[v2,6/9] PM / Domains: Don't attach devices in genpd with multi PM domains

Message ID 20180529100421.31022-7-ulf.hansson@linaro.org
State New
Headers show
Series
  • PM / Domains: Add support for multi PM domains per device
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Commit Message

Ulf Hansson May 29, 2018, 10:04 a.m.
The power-domain DT property may now contain a list of PM domain
specifiers, which represents that a device are partitioned across multiple
PM domains. This leads to a new situation in genpd_dev_pm_attach(), as only
one PM domain can be attached per device.

To remain things simple for the most common configuration, when a single PM
domain is used, let's treat the multiple PM domain case as being specific.

In other words, let's change genpd_dev_pm_attach() to check for multiple PM
domains and prevent it from attach any PM domain for this case. Instead,
leave this to be managed separately, from following changes to genpd.

Cc: Rob Herring <robh+dt@kernel.org>
Cc: devicetree@vger.kernel.org
Suggested-by: Jon Hunter <jonathanh@nvidia.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
---

Changes in v2:
	- Minor update to changelog to mention "PM domain specifiers" rather
	than a "list of phandles".

---
 drivers/base/power/domain.c | 18 +++++++++++++-----
 1 file changed, 13 insertions(+), 5 deletions(-)

Comments

Jon Hunter May 30, 2018, 4:06 p.m. | #1
On 29/05/18 11:04, Ulf Hansson wrote:
> The power-domain DT property may now contain a list of PM domain
> specifiers, which represents that a device are partitioned across multiple
> PM domains. This leads to a new situation in genpd_dev_pm_attach(), as only
> one PM domain can be attached per device.
> 
> To remain things simple for the most common configuration, when a single PM
> domain is used, let's treat the multiple PM domain case as being specific.
> 
> In other words, let's change genpd_dev_pm_attach() to check for multiple PM
> domains and prevent it from attach any PM domain for this case. Instead,
> leave this to be managed separately, from following changes to genpd.
> 
> Cc: Rob Herring <robh+dt@kernel.org>
> Cc: devicetree@vger.kernel.org
> Suggested-by: Jon Hunter <jonathanh@nvidia.com>
> Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
> ---
> 
> Changes in v2:
> 	- Minor update to changelog to mention "PM domain specifiers" rather
> 	than a "list of phandles".
> 
> ---
>  drivers/base/power/domain.c | 18 +++++++++++++-----
>  1 file changed, 13 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/base/power/domain.c b/drivers/base/power/domain.c
> index 7ebf7993273a..12a20f21974d 100644
> --- a/drivers/base/power/domain.c
> +++ b/drivers/base/power/domain.c
> @@ -2229,10 +2229,10 @@ static void genpd_dev_pm_sync(struct device *dev)
>   * attaches the device to retrieved pm_domain ops.
>   *
>   * Returns 1 on successfully attached PM domain, 0 when the device don't need a
> - * PM domain or a negative error code in case of failures. Note that if a
> - * power-domain exists for the device, but it cannot be found or turned on,
> - * then return -EPROBE_DEFER to ensure that the device is not probed and to
> - * re-try again later.
> + * PM domain or when multiple power-domains exists for it, else a negative error
> + * code. Note that if a power-domain exists for the device, but it cannot be
> + * found or turned on, then return -EPROBE_DEFER to ensure that the device is
> + * not probed and to re-try again later.
>   */
>  int genpd_dev_pm_attach(struct device *dev)
>  {
> @@ -2243,10 +2243,18 @@ int genpd_dev_pm_attach(struct device *dev)
>  	if (!dev->of_node)
>  		return 0;
>  
> +	/*
> +	 * Devices with multiple PM domains must be attached separately, as we
> +	 * can only attach one PM domain per device.
> +	 */
> +	if (of_count_phandle_with_args(dev->of_node, "power-domains",
> +				       "#power-domain-cells") != 1)
> +		return 0;
> +
>  	ret = of_parse_phandle_with_args(dev->of_node, "power-domains",
>  					"#power-domain-cells", 0, &pd_args);
>  	if (ret < 0)
> -		return 0;
> +		return ret;
>  
>  	mutex_lock(&gpd_list_lock);
>  	pd = genpd_get_from_provider(&pd_args);
> 

Acked-by: Jon Hunter <jonathanh@nvidia.com>
Tested-by: Jon Hunter <jonathanh@nvidia.com>

Cheers
Jon

Patch

diff --git a/drivers/base/power/domain.c b/drivers/base/power/domain.c
index 7ebf7993273a..12a20f21974d 100644
--- a/drivers/base/power/domain.c
+++ b/drivers/base/power/domain.c
@@ -2229,10 +2229,10 @@  static void genpd_dev_pm_sync(struct device *dev)
  * attaches the device to retrieved pm_domain ops.
  *
  * Returns 1 on successfully attached PM domain, 0 when the device don't need a
- * PM domain or a negative error code in case of failures. Note that if a
- * power-domain exists for the device, but it cannot be found or turned on,
- * then return -EPROBE_DEFER to ensure that the device is not probed and to
- * re-try again later.
+ * PM domain or when multiple power-domains exists for it, else a negative error
+ * code. Note that if a power-domain exists for the device, but it cannot be
+ * found or turned on, then return -EPROBE_DEFER to ensure that the device is
+ * not probed and to re-try again later.
  */
 int genpd_dev_pm_attach(struct device *dev)
 {
@@ -2243,10 +2243,18 @@  int genpd_dev_pm_attach(struct device *dev)
 	if (!dev->of_node)
 		return 0;
 
+	/*
+	 * Devices with multiple PM domains must be attached separately, as we
+	 * can only attach one PM domain per device.
+	 */
+	if (of_count_phandle_with_args(dev->of_node, "power-domains",
+				       "#power-domain-cells") != 1)
+		return 0;
+
 	ret = of_parse_phandle_with_args(dev->of_node, "power-domains",
 					"#power-domain-cells", 0, &pd_args);
 	if (ret < 0)
-		return 0;
+		return ret;
 
 	mutex_lock(&gpd_list_lock);
 	pd = genpd_get_from_provider(&pd_args);