Re: [PATCH v2 3/3] leds: rt5033: Add RT5033 Flash led device driver

Ingi Kim
2015-10-13T02:59:11Z

Hi Jacek,

Thanks for your kind comments
I also append reply below

On 2015년 10월 13일 00:10, Jacek Anaszewski wrote:
> Hi Ingi,
>
> Thanks for the update. Few comments below.
>
> On 10/12/2015 03:12 PM, Ingi Kim wrote:
>> This patch adds device driver of Richtek RT5033 PMIC.
>> The driver supports a current regulated output to drive
>> white LEDs for camera flash.
>>
>> Signed-off-by: Ingi Kim <ingi2.kim@samsung.com>
>> ---
>> drivers/leds/Kconfig | 8 ++
>> drivers/leds/Makefile | 1 +
>> drivers/leds/leds-rt5033.c | 223 +++++++++++++++++++++++++++++++++++++
>> include/linux/mfd/rt5033-private.h | 49 ++++++++
>> include/linux/mfd/rt5033.h | 22 +++-
>> 5 files changed, 301 insertions(+), 2 deletions(-)
>> create mode 100644 drivers/leds/leds-rt5033.c
>>
>> diff --git a/drivers/leds/Kconfig b/drivers/leds/Kconfig
>> index 42990f2..29613e3 100644
>> --- a/drivers/leds/Kconfig
>> +++ b/drivers/leds/Kconfig
>> @@ -345,6 +345,14 @@ config LEDS_PCA963X
>> LED driver chip accessed via the I2C bus. Supported
>> devices include PCA9633 and PCA9634
>>
>> +config LEDS_RT5033
>> + tristate "LED support for RT5033 PMIC"
>> + depends on LEDS_CLASS_FLASH && OF
>> + depends on MFD_RT5033
>> + help
>> + This option enables support for on-chip LED driver on
>> + RT5033 PMIC.
>> +
>> config LEDS_WM831X_STATUS
>> tristate "LED support for status LEDs on WM831x PMICs"
>> depends on LEDS_CLASS
>> diff --git a/drivers/leds/Makefile b/drivers/leds/Makefile
>> index b503f92..bcc4d93 100644
>> --- a/drivers/leds/Makefile
>> +++ b/drivers/leds/Makefile
>> @@ -23,6 +23,7 @@ obj-$(CONFIG_LEDS_COBALT_QUBE) += leds-cobalt-qube.o
>> obj-$(CONFIG_LEDS_COBALT_RAQ) += leds-cobalt-raq.o
>> obj-$(CONFIG_LEDS_SUNFIRE) += leds-sunfire.o
>> obj-$(CONFIG_LEDS_PCA9532) += leds-pca9532.o
>> +obj-$(CONFIG_LEDS_RT5033) += leds-rt5033.o
>> obj-$(CONFIG_LEDS_GPIO_REGISTER) += leds-gpio-register.o
>> obj-$(CONFIG_LEDS_GPIO) += leds-gpio.o
>> obj-$(CONFIG_LEDS_LP3944) += leds-lp3944.o
>> diff --git a/drivers/leds/leds-rt5033.c b/drivers/leds/leds-rt5033.c
>> new file mode 100644
>> index 0000000..b470c94
>> --- /dev/null
>> +++ b/drivers/leds/leds-rt5033.c
>> @@ -0,0 +1,223 @@
>> +/*
>> + * led driver for RT5033
>> + *
>> + * Copyright (C) 2015 Samsung Electronics, Co., Ltd.
>> + * 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/mfd/rt5033.h>
>> +#include <linux/mfd/rt5033-private.h>
>> +#include <linux/module.h>
>> +#include <linux/platform_device.h>
>> +
>> +#define RT5033_LED_FLASH_TIMEOUT_MIN 64000
>> +#define RT5033_LED_FLASH_TIMEOUT_STEPS 32000
>> +#define RT5033_LED_TORCH_CURRENT_LEVEL_MAX 16
>> +
>> +/* Macro for getting offset of flash timeout */
>> +#define GET_TIMEOUT_OFFSET(tm, step) ((tm) / (step) - 2)
>> +
>> +static struct rt5033_led *flcdev_to_led(
>> + struct led_classdev_flash *fled_cdev)
>> +{
>> + return container_of(fled_cdev, struct rt5033_led, fled_cdev);
>> +}
>> +
>> +static int rt5033_led_brightness_set(struct led_classdev *led_cdev,
>> + enum led_brightness brightness)
>> +{
>> + struct led_classdev_flash *fled_cdev = lcdev_to_flcdev(led_cdev);
>> + struct rt5033_led *led = flcdev_to_led(fled_cdev);
>
> I assume that you don't use mutex here deliberately?
>

