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Subject: Re: [PATCH] platform/chrome: wilco_ec: Fix keyboard backlight probing
To:     Daniel Campello <campello@chromium.org>,
        LKML <linux-kernel@vger.kernel.org>
Cc:     Nick Crews <ncrews@chromium.org>,
        Benson Leung <bleung@chromium.org>
References: <20200107112400.1.Iedcdbae5a7ed79291b557882130e967f72168a9f@changeid>
From:   Enric Balletbo i Serra <enric.balletbo@collabora.com>
Message-ID: <ab377eeb-f1bc-13c2-8bbc-ccc53ecb7c4d@collabora.com>
Date:   Wed, 8 Jan 2020 11:38:58 +0100
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Hi Daniel,

Many thanks for sending the patch upstream.

On 7/1/20 19:24, Daniel Campello wrote:
> The EC on the Wilco platform responds with 0xFF to commands related to
> the keyboard backlight on the absence of a keyboard backlight module.
> This change allows the EC driver to continue loading even if the
> backlight module is not present.
> 

Could you explain a bit more which is the problem you're trying to solve? I am
not sure I understand it, isn't the kbbl_exist call for that purpose? (in
absence of the keyboard backligh module just don't init the device?)

Thanks,
 Enric


> Signed-off-by: Daniel Campello <campello@chromium.org>
> ---
> 
>  .../platform/chrome/wilco_ec/keyboard_leds.c  | 28 +++++++++++++------
>  1 file changed, 20 insertions(+), 8 deletions(-)
> 
> diff --git a/drivers/platform/chrome/wilco_ec/keyboard_leds.c b/drivers/platform/chrome/wilco_ec/keyboard_leds.c
> index bb0edf51dfda..5731d1b60e28 100644
> --- a/drivers/platform/chrome/wilco_ec/keyboard_leds.c
> +++ b/drivers/platform/chrome/wilco_ec/keyboard_leds.c
> @@ -73,13 +73,6 @@ static int send_kbbl_msg(struct wilco_ec_device *ec,
>  		return ret;
>  	}
> 
> -	if (response->status) {
> -		dev_err(ec->dev,
> -			"EC reported failure sending keyboard LEDs command: %d",
> -			response->status);
> -		return -EIO;
> -	}
> -
>  	return 0;
>  }
> 
> @@ -87,6 +80,7 @@ static int set_kbbl(struct wilco_ec_device *ec, enum led_brightness brightness)
>  {
>  	struct wilco_keyboard_leds_msg request;
>  	struct wilco_keyboard_leds_msg response;
> +	int ret;
> 
>  	memset(&request, 0, sizeof(request));
>  	request.command = WILCO_EC_COMMAND_KBBL;
> @@ -94,7 +88,18 @@ static int set_kbbl(struct wilco_ec_device *ec, enum led_brightness brightness)
>  	request.mode    = WILCO_KBBL_MODE_FLAG_PWM;
>  	request.percent = brightness;
> 
> -	return send_kbbl_msg(ec, &request, &response);
> +	ret = send_kbbl_msg(ec, &request, &response);
> +	if (ret < 0)
> +		return ret;
> +
> +	if (response.status) {
> +		dev_err(ec->dev,
> +			"EC reported failure sending keyboard LEDs command: %d",
> +			response.status);
> +		return -EIO;
> +	}
> +
> +	return 0;
>  }
> 
>  static int kbbl_exist(struct wilco_ec_device *ec, bool *exists)
> @@ -140,6 +145,13 @@ static int kbbl_init(struct wilco_ec_device *ec)
>  	if (ret < 0)
>  		return ret;
> 
> +	if (response.status) {
> +		dev_err(ec->dev,
> +			"EC reported failure sending keyboard LEDs command: %d",
> +			response.status);
> +		return -EIO;
> +	}
> +
>  	if (response.mode & WILCO_KBBL_MODE_FLAG_PWM)
>  		return response.percent;
> 
> --
> 2.24.1.735.g03f4e72817-goog
>