Re: [PATCH v4 3/3] leds: Add ktd2692 flash LED driver
From: Sakari Ailus
Date: Wed Mar 25 2015 - 09:53:51 EST
Hi Ingi,
Thank you for the patch.
On Wed, Mar 25, 2015 at 10:30:44AM +0900, 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@xxxxxxxxxxx>
> ---
> drivers/leds/Kconfig | 9 +
> drivers/leds/Makefile | 1 +
> drivers/leds/leds-ktd2692.c | 412 ++++++++++++++++++++++++++++++++++++++++++++
> 3 files changed, 422 insertions(+)
> create mode 100644 drivers/leds/leds-ktd2692.c
>
> diff --git a/drivers/leds/Kconfig b/drivers/leds/Kconfig
> index 25b320d..9311cfc4 100644
> --- a/drivers/leds/Kconfig
> +++ b/drivers/leds/Kconfig
> @@ -498,6 +498,15 @@ 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 "Flash LED support for the KTD2692 Driver"
Does ktd2692 act as something else as well? If not, how about "KTD2692 LED
flash support"?
> + depends on LEDS_CLASS_FLASH && GPIOLIB
> + help
> + This option enables support for the KTD2692 connected through
> + ExpressWire Interface. Say Y to enabled these.
> + It depends on LEDS_CLASS_FLASH for using flash led (strobe) and
> + GPIOLIB for using gpio pin to control Expresswire interface
The dependencies are shown by make *config, I would drop them from here.
> +
> 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 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..c31ec9d
> --- /dev/null
> +++ b/drivers/leds/leds-ktd2692.c
> @@ -0,0 +1,412 @@
> +/*
> + * LED driver : leds-ktd2692.c
> + *
> + * 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/delay.h>
> +#include <linux/err.h>
> +#include <linux/led-class-flash.h>
> +#include <linux/module.h>
> +#include <linux/mutex.h>
> +#include <linux/of_gpio.h>
> +#include <linux/platform_device.h>
> +#include <linux/regulator/consumer.h>
> +#include <linux/workqueue.h>
> +
> +#define GET_BIT(bit, val) (((val) >> (bit)) & 0x01)
> +
> +/* Value related the flash mode */
> +#define KTD2692_FLASH_MODE_TIMEOUT_LEVELS 8
> +#define KTD2692_FLASH_MODE_TIMEOUT_DISABLE 0
> +#define KTD2692_FLASH_MODE_TIMEOUT_DEFAULT_US 1049000
> +#define KTD2692_FLASH_MODE_TIMEOUT_MAX_US 1835000
> +#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))
> +
> +/* 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_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_context {
> + /* Related LED Flash class device */
> + struct led_classdev_flash fled_cdev;
> +
> + struct mutex lock;
> + struct regulator *regulator;
> + struct work_struct work_brightness_set;
> +
> + int aux_gpio;
> + int 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_led_regulator_enable(struct ktd2692_context *led)
> +{
> + struct led_classdev_flash *fled_cdev = &led->fled_cdev;
> + struct led_classdev *led_cdev = &fled_cdev->led_cdev;
> + int ret;
> +
> + if (regulator_is_enabled(led->regulator) > 0)
> + return;
What's the purpose of this? Why not to just call regulator_enable() instead?
This way you could easily mess up with other users of the same regulator.
> +
> + ret = regulator_enable(led->regulator);
> + if (ret)
> + dev_err(led_cdev->dev, "Failed to enable vin:%d\n", ret);
> +}
> +
> +static void ktd2692_led_regulator_disable(struct ktd2692_context *led)
> +{
> + struct led_classdev_flash *fled_cdev = &led->fled_cdev;
> + struct led_classdev *led_cdev = &fled_cdev->led_cdev;
> + int ret;
> +
> + if (!regulator_is_enabled(led->regulator))
> + return;
> +
> + ret = regulator_disable(led->regulator);
> + if (ret)
> + dev_err(led_cdev->dev, "Failed to disable vin:%d\n", ret);
> +}
> +
> +static void ktd2692_expresswire_start(struct ktd2692_context *led)
> +{
> + gpio_set_value(led->ctrl_gpio, KTD2692_HIGH);
> + udelay(KTD2692_TIME_DATA_START_TIME_US);
> +}
> +
> +static void ktd2692_expresswire_reset(struct ktd2692_context *led)
> +{
> + gpio_set_value(led->ctrl_gpio, KTD2692_LOW);
> + udelay(KTD2692_TIME_RESET_US);
> +}
> +
> +static void ktd2692_expresswire_end(struct ktd2692_context *led)
> +{
> + gpio_set_value(led->ctrl_gpio, KTD2692_LOW);
> + udelay(KTD2692_TIME_LOW_END_OF_DATA_US);
> + gpio_set_value(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)
> +{
> + if (bit) {
> + gpio_set_value(led->ctrl_gpio, KTD2692_LOW);
> + udelay(KTD2692_TIME_SHORT_BITSET_US);
> + gpio_set_value(led->ctrl_gpio, KTD2692_HIGH);
> + udelay(KTD2692_TIME_LONG_BITSET_US);
> + } else {
> + gpio_set_value(led->ctrl_gpio, KTD2692_LOW);
> + udelay(KTD2692_TIME_LONG_BITSET_US);
> + gpio_set_value(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, GET_BIT(i, value));
I think this would be cleaner as:
value & BIT(i)
Casting an integer as bool will result in true if it's non-zero, so you
don't need to cast.