Actually I'm not sure why flash driver uses mutex.
In consideration of blocking competition, however, I'd be better to use it

>> + if (!brightness) {
>> + regmap_update_bits(led->regmap, RT5033_REG_FLED_FUNCTION2,
>> + RT5033_FLED_CTRL2_MASK, 0x0);
>> + } else {
>> + regmap_update_bits(led->regmap, RT5033_REG_FLED_FUNCTION1,
>> + RT5033_FLED_FUNC1_MASK, RT5033_FLED_PINCTRL);
>> + regmap_update_bits(led->regmap, RT5033_REG_FLED_CTRL1,
>> + RT5033_FLED_CTRL1_MASK,
>> + (brightness - 1) << 4);
>> + regmap_update_bits(led->regmap, RT5033_REG_FLED_FUNCTION2,
>> + RT5033_FLED_CTRL2_MASK, RT5033_FLED_ENFLED);
>> + }
>> +
>> + return 0;
>> +}
>> +
>> +static void rt5033_init_flash_timeout(struct rt5033_led *led)
>> +{
>> + struct led_flash_setting *setting;
>> +
>> + setting = &led->fled_cdev.timeout;
>> + setting->min = RT5033_LED_FLASH_TIMEOUT_MIN;
>> + setting->max = led->data->flash_max_timeout;
>> + setting->step = RT5033_LED_FLASH_TIMEOUT_STEPS;
>> + setting->val = led->data->flash_max_timeout;
>> +}
>> +
>> +static int rt5033_led_parse_dt(struct rt5033_led *led, struct device *dev)
>> +{
>> + struct device_node *np = dev->of_node;
>> + struct device_node *child_node;
>> + struct rt5033_led_config_data *data;
>> + int ret = 0;
>> +
>> + if (!np)
>> + return -ENXIO;
>> +
>> + data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
>> + if (!data)
>> + return -ENOMEM;
>
> This way data will remain allocated until driver removal, whereas
> you are using it only in rt5033_init_flash_timeout during driver
> probing AFAICS. Please define local variable in rt5033_led_probe,
> pass its pointer to this function and than pass the pointer to
> rt5033_init_flash_timeout.
>

You're right, I should have moved it to local,
I'll try to fix it.

>> + child_node = of_get_next_available_child(np, NULL);
>> + if (!child_node) {
>> + dev_err(dev, "DT child node isn't found\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",
>> + &data->torch_max_microamp);
>> + if (ret) {
>> + dev_err(dev, "failed to parse led-max-microamp\n");
>> + return ret;
>> + }
>
> data->torch_max_microamp isn't used anywhere, while it should be used
> for initializing led_cdev->max_brightness.
>

Oh, I see.
I'll fix it

>> +
>> + ret = of_property_read_u32(child_node, "flash-max-microamp",
>> + &data->flash_max_microamp);
>> + if (ret) {
>> + dev_err(dev, "failed to parse flash-max-microamp\n");
>> + return ret;
>> + }
>
> data->flash_max_microamp also isn't used anywhere. Does your device
> support flash brightness setting? If yes then you should implement
> also flash_brightness_set op. Otherwise this property is redundant.
>

Yes, It support to set flash brightness.
I should implement it.

