Re: [PATCH v2] ARM: tegra: enforce PM requirement

From: Sameer Pujar
Date: Wed Feb 27 2019 - 01:17:08 EST



On 2/26/2019 10:22 PM, Dmitry Osipenko wrote:
26.02.2019 12:13, Russell King - ARM Linux admin ÐÐÑÐÑ:
On Tue, Feb 26, 2019 at 01:55:37PM +0530, Sameer Pujar wrote:
The requirement for this came while adding runtime PM support for HDA
driver. There were concerns about driver explicitly handling !PM case.
In general, drivers need to handle !PM case with work arounds for
managing clocks and power explicitly, which is not really necessary
when PM support on tegra is in good shape. In fact ARM 64-bit Tegra
platforms enforce PM support and there is no reason why this cannot be
done for 32-bit.

More details with regards to above can be found in following patch,
http://patchwork.ozlabs.org/patch/1036645/

This patch selects PM unconditionally and drivers can rely on runtime
PM framework for clock and power management.
What if the drivers are re-used on another SoC IP? Doesn't this lead
to unexpected failures?

If you want to do this, maybe also make those drivers depend on PM as
well?
The commit message is inaccurate, it is intended for the Tegra HDA driver and not for some generic driver. The overall final intent is to remove dependency on the PM availability for all of Tegra drivers to "make Tegra maintainers life easier".
Wanted to convey that finally it would be the case for all Tegra drivers. I will update commit message to make it more clear.