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

Jacek Anaszewski
2015-05-08T08:33:59Z

Hi Ingi,

Thanks for the update. It looks like we're almost there.
I can see only two minor issues.

On 05/08/2015 05:03 AM, Ingi Kim wrote:
> 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"

Please keep the style of description in line with the existing
drivers. How about:

"LED support for KTD2692 flash LED controller"

> + 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) {

Coccinelle raises a warning here:

drivers/leds/leds-ktd2692.c:217:5-10: WARNING: Comparison of bool to 0/1

I had to fix it also in my leds-aat1290 driver recently:)

> + 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");
>

--
Best Regards,
Jacek Anaszewski