>> + ret = of_property_read_u32(child_node, "flash-max-timeout-us",
>> + &data->flash_max_timeout);
>> + if (ret)
>> + dev_err(dev, "failed to parse flash-max-timeout-us\n");
>> +
>> + of_node_put(child_node);
>> + led->data = data;
>> +
>> + return ret;
>> +}
>> +
>> +static int rt5033_led_flash_timeout_set(struct led_classdev_flash *fled_cdev,
>> + u32 timeout)
>> +{
>> + return 0;
>> +}
>> +
>> +static int rt5033_led_flash_strobe_set(struct led_classdev_flash *fled_cdev,
>> + bool state)
>> +{
>> + struct rt5033_led *led = flcdev_to_led(fled_cdev);
>> + u32 flash_tm_reg;
>
> I think that you need a mutex here and in rt5033_led_flash_strobe_set. Otherwise following is possible:
>
> Process 1:
> rt5033_led_flash_strobe_set(led_cdev, 1);
>
> regmap_update_bits(led->regmap, RT5033_REG_FLED_FUNCTION1,
> RT5033_FLED_FUNC1_MASK, RT5033_FLED_RESET);
> fled_cdev->led_cdev.brightness = LED_OFF;
>
> Process 2:
> led_set_brightness(led_cdev, 1);
>
> fled_cdev->led_cdev.brightness = 1;
>
> rt5033_led_brightness_set(led_cdev, LED_FULL);
>
> regmap_update_bits(led->regmap, RT5033_REG_FLED_FUNCTION1,
> RT5033_FLED_FUNC1_MASK, RT5033_FLED_PINCTRL);
> regmap_update_bits(led->regmap, RT5033_REG_FLED_CTRL1,
> RT5033_FLED_CTRL1_MASK,
> (brightness - 1) << 4);
> regmap_update_bits(led->regmap, RT5033_REG_FLED_FUNCTION2,
> RT5033_FLED_CTRL2_MASK, RT5033_FLED_ENFLED);
>
> Process 1:
> regmap_update_bits(led->regmap, RT5033_REG_FLED_STROBE_CTRL2,
> RT5033_FLED_STRBCTRL2_MASK, flash_tm_reg);
> regmap_update_bits(led->regmap, RT5033_REG_FLED_FUNCTION1,
> RT5033_FLED_FUNC1_MASK, RT5033_FLED_STRB_SEL
> | RT5033_FLED_PINCTRL);
> regmap_update_bits(led->regmap, RT5033_REG_FLED_FUNCTION2,
> RT5033_FLED_FUNC2_MASK, RT5033_FLED_ENFLED
>
> In a result LED class device will report brightness value 1,
> whereas it would be inconsistent with hardware state, since
> flash strobe turns torch mode off.
>
>

Thanks for your explanation in detail,
I was worried about cases of using shared resource for flash led.
because I thought flash led would be called just from camera or directly itself.
I should consider using mutex

>> +
>> + regmap_update_bits(led->regmap, RT5033_REG_FLED_FUNCTION1,
>> + RT5033_FLED_FUNC1_MASK, RT5033_FLED_RESET);
>> + fled_cdev->led_cdev.brightness = LED_OFF;
>> +
>> + if (state) {
>> + flash_tm_reg = GET_TIMEOUT_OFFSET(fled_cdev->timeout.val,
>> + fled_cdev->timeout.step);
>> + regmap_update_bits(led->regmap, RT5033_REG_FLED_STROBE_CTRL2,
>> + RT5033_FLED_STRBCTRL2_MASK, flash_tm_reg);
>> + regmap_update_bits(led->regmap, RT5033_REG_FLED_FUNCTION1,
>> + RT5033_FLED_FUNC1_MASK, RT5033_FLED_STRB_SEL
>> + | RT5033_FLED_PINCTRL);
>> + regmap_update_bits(led->regmap, RT5033_REG_FLED_FUNCTION2,
>> + RT5033_FLED_FUNC2_MASK, RT5033_FLED_ENFLED
>> + | RT5033_FLED_SREG_STRB);
>> + }
>> +
>> + return 0;
>> +}
>> +
>> +static const struct led_flash_ops flash_ops = {
>> + .strobe_set = rt5033_led_flash_strobe_set,
>> + .timeout_set = rt5033_led_flash_timeout_set,
>> +};
>> +
>> +static int rt5033_led_probe(struct platform_device *pdev)
>> +{
>> + struct rt5033_dev *rt5033 = dev_get_drvdata(pdev->dev.parent);
>> + struct rt5033_led *led;
>> + struct led_classdev *led_cdev;
>> + int ret;
>> +
>> + led = devm_kzalloc(&pdev->dev, sizeof(*led), GFP_KERNEL);
>> + if (!led)
>> + return -ENOMEM;
>> +
>> + platform_set_drvdata(pdev, led);
>> + led->dev = &pdev->dev;
>> + led->regmap = rt5033->regmap;
>> +
>> + ret = rt5033_led_parse_dt(led, &pdev->dev);
>> + if (ret)
>> + return ret;
>> +
>> + rt5033_init_flash_timeout(led);
>> + led->fled_cdev.ops = &flash_ops;
>> + led_cdev = &led->fled_cdev.led_cdev;
>> +
>> + led_cdev->max_brightness = RT5033_LED_TORCH_CURRENT_LEVEL_MAX;
>
> This should depend on led-max-microamp.
>

