Re: [PATCH v2 9/9] coresight: Refactor runtime PM

[Anshuman Khandual]

On 4/23/25 20:47, Leo Yan wrote:
> The validation for driver data pointers and clock pointers are redundant
> in the runtime PM callbacks.  After a driver's probing, its driver data
> and clocks have been initialized successfully, this ensures it is safe
> to access driver data and clocks in the runtime PM callbacks.  A corner
> case is a clock pointer is NULL, in this case, the clock core layer can
> handle it properly.  So remove these redundant checking.
> 
> In runtime resume, respect values returned from clock function and add
> error handling.

Although not checking drvdata and drvdata->apb_clk does make sense, but
why change the semantics on the resume paths as well, which now returns
stored error value from clk_prepare_enable().

> 
> Signed-off-by: Leo Yan <leo.yan@xxxxxxx>
> ---
>  drivers/hwtracing/coresight/coresight-cpu-debug.c  |  8 +++-----
>  drivers/hwtracing/coresight/coresight-ctcu-core.c  |  8 ++------
>  drivers/hwtracing/coresight/coresight-etb10.c      |  8 ++------
>  drivers/hwtracing/coresight/coresight-etm3x-core.c |  8 ++------
>  drivers/hwtracing/coresight/coresight-funnel.c     | 21 +++++++++++----------
>  drivers/hwtracing/coresight/coresight-replicator.c | 20 +++++++++++---------
>  drivers/hwtracing/coresight/coresight-stm.c        | 20 +++++++++++---------
>  drivers/hwtracing/coresight/coresight-tpiu.c       | 20 +++++++++++---------
>  8 files changed, 53 insertions(+), 60 deletions(-)
> 
> diff --git a/drivers/hwtracing/coresight/coresight-cpu-debug.c b/drivers/hwtracing/coresight/coresight-cpu-debug.c
> index 481ffcbed534..dff663ac7805 100644
> --- a/drivers/hwtracing/coresight/coresight-cpu-debug.c
> +++ b/drivers/hwtracing/coresight/coresight-cpu-debug.c
> @@ -731,8 +731,8 @@ static int debug_runtime_suspend(struct device *dev)
>  {
>  	struct debug_drvdata *drvdata = dev_get_drvdata(dev);
>  
> -	if (drvdata && !IS_ERR_OR_NULL(drvdata->pclk))
> -		clk_disable_unprepare(drvdata->pclk);
> +	clk_disable_unprepare(drvdata->pclk);
> +
>  	return 0;
>  }
>  
> @@ -740,9 +740,7 @@ static int debug_runtime_resume(struct device *dev)
>  {
>  	struct debug_drvdata *drvdata = dev_get_drvdata(dev);
>  
> -	if (drvdata && !IS_ERR_OR_NULL(drvdata->pclk))
> -		clk_prepare_enable(drvdata->pclk);
> -	return 0;
> +	return clk_prepare_enable(drvdata->pclk);
>  }
>  #endif
>  
> diff --git a/drivers/hwtracing/coresight/coresight-ctcu-core.c b/drivers/hwtracing/coresight/coresight-ctcu-core.c
> index 75b5114ef652..c586495e9a08 100644
> --- a/drivers/hwtracing/coresight/coresight-ctcu-core.c
> +++ b/drivers/hwtracing/coresight/coresight-ctcu-core.c
> @@ -278,8 +278,7 @@ static int ctcu_runtime_suspend(struct device *dev)
>  {
>  	struct ctcu_drvdata *drvdata = dev_get_drvdata(dev);
>  
> -	if (drvdata && !IS_ERR_OR_NULL(drvdata->apb_clk))
> -		clk_disable_unprepare(drvdata->apb_clk);
> +	clk_disable_unprepare(drvdata->apb_clk);
>  
>  	return 0;
>  }
> @@ -288,10 +287,7 @@ static int ctcu_runtime_resume(struct device *dev)
>  {
>  	struct ctcu_drvdata *drvdata = dev_get_drvdata(dev);
>  
> -	if (drvdata && !IS_ERR_OR_NULL(drvdata->apb_clk))
> -		clk_prepare_enable(drvdata->apb_clk);
> -
> -	return 0;
> +	return clk_prepare_enable(drvdata->apb_clk);
>  }
>  #endif
>  
> diff --git a/drivers/hwtracing/coresight/coresight-etb10.c b/drivers/hwtracing/coresight/coresight-etb10.c
