linux-kernel - Re: [PATCH v4 4/4] ASoC: samsung: Add machine driver for Exynos5433 based TM2 board

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Message-id: <5790A3D0.4070500@samsung.com>
Date:	Thu, 21 Jul 2016 19:28:32 +0900
From:	Chanwoo Choi <cw00.choi@...sung.com>
To:	Sylwester Nawrocki <s.nawrocki@...sung.com>
Cc:	broonie@...nel.org, robh@...nel.org, alsa-devel@...a-project.org,
	devicetree@...r.kernel.org, ideal.song@...sung.com,
	inki.dae@...sung.com, b.zolnierkie@...sung.com,
	linux-samsung-soc@...r.kernel.org, linux-kernel@...r.kernel.org,
	Krzysztof Kozlowski <k.kozlowski@...sung.com>
Subject: Re: [PATCH v4 4/4] ASoC: samsung: Add machine driver for Exynos5433
 based TM2 board

Hi Sylwester,

On 2016년 07월 18일 19:41, Sylwester Nawrocki wrote:
> Hi Chanwoo,
> 
> On 07/15/2016 07:18 AM, Chanwoo Choi wrote:
>>> +static int tm2_probe(struct platform_device *pdev)
>>> +{
>>> +	struct device *dev = &pdev->dev;
> 
>>> +	codec_dai_node = of_parse_phandle(dev->of_node, "audio-codec", 0);
>>> +	if (!codec_dai_node) {
>>> +		dev_err(dev, "audio-codec property invalid or missing\n");
>>> +		ret = -EINVAL;
>>> +		goto err_put_cpu_dai;
>>> +	}
> 
>>> +	priv->codec_mclk1 = of_clk_get_by_name(codec_dai_node, "mclk1");
>>> +	if (IS_ERR(priv->codec_mclk1)) {
>>> +		dev_err(dev, "Failed to get mclk1 clock\n");
>>> +		ret = PTR_ERR(priv->codec_mclk1);
>>> +		goto err_put_codec_dai;
>>> +	}
>>
>> I think that you better to use the devm_clk_get() instead of of_clk_get_by_name()
>> because you don't need to handle the clk_put() when error happen and remove the 
>> this driver.
>>
>> 	priv->codec_mclk1 = devm_clk_get(dev, "mclk1");
> 
> The clocks are from the CODEC DT node, for which we don't have struct
> device pointer here, that's why I used of_clk_get_by_name().

When I test it, I can get the clock pointer by devm_clk_get() as following:

diff --git a/sound/soc/samsung/tm2_wm5110.c b/sound/soc/samsung/tm2_wm5110.c
index 9728b3c5927f..5de4fc554aec 100644
--- a/sound/soc/samsung/tm2_wm5110.c
+++ b/sound/soc/samsung/tm2_wm5110.c
@@ -500,7 +500,7 @@ static int tm2_probe(struct platform_device *pdev)
                card->dai_link[i].platform_of_node = cpu_dai_node;
        }

-       priv->codec_mclk1 = of_clk_get_by_name(codec_dai_node, "mclk1");
+       priv->codec_mclk1 = devm_clk_get(dev, "mclk1");
        if (IS_ERR(priv->codec_mclk1)) {
                dev_err(dev, "Failed to get mclk1 clock\n");
                ret = PTR_ERR(priv->codec_mclk1);
@@ -508,7 +508,7 @@ static int tm2_probe(struct platform_device *pdev)
        }

        /* mclk2 is optional */
-       priv->codec_mclk2 = of_clk_get_by_name(codec_dai_node, "mclk2");
+       priv->codec_mclk2 = devm_clk_get(dev, "mclk2");
        if (IS_ERR(priv->codec_mclk2))
                dev_info(dev, "Not using mclk2 clock\n");

@@ -516,21 +516,17 @@ static int tm2_probe(struct platform_device *pdev)
                                tm2_ext_dai, ARRAY_SIZE(tm2_ext_dai));
        if (ret < 0) {
                dev_err(dev, "Failed to register component: %d\n", ret);
-               goto err_put_mclk;
+               goto err_put_codec_dai;
        }

        ret = devm_snd_soc_register_card(dev, card);
        if (ret < 0) {
                dev_err(dev, "Failed to register card: %d\n", ret);
-               goto err_put_mclk;
+               goto err_put_codec_dai;
        }

        return 0;

-err_put_mclk:
-       clk_put(priv->codec_mclk1);
-       if (!IS_ERR(priv->codec_mclk2))
-               clk_put(priv->codec_mclk2);
 err_put_codec_dai:
        of_node_put(codec_dai_node);
 err_put_cpu_dai:
@@ -543,11 +539,6 @@ err_put_amp:
 static int tm2_remove(struct platform_device *pdev)
 {
        struct snd_soc_card *card = &tm2_card;
-       struct tm2_machine_priv *priv = snd_soc_card_get_drvdata(card);
-
-       clk_put(priv->codec_mclk1);
-       if (!IS_ERR(priv->codec_mclk2))
-               clk_put(priv->codec_mclk2);


Regards,
Chanwoo Choi