
+ platform_set_drvdata(pdev, led);
+
+ ret = led_classdev_register(&pdev->dev, &led->cdev);
+ if (ret) {
+ dev_err(dev, "couldn't register LED %s\n", led->cdev.name);
+ return ret;
+ }
+
+ ret = ktd2692_brightness_set_gpio(led);
+ if (ret) {
+ led_classdev_unregister(&led->cdev);
+ return ret;
+ }
+
+ ktd2692_expresswire_reset(led);
+
+ return ret;
+}
+
+static int ktd2692_remove(struct platform_device *pdev)
+{
+ struct ktd2692_context *led = platform_get_drvdata(pdev);
+
+ led_classdev_unregister(&led->cdev);
+
+ return 0;
+}
+
+static const struct of_device_id ktd2692_match[] = {
+ { .compatible = "kinetic,ktd2692", },
+ { /* sentinel */ },
+};
+
+static struct platform_driver ktd2692_driver = {
+ .driver = {
+ .name = "leds-ktd2692",
+ .of_match_table = ktd2692_match,
+ },
+ .probe = ktd2692_probe,
+ .remove = ktd2692_remove,
+};
+
+module_platform_driver(ktd2692_driver);
+
+MODULE_AUTHOR("Ingi Kim <ingi2.kim@xxxxxxxxxxx>");
+MODULE_DESCRIPTION("Kinetic KTD2692 LED driver");
+MODULE_LICENSE("GPL v2");
--
1.7.9.5
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