[PATCH] spi: imx: do not access registers while clocks disabled

From: Stefan Agner
Date: Sun Jan 07 2018 - 09:05:49 EST


Since clocks are disabled except during message transfer clocks
are also disabled when spi_imx_remove gets called. Accessing
registers leads to a freeeze at least on a i.MX 6ULL. Enable
clocks before disabling accessing the MXC_CSPICTRL register.

Fixes: 9e556dcc55774 ("spi: spi-imx: only enable the clocks when we start to transfer a message")
Signed-off-by: Stefan Agner <stefan@xxxxxxxx>
Signed-off-by: Mark Brown <broonie@xxxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx
---
drivers/spi/spi-imx.c | 15 +++++++++++++--
1 file changed, 13 insertions(+), 2 deletions(-)

diff --git a/drivers/spi/spi-imx.c b/drivers/spi/spi-imx.c
index 79ddefe4180d..40390d31a93b 100644
--- a/drivers/spi/spi-imx.c
+++ b/drivers/spi/spi-imx.c
@@ -1668,12 +1668,23 @@ static int spi_imx_remove(struct platform_device *pdev)
{
struct spi_master *master = platform_get_drvdata(pdev);
struct spi_imx_data *spi_imx = spi_master_get_devdata(master);
+ int ret;

spi_bitbang_stop(&spi_imx->bitbang);

+ ret = clk_enable(spi_imx->clk_per);
+ if (ret)
+ return ret;
+
+ ret = clk_enable(spi_imx->clk_ipg);
+ if (ret) {
+ clk_disable(spi_imx->clk_per);
+ return ret;
+ }
+
writel(0, spi_imx->base + MXC_CSPICTRL);
- clk_unprepare(spi_imx->clk_ipg);
- clk_unprepare(spi_imx->clk_per);
+ clk_disable_unprepare(spi_imx->clk_ipg);
+ clk_disable_unprepare(spi_imx->clk_per);
spi_imx_sdma_exit(spi_imx);
spi_master_put(master);

--
2.15.1