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    SubjectRe: [PATCH V4 1/5] phy: Add new Exynos5 USB 3.0 PHY driver
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    On Mon, Apr 14, 2014 at 6:29 PM, Kishon Vijay Abraham I <kishon@ti.com> wrote:
    >
    >
    > On Monday 14 April 2014 06:12 PM, Vivek Gautam wrote:
    >> Hi,
    >>
    >>
    >> On Mon, Apr 14, 2014 at 5:57 PM, Kishon Vijay Abraham I <kishon@ti.com> wrote:
    >>> Hi,
    >>>
    >>> On Tuesday 08 April 2014 08:06 PM, Vivek Gautam wrote:
    >>>> Add a new driver for the USB 3.0 PHY on Exynos5 series of SoCs.
    >>>> The new driver uses the generic PHY framework and will interact
    >>>> with DWC3 controller present on Exynos5 series of SoCs.
    >>>> Thereby, removing old phy-samsung-usb3 driver and related code
    >>>> used untill now which was based on usb/phy framework.
    >>>>
    >>>> Signed-off-by: Vivek Gautam <gautam.vivek@samsung.com>
    >>>> ---
    >>>> .../devicetree/bindings/phy/samsung-phy.txt | 42 ++
    >>>> drivers/phy/Kconfig | 11 +
    >>>> drivers/phy/Makefile | 1 +
    >>>> drivers/phy/phy-exynos5-usbdrd.c | 668 ++++++++++++++++++++
    >>>> 4 files changed, 722 insertions(+)
    >>>> create mode 100644 drivers/phy/phy-exynos5-usbdrd.c
    >>>>
    >>>> diff --git a/Documentation/devicetree/bindings/phy/samsung-phy.txt b/Documentation/devicetree/bindings/phy/samsung-phy.txt
    >>>> index 28f9edb..6d99ba9 100644
    >>>> --- a/Documentation/devicetree/bindings/phy/samsung-phy.txt
    >>>> +++ b/Documentation/devicetree/bindings/phy/samsung-phy.txt
    >>>> @@ -74,3 +74,45 @@ phy-consumer@12340000 {
    >>>>
    >>>> Refer to DT bindings documentation of particular PHY consumer devices for more
    >>>> information about required PHYs and the way of specification.
    >>>> +
    >>>> +Samsung Exynos5 SoC series USB DRD PHY controller
    >>>> +--------------------------------------------------
    >>>> +
    >>>> +Required properties:
    >>>> +- compatible : Should be set to one of the following supported values:
    >>>> + - "samsung,exynos5250-usbdrd-phy" - for exynos5250 SoC,
    >>>> + - "samsung,exynos5420-usbdrd-phy" - for exynos5420 SoC.
    >>>> +- reg : Register offset and length of USB DRD PHY register set;
    >>>> +- clocks: Clock IDs array as required by the controller
    >>>> +- clock-names: names of clocks correseponding to IDs in the clock property;
    >>>> + Required clocks:
    >>>> + - phy: main PHY clock (same as USB DRD controller i.e. DWC3 IP clock),
    >>>> + used for register access.
    >>>> + - ref: PHY's reference clock (usually crystal clock), associated by
    >>>> + phy name, used to determine bit values for clock settings
    >>>> + register.
    >>>> + Additional clock required for Exynos5420:
    >>>> + - usb30_sclk_100m: Additional special clock used for PHY operation
    >>>> + depicted as 'sclk_usbphy30' in CMU of Exynos5420.
    >>>> +- samsung,syscon-phandle: phandle for syscon interface, which is used to
    >>>> + control pmu registers for power isolation.
    >>>> +- samsung,pmu-offset: phy power control register offset to pmu-system-controller
    >>>> + base.
    >>>> +- #phy-cells : from the generic PHY bindings, must be 1;
    >>>> +
    >>>> +For "samsung,exynos5250-usbdrd-phy" and "samsung,exynos5420-usbdrd-phy"
    >>>> +compatible PHYs, the second cell in the PHY specifier identifies the
    >>>> +PHY id, which is interpreted as follows:
    >>>> + 0 - UTMI+ type phy,
    >>>> + 1 - PIPE3 type phy,
    >>>> +
    >>>> +Example:
    >>>> + usb3_phy: usbphy@12100000 {
    >>>> + compatible = "samsung,exynos5250-usbdrd-phy";
    >>>> + reg = <0x12100000 0x100>;
    >>>> + clocks = <&clock 286>, <&clock 1>;
    >>>> + clock-names = "phy", "usb3phy_refclk";
    >>>> + samsung,syscon-phandle = <&pmu_syscon>;
    >>>> + samsung,pmu-offset = <0x704>;
    >>>> + #phy-cells = <1>;
    >>>> + };
    >>>> diff --git a/drivers/phy/Kconfig b/drivers/phy/Kconfig
    >>>> index 8d3c49c..d955a05 100644
    >>>> --- a/drivers/phy/Kconfig
    >>>> +++ b/drivers/phy/Kconfig
    >>>> @@ -166,4 +166,15 @@ config PHY_XGENE
    >>>> help
    >>>> This option enables support for APM X-Gene SoC multi-purpose PHY.
    >>>>
    >>>> +config PHY_EXYNOS5_USBDRD
    >>>> + tristate "Exynos5 SoC series USB DRD PHY driver"
    >>>> + depends on ARCH_EXYNOS5 && OF
    >>>> + depends on HAS_IOMEM
    >>>> + select GENERIC_PHY
    >>>> + select MFD_SYSCON
    >>>
    >>> Lets try to avoid select in Kconfig. We've got enough problems with that.
    >>
    >> I hope you meant with "select MFD_SYSCON".
    >> We are referencing the syscon for accessing pmu reg, for which we need
    >> this config to be selected.
    >> Other Exynos phy drivers also need this config and for that they have
    >> selected this.
    >>
    >> Do you want me to do it any other way ?
    >
    > depends on is one option.

    Ok, i can see there are places where depends_on MFD_SYSCON is used.
    "drivers/gpu/drm/exynos/Kconfig:60"

    so, do you want me to fix at other places too ?

    But i also have a question here.
    MFD_SYSCON is a subsystem that's facilitating us in getting our work
    done here by giving an access to pmu_system_controller.
    So unless MFD_SYSCON is exposed, the phy driver will not be exposed to us.
    So is that valid enough really ?

    >
    > Thanks
    > Kishon
    > --
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    --
    Best Regards
    Vivek Gautam
    Samsung R&D Institute, Bangalore
    India


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