[PATCH v8 3/3] leds: Add ktd2692 flash LED driver

Ingi Kim
2015-05-08T03:04:34Z

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@samsung.com>
Acked-by: Seung-Woo Kim <sw0312.kim@samsung.com>
Reviewed-by: Varka Bhadram <varkabhadram@gmail.com>
---
drivers/leds/Kconfig | 9 +
drivers/leds/Makefile | 1 +
drivers/leds/leds-ktd2692.c | 443 ++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 453 insertions(+)
create mode 100644 drivers/leds/leds-ktd2692.c

diff --git a/drivers/leds/Kconfig b/drivers/leds/Kconfig
index 51059bb..bfbdbd1 100644
--- a/drivers/leds/Kconfig
+++ b/drivers/leds/Kconfig
@@ -505,6 +505,15 @@ config LEDS_MENF21BMC
This driver can also be built as a module. If so the module
will be called leds-menf21bmc.

+config LEDS_KTD2692
+ tristate "KTD2692 LED flash support"
+ depends on LEDS_CLASS_FLASH && GPIOLIB && OF
+ help
+ This option enables support for KTD2692 LED flash connected
+ through ExpressWire interface.
+
+ Say Y to enable this driver.
+
comment "LED driver for blink(1) USB RGB LED is under Special HID drivers (HID_THINGM)"

config LEDS_BLINKM
diff --git a/drivers/leds/Makefile b/drivers/leds/Makefile
index a739ae2..ed5ed79 100644
--- a/drivers/leds/Makefile
+++ b/drivers/leds/Makefile
@@ -59,6 +59,7 @@ 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..9d878a4
--- /dev/null
+++ b/drivers/leds/leds-ktd2692.c
@@ -0,0 +1,443 @@
+/*
+ * LED driver : leds-ktd2692.c
+ *
+ * Copyright (C) 2015 Samsung Electronics
+ * Ingi Kim <ingi2.kim@samsung.com>
+ *
+ * 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/delay.h>
+#include <linux/err.h>
+#include <linux/gpio/consumer.h>
+#include <linux/led-class-flash.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/regulator/consumer.h>
+#include <linux/workqueue.h>
+
+/* Value related the movie mode */
+#define KTD2692_MOVIE_MODE_CURRENT_LEVELS 16
+#define KTD2692_MM_TO_FL_RATIO(x) ((x) / 3)
+#define KTD2962_MM_MIN_CURR_THRESHOLD_SCALE 8
+
+/* Value related the flash mode */
+#define KTD2692_FLASH_MODE_TIMEOUT_LEVELS 8
+#define KTD2692_FLASH_MODE_TIMEOUT_DISABLE 0
+#define KTD2692_FLASH_MODE_CURR_PERCENT(x) (((x) * 16) / 100)
+
+/* Macro for getting offset of flash timeout */
+#define GET_TIMEOUT_OFFSET(timeout, step) ((timeout) / (step))
+
+/* Base register address */
+#define KTD2692_REG_LVP_BASE 0x00
+#define KTD2692_REG_FLASH_TIMEOUT_BASE 0x20
+#define KTD2692_REG_MM_MIN_CURR_THRESHOLD_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
+
+enum ktd2692_bitset {
+ KTD2692_LOW = 0,
+ KTD2692_HIGH,
+};
+
+/* Movie / Flash Mode Control */
+enum ktd2692_led_mode {
+ KTD2692_MODE_DISABLE = 0, /* default */
+ KTD2692_MODE_MOVIE,
+ KTD2692_MODE_FLASH,
+};
+
+struct ktd2692_led_config_data {
+ /* maximum LED current in movie mode */
+ u32 movie_max_microamp;
+ /* maximum LED current in flash mode */
+ u32 flash_max_microamp;
+ /* maximum flash timeout */
+ u32 flash_max_timeout;
+ /* max LED brightness level */
+ enum led_brightness max_brightness;
+};
+
+struct ktd2692_context {
+ /* Related LED Flash class device */
+ struct led_classdev_flash fled_cdev;
+
+ /* secures access to the device */
+ struct mutex lock;
+ struct regulator *regulator;
