Re: [PATCH v8 00/18] Tegra124 CL-DVFS / DFLL clocksource + cpufreq

Mikko Perttunen
2015-04-14T11:26:21Z

On 04/11/2015 12:11 AM, Michael Turquette wrote:
> Quoting Thierry Reding (2015-03-11 03:07:43)
>> Hi Mike,
>>
>> Have you had a chance to look at these changes to the Tegra clock
>> driver? If you're fine with it, I'd like to take these patches through
>> the Tegra tree because the rest of the series depends on them. I can
>> provide a stable branch in case we need to base other Tegra clock
>> changes on top of this.
>
> Hi Thierry,
>
> Clock patches (and corresponding DT binding descriptions and changes to
> DTS) look fine to me. Please add:
>
> Acked-by: Michael Turquette <mturquette@linaro.org>
>
> I did have a question about the beahvior of clk_put in one of Mikko's
> patches but it should not gate this series. I'm just trying to find out
> if we have a bug in the framework or if the Tegra driver is a special
> case.
>
> Also I do not think a stable branch is necessary.
>
> Regards,
> Mike
>

Looks like in the meantime, this has been partially broken by
03bc10ab5b0f "clk: check ->determine/round_rate() return value in
clk_calc_new_rates". The highest rates supported by the DFLL clock have
1 in the MSB, so those cannot be entered after the aforementioned patch,
as the return value of round_rate is interpreted as an error. Avenues
that I can see: 1) revert the above patch 2) restrict the cpu clock rate
to those with 0 in the MSB 3) move to 64-bit clock rates.

Cheers,
Mikko.

