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Sender: Guenter Roeck <groeck7@gmail.com>
Date:   Wed, 25 Oct 2023 12:41:00 -0700
From:   Guenter Roeck <linux@roeck-us.net>
To:     Aleksa Savic <savicaleksa83@gmail.com>
Cc:     linux-hwmon@vger.kernel.org, leonard.anderweit@gmail.com,
        Jack Doan <me@jackdoan.com>, Jean Delvare <jdelvare@suse.com>,
        Jonathan Corbet <corbet@lwn.net>, linux-doc@vger.kernel.org,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH 1/2] hwmon: (aquacomputer_d5next) Check if temp sensors
 of legacy devices are connected
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References: <20231016083559.139341-1-savicaleksa83@gmail.com>
 <20231016083559.139341-2-savicaleksa83@gmail.com>
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On Mon, Oct 16, 2023 at 10:35:57AM +0200, Aleksa Savic wrote:
> Return -ENODATA if a temp sensor of a legacy device
> does not contain a reading.
> 

Why is the sensor instantiated in the first place ?
Returning -ENODATA for every reading is not desirable.
If this can happen, the is_visible function should check
for it and skip affected sensors.

Guenter

> Originally-from: Leonard Anderweit <leonard.anderweit@gmail.com>
> Signed-off-by: Aleksa Savic <savicaleksa83@gmail.com>
> ---
>  drivers/hwmon/aquacomputer_d5next.c | 5 ++++-
>  1 file changed, 4 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/hwmon/aquacomputer_d5next.c b/drivers/hwmon/aquacomputer_d5next.c
> index 023807859be7..46ff4fd4f87d 100644
> --- a/drivers/hwmon/aquacomputer_d5next.c
> +++ b/drivers/hwmon/aquacomputer_d5next.c
> @@ -926,7 +926,10 @@ static int aqc_legacy_read(struct aqc_data *priv)
>  	for (i = 0; i < priv->num_temp_sensors; i++) {
>  		sensor_value = get_unaligned_le16(priv->buffer + priv->temp_sensor_start_offset +
>  						  i * AQC_SENSOR_SIZE);
> -		priv->temp_input[i] = sensor_value * 10;
> +		if (sensor_value == AQC_SENSOR_NA)
> +			priv->temp_input[i] = -ENODATA;
> +		else
> +			priv->temp_input[i] = sensor_value * 10;
>  	}
>  
>  	/* Special-case sensor readings */