Re: [PATCH] leds:lp55xx: fix firmware loading error

[Jacek Anaszewski <j.anaszewski@samsung.com>]

Hi Milo,

Thanks for the patch.

On 06/25/2015 09:33 PM, Milo Kim wrote:
> LP55xx driver uses not firmware file but raw data to load program data through
> the firmware interface.(Documents/leds/leds-lp55xx.txt)
>
>    For example, run blinking green channel pattern,
>    echo 2 > /sys/bus/i2c/devices/xxxx/select_engine     # 2 is for green channel
>    echo "RGB" > /sys/bus/i2c/devices/xxxx/engine_mux    # engine mux for RGB
>    echo 1 > /sys/class/firmware/lp5562/loading
>    echo "4000600040FF6000" > /sys/class/firmware/lp5562/data
>    echo 0 > /sys/class/firmware/lp5562/loading
>    echo 1 > /sys/bus/i2c/devices/xxxx/run_engine

Please don't exceed 75 characters line length limit.

>
> However, '/sys/class/firmware/<device name>' is not created after
> firmware load user helper was introduced.
>
> LP55xx driver requires not only enabling CONFIG_FW_LOADER_USER_HELPER_FALLBACK
> but also option, 'FW_OPT_USERHELPER'.
> When _request_firmware() is invoked, this option enables to load raw data
> manually (aka, fw_load_from_user_helper() is called)
> The second parameter 'uevent' of request_firmware_nowait() is used for this
> option, 'FW_OPT_USERHELPER'.

Could you describe it more clearly, i.e. how 'uevent' is used for the
option FW_OPT_USERHELPER? I can't get the relationship without going
deeper into details.

>
> Signed-off-by: Milo Kim <milo.kim@ti.com>
> Cc: Bryan Wu <cooloney@gmail.com>
> Cc: Jacek Anaszewski <j.anaszewski@samsung.com>
> Cc: linux-leds@vger.kernel.org
> ---
>   drivers/leds/Kconfig              | 1 +
>   drivers/leds/leds-lp55xx-common.c | 2 +-
>   2 files changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/leds/Kconfig b/drivers/leds/Kconfig
> index 966b960..a39d608 100644
> --- a/drivers/leds/Kconfig
> +++ b/drivers/leds/Kconfig
> @@ -206,6 +206,7 @@ config LEDS_LP55XX_COMMON
>   	tristate "Common Driver for TI/National LP5521/5523/55231/5562/8501"
>   	depends on LEDS_LP5521 || LEDS_LP5523 || LEDS_LP5562 || LEDS_LP8501
>   	select FW_LOADER
> +	select FW_LOADER_USER_HELPER_FALLBACK
>   	help
>   	  This option supports common operations for LP5521/5523/55231/5562/8501
>   	  devices.
> diff --git a/drivers/leds/leds-lp55xx-common.c b/drivers/leds/leds-lp55xx-common.c
> index 77c26bc..96d51e9 100644
> --- a/drivers/leds/leds-lp55xx-common.c
> +++ b/drivers/leds/leds-lp55xx-common.c
> @@ -223,7 +223,7 @@ static int lp55xx_request_firmware(struct lp55xx_chip *chip)
>   	const char *name = chip->cl->name;
>   	struct device *dev = &chip->cl->dev;
>
> -	return request_firmware_nowait(THIS_MODULE, true, name, dev,
> +	return request_firmware_nowait(THIS_MODULE, false, name, dev,
>   				GFP_KERNEL, chip, lp55xx_firmware_loaded);
>   }
>
>


-- 
Best Regards,
Jacek Anaszewski