diff mbox series

[1/1] i2c: imx-lpi2c: avoid taking clk_prepare mutex in PM callbacks

Message ID 20230424080627.20564-1-alexander.stein@ew.tq-group.com (mailing list archive)
State New, archived
Headers show
Series [1/1] i2c: imx-lpi2c: avoid taking clk_prepare mutex in PM callbacks | expand

Commit Message

Alexander Stein April 24, 2023, 8:06 a.m. UTC
This is unsafe, as the runtime PM callbacks are called from the PM
workqueue, so this may deadlock when handling an i2c attached clock,
which may already hold the clk_prepare mutex from another context.

Signed-off-by: Alexander Stein <alexander.stein@ew.tq-group.com>
---
This is the imx-lpi2c equivalent to commit d9a22d713acb ("i2c: imx: avoid
taking clk_prepare mutex in PM callbacks"). This patch needs to be used
together with [1] in order to fix the deadlock conditions.

Commit message is shamlessly taken from commit d9a22d713acb.

Best regards,
Alexander

[1] https://patchwork.ozlabs.org/project/linux-i2c/patch/20230310130815.562418-1-alexander.sverdlin@siemens.com/

 drivers/i2c/busses/i2c-imx-lpi2c.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

Comments

Wolfram Sang April 30, 2023, 6:58 a.m. UTC | #1
On Mon, Apr 24, 2023 at 10:06:27AM +0200, Alexander Stein wrote:
> This is unsafe, as the runtime PM callbacks are called from the PM
> workqueue, so this may deadlock when handling an i2c attached clock,
> which may already hold the clk_prepare mutex from another context.
> 
> Signed-off-by: Alexander Stein <alexander.stein@ew.tq-group.com>

Applied to for-current, thanks!
diff mbox series

Patch

diff --git a/drivers/i2c/busses/i2c-imx-lpi2c.c b/drivers/i2c/busses/i2c-imx-lpi2c.c
index a49b14d52a98..1af0a637d7f1 100644
--- a/drivers/i2c/busses/i2c-imx-lpi2c.c
+++ b/drivers/i2c/busses/i2c-imx-lpi2c.c
@@ -639,7 +639,7 @@  static int __maybe_unused lpi2c_runtime_suspend(struct device *dev)
 {
 	struct lpi2c_imx_struct *lpi2c_imx = dev_get_drvdata(dev);
 
-	clk_bulk_disable_unprepare(lpi2c_imx->num_clks, lpi2c_imx->clks);
+	clk_bulk_disable(lpi2c_imx->num_clks, lpi2c_imx->clks);
 	pinctrl_pm_select_sleep_state(dev);
 
 	return 0;
@@ -651,7 +651,7 @@  static int __maybe_unused lpi2c_runtime_resume(struct device *dev)
 	int ret;
 
 	pinctrl_pm_select_default_state(dev);
-	ret = clk_bulk_prepare_enable(lpi2c_imx->num_clks, lpi2c_imx->clks);
+	ret = clk_bulk_enable(lpi2c_imx->num_clks, lpi2c_imx->clks);
 	if (ret) {
 		dev_err(dev, "failed to enable I2C clock, ret=%d\n", ret);
 		return ret;