Hi,
This RFC patch series adds Clock Domain support to the R-Car Gen2 Clock
Pulse Generator (CPG) driver using the generic PM Domain. This allows
to power-manage the module clocks of SoC devices that are part of the
CPG Clock Domain using Runtime PM, or for system suspend/resume.
SoC devices that are part of the CPG Clock Domain and can be
power-managed through their primary clock are tagged in DT with a proper
"power-domains" property. Drivers for devices with multiple clocks
(notably du and rcar-sound) still have to manage their (multiple module)
clocks themselves.
Finally, the legacy default PM domain hack in drivers/sh/pm_runtime.c is
disabled when running on an R-Car Gen2 SoC with genpd support.
Compared to the legacy default PM domain hack, the CPG Clock Domain has
several advantages:
- It only affects on-SoC devices, not all platform devices,
- It only affects the on-SoC devices we want, as specified in DT,
- Allmost all module clocks of all on-SoC devices (barring devices
needed for wake-up[*]) are now gated during s2ram, saving more
power.
Here's a list of all devices in the CPG Clock Domain on r8a7791:
root@koelsch:~# cat /sys/kernel/debug/pm_genpd/pm_genpd_summary
domain status slaves
/device runtime status
----------------------------------------------------------------------
cpg_clocks on
/devices/platform/e61c0000.interrupt-controller active
/devices/platform/e60b0000.i2c suspended
/devices/platform/ffca0000.timer suspended
/devices/platform/e6050000.gpio active
/devices/platform/e6051000.gpio active
/devices/platform/e6052000.gpio active
/devices/platform/e6053000.gpio active
/devices/platform/e6054000.gpio active
/devices/platform/e6055000.gpio active
/devices/platform/e6055400.gpio active
/devices/platform/e6055800.gpio active
/devices/platform/ee090000.pci active
/devices/platform/ee0d0000.pci active
/devices/platform/fe000000.pcie unsupported
/devices/platform/e6700000.dma-controller active
/devices/platform/e6720000.dma-controller active
/devices/platform/ec700000.dma-controller active
/devices/platform/ec720000.dma-controller suspended
/devices/platform/e6e60000.serial active
/devices/platform/e6e68000.serial active
/devices/platform/ee300000.sata unsupported
/devices/platform/e6b10000.spi suspended
/devices/platform/e6e20000.spi suspended
/devices/platform/ee700000.ethernet active
/devices/platform/e6530000.i2c suspended
/devices/platform/e6ef1000.video suspended
/devices/platform/e61f0000.thermal active
/devices/platform/ee100000.sd active
/devices/platform/ee140000.sd active
/devices/platform/ee160000.sd active
root@koelsch:~#
Logically, the CPG Clock Domain operates on the SoC CPG/MSTP block.
As there's no single device node in DT representing this block (there
are separate device nodes for the CPG and for the individual MSTP
clocks), I bound the logic to the CPG device node.
Perhaps this is something we should change for future SoCs?
As usual when involving clocks and/or PM Domains, the DTS changes depend
stricly on the driver change. The final patch must be applied last.
The DTS changes also depend on the series "[PATCH 0/5] ARM: shmobile:
Add INTC-SYS clock to device tree" I've just sent.
This was tested on r8a7791/koelsch.
Thanks for your comments!
[*] GPIO wake-up requires "[PATCH 0/3] gpio: rcar: Fix wake up using
gpio-keys with PM domain").
Geert Uytterhoeven (5):
[RFC] clk: shmobile: rcar-gen2: Add CPG Clock Domain support
[RFC] ARM: shmobile: r8a7790 dtsi: Add CPG Clock Domain
[RFC] ARM: shmobile: r8a7791 dtsi: Add CPG Clock Domain
[RFC] ARM: shmobile: r8a7794 dtsi: Add CPG Clock Domain
drivers: sh: Disable PM runtime for multi-platform R-Car Gen2 with
genpd
.../clock/renesas,rcar-gen2-cpg-clocks.txt | 26 ++++++-
arch/arm/boot/dts/r8a7790.dtsi | 77 +++++++++++++++++++--
arch/arm/boot/dts/r8a7791.dtsi | 80 ++++++++++++++++++++--
arch/arm/boot/dts/r8a7794.dtsi | 29 ++++++++
arch/arm/mach-shmobile/Kconfig | 1 +
drivers/clk/shmobile/clk-rcar-gen2.c | 63 +++++++++++++++++
drivers/sh/pm_runtime.c | 10 +--
7 files changed, 268 insertions(+), 18 deletions(-)
--
1.9.1
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
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