Re: [PATCH v4 1/3] bus: simple-pm: add support to pm clocks

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Hey Srini,

On 11/15/2016 4:55 PM, Srinivas Kandagatla wrote:
+ Rajendra (qcom,gdsc author)
[]..


---
 drivers/bus/simple-pm-bus.c | 13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/drivers/bus/simple-pm-bus.c b/drivers/bus/simple-pm-bus.c
index c5eb46c..63b7e8c 100644
--- a/drivers/bus/simple-pm-bus.c
+++ b/drivers/bus/simple-pm-bus.c
@@ -11,6 +11,7 @@
 #include <linux/module.h>
 #include <linux/of_platform.h>
 #include <linux/platform_device.h>
+#include <linux/pm_clock.h>
 #include <linux/pm_runtime.h>


@@ -22,17 +23,26 @@ static int simple_pm_bus_probe(struct
platform_device *pdev)

      pm_runtime_enable(&pdev->dev);

-     if (np)
+     if (np) {
+             of_pm_clk_add_clks(&pdev->dev);

This should work out-of-the-box (that's the actual purpose of this
driver),
if the platform code that registers your PM Domain would take care
of registering the clocks needed for PM management of the bus.

Yep, if the pm domain provider takes care of the bus clks, then it would
work.

Am guessing that the clocks property in the DT node would be read by the
PM domain provider and enable/disable during attach/detach callbacks.
If that is true, then any device tree nodes which are not children of
"simple-pm-bus" and consumers of power-domain provider would enable all
(including non-bus clks) clks twice. Once in the power-domain provider
and once in the actual driver. Is this expected behavior from
power-domains in general?


Adding of_pm_clk_add_clks() here will start managing all clocks of the
bus,
which may not be wanted on all platforms.

That was the purpose.


Rajendra,
Looks like qcom gdsc pm domain provider driver does not handle bus clks
along with power-domain, Is this something we should do? Or the bus
driver take care of it?

I did post some patches to support handling of clocks associated with
gdscs [1], but it got dropped at that point since there wasn't a
real user, besides there were some open issues wrt the handling of
!CONFIG_PM cases etc.
I will revive and repost those patches again now based on the
discussions last time around.

[1] http://lists.infradead.org/pipermail/linux-arm-kernel/2015-August/362492.html

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