linux-kernel - [PATCH v3 03/12] iio: adc: ad7192: Avoid disabling a clock that was never enabled.

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Date:   Wed, 12 May 2021 20:49:05 +0300
From:   Alexandru Ardelean <aardelean@...iqon.com>
To:     linux-iio@...r.kernel.org, linux-kernel@...r.kernel.org
Cc:     jic23@...nel.org, Jonathan.Cameron@...wei.com,
        alexandru.tachici@...log.com, linux@...iqon.com,
        Alexandru Ardelean <ardeleanalex@...il.com>,
        Alexandru Ardelean <aardelean@...iqon.com>
Subject: [PATCH v3 03/12] iio: adc: ad7192: Avoid disabling a clock that was never enabled.

From: Jonathan Cameron <Jonathan.Cameron@...wei.com>

Found by inspection.

If the internal clock source is being used, the driver doesn't
call clk_prepare_enable() and as such we should not call
clk_disable_unprepare()

Use the same condition to protect the disable path as is used
on the enable one.  Note this will all get simplified when
the driver moves over to a full devm_ flow, but that would make
backporting the fix harder.

Fix obviously predates move out of staging, but backporting will
become more complex (and is unlikely to happen), hence that patch
is given in the fixes tag.

Fixes: b581f748cce0 ("staging: iio: adc: ad7192: move out of staging")
Cc: Alexandru Tachici <alexandru.tachici@...log.com>
Reviewed-by: Alexandru Ardelean <ardeleanalex@...il.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@...wei.com>
Signed-off-by: Alexandru Ardelean <aardelean@...iqon.com>
---
 drivers/iio/adc/ad7192.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/drivers/iio/adc/ad7192.c b/drivers/iio/adc/ad7192.c
index 2ed580521d81..d3be67aa0522 100644
--- a/drivers/iio/adc/ad7192.c
+++ b/drivers/iio/adc/ad7192.c
@@ -1014,7 +1014,9 @@ static int ad7192_probe(struct spi_device *spi)
 	return 0;
 
 error_disable_clk:
-	clk_disable_unprepare(st->mclk);
+	if (st->clock_sel == AD7192_CLK_EXT_MCLK1_2 ||
+	    st->clock_sel == AD7192_CLK_EXT_MCLK2)
+		clk_disable_unprepare(st->mclk);
 error_remove_trigger:
 	ad_sd_cleanup_buffer_and_trigger(indio_dev);
 error_disable_dvdd:
@@ -1031,7 +1033,9 @@ static int ad7192_remove(struct spi_device *spi)
 	struct ad7192_state *st = iio_priv(indio_dev);
 
 	iio_device_unregister(indio_dev);
-	clk_disable_unprepare(st->mclk);
+	if (st->clock_sel == AD7192_CLK_EXT_MCLK1_2 ||
+	    st->clock_sel == AD7192_CLK_EXT_MCLK2)
+		clk_disable_unprepare(st->mclk);
 	ad_sd_cleanup_buffer_and_trigger(indio_dev);
 
 	regulator_disable(st->dvdd);
-- 
2.31.1