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Subject: Re: [PATCH v4 14/37] PM / devfreq: tegra20: Add error messages to
 tegra_devfreq_target()
To:     Dmitry Osipenko <digetx@gmail.com>,
        Thierry Reding <thierry.reding@gmail.com>,
        Jonathan Hunter <jonathanh@nvidia.com>,
        Georgi Djakov <georgi.djakov@linaro.org>,
        Rob Herring <robh+dt@kernel.org>,
        Michael Turquette <mturquette@baylibre.com>,
        Stephen Boyd <sboyd@kernel.org>,
        Peter De Schrijver <pdeschrijver@nvidia.com>,
        MyungJoo Ham <myungjoo.ham@samsung.com>,
        Kyungmin Park <kyungmin.park@samsung.com>,
        Mikko Perttunen <cyndis@kapsi.fi>
Cc:     =?UTF-8?B?QXJ0dXIgxZp3aWdvxYQ=?= <a.swigon@samsung.com>,
        linux-tegra@vger.kernel.org, linux-pm@vger.kernel.org,
        linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org,
        devicetree@vger.kernel.org
From:   Chanwoo Choi <cw00.choi@samsung.com>
Organization: Samsung Electronics
Message-ID: <5d83261b-12e5-9734-f793-0600212bcee1@samsung.com>
Date:   Thu, 2 Jul 2020 10:12:24 +0900
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On 6/9/20 10:13 PM, Dmitry Osipenko wrote:
> It's useful to now when something goes wrong instead of failing silently,
> so let's add error messages to tegra_devfreq_target() to prevent situation
> where it fails silently.
> 
> Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
> ---
>  drivers/devfreq/tegra20-devfreq.c | 12 +++++++++---
>  1 file changed, 9 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/devfreq/tegra20-devfreq.c b/drivers/devfreq/tegra20-devfreq.c
> index bf504ca4dea2..249d0dc44f6c 100644
> --- a/drivers/devfreq/tegra20-devfreq.c
> +++ b/drivers/devfreq/tegra20-devfreq.c
> @@ -44,19 +44,25 @@ static int tegra_devfreq_target(struct device *dev, unsigned long *freq,
>  	int err;
>  
>  	opp = devfreq_recommended_opp(dev, freq, flags);
> -	if (IS_ERR(opp))
> +	if (IS_ERR(opp)) {
> +		dev_err(dev, "failed to find opp for %lu Hz\n", *freq);
>  		return PTR_ERR(opp);
> +	}
>  
>  	rate = dev_pm_opp_get_freq(opp);
>  	dev_pm_opp_put(opp);
>  
>  	err = clk_set_min_rate(tegra->emc_clock, rate);
> -	if (err)
> +	if (err) {
> +		dev_err(dev, "failed to set min rate: %d\n", err);
>  		return err;
> +	}
>  
>  	err = clk_set_rate(tegra->emc_clock, 0);
> -	if (err)
> +	if (err) {
> +		dev_err(dev, "failed to set rate: %d\n", err);
>  		goto restore_min_rate;
> +	}
>  
>  	return 0;
>  
> 

Acked-by: Chanwoo Choi <cw00.choi@samsung.com>

-- 
Best Regards,
Chanwoo Choi
Samsung Electronics