From 97db2ca4485dc7b10b8382832befe607ade59a6b Mon Sep 17 00:00:00 2001 From: Dong Aisheng Date: Sat, 26 Jan 2019 17:51:59 +0800 Subject: [PATCH] i2c: imx: fix system hang due to access i2c registers without clock Currently, i2c_imx_bus_busy in i2c_imx_xfer is called before pm_runtime_get which means the clocks are still not enabled. This will cause a hang on IMX as IMX requires accessing registers with clocks. So let's change the order to ensure the clocks are enabled before accessing registers. This is also a more safe way to access registers, suppose shouldn't affect other platforms. Fixes: 4a6ebf1c125c ("i2c: imx: add workaround for erratum ERR010027") Reviewed-by: Biwen Li Signed-off-by: Dong Aisheng --- drivers/i2c/busses/i2c-imx.c | 9 ++++----- 1 file changed, 4 insertions(+), 5 deletions(-) --- a/drivers/i2c/busses/i2c-imx.c +++ b/drivers/i2c/busses/i2c-imx.c @@ -1066,12 +1066,15 @@ static int i2c_imx_xfer(struct i2c_adapt dev_dbg(&i2c_imx->adapter.dev, "<%s>\n", __func__); - if (!pm_runtime_enabled(i2c_imx->adapter.dev.parent)) { pm_runtime_enable(i2c_imx->adapter.dev.parent); enable_runtime_pm = true; } + result = pm_runtime_get_sync(i2c_imx->adapter.dev.parent); + if (result < 0) + goto out; + /* * workround for ERR010027: ensure that the I2C BUS is idle * before switching to master mode and attempting a Start cycle @@ -1085,10 +1088,6 @@ static int i2c_imx_xfer(struct i2c_adapt goto out; } - result = pm_runtime_get_sync(i2c_imx->adapter.dev.parent); - if (result < 0) - goto out; - /* Start I2C transfer */ result = i2c_imx_start(i2c_imx); if (result) {