Received-SPF: pass (google.com: domain of linux-crypto-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
Subject: Re: [PATCH] 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:     Jerome Brunet <jbrunet@baylibre.com>,
        Martin Blumenstingl <martin.blumenstingl@googlemail.com>,
        linux-crypto@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
        linux-amlogic@lists.infradead.org, kernel@pengutronix.de
References: <20210914142428.57099-1-u.kleine-koenig@pengutronix.de>
From:   Neil Armstrong <narmstrong@baylibre.com>
Organization: Baylibre
Message-ID: <07a4f824-5a80-7c0b-d8c9-82e89446bd87@baylibre.com>
Date:   Wed, 15 Sep 2021 10:13:54 +0200
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101
 Thunderbird/78.11.0
MIME-Version: 1.0
In-Reply-To: <20210914142428.57099-1-u.kleine-koenig@pengutronix.de>
Content-Type: text/plain; charset=utf-8
Content-Language: en-US
Content-Transfer-Encoding: 8bit
Precedence: bulk

On 14/09/2021 16:24, 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>
> ---
>  drivers/char/hw_random/meson-rng.c | 12 +++++++++---
>  1 file changed, 9 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/char/hw_random/meson-rng.c b/drivers/char/hw_random/meson-rng.c
> index e446236e81f2..9f3e2eb8011d 100644
> --- a/drivers/char/hw_random/meson-rng.c
> +++ b/drivers/char/hw_random/meson-rng.c
> @@ -54,9 +54,15 @@ 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");
> -	if (IS_ERR(data->core_clk))
> -		data->core_clk = NULL;
> +	data->core_clk = devm_clk_get_optional(dev, "core");
> +	if (IS_ERR(data->core_clk)) {
> +		ret = PTR_ERR(data->core_clk);
> +		if (ret != -EPROBE_DEFER)
> +			dev_err(dev, "Failed to get core clock: %pe\n",
> +				data->core_clk);
> +
> +		return ret;
> +	}
>  
>  	if (data->core_clk) {
>  		ret = clk_prepare_enable(data->core_clk);
> 

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

Thanks,
Neil