linux-kernel - Re: [PATCH v2 2/5] crypto: ccree: better clock handling

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Date:   Tue, 29 May 2018 17:13:32 +0100
From:   Simon Horman <horms@...ge.net.au>
To:     Gilad Ben-Yossef <gilad@...yossef.com>
Cc:     Magnus Damm <magnus.damm@...il.com>,
        Rob Herring <robh+dt@...nel.org>,
        Mark Rutland <mark.rutland@....com>,
        Catalin Marinas <catalin.marinas@....com>,
        Will Deacon <will.deacon@....com>,
        Geert Uytterhoeven <geert+renesas@...der.be>,
        Michael Turquette <mturquette@...libre.com>,
        Stephen Boyd <sboyd@...nel.org>,
        Herbert Xu <herbert@...dor.apana.org.au>,
        "David S. Miller" <davem@...emloft.net>,
        Ofir Drang <ofir.drang@....com>,
        linux-renesas-soc@...r.kernel.org, devicetree@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
        linux-clk@...r.kernel.org, linux-crypto@...r.kernel.org
Subject: Re: [PATCH v2 2/5] crypto: ccree: better clock handling

On Thu, May 24, 2018 at 03:19:07PM +0100, Gilad Ben-Yossef wrote:
> Use managed clock handling, differentiate between no clock (possibly OK)
> and clock init failure (never OK) and correctly handle clock detection
> being deferred.
> 
> Suggested-by: Geert Uytterhoeven <geert@...ux-m68k.org>
> Signed-off-by: Gilad Ben-Yossef <gilad@...yossef.com>

Reviewed-by: Simon Horman <horms+renesas@...ge.net.au>

> ---
>  drivers/crypto/ccree/cc_driver.c | 20 +++++++++++++++++++-
>  1 file changed, 19 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/crypto/ccree/cc_driver.c b/drivers/crypto/ccree/cc_driver.c
> index 6f93ce7..b266657 100644
> --- a/drivers/crypto/ccree/cc_driver.c
> +++ b/drivers/crypto/ccree/cc_driver.c
> @@ -190,6 +190,7 @@ static int init_cc_resources(struct platform_device *plat_dev)
>  	u64 dma_mask;
>  	const struct cc_hw_data *hw_rev;
>  	const struct of_device_id *dev_id;
> +	struct clk *clk;
>  	int rc = 0;
>  
>  	new_drvdata = devm_kzalloc(dev, sizeof(*new_drvdata), GFP_KERNEL);
> @@ -219,7 +220,24 @@ static int init_cc_resources(struct platform_device *plat_dev)
>  	platform_set_drvdata(plat_dev, new_drvdata);
>  	new_drvdata->plat_dev = plat_dev;
>  
> -	new_drvdata->clk = of_clk_get(np, 0);
> +	clk = devm_clk_get(dev, NULL);
> +	if (IS_ERR(clk))
> +		switch (PTR_ERR(clk)) {
> +		/* Clock is optional so this might be fine */
> +		case -ENOENT:
> +			break;
> +
> +		/* Clock not available, let's try again soon */
> +		case -EPROBE_DEFER:
> +			return -EPROBE_DEFER;
> +
> +		default:
> +			dev_err(dev, "Error getting clock: %ld\n",
> +				PTR_ERR(clk));
> +			return PTR_ERR(clk);
> +		}
> +	new_drvdata->clk = clk;
> +
>  	new_drvdata->coherent = of_dma_is_coherent(np);
>  
>  	/* Get device resources */
> -- 
> 2.7.4
>