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

Tue Apr 14 04:25:59 PDT 2015

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 at 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
>>>