linux-kernel - Re: [PATCH 2/6] platform/x86/intel/tpmi: Don't create devices for disabled features

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Date:   Thu, 30 Nov 2023 14:26:18 +0200 (EET)
From:   Ilpo Järvinen <ilpo.jarvinen@...ux.intel.com>
To:     Srinivas Pandruvada <srinivas.pandruvada@...ux.intel.com>
cc:     Hans de Goede <hdegoede@...hat.com>, markgross@...nel.org,
        Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
        platform-driver-x86@...r.kernel.org,
        LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 2/6] platform/x86/intel/tpmi: Don't create devices for
 disabled features

On Tue, 28 Nov 2023, Srinivas Pandruvada wrote:

> If some TPMI features are disabled, don't create auxiliary devices. In
> this way feature drivers will not load.
> 
> While creating auxiliary devices, call tpmi_read_feature_status() to
> check feature state and return if the feature is disabled without
> creating a device.
> 
> Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@...ux.intel.com>
> ---
>  drivers/platform/x86/intel/tpmi.c | 10 +++++++++-
>  1 file changed, 9 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/platform/x86/intel/tpmi.c b/drivers/platform/x86/intel/tpmi.c
> index c89aa4d14bea..4edaa182db04 100644
> --- a/drivers/platform/x86/intel/tpmi.c
> +++ b/drivers/platform/x86/intel/tpmi.c
> @@ -604,9 +604,17 @@ static int tpmi_create_device(struct intel_tpmi_info *tpmi_info,
>  	struct intel_vsec_device *vsec_dev = tpmi_info->vsec_dev;
>  	char feature_id_name[TPMI_FEATURE_NAME_LEN];
>  	struct intel_vsec_device *feature_vsec_dev;
> +	struct tpmi_feature_state feature_state;
>  	struct resource *res, *tmp;
>  	const char *name;
> -	int i;
> +	int i, ret;
> +
> +	ret = tpmi_read_feature_status(tpmi_info, pfs->pfs_header.tpmi_id, &feature_state);
> +	if (ret)
> +		return ret;
> +
> +	if (!feature_state.enabled)
> +		return -EOPNOTSUPP;

-ENODEV sounds more appropriate.  

-- 
 i.