[PATCH AUTOSEL 6.0 17/39] spi: mediatek: Fix DEVAPC Violation at KO Remove

Sasha Levin
2022-11-28T17:39:50Z

From: Zhichao Liu <zhichao.liu@mediatek.com>

[ Upstream commit 0d10e90cee9eb57882b0f7e19fd699033722e226 ]

A DEVAPC violation occurs when removing the module
due to accessing HW registers without base clock.
To fix this bug, the correct method is:
1. Call the runtime resume function to enable the
clock;
2. Operate the registers to reset the HW;
3. Turn off the clocks and disable the device
RPM mechanism.

Signed-off-by: Zhichao Liu <zhichao.liu@mediatek.com>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Link: https://lore.kernel.org/r/20221110072839.30961-1-zhichao.liu@mediatek.com
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/spi/spi-mt65xx.c | 8 +++++++-
1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/drivers/spi/spi-mt65xx.c b/drivers/spi/spi-mt65xx.c
index cd9dc358d396..a7cc96aeb590 100644
--- a/drivers/spi/spi-mt65xx.c
+++ b/drivers/spi/spi-mt65xx.c
@@ -1268,8 +1268,11 @@ static int mtk_spi_remove(struct platform_device *pdev)
{
struct spi_master *master = platform_get_drvdata(pdev);
struct mtk_spi *mdata = spi_master_get_devdata(master);
+ int ret;

- pm_runtime_disable(&pdev->dev);
+ ret = pm_runtime_resume_and_get(&pdev->dev);
+ if (ret < 0)
+ return ret;

mtk_spi_reset(mdata);

@@ -1278,6 +1281,9 @@ static int mtk_spi_remove(struct platform_device *pdev)
clk_unprepare(mdata->spi_hclk);
}

+ pm_runtime_put_noidle(&pdev->dev);
+ pm_runtime_disable(&pdev->dev);
+
return 0;
}

--
2.35.1