linux-kernel - [PATCH v2 1/2] iio: adc: meson: fix core clock enable/disable moment

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Message-ID: <20230721102413.255726-2-gnstark@sberdevices.ru>
Date:   Fri, 21 Jul 2023 13:23:08 +0300
From:   George Stark <gnstark@...rdevices.ru>
To:     <jic23@...nel.org>, <lars@...afoo.de>, <neil.armstrong@...aro.org>,
        <khilman@...libre.com>, <jbrunet@...libre.com>,
        <martin.blumenstingl@...glemail.com>,
        <andriy.shevchenko@...ux.intel.com>, <nuno.sa@...log.com>,
        <gnstark@...rdevices.ru>
CC:     <linux-iio@...r.kernel.org>,
        <linux-arm-kernel@...ts.infradead.org>,
        <linux-kernel@...r.kernel.org>,
        <linux-amlogic@...ts.infradead.org>, <kernel@...rdevices.ru>
Subject: [PATCH v2 1/2] iio: adc: meson: fix core clock enable/disable moment

Enable core clock at probe stage and disable it at remove stage.
Core clock is responsible for turning on/off the entire SoC module so
it should be on before the first module register is touched and be off
at very last moment.

Fixes: 3adbf3427330 ("iio: adc: add a driver for the SAR ADC found in Amlogic Meson SoCs")
Signed-off-by: George Stark <gnstark@...rdevices.ru>
---
 drivers/iio/adc/meson_saradc.c | 23 ++++++++++++-----------
 1 file changed, 12 insertions(+), 11 deletions(-)

diff --git a/drivers/iio/adc/meson_saradc.c b/drivers/iio/adc/meson_saradc.c
index 2ee12f3ad312..8397a5347f32 100644
--- a/drivers/iio/adc/meson_saradc.c
+++ b/drivers/iio/adc/meson_saradc.c
@@ -1055,12 +1055,6 @@ static int meson_sar_adc_hw_enable(struct iio_dev *indio_dev)
 		goto err_vref;
 	}
 
-	ret = clk_prepare_enable(priv->core_clk);
-	if (ret) {
-		dev_err(dev, "failed to enable core clk\n");
-		goto err_core_clk;
-	}
-
 	regval = FIELD_PREP(MESON_SAR_ADC_REG0_FIFO_CNT_IRQ_MASK, 1);
 	regmap_update_bits(priv->regmap, MESON_SAR_ADC_REG0,
 			   MESON_SAR_ADC_REG0_FIFO_CNT_IRQ_MASK, regval);
@@ -1087,8 +1081,6 @@ static int meson_sar_adc_hw_enable(struct iio_dev *indio_dev)
 	regmap_update_bits(priv->regmap, MESON_SAR_ADC_REG3,
 			   MESON_SAR_ADC_REG3_ADC_EN, 0);
 	meson_sar_adc_set_bandgap(indio_dev, false);
-	clk_disable_unprepare(priv->core_clk);
-err_core_clk:
 	regulator_disable(priv->vref);
 err_vref:
 	meson_sar_adc_unlock(indio_dev);
@@ -1116,8 +1108,6 @@ static void meson_sar_adc_hw_disable(struct iio_dev *indio_dev)
 
 	meson_sar_adc_set_bandgap(indio_dev, false);
 
-	clk_disable_unprepare(priv->core_clk);
-
 	regulator_disable(priv->vref);
 
 	if (!ret)
@@ -1379,7 +1369,7 @@ static int meson_sar_adc_probe(struct platform_device *pdev)
 	if (IS_ERR(priv->clkin))
 		return dev_err_probe(dev, PTR_ERR(priv->clkin), "failed to get clkin\n");
 
-	priv->core_clk = devm_clk_get(dev, "core");
+	priv->core_clk = devm_clk_get_enabled(dev, "core");
 	if (IS_ERR(priv->core_clk))
 		return dev_err_probe(dev, PTR_ERR(priv->core_clk), "failed to get core clk\n");
 
@@ -1462,15 +1452,26 @@ static int meson_sar_adc_remove(struct platform_device *pdev)
 static int meson_sar_adc_suspend(struct device *dev)
 {
 	struct iio_dev *indio_dev = dev_get_drvdata(dev);
+	struct meson_sar_adc_priv *priv = iio_priv(indio_dev);
 
 	meson_sar_adc_hw_disable(indio_dev);
 
+	clk_disable_unprepare(priv->core_clk);
+
 	return 0;
 }
 
 static int meson_sar_adc_resume(struct device *dev)
 {
 	struct iio_dev *indio_dev = dev_get_drvdata(dev);
+	struct meson_sar_adc_priv *priv = iio_priv(indio_dev);
+	int ret;
+
+	ret = clk_prepare_enable(priv->core_clk);
+	if (ret) {
+		dev_err(dev, "failed to enable core clk\n");
+		return ret;
+	}
 
 	return meson_sar_adc_hw_enable(indio_dev);
 }
-- 
2.38.4