patch "iio: adc: ad7192: Avoid disabling a clock that was never enabled." added to staging-linus

This is a note to let you know that I've just added the patch titled

iio: adc: ad7192: Avoid disabling a clock that was never enabled.

to my staging git tree which can be found at
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging.git
in the staging-linus branch.

The patch will show up in the next release of the linux-next tree (usually sometime within the next 24 hours during the week.)

The patch will hopefully also be merged in Linus's tree for the next -rc kernel release.

If you have any questions about this process, please let me know.

From e32fe6d90f44922ccbb94016cfc3c238359e3e39 Mon Sep 17 00:00:00 2001
From: Jonathan Cameron <[email protected]>
Date: Thu, 13 May 2021 15:07:43 +0300
Subject: iio: adc: ad7192: Avoid disabling a clock that was never enabled.

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.

Alexandru's sign off is here because he added this patch into a larger series that Jonathan then applied.

---
 drivers/iio/adc/ad7192.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

index 2ed580521d81..d3be67aa0522 100644
@@ -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