linux-kernel - [PATCH v3 1/1] spi: spi-cadence-quadspi: Fix pm runtime unbalance

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Message-Id: <4e7a4b8aba300e629b45a04f90bddf665fbdb335.1749601877.git.khairul.anuar.romli@altera.com>
Date: Mon, 16 Jun 2025 09:13:53 +0800
From: khairul.anuar.romli@...era.com
To: Mark Brown <broonie@...nel.org>,
	linux-spi@...r.kernel.org (open list:SPI SUBSYSTEM),
	linux-kernel@...r.kernel.org (open list),
	Matthew Gerlach <matthew.gerlach@...era.com>,
	Khairul Anuar Romli <khairulanuar.romli@...era.com>
Subject: [PATCH v3 1/1] spi: spi-cadence-quadspi: Fix pm runtime unbalance

From: Khairul Anuar Romli <khairul.anuar.romli@...era.com>

Having PM put sync in remove function is causing PM underflow during
remove operation. This is caused by the function, runtime_pm_get_sync,
not being called anywhere during the op. Ensure that calls to
pm_runtime_enable()/pm_runtime_disable() and
pm_runtime_get_sync()/pm_runtime_put_sync() match.

echo 108d2000.spi > /sys/bus/platform/drivers/cadence-qspi/unbind
[   49.644256] Deleting MTD partitions on "108d2000.spi.0":
[   49.649575] Deleting u-boot MTD partition
[   49.684087] Deleting root MTD partition
[   49.724188] cadence-qspi 108d2000.spi: Runtime PM usage count underflow!

Continuous bind/unbind will result in an "Unbalanced pm_runtime_enable" error.
Subsequent unbind attempts will return a "No such device" error, while bind
attempts will return a "Resource temporarily unavailable" error.

[   47.592434] cadence-qspi 108d2000.spi: Runtime PM usage count underflow!
[   49.592233] cadence-qspi 108d2000.spi: detected FIFO depth (1024) different from config (128)
[   53.232309] cadence-qspi 108d2000.spi: Runtime PM usage count underflow!
[   55.828550] cadence-qspi 108d2000.spi: detected FIFO depth (1024) different from config (128)
[   57.940627] cadence-qspi 108d2000.spi: Runtime PM usage count underflow!
[   59.912490] cadence-qspi 108d2000.spi: detected FIFO depth (1024) different from config (128)
[   61.876243] cadence-qspi 108d2000.spi: Runtime PM usage count underflow!
[   61.883000] platform 108d2000.spi: Unbalanced pm_runtime_enable!
[  532.012270] cadence-qspi 108d2000.spi: probe with driver cadence-qspi failed1

Also, change clk_disable_unprepare() to clk_disable() since continuous
bind and unbind operations will trigger a warning indicating that the clock is
already unprepared.

Fixes: 4892b374c9b7 ("mtd: spi-nor: cadence-quadspi: Add runtime PM support")
cc: stable@...r.kernel.org # 6.6+
Signed-off-by: Khairul Anuar Romli <khairul.anuar.romli@...era.com>
Reviewed-by: Matthew Gerlach <matthew.gerlach@...era.com>
---
Changes in v3:
    - v2 was sent without a "Changes in v2" section.

Changes in v2:
    - Remove the runtime_pm variable from the struct, as it’s not needed for the fix.
---
 drivers/spi/spi-cadence-quadspi.c | 12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)

diff --git a/drivers/spi/spi-cadence-quadspi.c b/drivers/spi/spi-cadence-quadspi.c
index c90462783b3f..506a139fbd2c 100644
--- a/drivers/spi/spi-cadence-quadspi.c
+++ b/drivers/spi/spi-cadence-quadspi.c
@@ -1958,10 +1958,10 @@ static int cqspi_probe(struct platform_device *pdev)
 			goto probe_setup_failed;
 	}
 
-	ret = devm_pm_runtime_enable(dev);
-	if (ret) {
-		if (cqspi->rx_chan)
-			dma_release_channel(cqspi->rx_chan);
+	pm_runtime_enable(dev);
+
+	if (cqspi->rx_chan) {
+		dma_release_channel(cqspi->rx_chan);
 		goto probe_setup_failed;
 	}
 
@@ -1981,6 +1981,7 @@ static int cqspi_probe(struct platform_device *pdev)
 	return 0;
 probe_setup_failed:
 	cqspi_controller_enable(cqspi, 0);
+	pm_runtime_disable(dev);
 probe_reset_failed:
 	if (cqspi->is_jh7110)
 		cqspi_jh7110_disable_clk(pdev, cqspi);
@@ -1999,7 +2000,8 @@ static void cqspi_remove(struct platform_device *pdev)
 	if (cqspi->rx_chan)
 		dma_release_channel(cqspi->rx_chan);
 
-	clk_disable_unprepare(cqspi->clk);
+	if (pm_runtime_get_sync(&pdev->dev) >= 0)
+		clk_disable(cqspi->clk);
 
 	if (cqspi->is_jh7110)
 		cqspi_jh7110_disable_clk(pdev, cqspi);
-- 
2.35.3