spi: mediatek: Fix DEVAPC Violation at KO Remove

[ 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>

diff --git a/drivers/spi/spi-mt65xx.c b/drivers/spi/spi-mt65xx.c
index 2ca19b0..49acba1 100644 (file)
--- a/drivers/spi/spi-mt65xx.c
+++ b/drivers/spi/spi-mt65xx.c
@@ -912,14 +912,20 @@ 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);
 
        if (mdata->dev_comp->no_need_unprepare)
                clk_unprepare(mdata->spi_clk);
 
+       pm_runtime_put_noidle(&pdev->dev);
+       pm_runtime_disable(&pdev->dev);
+
        return 0;
 }