> index 45c2f8f50a3f..3f3b0eb48fdb 100644
> --- a/drivers/hwtracing/coresight/coresight-etb10.c
> +++ b/drivers/hwtracing/coresight/coresight-etb10.c
> @@ -807,8 +807,7 @@ static int etb_runtime_suspend(struct device *dev)
>  {
>  	struct etb_drvdata *drvdata = dev_get_drvdata(dev);
>  
> -	if (drvdata && !IS_ERR(drvdata->atclk))
> -		clk_disable_unprepare(drvdata->atclk);
> +	clk_disable_unprepare(drvdata->atclk);
>  
>  	return 0;
>  }
> @@ -817,10 +816,7 @@ static int etb_runtime_resume(struct device *dev)
>  {
>  	struct etb_drvdata *drvdata = dev_get_drvdata(dev);
>  
> -	if (drvdata && !IS_ERR(drvdata->atclk))
> -		clk_prepare_enable(drvdata->atclk);
> -
> -	return 0;
> +	return clk_prepare_enable(drvdata->atclk);
>  }
>  #endif
>  
> diff --git a/drivers/hwtracing/coresight/coresight-etm3x-core.c b/drivers/hwtracing/coresight/coresight-etm3x-core.c
> index adbb134f80e6..615ff743eef0 100644
> --- a/drivers/hwtracing/coresight/coresight-etm3x-core.c
> +++ b/drivers/hwtracing/coresight/coresight-etm3x-core.c
> @@ -925,8 +925,7 @@ static int etm_runtime_suspend(struct device *dev)
>  {
>  	struct etm_drvdata *drvdata = dev_get_drvdata(dev);
>  
> -	if (drvdata && !IS_ERR(drvdata->atclk))
> -		clk_disable_unprepare(drvdata->atclk);
> +	clk_disable_unprepare(drvdata->atclk);
>  
>  	return 0;
>  }
> @@ -935,10 +934,7 @@ static int etm_runtime_resume(struct device *dev)
>  {
>  	struct etm_drvdata *drvdata = dev_get_drvdata(dev);
>  
> -	if (drvdata && !IS_ERR(drvdata->atclk))
> -		clk_prepare_enable(drvdata->atclk);
> -
> -	return 0;
> +	return clk_prepare_enable(drvdata->atclk);
>  }
>  #endif
>  
> diff --git a/drivers/hwtracing/coresight/coresight-funnel.c b/drivers/hwtracing/coresight/coresight-funnel.c
> index 62e5125c37ad..6494a3b5d18e 100644
> --- a/drivers/hwtracing/coresight/coresight-funnel.c
> +++ b/drivers/hwtracing/coresight/coresight-funnel.c
> @@ -283,11 +283,8 @@ static int funnel_runtime_suspend(struct device *dev)
>  {
>  	struct funnel_drvdata *drvdata = dev_get_drvdata(dev);
>  
> -	if (drvdata && !IS_ERR(drvdata->atclk))
> -		clk_disable_unprepare(drvdata->atclk);
> -
> -	if (drvdata && !IS_ERR_OR_NULL(drvdata->pclk))
> -		clk_disable_unprepare(drvdata->pclk);
> +	clk_disable_unprepare(drvdata->atclk);
> +	clk_disable_unprepare(drvdata->pclk);
>  
>  	return 0;
>  }
> @@ -295,13 +292,17 @@ static int funnel_runtime_suspend(struct device *dev)
>  static int funnel_runtime_resume(struct device *dev)
>  {
>  	struct funnel_drvdata *drvdata = dev_get_drvdata(dev);
> +	int ret;
> +
> +	ret = clk_prepare_enable(drvdata->pclk);
> +	if (ret)
> +		return ret;
>  
> -	if (drvdata && !IS_ERR_OR_NULL(drvdata->pclk))
> -		clk_prepare_enable(drvdata->pclk);
> +	ret = clk_prepare_enable(drvdata->atclk);
> +	if (ret)
> +		clk_disable_unprepare(drvdata->pclk);
>  
> -	if (drvdata && !IS_ERR(drvdata->atclk))
> -		clk_prepare_enable(drvdata->atclk);
> -	return 0;
> +	return ret;
>  }
>  #endif
>  
> diff --git a/drivers/hwtracing/coresight/coresight-replicator.c b/drivers/hwtracing/coresight/coresight-replicator.c
> index 56b03e6d8336..8595dc104795 100644
> --- a/drivers/hwtracing/coresight/coresight-replicator.c
> +++ b/drivers/hwtracing/coresight/coresight-replicator.c
> @@ -322,24 +322,26 @@ static int replicator_runtime_suspend(struct device *dev)
>  {
