Re: [PATCH 1/2] clk: qcom: Add support for RPM Clocks

[Bjorn Andersson <bjorn.andersson@sonymobile.com>]

On Thu 09 Jul 08:22 PDT 2015, Georgi Djakov wrote:

> Hi Srini,
> 
> On 07/09/2015 03:27 PM, Srinivas Kandagatla wrote:
> > 
> > On 09/07/15 13:18, Georgi Djakov wrote:
> >> This patch adds initial support for clocks controlled by the RPM
> >> (Resource Power Manager) processor found on some Qualcomm SoCs.
> >>
> >> The RPM is a dedicated hardware engine for managing the shared
> >> SoC resources in order to keep the lowest power profile. It
> >> communicates with other hardware subsystems via shared memory
> >> and accepts clock requests, aggregates the requests and turns
> >> the clocks on/off or scales them on demand.
> >>
> >> This work is based on the codeaurora.org driver:
> >> https://www.codeaurora.org/cgit/quic/la/kernel/msm-3.10/tree/drivers/clk/qcom/clock-rpm.c
> >>
> >> Signed-off-by: Georgi Djakov <georgi.djakov@linaro.org>
> >> ---
> >>   drivers/clk/qcom/Makefile  |    1 +
> >>   drivers/clk/qcom/clk-rpm.c |  164 ++++++++++++++++++++++++++++++++++++++++++++
> >>   drivers/clk/qcom/clk-rpm.h |  137 ++++++++++++++++++++++++++++++++++++
> >>   3 files changed, 302 insertions(+)
> >>   create mode 100644 drivers/clk/qcom/clk-rpm.c
> >>   create mode 100644 drivers/clk/qcom/clk-rpm.h
> >>
> >> diff --git a/drivers/clk/qcom/Makefile b/drivers/clk/qcom/Makefile
> >> index 50b337a24a87..4d14a73ee4ed 100644
> >> --- a/drivers/clk/qcom/Makefile
> >> +++ b/drivers/clk/qcom/Makefile
> >> @@ -8,6 +8,7 @@ clk-qcom-y += clk-rcg2.o
> >>   clk-qcom-y += clk-branch.o
> >>   clk-qcom-y += clk-regmap-divider.o
> >>   clk-qcom-y += clk-regmap-mux.o
> >> +clk-qcom-y += clk-rpm.o
> > 
> > Is this generic enough to be built by default. It will break builds on A family whose rpm clocks are not based on SMD.
> > 
> > IMO, this should be either renamed to clk-rpm-smd.* or only built with SOC's which support rpm-clks based on SMD.
> > 
> 
> There is no A-family RPM clock support in the upstream kernel yet,
> but sure, you are right, we want to build only what is actually used.
> Thanks for the suggestion!
> 

Following the regulator naming I would suggest this being the
clk-smd-rpm driver - unless one driver is enough for both.

It should definitely be possible to build and boot a kernel with both a
family A and B rpm-clock driver compiled in. The details seems to be a
little bit different in the A driver, but I think that with this driver
as reference it should be an easy writeup.

Regards,
Bjorn