+ struct work_struct work_brightness_set;
+
+ struct gpio_desc *aux_gpio;
+ struct gpio_desc *ctrl_gpio;
+
+ enum ktd2692_led_mode mode;
+ enum led_brightness torch_brightness;
+};
+
+static struct ktd2692_context *fled_cdev_to_led(
+ struct led_classdev_flash *fled_cdev)
+{
+ return container_of(fled_cdev, struct ktd2692_context, fled_cdev);
+}
+
+static void ktd2692_expresswire_start(struct ktd2692_context *led)
+{
+ gpiod_direction_output(led->ctrl_gpio, KTD2692_HIGH);
+ udelay(KTD2692_TIME_DATA_START_TIME_US);
+}
+
+static void ktd2692_expresswire_reset(struct ktd2692_context *led)
+{
+ gpiod_direction_output(led->ctrl_gpio, KTD2692_LOW);
+ udelay(KTD2692_TIME_RESET_US);
+}
+
+static void ktd2692_expresswire_end(struct ktd2692_context *led)
+{
+ gpiod_direction_output(led->ctrl_gpio, KTD2692_LOW);
+ udelay(KTD2692_TIME_LOW_END_OF_DATA_US);
+ gpiod_direction_output(led->ctrl_gpio, KTD2692_HIGH);
+ udelay(KTD2692_TIME_HIGH_END_OF_DATA_US);
+}
+
+static void ktd2692_expresswire_set_bit(struct ktd2692_context *led, bool bit)
+{
+ /*
+ * The Low Bit(0) and High Bit(1) is based on a time detection
+ * algorithm between time low and time high
+ * Time_(L_LB) : Low time of the Low Bit(0)
+ * Time_(H_LB) : High time of the LOW Bit(0)
+ * Time_(L_HB) : Low time of the High Bit(1)
+ * Time_(H_HB) : High time of the High Bit(1)
+ *
+ * It can be simplified to:
+ * Low Bit(0) : 2 * Time_(H_LB) < Time_(L_LB)
+ * High Bit(1) : 2 * Time_(L_HB) < Time_(H_HB)
+ * HIGH ___ ____ _.. _________ ___
+ * |_________| |_.. |____| |__|
+ * LOW <L_LB> <H_LB> <L_HB> <H_HB>
+ * [ Low Bit (0) ] [ High Bit(1) ]
+ */
+ if (bit) {
+ gpiod_direction_output(led->ctrl_gpio, KTD2692_LOW);
+ udelay(KTD2692_TIME_SHORT_BITSET_US);
+ gpiod_direction_output(led->ctrl_gpio, KTD2692_HIGH);
+ udelay(KTD2692_TIME_LONG_BITSET_US);
+ } else {
+ gpiod_direction_output(led->ctrl_gpio, KTD2692_LOW);
+ udelay(KTD2692_TIME_LONG_BITSET_US);
+ gpiod_direction_output(led->ctrl_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, value & BIT(i));
+ ktd2692_expresswire_end(led);
+}
+
+static void ktd2692_brightness_set(struct ktd2692_context *led,
+ enum led_brightness brightness)
+{
+ mutex_lock(&led->lock);
+
+ if (brightness == LED_OFF) {
+ led->mode = KTD2692_MODE_DISABLE;
+ gpiod_direction_output(led->aux_gpio, KTD2692_LOW);
+ } else {
+ ktd2692_expresswire_write(led, brightness |
+ KTD2692_REG_MOVIE_CURRENT_BASE);
+ led->mode = KTD2692_MODE_MOVIE;
+ }
+
+ ktd2692_expresswire_write(led, led->mode | KTD2692_REG_MODE_BASE);
+ mutex_unlock(&led->lock);
+}
+
+static void ktd2692_brightness_set_work(struct work_struct *work)
+{
+ struct ktd2692_context *led =
+ container_of(work, struct ktd2692_context, work_brightness_set);
+
+ ktd2692_brightness_set(led, led->torch_brightness);
+}
+
+static void ktd2692_led_brightness_set(struct led_classdev *led_cdev,
+ enum led_brightness brightness)
+{
+ struct led_classdev_flash *fled_cdev = lcdev_to_flcdev(led_cdev);
+ struct ktd2692_context *led = fled_cdev_to_led(fled_cdev);
+
+ led->torch_brightness = brightness;
+ schedule_work(&led->work_brightness_set);
+}
+
+static int ktd2692_led_brightness_set_sync(struct led_classdev *led_cdev,
+ enum led_brightness brightness)