>>
>> Thierry
>>
>> On Sun, Mar 01, 2015 at 02:44:23PM +0200, Mikko Perttunen wrote:
>>> Hi, this is v8 of the Tegra124 cpufreq series. Aside rebasing on latest -next,
>>> the following changes have been done:
>>>
>>> clk: tegra: Add binding for the Tegra124 DFLL clocksource
>>> - Changed dfll@ -> clock@
>>> - Changed compatibility string to "nvidia,tegra124-dfll"
>>> - Clarified how the vdd-cpu-supply property is used
>>> - Marked nvidia,cg-scale as optional since it is a boolean property
>>> - Expanded the 'FS mode' term to 'full speed mode'
>>> - Added dvco reset control
>>>
>>> ARM: tegra: Add the DFLL to Tegra124 device tree
>>> - Changed dfll@ -> clock@
>>> - Added dvco reset control
>>>
>>> ARM: tegra: Enable the DFLL on the Jetson TK1
>>> - Changed dfll@ -> clock@
>>>
>>> clk: tegra: Initialize PLL_X before CCLK_G to ensure it has a parent
>>> - Added
>>>
>>> clk: tegra: Introduce ability for SoC-specific reset control callbacks
>>> - Added
>>>
>>> clk: tegra: Add DFLL DVCO reset control for Tegra124
>>> - Changed to use SoC-specific reset control callback
>>>
>>> clk: tegra: Add Tegra124 DFLL clocksource platform driver
>>> - Don't set DVCO reset handlers
>>>
>>> clk: tegra: Add library for the DFLL clock source (open-loop mode)
>>> - Use reset control instead of function pointers
>>>
>>> also added acks from v7.
>>>
>>> The series is available in a git repository at
>>> git://github.com/cyndis/linux.git cldvfs-v8
>>>
>>> Tested by me on Jetson-TK1 (rev. D).
>>>
>>> Original cover letter:
>>>
>>> This series implements the DFLL/CL-DVFS clock source for the fast CPU
>>> cluster on Tegra124, and a cpufreq driver that uses the DFLL for
>>> clocking the CPU. Most of this is based on Paul Walmsley's public patch
>>> set from December 2013, which is available at
>>> http://comments.gmane.org/gmane.linux.ports.tegra/15273
>>>
>>> The DFLL clock hardware is a voltage-controlled oscillator plus
>>> control logic that compares the generated output clock with a
>>> 51 MHz reference clock, and can make decisions to either lower
>>> or raise the DFLL voltage to keep the output rate close to the
>>> software-requested rate. The voltage changes are done by
>>> communicating with an off-chip PMIC via either I2C or PWM.
>>> As the DFLL oscillator is powered via the CPU rail, using
>>> the DFLL as the CPU clocksource also gives us dynamic CPU
>>> voltage scaling.
>>>
>>> This series has been tested on the Jetson TK1 (Rev C). Porting this to
>>> the Venice2 should be simple, though do note that it does not have
>>> active cooling.
>>>
>>> Thanks,
>>> Tuomas
>>>
>>> Mikko Perttunen (3):
>>> clk: tegra: Introduce ability for SoC-specific reset control callbacks
>>> clk: tegra: Initialize PLL_X before CCLK_G to ensure it has a parent
>>> ARM: tegra: Add CPU regulator to the Jetson TK1 device tree
>>>
>>> Paul Walmsley (1):
>>> clk: tegra: Add DFLL DVCO reset control for Tegra124
>>>
>>> Tuomas Tynkkynen (14):
>>> clk: tegra: Add binding for the Tegra124 DFLL clocksource
>>> clk: tegra: Add library for the DFLL clock source (open-loop mode)
>>> clk: tegra: Add closed loop support for the DFLL
>>> clk: tegra: Add functions for parsing CVB tables
>>> clk: tegra: Add Tegra124 DFLL clocksource platform driver
>>> clk: tegra: Save/restore CCLKG_BURST_POLICY on suspend
>>> clk: tegra: Add the DFLL as a possible parent of the cclk_g clock
>>> ARM: tegra: Add the DFLL to Tegra124 device tree
>>> ARM: tegra: Enable the DFLL on the Jetson TK1
>>> cpufreq: tegra124: Add device tree bindings
>>> cpufreq: tegra: Rename tegra-cpufreq to tegra20-cpufreq
>>> cpufreq: Add cpufreq driver for Tegra124
>>> ARM: tegra: Add entries for cpufreq on Tegra124
>>> ARM: tegra: enable Tegra124 cpufreq driver by default
>>>
>>> .../bindings/clock/nvidia,tegra124-dfll.txt | 79 +
>>> .../bindings/cpufreq/tegra124-cpufreq.txt | 44 +
>>> arch/arm/boot/dts/tegra124-jetson-tk1.dts | 15 +-
>>> arch/arm/boot/dts/tegra124.dtsi | 34 +
>>> arch/arm/configs/tegra_defconfig | 1 +
>>> arch/arm/mach-tegra/Kconfig | 1 +
>>> drivers/clk/tegra/Makefile | 3 +
>>> drivers/clk/tegra/clk-dfll.c | 1755 ++++++++++++++++++++
>>> drivers/clk/tegra/clk-dfll.h | 54 +
>>> drivers/clk/tegra/clk-tegra-super-gen4.c | 50 +-
>>> drivers/clk/tegra/clk-tegra124-dfll-fcpu.c | 163 ++
>>> drivers/clk/tegra/clk-tegra124.c | 82 +
>>> drivers/clk/tegra/clk.c | 36 +-
>>> drivers/clk/tegra/clk.h | 3 +
>>> drivers/clk/tegra/cvb.c | 133 ++
>>> drivers/clk/tegra/cvb.h | 67 +
>>> drivers/cpufreq/Kconfig.arm | 13 +-
>>> drivers/cpufreq/Makefile | 3 +-
>>> drivers/cpufreq/tegra124-cpufreq.c | 217 +++
>>> .../cpufreq/{tegra-cpufreq.c => tegra20-cpufreq.c} | 0
>>> include/dt-bindings/reset/tegra124-car.h | 11 +
>>> 21 files changed, 2730 insertions(+), 34 deletions(-)
>>> create mode 100644 Documentation/devicetree/bindings/clock/nvidia,tegra124-dfll.txt
>>> create mode 100644 Documentation/devicetree/bindings/cpufreq/tegra124-cpufreq.txt
>>> create mode 100644 drivers/clk/tegra/clk-dfll.c
>>> create mode 100644 drivers/clk/tegra/clk-dfll.h
>>> create mode 100644 drivers/clk/tegra/clk-tegra124-dfll-fcpu.c
>>> create mode 100644 drivers/clk/tegra/cvb.c
>>> create mode 100644 drivers/clk/tegra/cvb.h
>>> create mode 100644 drivers/cpufreq/tegra124-cpufreq.c
>>> rename drivers/cpufreq/{tegra-cpufreq.c => tegra20-cpufreq.c} (100%)
>>> create mode 100644 include/dt-bindings/reset/tegra124-car.h
>>>
>>> --
>>> 2.3.0
>>>