Message-id: <550F7F70.2010205@samsung.com>
Date:	Mon, 23 Mar 2015 11:50:24 +0900
From:	Ingi Kim <ingi2.kim@...sung.com>
To:	Jacek Anaszewski <j.anaszewski@...sung.com>
Cc:	cooloney@...il.com, rpurdie@...ys.net, robh+dt@...nel.org,
	pawel.moll@....com, mark.rutland@....com,
	ijc+devicetree@...lion.org.uk, galak@...eaurora.org,
	sakari.ailus@....fi, varkabhadram@...il.com,
	sw0312.kim@...sung.com, cw00.choi@...sung.com,
	jh80.chung@...sung.com, ideal.song@...sung.com,
	devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
	linux-leds@...r.kernel.org
Subject: Re: [PATCH v3 3/3] leds: Add ktd2692 flash LED driver

Hi Jacek,

On 2015년 03월 21일 01:26, Jacek Anaszewski wrote:
> Hi Ingi,
> 
> Thanks for the update.
> 
> On 03/20/2015 06:31 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@...sung.com>
>> ---
>>   drivers/leds/Kconfig        |   9 +
>>   drivers/leds/Makefile       |   1 +
>>   drivers/leds/leds-ktd2692.c | 438 ++++++++++++++++++++++++++++++++++++++++++++
>>   3 files changed, 448 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"
>> +    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
>> +
>>   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..38d6145
>> --- /dev/null
>> +++ b/drivers/leds/leds-ktd2692.c
>> @@ -0,0 +1,438 @@
>> +/*
>> + * LED driver : leds-ktd2692.c
>> + *
>> + * Copyright (C) 2015 Samsung Electronics
>> + * Ingi Kim <ingi2.kim@...sung.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_flash_timeout_setting {
>> +    struct led_flash_setting flash_timeout;
>> +};
> 
> You don't need to nest these structures like that.
> You probably followed previous version of the leds-aat1290 driver
> patch from my LED/flash API integration patch set, but the parent
> structure was named aat1290_led_settings and was intended for gathering
> two settings (torch setting was added in the patch adding support
> for V4L2 Flash API).
> 
> 

Oh, I see,
I've wondered why this structure should nest led_flash_setting structure.
I'll fix.

Thanks

>> +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 int 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 0;
>> +
>> +    ret = regulator_enable(led->regulator);
>> +    if (ret)
>> +        dev_err(led_cdev->dev, "Failed to enable vin:%d\n", ret);
>> +
>> +    return 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));
>> +    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;
>> +    }
>> +
>> +    if (brightness < LED_OFF) {
>> +        dev_err(led->fled_cdev.led_cdev.dev,
>> +            "Invalid brightness %d\n", brightness);
>> +        goto unlock;
>> +    }
> 
> You don't need to do this. It is not possible to get value less than
> 0 from brightness_store callback.
> 

Thanks, Check it

>> +    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);
>> +unlock:
>> +    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_set(u32 flash_timeout_us,
>> +                    struct ktd2692_flash_timeout_setting *s)
>> +{
>> +    struct led_flash_setting *setting;
>> +
>> +    setting = &s->flash_timeout;
>> +    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;
>> +}
> 
> Please skip the '_set' postfix from the function name and pass directly a pointer to struct led_flash_setting.
> 
> We can change it to something more generic when more settings will
> need initialization to pass them to v4l2 Flash sub-device.
> 

Thanks, Check it.

>> +static void ktd2692_init_flash_register_set(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);
>> +}
> 
> I'd call this function ktd2692_setup().
> 

Suitable name, Thanks!

>> +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 ktd2692_flash_timeout_setting timeout_setting;
>> +    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;
>> +    platform_set_drvdata(pdev, led);
>> +
>> +    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");
>> +        ret = PTR_ERR(led->regulator);
>> +        led->regulator = NULL;
>> +        return ret;
>> +    }
>> +
>> +    ret = ktd2692_led_regulator_enable(led);
>> +    if (ret)
>> +        goto err_regulator;
>> +
>> +    ktd2692_init_flash_timeout_set(flash_timeout_us, &timeout_setting);
>> +
>> +    fled_cdev->timeout = timeout_setting.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;
>> +
>> +    INIT_WORK(&led->work_brightness_set, ktd2692_brightness_set_work);
>> +
>> +    ret = led_classdev_flash_register(&pdev->dev, fled_cdev);
>> +    if (ret) {
>> +        dev_err(&pdev->dev, "can't register LED %s\n", led_cdev->name);
>> +        goto err_register;
>> +    }
>> +
>> +    ktd2692_init_flash_register_set(led);
>> +
>> +    mutex_init(&led->lock);
>> +
>> +    return 0;
>> +err_register:
>> +    cancel_work_sync(&led->work_brightness_set);
>> +err_regulator:
>> +    ktd2692_led_regulator_disable(led);
>> +    platform_set_drvdata(pdev, NULL);
>> +    return ret;
>> +}
>> +
>> +static int ktd2692_remove(struct platform_device *pdev)
>> +{
>> +    struct ktd2692_context *led = platform_get_drvdata(pdev);
>> +
>> +    cancel_work_sync(&led->work_brightness_set);
>> +    led_classdev_flash_unregister(&led->fled_cdev);
>> +    ktd2692_led_regulator_disable(led);
>> +
>> +    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@...sung.com>");
>> +MODULE_DESCRIPTION("Kinetic KTD2692 LED driver");
>> +MODULE_LICENSE("GPL v2");
>>
> 
> 
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