[PATCH 2/2] ath10k: search DT for qcom, ath10k-calibration-variant

[Kalle Valo]

Sven Eckelmann <sven.eckelmann at openmesh.com> writes:

> Board Data File (BDF) is loaded upon driver boot-up procedure. The right
> board data file is identified on QCA4019 using bus, bmi-chip-id and
> bmi-board-id.
>
> The problem, however, can occur when the (default) board data file cannot
> fulfill with the vendor requirements and it is necessary to use a different
> board data file.
>
> This problem was solved for SMBIOS by adding a special SMBIOS type 0xF8.
> Something similar has to be provided for systems without SMBIOS but with
> device trees. No solution was specified by QCA and therefore a new one has
> to be found for ath10k.
>
> The device tree requires addition strings to define the variant name
>
>     wifi at a000000 {
>     	status = "okay";
>     	qcom,ath10k-calibration-variant = "RT-AC58U";
>     };
>
>     wifi at a800000 {
>     	status = "okay";
>     	qcom,ath10k-calibration-variant = "RT-AC58U";
>     };
>
> This would create the boarddata identifiers for the board-2.bin search
>
>  *  bus=ahb,bmi-chip-id=0,bmi-board-id=16,variant=RT-AC58U
>  *  bus=ahb,bmi-chip-id=0,bmi-board-id=17,variant=RT-AC58U
>
> Signed-off-by: Sven Eckelmann <sven.eckelmann at openmesh.com>
> ---
> Since RFC:
>
>  - initialize variant pointer to have it initialized to NULL when
>    of_property_read_string fails (thanks Christian Lamparter)
>  - Only print warning that DT doesn't contain string ones (thanks Christian
>    Lamparter)
>  - Split patch in DT doc and ath10k part (thanks Christian Lamparter)
>  - Allow to overwrite the variant string via DT and ignore that SMBIOS had
>    written anything to it

[...]

> --- a/drivers/net/wireless/ath/ath10k/core.c
> +++ b/drivers/net/wireless/ath/ath10k/core.c
> @@ -779,6 +779,25 @@ static int ath10k_core_check_smbios(struct ath10k *ar)
>  	return 0;
>  }
>  
> +static int ath10k_core_check_dt(struct ath10k *ar)
> +{
> +	struct device_node *node;
> +	const char *variant = NULL;
> +
> +	node = ar->dev->of_node;
> +	if (!node)
> +		return -ENOENT;
> +
> +	of_property_read_string(node, "qcom,ath10k-calibration-variant",
> +				&variant);
> +	if (!variant)
> +		return -ENODATA;
> +
> +	strscpy(ar->id.bdf_ext, variant, sizeof(ar->id.bdf_ext));

Kbuild bot found a warning here:

   drivers/net/wireless/ath/ath10k/core.c: In function 'ath10k_core_check_dt':
>> drivers/net/wireless/ath/ath10k/core.c:877:2: warning: ignoring return value of 'strscpy', declared with attribute warn_unused_result [-Wunused-result]
     strscpy(ar->id.bdf_ext, variant, sizeof(ar->id.bdf_ext));
     ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

I guess warn_unused_result in strscpy() is a recent addition and that's
why you didn't see it.

-- 
Kalle Valo