On Thu, May 1, 2014 at 2:41 PM, Geert Uytterhoeven <geert@xxxxxxxxxxxxxx> wrote: > Hi Grant, > > On Thu, May 1, 2014 at 10:03 AM, Grant Likely <grant.likely@xxxxxxxxxxxx> wrote: >> On Wed, 30 Apr 2014 23:54:37 +0200, Geert Uytterhoeven <geert@xxxxxxxxxxxxxx> wrote: >>> On Tue, Apr 29, 2014 at 3:16 PM, Grant Likely <grant.likely@xxxxxxxxxxxx> wrote: >>> > I also don't like that it tries to set up every clock, but there is no >>> > guarantee that the driver will even use it. I would rather see this >>> > behaviour linked into the function that obtains the clock at driver >>> > .probe() time. That way it can handle deferred probe correctly and it >>> > only sets up clocks that are actually used by the driver. >>> >>> Not every clock. Only the clocks that are advertised by the clock driver as >>> being suitable for runtime_pm management. These are typically module >>> clocks, that must be enabled for the module to work. The driver doesn't >>> always want to handle these explicitly. >> >> Help me out here becasue I don't understand how that works with this >> patch set. From my, admittedly naive, reading it looks like the setup is >> being done at device creation time, but if the driver (or module) gets >> to declare which clocks need to be enabled in order to work, then that >> information is not available at device creation time. > > Setup is indeed done at registration time. Note the check calling > clk_may_runtime_pm(), which is introduced in "[PATCH/RFC 1/4] clk: Add > CLK_RUNTIME_PM and clk_may_runtime_pm()". > > Clock drivers are initialized much earlier, so they can set the CLK_RUNTIME_PM > flag for suitable clocks before platform devices are created from DT, cfr. the > example for shmobile MSTP clocks in "[PATCH/RFC 4/4] clk: shmobile: mstp: > Set CLK_RUNTIME_PM flag". This is where I have issue. You're *assuming* clock drivers are initialized much earlier. That is not guaranteed. It is perfectly valid for clocks to be set up by a normal device driver, just like for interrupt controllers or gpio controllers. g. -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