+{
+ struct led_classdev_flash *fled_cdev = lcdev_to_flcdev(led_cdev);
+ struct ktd2692_context *led = fled_cdev_to_led(fled_cdev);
+
+ ktd2692_brightness_set(led, brightness);
+
+ return 0;
+}
+
+static int ktd2692_led_flash_strobe_set(struct led_classdev_flash *fled_cdev,
+ bool state)
+{
+ struct ktd2692_context *led = fled_cdev_to_led(fled_cdev);
+ struct led_flash_setting *timeout = &fled_cdev->timeout;
+ u32 flash_tm_reg;
+
+ mutex_lock(&led->lock);
+
+ if (state == 0) {
+ led->mode = KTD2692_MODE_DISABLE;
+ gpiod_direction_output(led->aux_gpio, KTD2692_LOW);
+ } else {
+ flash_tm_reg = GET_TIMEOUT_OFFSET(timeout->val, timeout->step);
+ ktd2692_expresswire_write(led, flash_tm_reg
+ | KTD2692_REG_FLASH_TIMEOUT_BASE);
+
+ led->mode = KTD2692_MODE_FLASH;
+ gpiod_direction_output(led->aux_gpio, KTD2692_HIGH);
+ }
+
+ ktd2692_expresswire_write(led, led->mode | KTD2692_REG_MODE_BASE);
+
+ fled_cdev->led_cdev.brightness = LED_OFF;
+ led->mode = KTD2692_MODE_DISABLE;
+
+ mutex_unlock(&led->lock);
+
+ return 0;
+}
+
+static int ktd2692_led_flash_timeout_set(struct led_classdev_flash *fled_cdev,
+ u32 timeout)
+{
+ return 0;
+}
+
+static void ktd2692_init_movie_current_max(struct ktd2692_led_config_data *cfg)
+{
+ u32 offset, step;
+ u32 movie_current_microamp;
+
+ offset = KTD2692_MOVIE_MODE_CURRENT_LEVELS;
+ step = KTD2692_MM_TO_FL_RATIO(cfg->flash_max_microamp)
+ / KTD2692_MOVIE_MODE_CURRENT_LEVELS;
+
+ do {
+ movie_current_microamp = step * offset;
+ offset--;
+ } while ((movie_current_microamp > cfg->movie_max_microamp) &&
+ (offset > 0));
+
+ cfg->max_brightness = offset;
+}
+
+static void ktd2692_init_flash_timeout(struct led_classdev_flash *fled_cdev,
+ struct ktd2692_led_config_data *cfg)
+{
+ struct led_flash_setting *setting;
+
+ setting = &fled_cdev->timeout;
+ setting->min = KTD2692_FLASH_MODE_TIMEOUT_DISABLE;
+ setting->max = cfg->flash_max_timeout;
+ setting->step = cfg->flash_max_timeout
+ / (KTD2692_FLASH_MODE_TIMEOUT_LEVELS - 1);
+ setting->val = cfg->flash_max_timeout;
+}
+
+static void ktd2692_setup(struct ktd2692_context *led)
+{
+ led->mode = KTD2692_MODE_DISABLE;
+ ktd2692_expresswire_reset(led);
+ gpiod_direction_output(led->aux_gpio, KTD2692_LOW);
+
+ ktd2692_expresswire_write(led, (KTD2962_MM_MIN_CURR_THRESHOLD_SCALE - 1)
+ | KTD2692_REG_MM_MIN_CURR_THRESHOLD_BASE);
+ ktd2692_expresswire_write(led, KTD2692_FLASH_MODE_CURR_PERCENT(45)
+ | KTD2692_REG_FLASH_CURRENT_BASE);
+}
+
+static int ktd2692_parse_dt(struct ktd2692_context *led, struct device *dev,
+ struct ktd2692_led_config_data *cfg)
+{
+ struct device_node *np = dev->of_node;
+ struct device_node *child_node;
+ int ret;
+
+ if (!dev->of_node)
+ return -ENXIO;
+
+ led->ctrl_gpio = devm_gpiod_get(dev, "ctrl");
+ if (IS_ERR(led->ctrl_gpio)) {
+ ret = PTR_ERR(led->ctrl_gpio);
+ dev_err(dev, "cannot get ctrl-gpio %d\n", ret);
+ return ret;
+ }
+
+ led->aux_gpio = devm_gpiod_get(dev, "aux");
+ if (IS_ERR(led->aux_gpio)) {
+ ret = PTR_ERR(led->aux_gpio);
+ dev_err(dev, "cannot get aux-gpio %d\n", ret);
+ return ret;
+ }
+
+ led->regulator = devm_regulator_get(dev, "vin");
+ if (IS_ERR(led->regulator))
+ led->regulator = NULL;
+
+ if (led->regulator) {
