[PATCH 0/2] Simplify clock handling and fix probe error handling sequence

[PATCH 0/2] Simplify clock handling and fix probe error handling sequence

[Manikanta Guntupalli]

This series includes two patches that improve the Cadence I2C driver
by simplifying clock handling and ensuring correct reset sequencing
in the probe error path.

Manikanta Guntupalli (1):
  i2c: cadence: Move reset_control_assert after pm_runtime_set_suspended
    in probe error path

Michal Simek (1):
  i2c: cadence: Simplify using devm_clk_get_enabled()

 drivers/i2c/busses/i2c-cadence.c | 19 +++++--------------
 1 file changed, 5 insertions(+), 14 deletions(-)

-- 
2.34.1

[PATCH 1/2] i2c: cadence: Simplify using devm_clk_get_enabled()

[Manikanta Guntupalli]

From: Michal Simek <michal.simek@amd.com>

Clock handling can be very simplified with using devm_clk_get_enabled() as
was done by commit 8d2aaf4382b7 ("gpio: zynq: Simplify using
devm_clk_get_enabled()").
And also fix issue in connection to incorrect sequence when err_clk_dis
label is called.
When reset_control_deassert() fails it jumps to err_clk_dis label which
disables clock and also disable pm_runtime setup but nothing has been setup
at this time of failure because initialization is done below
reset_control_deassert() call.

Signed-off-by: Michal Simek <michal.simek@amd.com>
Signed-off-by: Manikanta Guntupalli <manikanta.guntupalli@amd.com>
---
 drivers/i2c/busses/i2c-cadence.c | 17 ++++-------------
 1 file changed, 4 insertions(+), 13 deletions(-)

diff --git a/drivers/i2c/busses/i2c-cadence.c b/drivers/i2c/busses/i2c-cadence.c
index b64026fbca66..51dc7728d133 100644
--- a/drivers/i2c/busses/i2c-cadence.c
+++ b/drivers/i2c/busses/i2c-cadence.c
@@ -1541,7 +1541,7 @@ static int cdns_i2c_probe(struct platform_device *pdev)
 	snprintf(id->adap.name, sizeof(id->adap.name),
 		 "Cadence I2C at %08lx", (unsigned long)r_mem->start);
 
-	id->clk = devm_clk_get(&pdev->dev, NULL);
+	id->clk = devm_clk_get_enabled(&pdev->dev, NULL);
 	if (IS_ERR(id->clk))
 		return dev_err_probe(&pdev->dev, PTR_ERR(id->clk),
 				     "input clock not found.\n");
@@ -1551,16 +1551,10 @@ static int cdns_i2c_probe(struct platform_device *pdev)
 		return dev_err_probe(&pdev->dev, PTR_ERR(id->reset),
 				     "Failed to request reset.\n");
 
-	ret = clk_prepare_enable(id->clk);
-	if (ret)
-		dev_err(&pdev->dev, "Unable to enable clock.\n");
-
 	ret = reset_control_deassert(id->reset);
-	if (ret) {
-		dev_err_probe(&pdev->dev, ret,
-			      "Failed to de-assert reset.\n");
-		goto err_clk_dis;
-	}
+	if (ret)
+		return dev_err_probe(&pdev->dev, ret,
+				     "Failed to de-assert reset.\n");
 
 	pm_runtime_set_autosuspend_delay(id->dev, CNDS_I2C_PM_TIMEOUT);
 	pm_runtime_use_autosuspend(id->dev);
@@ -1616,8 +1610,6 @@ static int cdns_i2c_probe(struct platform_device *pdev)
 err_clk_notifier_unregister:
 	clk_notifier_unregister(id->clk, &id->clk_rate_change_nb);
 	reset_control_assert(id->reset);
-err_clk_dis:
-	clk_disable_unprepare(id->clk);
 	pm_runtime_disable(&pdev->dev);
 	pm_runtime_set_suspended(&pdev->dev);
 	return ret;
@@ -1642,7 +1634,6 @@ static void cdns_i2c_remove(struct platform_device *pdev)
 	i2c_del_adapter(&id->adap);
 	clk_notifier_unregister(id->clk, &id->clk_rate_change_nb);
 	reset_control_assert(id->reset);
-	clk_disable_unprepare(id->clk);
 }
 
 static struct platform_driver cdns_i2c_drv = {
-- 
2.34.1

[PATCH 2/2] i2c: cadence: Move reset_control_assert after pm_runtime_set_suspended in probe error path

[Manikanta Guntupalli]

Ensure reset_control_assert() is called after pm_runtime_set_suspended()
in the cdns_i2c_probe exit path to maintain proper power management
sequence in error cases.

Signed-off-by: Manikanta Guntupalli <manikanta.guntupalli@amd.com>
---
 drivers/i2c/busses/i2c-cadence.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/i2c/busses/i2c-cadence.c b/drivers/i2c/busses/i2c-cadence.c
index 51dc7728d133..8df63aaf2a80 100644
--- a/drivers/i2c/busses/i2c-cadence.c
+++ b/drivers/i2c/busses/i2c-cadence.c
@@ -1609,9 +1609,9 @@ static int cdns_i2c_probe(struct platform_device *pdev)
 
 err_clk_notifier_unregister:
 	clk_notifier_unregister(id->clk, &id->clk_rate_change_nb);
-	reset_control_assert(id->reset);
 	pm_runtime_disable(&pdev->dev);
 	pm_runtime_set_suspended(&pdev->dev);
+	reset_control_assert(id->reset);
 	return ret;
 }
 
-- 
2.34.1

Re: [PATCH 0/2] Simplify clock handling and fix probe error handling sequence

[Michal Simek]

On 2/6/25 12:57, Manikanta Guntupalli wrote:
> This series includes two patches that improve the Cadence I2C driver
> by simplifying clock handling and ensuring correct reset sequencing
> in the probe error path.
> 
> Manikanta Guntupalli (1):
>    i2c: cadence: Move reset_control_assert after pm_runtime_set_suspended
>      in probe error path
> 
> Michal Simek (1):
>    i2c: cadence: Simplify using devm_clk_get_enabled()
> 
>   drivers/i2c/busses/i2c-cadence.c | 19 +++++--------------
>   1 file changed, 5 insertions(+), 14 deletions(-)
> 

Looks good to me.

M

Re: [PATCH 0/2] Simplify clock handling and fix probe error handling sequence

[Andi Shyti]

Hi,

On Thu, Feb 06, 2025 at 05:27:06PM +0530, Manikanta Guntupalli wrote:
> This series includes two patches that improve the Cadence I2C driver
> by simplifying clock handling and ensuring correct reset sequencing
> in the probe error path.
> 
> Manikanta Guntupalli (1):
>   i2c: cadence: Move reset_control_assert after pm_runtime_set_suspended
>     in probe error path
> 
> Michal Simek (1):
>   i2c: cadence: Simplify using devm_clk_get_enabled()

I was sure I did take this patch, but unfortunately I forgot it.
Feel free to ping me in such case.

Merged to i2c/i2c-host.

Thanks,
Andi