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....@samsung.com>
> ---
>  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....@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/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....@samsung.com>");
> +MODULE_DESCRIPTION("Kinetic KTD2692 LED driver");
> +MODULE_LICENSE("GPL v2");

-- 
Kind regards,

Sakari Ailus
e-mail: sakari.ai...@iki.fi     XMPP: sai...@retiisi.org.uk
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