[PATCH] firmware: imx: scu-pd: Update comments for single global power domain

From: Ulf Hansson
Date: Wed Mar 17 2021 - 05:32:46 EST


Since the introduction of the PM domain support for the scu-pd, the genpd
framework has been continuously improved. More preciously, using a single
global power domain can quite easily be deployed for imx platforms.

To avoid confusions, let's therefore make an update to the comments about
the missing pieces.

Signed-off-by: Ulf Hansson <ulf.hansson@xxxxxxxxxx>
---
drivers/firmware/imx/scu-pd.c | 11 +++++++++--
1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/drivers/firmware/imx/scu-pd.c b/drivers/firmware/imx/scu-pd.c
index 08533ee67626..6e178a63442d 100644
--- a/drivers/firmware/imx/scu-pd.c
+++ b/drivers/firmware/imx/scu-pd.c
@@ -29,6 +29,10 @@
* The framework needs some proper extension to support multi power
* domain cases.
*
+ * Update: Genpd assigns the ->of_node for the virtual device before it
+ * invokes ->attach_dev() callback, hence parsing for device resources via
+ * DT should work fine.
+ *
* 2. It also breaks most of current drivers as the driver probe sequence
* behavior changed if removing ->power_on|off() callback and use
* ->start() and ->stop() instead. genpd_dev_pm_attach will only power
@@ -39,8 +43,11 @@
* domain enabled will trigger a HW access error. That means we need fix
* most drivers probe sequence with proper runtime pm.
*
- * In summary, we need fix above two issue before being able to switch to
- * the "single global power domain" way.
+ * Update: Runtime PM support isn't necessary. Instead, this can easily be
+ * fixed in drivers by adding a call to dev_pm_domain_start() during probe.
+ *
+ * In summary, the second part needs to be addressed via minor updates to the
+ * relevant drivers, before the "single global power domain" model can be used.
*
*/

--
2.25.1