> + 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;
> + gpio_set_value(led->aux_gpio, KTD2692_LOW);
> + goto out;
> + }
> +
> + ktd2692_expresswire_write(led, KTD2692_REG_MOVIE_CURRENT_BASE |
> + KTD2692_BRIGHTNESS_RANGE_255_TO_8(brightness));
> + led->mode = KTD2692_MODE_MOVIE;
> +
> +out:
> + 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;
> + gpio_set_value(led->aux_gpio, KTD2692_LOW);
> + goto done;
> + }
> +
> + 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;
> + gpio_set_value(led->aux_gpio, KTD2692_HIGH);
> +
> +done:
> + 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_flash_timeout(u32 flash_timeout_us,
> + struct led_flash_setting *setting)
> +{
> + setting->min = KTD2692_FLASH_MODE_TIMEOUT_DISABLE;
> + setting->max = KTD2692_FLASH_MODE_TIMEOUT_MAX_US;
> + setting->step = KTD2692_FLASH_MODE_TIMEOUT_MAX_US
> + / (KTD2692_FLASH_MODE_TIMEOUT_LEVELS - 1);
> + setting->val = flash_timeout_us;
> +}
> +
> +static void ktd2692_setup(struct ktd2692_context *led)
> +{
> + led->mode = KTD2692_MODE_DISABLE;
> + ktd2692_expresswire_reset(led);
> + gpio_set_value(led->aux_gpio, KTD2692_LOW);
> +
> + 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,
> + u32 *flash_timeout_us)
> +{
> + struct device_node *np = dev->of_node;
> +
> + int ret;
> +
> + led->ctrl_gpio = of_get_named_gpio(np, "ctrl-gpio", 0);
> + if (!gpio_is_valid(led->ctrl_gpio)) {
> + dev_err(dev, "no ctrl-gpio property found\n");
> + return -EINVAL;
> + }
> +
> + led->aux_gpio = of_get_named_gpio(np, "aux-gpio", 0);
> + if (!gpio_is_valid(led->aux_gpio)) {
> + dev_err(dev, "no aux-gpio property found\n");
> + return -EINVAL;
> + }
> +
> + ret = devm_gpio_request_one(dev, led->ctrl_gpio,
> + GPIOF_OPEN_SOURCE, "ctrl-gpio");
> + if (ret) {
> + dev_err(dev, "failed to request ctrl-gpio %d error %d\n",
> + led->ctrl_gpio, ret);
> + return ret;
> + }
> +
> + ret = devm_gpio_request_one(dev, led->aux_gpio,
> + GPIOF_OPEN_SOURCE, "aux-gpio");
> + if (ret) {
> + dev_err(dev, "failed to request aux-gpio %d error %d\n",
> + led->aux_gpio, ret);
> + return ret;
> + }
> +
> + ret = of_property_read_u32(np, "flash-timeout-us", flash_timeout_us);
> + /* default setting */
> + if (ret)
> + *flash_timeout_us = KTD2692_FLASH_MODE_TIMEOUT_DEFAULT_US;
> +
> + return 0;
> +}
> +
> +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 led_flash_setting flash_timeout;
> + u32 flash_timeout_us;
> + int ret;
> +
> + led = devm_kzalloc(&pdev->dev, sizeof(*led), GFP_KERNEL);
> + if (!led)
> + return -ENOMEM;
> +
> + if (!pdev->dev.of_node)
> + return -ENXIO;
> +
> + fled_cdev = &led->fled_cdev;
> + led_cdev = &fled_cdev->led_cdev;
> +
> + ret = ktd2692_parse_dt(led, &pdev->dev, &flash_timeout_us);
> + if (ret)
> + return ret;
> +
> + led->regulator = devm_regulator_get(&pdev->dev, "vin");
> + if (IS_ERR(led->regulator)) {
> + dev_err(&pdev->dev, "regulator get failed\n");
> + return PTR_ERR(led->regulator);
> + }
> +
> + ktd2692_init_flash_timeout(flash_timeout_us, &flash_timeout);
> +
> + fled_cdev->timeout = flash_timeout;
> + fled_cdev->ops = &flash_ops;
> +
> + led_cdev->name = KTD2692_DEFAULT_NAME;
> + 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_cdev->flags |= LED_DEV_CAP_FLASH;
You could unify the above two lines.
> +
> + 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);
You should do mutex_destroy() here.
> + cancel_work_sync(&led->work_brightness_set);
> + return ret;
> + }
> +
This is a LED flash device. Do you intend to add support for the V4L2 flash
API as well?
> + ktd2692_setup(led);
> + ktd2692_led_regulator_enable(led);
Hmm. I guess the regulator was already enabled, assuming you have tested
this. :-)
> +
> + return 0;
> +}
> +
> +static int ktd2692_remove(struct platform_device *pdev)
> +{
> + struct ktd2692_context *led = platform_get_drvdata(pdev);
> +
> + ktd2692_led_regulator_disable(led);
> + led_classdev_flash_unregister(&led->fled_cdev);
> + cancel_work_sync(&led->work_brightness_set);
> +
> + 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 = "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");
--
Kind regards,
Sakari Ailus
e-mail: sakari.ailus@xxxxxx XMPP: sailus@xxxxxxxxxxxxxx
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