>  	struct replicator_drvdata *drvdata = dev_get_drvdata(dev);
>  
> -	if (drvdata && !IS_ERR(drvdata->atclk))
> -		clk_disable_unprepare(drvdata->atclk);
> +	clk_disable_unprepare(drvdata->atclk);
> +	clk_disable_unprepare(drvdata->pclk);
>  
> -	if (drvdata && !IS_ERR_OR_NULL(drvdata->pclk))
> -		clk_disable_unprepare(drvdata->pclk);
>  	return 0;
>  }
>  
>  static int replicator_runtime_resume(struct device *dev)
>  {
>  	struct replicator_drvdata *drvdata = dev_get_drvdata(dev);
> +	int ret;
>  
> -	if (drvdata && !IS_ERR_OR_NULL(drvdata->pclk))
> -		clk_prepare_enable(drvdata->pclk);
> +	ret = clk_prepare_enable(drvdata->pclk);
> +	if (ret)
> +		return ret;
>  
> -	if (drvdata && !IS_ERR(drvdata->atclk))
> -		clk_prepare_enable(drvdata->atclk);
> -	return 0;
> +	ret = clk_prepare_enable(drvdata->atclk);
> +	if (ret)
> +		clk_disable_unprepare(drvdata->pclk);
> +
> +	return ret;
>  }
>  #endif
>  
> diff --git a/drivers/hwtracing/coresight/coresight-stm.c b/drivers/hwtracing/coresight/coresight-stm.c
> index f17986edac00..f859ab932d22 100644
> --- a/drivers/hwtracing/coresight/coresight-stm.c
> +++ b/drivers/hwtracing/coresight/coresight-stm.c
> @@ -957,24 +957,26 @@ static int stm_runtime_suspend(struct device *dev)
>  {
>  	struct stm_drvdata *drvdata = dev_get_drvdata(dev);
>  
> -	if (drvdata && !IS_ERR(drvdata->atclk))
> -		clk_disable_unprepare(drvdata->atclk);
> +	clk_disable_unprepare(drvdata->atclk);
> +	clk_disable_unprepare(drvdata->pclk);
>  
> -	if (drvdata && !IS_ERR_OR_NULL(drvdata->pclk))
> -		clk_disable_unprepare(drvdata->pclk);
>  	return 0;
>  }
>  
>  static int stm_runtime_resume(struct device *dev)
>  {
>  	struct stm_drvdata *drvdata = dev_get_drvdata(dev);
> +	int ret;
>  
> -	if (drvdata && !IS_ERR_OR_NULL(drvdata->pclk))
> -		clk_prepare_enable(drvdata->pclk);
> +	ret = clk_prepare_enable(drvdata->pclk);
> +	if (ret)
> +		return ret;
>  
> -	if (drvdata && !IS_ERR(drvdata->atclk))
> -		clk_prepare_enable(drvdata->atclk);
> -	return 0;
> +	ret = clk_prepare_enable(drvdata->atclk);
> +	if (ret)
> +		clk_disable_unprepare(drvdata->pclk);
> +
> +	return ret;
>  }
>  #endif
>  
> diff --git a/drivers/hwtracing/coresight/coresight-tpiu.c b/drivers/hwtracing/coresight/coresight-tpiu.c
> index 4701b34778bd..a68ed6b97bf7 100644
> --- a/drivers/hwtracing/coresight/coresight-tpiu.c
> +++ b/drivers/hwtracing/coresight/coresight-tpiu.c
> @@ -206,24 +206,26 @@ static int tpiu_runtime_suspend(struct device *dev)
>  {
>  	struct tpiu_drvdata *drvdata = dev_get_drvdata(dev);
>  
> -	if (drvdata && !IS_ERR(drvdata->atclk))
> -		clk_disable_unprepare(drvdata->atclk);
> +	clk_disable_unprepare(drvdata->atclk);
> +	clk_disable_unprepare(drvdata->pclk);
>  
> -	if (drvdata && !IS_ERR_OR_NULL(drvdata->pclk))
> -		clk_disable_unprepare(drvdata->pclk);
>  	return 0;
>  }
>  
>  static int tpiu_runtime_resume(struct device *dev)
>  {
>  	struct tpiu_drvdata *drvdata = dev_get_drvdata(dev);
> +	int ret;
>  
> -	if (drvdata && !IS_ERR_OR_NULL(drvdata->pclk))
> -		clk_prepare_enable(drvdata->pclk);
> +	ret = clk_prepare_enable(drvdata->pclk);
> +	if (ret)
> +		return ret;
>  
> -	if (drvdata && !IS_ERR(drvdata->atclk))
> -		clk_prepare_enable(drvdata->atclk);
> -	return 0;
> +	ret = clk_prepare_enable(drvdata->atclk);
> +	if (ret)
> +		clk_disable_unprepare(drvdata->pclk);
> +
> +	return ret;
>  }
>  #endif
>