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Subject: Re: [PATCH v2] hwrng: meson - Improve error handling for core clock
To:     =?UTF-8?Q?Uwe_Kleine-K=c3=b6nig?= <u.kleine-koenig@pengutronix.de>,
        Matt Mackall <mpm@selenic.com>,
        Herbert Xu <herbert@gondor.apana.org.au>,
        Kevin Hilman <khilman@baylibre.com>
Cc:     Martin Blumenstingl <martin.blumenstingl@googlemail.com>,
        linux-crypto@vger.kernel.org, kernel@pengutronix.de,
        linux-amlogic@lists.infradead.org,
        linux-arm-kernel@lists.infradead.org,
        Jerome Brunet <jbrunet@baylibre.com>
References: <20210920074405.252477-1-u.kleine-koenig@pengutronix.de>
From:   Neil Armstrong <narmstrong@baylibre.com>
Organization: Baylibre
Message-ID: <27b24b0e-7804-0a92-6022-ad828e1a45b5@baylibre.com>
Date:   Mon, 20 Sep 2021 10:16:02 +0200
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On 20/09/2021 09:44, Uwe Kleine-König wrote:
> -ENOENT (ie. "there is no clock") is fine to ignore for an optional
> clock, other values are not supposed to be ignored and should be
> escalated to the caller (e.g. -EPROBE_DEFER). Ignore -ENOENT by using
> devm_clk_get_optional().
> 
> While touching this code also add an error message for the fatal errors.
> 
> Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
> ---
> Hello,
> 
> compared to (implicit) v1
> (https://lore.kernel.org/r/20210914142428.57099-1-u.kleine-koenig@pengutronix.de)
> this used dev_err_probe() as suggested by Martin Blumenstingl.
> 
> v1 got a "Reviewed-by: Neil Armstrong <narmstrong@baylibre.com>", I didn't add
> that because of the above change.
> 

Hopefully martin did a better review than me !

Anyway,
Reviewed-by: Neil Armstrong <narmstrong@baylibre.com>

Neil

> (Hmm, my setup is broken, the b4 patch signature was done before I added this
> message. I wonder if this will break the signature ...)
> 
> Best regards
> Uwe
> 
>  drivers/char/hw_random/meson-rng.c | 5 +++--
>  1 file changed, 3 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/char/hw_random/meson-rng.c b/drivers/char/hw_random/meson-rng.c
> index e446236e81f2..8bb30282ca46 100644
> --- a/drivers/char/hw_random/meson-rng.c
> +++ b/drivers/char/hw_random/meson-rng.c
> @@ -54,9 +54,10 @@ static int meson_rng_probe(struct platform_device *pdev)
>  	if (IS_ERR(data->base))
>  		return PTR_ERR(data->base);
>  
> -	data->core_clk = devm_clk_get(dev, "core");
> +	data->core_clk = devm_clk_get_optional(dev, "core");
>  	if (IS_ERR(data->core_clk))
> -		data->core_clk = NULL;
> +		return dev_err_probe(dev, PTR_ERR(data->core_clk),
> +				     "Failed to get core clock\n");
>  
>  	if (data->core_clk) {
>  		ret = clk_prepare_enable(data->core_clk);
> 
> base-commit: 7d2a07b769330c34b4deabeed939325c77a7ec2f
>