Re: [PATCH v5 4/4] mmc: mtk-sd: Protect crypto capability with crypto config

[Eric Biggers <ebiggers@kernel.org>]

On Thu, Jul 30, 2026 at 07:38:22PM +0530, Neeraj Soni wrote:
> Host crypto capability can not be used if CONFIG_MMC_CRYPTO=n.
> So set MMC_CAP2_CRYPTO in mmc->caps2 only if CONFIG_MMC_CRYPTO=y.
> 
> Signed-off-by: Neeraj Soni <neeraj.soni@oss.qualcomm.com>
> ---
>  drivers/mmc/host/mtk-sd.c | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/drivers/mmc/host/mtk-sd.c b/drivers/mmc/host/mtk-sd.c
> index 01ea3adbdf3b..c415ed97e3c2 100644
> --- a/drivers/mmc/host/mtk-sd.c
> +++ b/drivers/mmc/host/mtk-sd.c
> @@ -3031,7 +3031,11 @@ static int msdc_drv_probe(struct platform_device *pdev)
>  		if (IS_ERR(host->crypto_clk))
>  			return PTR_ERR(host->crypto_clk);
>  		else if (host->crypto_clk)
> +#ifdef CONFIG_MMC_CRYPTO
>  			mmc->caps2 |= MMC_CAP2_CRYPTO;
> +#else
> +			dev_dbg(host->dev, "Enable necessary crypto config\n");
> +#endif

host->dev is still NULL at this point.  So if the log message were to be
actually reached it would show '(NULL device *)'.

But the message doesn't seem very useful anyway, especially when it's
logged only at debug level.  So maybe just drop it.

Is there a reason to even enable the crypto clock when CONFIG_MMC_CRYPTO
is disabled?  If no, then the 'if' condition above could just be changed
to:

    if (IS_ENABLED(CONFIG_MMC_CRYPTO) && !(mmc->caps2 & MMC_CAP2_NO_MMC)) {

- Eric