Re: [PATCH v7 1/2] phy: Add new Exynos5 USB 3.0 PHY driver

Tomasz Figa
2014-05-09T09:47:07Z

[CCing DT maintainers]

On 08.05.2014 11:03, Vivek Gautam wrote:
> On Thu, May 8, 2014 at 11:35 AM, Vivek Gautam <gautam.vivek@samsung.com> wrote:
>> Hi Sylwester,
>>
>>
>> On Tue, May 6, 2014 at 7:57 PM, Sylwester Nawrocki
>> <s.nawrocki@samsung.com> wrote:
>>> On 28/04/14 08:17, 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>
>>>> ---
>>>>
>>>> Changes from v6:
>>>> - Addressed review comments:
>>>> -- Sorted config entries in Kconfig and Makefile
>>>> -- Made #define to_usbdrd_phy(inst) to a static inline routine.
>>>> -- Restructured exynos5_rate_to_clk() as suggested.
>>>> -- Amended 'val' field for regmap_update_bits() in the routine
>>>> exynos5_usbdrd_phy_isol().
>>>> -- Removed sentinel entry from exynos5_usbdrd_phy_cfg[] struct.
>>>> -- Removed check for 'match' entry in probe().
>>>>
>>>> .../devicetree/bindings/phy/samsung-phy.txt | 40 ++
>>>> drivers/phy/Kconfig | 11 +
>>>> drivers/phy/Makefile | 1 +
>>>> drivers/phy/phy-exynos5-usbdrd.c | 627 ++++++++++++++++++++
>>>> 4 files changed, 679 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 b422e38..51efe4c 100644
>>>> --- a/Documentation/devicetree/bindings/phy/samsung-phy.txt
>>>> +++ b/Documentation/devicetree/bindings/phy/samsung-phy.txt
>>>> @@ -114,3 +114,43 @@ Example:
>>>> compatible = "samsung,exynos-sataphy-i2c";
>>>> reg = <0x38>;
>>>> };
>>>> +
>>>> +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), used for
>>>> + PHY operations, associated by phy name. It is used to
>>>> + determine bit values for clock settings register.
>>>> + For Exynos5420 this is given as 'sclk_usbphy30' in CMU.
>>>> +- samsung,pmu-syscon: phandle for PMU system controller interface, used to
>>>> + control pmu registers for power isolation.
>>>> +- samsung,pmu-offset: phy power control register offset to pmu-system-controller
>>>> + base.
>>>
>>> It doesn't seem right to have register offset encoded in the device tree
>>> like this. I think it'd be more appropriate to associate such an offset
>>> with the compatible string's value in the driver.
>>
>> Ok, it makes more sense.
>> Just out of curiosity, what difference would this make ?
>
> Moreover, in case of Exynos5420 (and may be in future SoCs), where we
> have 2 USB DRD PHY controllers,
> we will need to have a way around to deal with two separate offsets in
> the driver for one compatible string.
>
> Getting the offsets from DT seems a cleaner way to handle this case of
> multi controllers.

Mark, Rob, what is your opinion on this?

Best regards,
Tomasz