On 03/14/2014 10:36 AM, Nishanth Menon wrote:
On 03/14/2014 07:32 AM, Shawn Guo wrote:
On Thu, Mar 13, 2014 at 07:44:24PM +0800, Jisheng Zhang wrote:
On 13 March 2014 16:25, Viresh Kumar <viresh.kumar@xxxxxxxxxx> wrote:
On 13 March 2014 16:18, Jisheng Zhang <jszhang@xxxxxxxxxxx> wrote:
Hi all,
cpufreq-cpu0 is suitable for Marvell Berlin SoC. But there's one issue
to address. The opp is different between chips even on the same step
SoC, BG2Q for example. we can calculate the OPP table from the value of
one OTP register. We have two solutions:
1. bootloader reads OTP register and calculate the OPP table then change
dtb danamically
2. supply one driver in mach-berlin to initialize the OPP table; and
modify cpufreq-cpu0 to allow platform supply OPP table, fall back to
of_init_opp_table() if there's no OPP table.
Which solution is better?
I think we can go ahead with second option here. We can just check if opp
tables are already initialized or not. In case they are, don't probe from
dt..
But lets see with others have to say here..
Yea, we had gone for the second option on imx6q-cpufreq driver with
commit 20b7cbe (cpufreq: imx6q: add of_init_opp_table).
There might be a better alternative here given the scope of potential
reuse cross SoCs - a generic opp modifier logic which'd work for all
of us. I will let Dave Gerlach post his series to give an idea.
I have posted an RFC for a small opp-modifier framework along with a
driver that uses it to enable or disable OPPs based on a register value.
I copied everyone from this thread but in case I forgot anyone the
series is here http://marc.info/?l=linux-pm&m=139482524506817&w=2.
Regards,
Dave
--
To unsubscribe from this list: send the line "unsubscribe cpufreq" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