Right, I'll fix it

>> + led_cdev->brightness_set_sync = rt5033_led_brightness_set;
>> + led_cdev->flags |= LED_CORE_SUSPENDRESUME | LED_DEV_CAP_FLASH;
>
> You need also a work queue since your ops can sleep.
>

Ok, I'll try to implement it

>> +
>> + ret = led_classdev_flash_register(&pdev->dev, &led->fled_cdev);
>> + if (ret < 0) {
>> + dev_err(&pdev->dev, "can't register LED %s\n", led_cdev->name);
>> + return ret;
>> + }
>> +
>> + regmap_update_bits(led->regmap, RT5033_REG_FLED_FUNCTION1,
>> + RT5033_FLED_FUNC1_MASK, RT5033_FLED_RESET);
>> +
>> + return 0;
>> +}
>> +
>> +static int rt5033_led_remove(struct platform_device *pdev)
>> +{
>> + struct rt5033_led *led = platform_get_drvdata(pdev);
>> +
>> + led_classdev_flash_unregister(&led->fled_cdev);
>> +
>> + return 0;
>> +}
>> +
>> +static const struct platform_device_id rt5033_led_id[] = {
>> + { "rt5033-led", },
>> + { /* sentinel */ },
>> +};
>> +MODULE_DEVICE_TABLE(platform, rt5033_led_id);
>> +
>> +static const struct of_device_id rt5033_led_match[] = {
>> + { .compatible = "richtek,rt5033-led", },
>> + { /* sentinel */ },
>> +};
>> +MODULE_DEVICE_TABLE(of, rt5033_led_match);
>> +
>> +static struct platform_driver rt5033_led_driver = {
>> + .driver = {
>> + .name = "rt5033-led",
>> + .of_match_table = rt5033_led_match,
>> + },
>> + .probe = rt5033_led_probe,
>> + .id_table = rt5033_led_id,
>> + .remove = rt5033_led_remove,
>> +};
>> +module_platform_driver(rt5033_led_driver);
>> +
>> +MODULE_AUTHOR("Ingi Kim <ingi2.kim@samsung.com>");
>> +MODULE_DESCRIPTION("Richtek RT5033 LED driver");
>> +MODULE_LICENSE("GPL v2");
>> +MODULE_ALIAS("platform:rt5033-led");
>> diff --git a/include/linux/mfd/rt5033-private.h b/include/linux/mfd/rt5033-private.h
>> index 1b63fc2..c8e99e4 100644
>> --- a/include/linux/mfd/rt5033-private.h
>> +++ b/include/linux/mfd/rt5033-private.h
>> @@ -93,6 +93,55 @@ enum rt5033_reg {
>> #define RT5033_RT_CTRL1_UUG_MASK 0x02
>> #define RT5033_RT_HZ_MASK 0x01
>>

[..]

>>
>> +/* RT5033 Flash led platform data */
>> +struct rt5033_led_config_data {
>> + u32 torch_max_microamp;
>> + u32 flash_max_microamp;
>> + u32 flash_max_timeout;
>> + enum led_brightness max_brightness;
>> +};
>> +
>> +struct rt5033_led {
>> + struct device *dev;
>> + struct rt5033_dev *rt5033;
>> + struct regmap *regmap;
>> +
>> + struct led_classdev_flash fled_cdev;
>> + struct rt5033_led_config_data *data;
>
> It is not needed to have config data here.
>

Okay, I try to move config data to local.

>> +};
>> +
>> #endif /* __RT5033_H__ */
>>
>
>