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

From: Mikko Perttunen
Date: Tue Apr 14 2015 - 07:26:25 EST


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@xxxxxxxxxx>

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


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