linux-kernel - [PATCH 1/2] ASoC: atmel-i2s: Remove unnecessary audio PLL clock (aclk)

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Message-ID: <20180703145631.15246-2-codrin.ciubotariu@microchip.com>
Date:   Tue, 3 Jul 2018 17:56:30 +0300
From:   Codrin Ciubotariu <codrin.ciubotariu@...rochip.com>
To:     <linux-arm-kernel@...ts.infradead.org>,
        <linux-kernel@...r.kernel.org>, <devicetree@...r.kernel.org>,
        <alsa-devel@...a-project.org>, <alexandre.belloni@...tlin.com>,
        <nicolas.ferre@...rochip.com>, <robh+dt@...nel.org>,
        <broonie@...nel.org>, <quentin.schulz@...tlin.com>
CC:     <Cristian.Birsan@...rochip.com>
Subject: [PATCH 1/2] ASoC: atmel-i2s: Remove unnecessary audio PLL clock (aclk)

The generated clock (gclk) driver is able to set aclk as its parent and
change its rate alone, if needed. This means that our driver no longer
needs to configure aclk and we can let gclk select and configure its
clock source.

Signed-off-by: Codrin Ciubotariu <codrin.ciubotariu@...rochip.com>
---
 sound/soc/atmel/atmel-i2s.c | 46 ++++++-------------------------------
 1 file changed, 7 insertions(+), 39 deletions(-)

diff --git a/sound/soc/atmel/atmel-i2s.c b/sound/soc/atmel/atmel-i2s.c
index 5d3b5af9fd92..d88c1d995036 100644
--- a/sound/soc/atmel/atmel-i2s.c
+++ b/sound/soc/atmel/atmel-i2s.c
@@ -206,7 +206,6 @@ struct atmel_i2s_dev {
 	struct regmap				*regmap;
 	struct clk				*pclk;
 	struct clk				*gclk;
-	struct clk				*aclk;
 	struct snd_dmaengine_dai_dma_data	playback;
 	struct snd_dmaengine_dai_dma_data	capture;
 	unsigned int				fmt;
@@ -303,7 +302,7 @@ static int atmel_i2s_get_gck_param(struct atmel_i2s_dev *dev, int fs)
 {
 	int i, best;
 
-	if (!dev->gclk || !dev->aclk) {
+	if (!dev->gclk) {
 		dev_err(dev->dev, "cannot generate the I2S Master Clock\n");
 		return -EINVAL;
 	}
@@ -421,7 +420,7 @@ static int atmel_i2s_switch_mck_generator(struct atmel_i2s_dev *dev,
 					  bool enabled)
 {
 	unsigned int mr, mr_mask;
-	unsigned long aclk_rate;
+	unsigned long gclk_rate;
 	int ret;
 
 	mr = 0;
@@ -445,35 +444,18 @@ static int atmel_i2s_switch_mck_generator(struct atmel_i2s_dev *dev,
 		/* Disable/unprepare the PMC generated clock. */
 		clk_disable_unprepare(dev->gclk);
 
-		/* Disable/unprepare the PLL audio clock. */
-		clk_disable_unprepare(dev->aclk);
 		return 0;
 	}
 
 	if (!dev->gck_param)
 		return -EINVAL;
 
-	aclk_rate = dev->gck_param->mck * (dev->gck_param->imckdiv + 1);
+	gclk_rate = dev->gck_param->mck * (dev->gck_param->imckdiv + 1);
 
-	/* Fist change the PLL audio clock frequency ... */
-	ret = clk_set_rate(dev->aclk, aclk_rate);
+	ret = clk_set_rate(dev->gclk, gclk_rate);
 	if (ret)
 		return ret;
 
-	/*
-	 * ... then set the PMC generated clock rate to the very same frequency
-	 * to set the gclk parent to aclk.
-	 */
-	ret = clk_set_rate(dev->gclk, aclk_rate);
-	if (ret)
-		return ret;
-
-	/* Prepare and enable the PLL audio clock first ... */
-	ret = clk_prepare_enable(dev->aclk);
-	if (ret)
-		return ret;
-
-	/* ... then prepare and enable the PMC generated clock. */
 	ret = clk_prepare_enable(dev->gclk);
 	if (ret)
 		return ret;
@@ -668,28 +650,14 @@ static int atmel_i2s_probe(struct platform_device *pdev)
 		return err;
 	}
 
-	/* Get audio clocks to generate the I2S Master Clock (I2S_MCK) */
-	dev->aclk = devm_clk_get(&pdev->dev, "aclk");
+	/* Get audio clock to generate the I2S Master Clock (I2S_MCK) */
 	dev->gclk = devm_clk_get(&pdev->dev, "gclk");
-	if (IS_ERR(dev->aclk) && IS_ERR(dev->gclk)) {
-		if (PTR_ERR(dev->aclk) == -EPROBE_DEFER ||
-		    PTR_ERR(dev->gclk) == -EPROBE_DEFER)
+	if (IS_ERR(dev->gclk)) {
+		if (PTR_ERR(dev->gclk) == -EPROBE_DEFER)
 			return -EPROBE_DEFER;
 		/* Master Mode not supported */
-		dev->aclk = NULL;
 		dev->gclk = NULL;
-	} else if (IS_ERR(dev->gclk)) {
-		err = PTR_ERR(dev->gclk);
-		dev_err(&pdev->dev,
-			"failed to get the PMC generated clock: %d\n", err);
-		return err;
-	} else if (IS_ERR(dev->aclk)) {
-		err = PTR_ERR(dev->aclk);
-		dev_err(&pdev->dev,
-			"failed to get the PLL audio clock: %d\n", err);
-		return err;
 	}
-
 	dev->dev = &pdev->dev;
 	dev->regmap = regmap;
 	platform_set_drvdata(pdev, dev);
-- 
2.17.1