+ ret = regulator_enable(led->regulator);
+ if (ret)
+ dev_err(dev, "Failed to enable supply: %d\n", ret);
+ }
+
+ child_node = of_get_next_available_child(np, NULL);
+ if (!child_node) {
+ dev_err(dev, "No DT child node found for connected LED.\n");
+ return -EINVAL;
+ }
+
+ led->fled_cdev.led_cdev.name =
+ of_get_property(child_node, "label", NULL) ? : child_node->name;
+
+ ret = of_property_read_u32(child_node, "led-max-microamp",
+ &cfg->movie_max_microamp);
+ if (ret) {
+ dev_err(dev, "failed to parse led-max-microamp\n");
+ return ret;
+ }
+
+ ret = of_property_read_u32(child_node, "flash-max-microamp",
+ &cfg->flash_max_microamp);
+ if (ret) {
+ dev_err(dev, "failed to parse flash-max-microamp\n");
+ return ret;
+ }
+
+ ret = of_property_read_u32(child_node, "flash-max-timeout-us",
+ &cfg->flash_max_timeout);
+ if (ret)
+ dev_err(dev, "failed to parse flash-max-timeout-us\n");
+
+ of_node_put(child_node);
+ return ret;
+}
+
+static const struct led_flash_ops flash_ops = {
+ .strobe_set = ktd2692_led_flash_strobe_set,
+ .timeout_set = ktd2692_led_flash_timeout_set,
+};
+
+static int ktd2692_probe(struct platform_device *pdev)
+{
+ struct ktd2692_context *led;
+ struct led_classdev *led_cdev;
+ struct led_classdev_flash *fled_cdev;
+ struct ktd2692_led_config_data led_cfg;
+ int ret;
+
+ led = devm_kzalloc(&pdev->dev, sizeof(*led), GFP_KERNEL);
+ if (!led)
+ return -ENOMEM;
+
+ fled_cdev = &led->fled_cdev;
+ led_cdev = &fled_cdev->led_cdev;
+
+ ret = ktd2692_parse_dt(led, &pdev->dev, &led_cfg);
+ if (ret)
+ return ret;
+
+ ktd2692_init_flash_timeout(fled_cdev, &led_cfg);
+ ktd2692_init_movie_current_max(&led_cfg);
+
+ fled_cdev->ops = &flash_ops;
+
+ led_cdev->max_brightness = led_cfg.max_brightness;
+ led_cdev->brightness_set = ktd2692_led_brightness_set;
+ led_cdev->brightness_set_sync = ktd2692_led_brightness_set_sync;
+ led_cdev->flags |= LED_CORE_SUSPENDRESUME | LED_DEV_CAP_FLASH;
+
+ mutex_init(&led->lock);
+ INIT_WORK(&led->work_brightness_set, ktd2692_brightness_set_work);
+
+ platform_set_drvdata(pdev, led);
+
+ ret = led_classdev_flash_register(&pdev->dev, fled_cdev);
+ if (ret) {
+ dev_err(&pdev->dev, "can't register LED %s\n", led_cdev->name);
+ mutex_destroy(&led->lock);
+ return ret;
+ }
+
+ ktd2692_setup(led);
+
+ return 0;
+}
+
+static int ktd2692_remove(struct platform_device *pdev)
+{
+ struct ktd2692_context *led = platform_get_drvdata(pdev);
+ int ret;
+
+ led_classdev_flash_unregister(&led->fled_cdev);
+ cancel_work_sync(&led->work_brightness_set);
+
+ if (led->regulator) {
+ ret = regulator_disable(led->regulator);
+ if (ret)
+ dev_err(&pdev->dev,
+ "Failed to disable supply: %d\n", ret);
+ }
+
+ mutex_destroy(&led->lock);
+
+ return 0;
+}
+
+static const struct of_device_id ktd2692_match[] = {
+ { .compatible = "kinetic,ktd2692", },
+ { /* sentinel */ },
+};
+
+static struct platform_driver ktd2692_driver = {
+ .driver = {
+ .name = "ktd2692",
+ .of_match_table = ktd2692_match,
+ },
+ .probe = ktd2692_probe,
+ .remove = ktd2692_remove,
+};
+
+module_platform_driver(ktd2692_driver);
+
+MODULE_AUTHOR("Ingi Kim <ingi2.kim@samsung.com>");
+MODULE_DESCRIPTION("Kinetic KTD2692 LED driver");
+MODULE_LICENSE("GPL v2");
--
2.0.5