Re: [PATCH v7 1/2] dt-bindings: Add GPCv2 power gating driver

[Dong Aisheng]

On Mon, Mar 27, 2017 at 11:42:51AM -0700, Andrey Smirnov wrote:
> On Thu, Mar 23, 2017 at 11:32 PM, Dong Aisheng <dongas86@xxxxxxxxx> wrote:
> > On Tue, Mar 21, 2017 at 07:50:03AM -0700, Andrey Smirnov wrote:
> >> Add DT bindings for power domain driver for GPCv2 IP block found in
> >> i.MX7 SoCs.
> >>
> >> Cc: yurovsky@xxxxxxxxx
> >> Cc: Lucas Stach <l.stach@xxxxxxxxxxxxxx>
> >> Cc: Rob Herring <robh+dt@xxxxxxxxxx>
> >> Cc: Mark Rutland <mark.rutland@xxxxxxx>
> >> Cc: Fabio Estevam <fabio.estevam@xxxxxxx>
> >> Cc: Dong Aisheng <dongas86@xxxxxxxxx>
> >> Cc: devicetree@xxxxxxxxxxxxxxx
> >> Cc: linux-arm-kernel@xxxxxxxxxxxxxxxxxxx
> >> Cc: linux-kernel@xxxxxxxxxxxxxxx
> >> Acked-by: Rob Herring <robh@xxxxxxxxxx>
> >> Signed-off-by: Andrey Smirnov <andrew.smirnov@xxxxxxxxx>
> >> ---
> >>  .../devicetree/bindings/power/fsl,imx-gpcv2.txt    | 71 ++++++++++++++++++++++
> >>  include/dt-bindings/power/imx7-power.h             | 18 ++++++
> >>  2 files changed, 89 insertions(+)
> >>  create mode 100644 Documentation/devicetree/bindings/power/fsl,imx-gpcv2.txt
> >>  create mode 100644 include/dt-bindings/power/imx7-power.h
> >>
> >> diff --git a/Documentation/devicetree/bindings/power/fsl,imx-gpcv2.txt b/Documentation/devicetree/bindings/power/fsl,imx-gpcv2.txt
> >> new file mode 100644
> >> index 0000000..02f45c6
> >> --- /dev/null
> >> +++ b/Documentation/devicetree/bindings/power/fsl,imx-gpcv2.txt
> >> @@ -0,0 +1,71 @@
> >> +Freescale i.MX General Power Controller v2
> >> +==========================================
> >> +
> >> +The i.MX7S/D General Power Control (GPC) block contains Power Gating
> >> +Control (PGC) for various power domains.
> >> +
> >> +Required properties:
> >> +
> >> +- compatible: Should be "fsl,imx7d-gpc"
> >> +
> >> +- reg: should be register base and length as documented in the
> >> +  datasheet
> >> +
> >> +- interrupts: Should contain GPC interrupt request 1
> >> +
> >> +Power domains contained within GPC node are generic power domain
> >> +providers, documented in
> >> +Documentation/devicetree/bindings/power/power_domain.txt, which are
> >> +described as subnodes of the power gating controller 'pgc' node,
> >> +which, in turn, is expected to contain the following:
> >> +
> >> +Required properties:
> >> +
> >> +- reg: Power domain index. Valid values are defined in
> >> +  include/dt-bindings/power/imx7-power.h
> >> +
> >> +- #power-domain-cells: Should be 0
> >> +
> >> +Optional properties:
> >> +
> >> +- power-supply: Power supply used to power the domain
> >> +
> >> +Example:
> >> +
> >> +     gpc: gpc@303a0000 {
> >> +             compatible = "fsl,imx7d-gpc";
> >> +             reg = <0x303a0000 0x1000>;
> >> +             interrupt-controller;
> >> +             interrupts = <GIC_SPI 87 IRQ_TYPE_LEVEL_HIGH>;
> >> +             #interrupt-cells = <3>;
> >> +             interrupt-parent = <&intc>;
> >> +
> >> +             pgc {
> >> +                     #address-cells = <1>;
> >> +                     #size-cells = <0>;
> >> +
> >> +                     pgc_pcie_phy: power-domain@3 {
> >> +                             #power-domain-cells = <0>;
> >> +
> >> +                             reg = <IMX7_POWER_DOMAIN_PCIE_PHY>;
> >> +                             power-supply = <&reg_1p0d>;
> >> +                     };
> >> +             };
> >> +     };
> >> +
> >> +
> >> +Specifying power domain for IP modules
> >> +======================================
> >> +
> >> +IP cores belonging to a power domain should contain a 'power-domains'
> >> +property that is a phandle for PGC node representing the domain.
> >> +
> >> +Example of a device that is part of the PCIE_PHY power domain:
> >> +
> >> +     pcie: pcie@33800000 {
> >> +           reg = <0x33800000 0x4000>,
> >> +                 <0x4ff00000 0x80000>;
> >> +             /* ... */
> >> +             power-domains = <&pgc_pcie_phy>;
> >> +             /* ... */
> >> +     };
> >> diff --git a/include/dt-bindings/power/imx7-power.h b/include/dt-bindings/power/imx7-power.h
> >> new file mode 100644
> >> index 0000000..eb70023
> >> --- /dev/null
> >> +++ b/include/dt-bindings/power/imx7-power.h
> >> @@ -0,0 +1,18 @@
> >> +/*
> >> + *  Copyright (C) 2017 Impinj
> >> + *
> >> + * This program is free software; you can redistribute it and/or modify
> >> + * it under the terms of the GNU General Public License version 2 as
> >> + * published by the Free Software Foundation.
> >> + */
> >> +
> >> +#ifndef __DT_BINDINGS_IMX7_POWER_H__
> >> +#define __DT_BINDINGS_IMX7_POWER_H__
> >> +
> >> +#define IMX7_POWER_DOMAIN_USB_HSIC_PHY       0
> >> +#define IMX7_POWER_DOMAIN_USB_OTG2_PHY       1
> >> +#define IMX7_POWER_DOMAIN_USB_OTG1_PHY       2
> >> +#define IMX7_POWER_DOMAIN_PCIE_PHY   3
> >> +#define IMX7_POWER_DOMAIN_MIPI_PHY   4
> >
> > Nitpick: Probably better to define according to the reference manual
> > defined order.
> >
> > 0x800 ~ 0x83F : PGC for A7 core0
> > 0x840 ~ 0x87F: PGC for A7 core1
> > 0x880 ~ 0x8BF: PGC for A7 SCU
> > 0xA00 ~ 0xA3F: PGC for fastmix/megamix
> > 0xC00 ~ 0xC3F: PGC for MIPI PHY
> > 0xC40 ~ 0xC7F: PGC for PCIE_PHY
> > 0xC80 ~ 0xCBF: Reserved
> > 0xCC0 ~ 0xCFF: Reserved
> > 0xD00 ~ 0xD3F: PGC for USB HSIC PHY
> >
> > You can drop A7 core/scu/fastmix/megamix as well.
> >
> 
> Sure, will do.
> 

BTW, i read some other SoC power domain implementations,
they keep the CPU domains although not used in kernel.
e.g.
include/dt-bindings/power/rk3288-power.h
include/soc/tegra/pmc.h

That probably is a good reference in case we may need them in the future.
And device tree actually is describe HW.
I wonder we may be better to keep them as well.

Regards
Dong Aisheng

> Thanks,
> Andrey Smirnov