From: Bastien Curutchet bastien.curutchet@bootlin.com
[ Upstream commit 1762dc01fc78ef5f19693e9317eae7491c6c7e1b ]
On the OMAPL138, the SPI reference clock is provided by the Power and Sleep Controller (PSC). The PSC's datasheet says that 'some peripherals have special programming requirements and additional recommended steps you must take before you can invoke the PSC module state transition'. I didn't find more details in documentation but it appears that PSC needs the SPI to clear the POWERDOWN bit before disabling the clock. Indeed, when this bit is set, the PSC gets stuck in transitions from enable to disable state.
Clear the POWERDOWN bit when releasing driver's resources
Signed-off-by: Bastien Curutchet bastien.curutchet@bootlin.com Link: https://patch.msgid.link/20240624071745.17409-1-bastien.curutchet@bootlin.co... Signed-off-by: Mark Brown broonie@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/spi/spi-davinci.c | 6 ++++++ 1 file changed, 6 insertions(+)
diff --git a/drivers/spi/spi-davinci.c b/drivers/spi/spi-davinci.c index be3998104bfbb..f7e8b5efa50e5 100644 --- a/drivers/spi/spi-davinci.c +++ b/drivers/spi/spi-davinci.c @@ -984,6 +984,9 @@ static int davinci_spi_probe(struct platform_device *pdev) return ret;
free_dma: + /* This bit needs to be cleared to disable dpsi->clk */ + clear_io_bits(dspi->base + SPIGCR1, SPIGCR1_POWERDOWN_MASK); + if (dspi->dma_rx) { dma_release_channel(dspi->dma_rx); dma_release_channel(dspi->dma_tx); @@ -1013,6 +1016,9 @@ static void davinci_spi_remove(struct platform_device *pdev)
spi_bitbang_stop(&dspi->bitbang);
+ /* This bit needs to be cleared to disable dpsi->clk */ + clear_io_bits(dspi->base + SPIGCR1, SPIGCR1_POWERDOWN_MASK); + if (dspi->dma_rx) { dma_release_channel(dspi->dma_rx); dma_release_channel(dspi->dma_tx);