Re: [RFC PATCH 2/5] phy: Add WIP Exynos 5250 support to the ExynosUSB PHY driver

[Kishon Vijay Abraham I]

Hi,

On Tuesday 29 October 2013 03:44 PM, Kamil Debski wrote:
> Hi,
> 
>> From: Kishon Vijay Abraham I [mailto:kishon@xxxxxx]
>> Sent: Tuesday, October 29, 2013 10:55 AM
>>
>> Hi,
>>
>> On Monday 28 October 2013 08:11 PM, Vivek Gautam wrote:
>>> Hi Kishon,
>>>
>>>
>>> On Fri, Oct 25, 2013 at 9:13 PM, Kishon Vijay Abraham I
>> <kishon@xxxxxx> wrote:
>>>> Hi,
>>>>
>>>> On Friday 25 October 2013 07:45 PM, Kamil Debski wrote:
>>>>> Add support for Exynos 5250. This is work-in-progress commit. Not
>>>>> for merging.
>>>>>
>>>>> Signed-off-by: Kamil Debski <k.debski@xxxxxxxxxxx>
>>>>> Signed-off-by: Kyungmin Park <kyungmin.park@xxxxxxxxxxx>
>>>>> ---
>>>>>  drivers/phy/Kconfig              |    7 +
>>>>>  drivers/phy/Makefile             |    1 +
>>>>>  drivers/phy/phy-exynos-usb.c     |   10 +
>>>>>  drivers/phy/phy-exynos-usb.h     |    1 +
>>>>>  drivers/phy/phy-exynos5250-usb.c |  411
>>>>> ++++++++++++++++++++++++++++++++++++++
>>>>>  5 files changed, 430 insertions(+)
>>>>>  create mode 100644 drivers/phy/phy-exynos5250-usb.c
>>>>>
>>>>> diff --git a/drivers/phy/Kconfig b/drivers/phy/Kconfig index
>>>>> 2f7ac0a..0f598d0 100644
>>>>> --- a/drivers/phy/Kconfig
>>>>> +++ b/drivers/phy/Kconfig
>>>>> @@ -36,4 +36,11 @@ config PHY_EXYNOS4212_USB
>>>>>       help
>>>>>         Enable USB PHY support for Exynos 4212
>>>>>
>>>>> +config PHY_EXYNOS5250_USB
>>>>> +     bool "Support for Exynos 5250"
>>>>> +     depends on PHY_EXYNOS_USB
>>>>
>>>> This should be a separate driver. Not necessary to use
>> PHY_EXYNOS_USB.
>>>>> +     depends on SOC_EXYNOS5250
>>>>> +     help
>>>>> +       Enable USB PHY support for Exynos 5250
>>>>> +
>>>>>  endmenu
>>>>> diff --git a/drivers/phy/Makefile b/drivers/phy/Makefile index
>>>>> ca3dc82..0dff0dd 100644
>>>>> --- a/drivers/phy/Makefile
>>>>> +++ b/drivers/phy/Makefile
>>>>> @@ -6,3 +6,4 @@ obj-$(CONFIG_GENERIC_PHY)     += phy-core.o
>>>>>  obj-$(CONFIG_PHY_EXYNOS_USB)         += phy-exynos-usb.o
>>>>>  obj-$(CONFIG_PHY_EXYNOS4210_USB)     += phy-exynos4210-usb.o
>>>>>  obj-$(CONFIG_PHY_EXYNOS4212_USB)     += phy-exynos4212-usb.o
>>>>> +obj-$(CONFIG_PHY_EXYNOS5250_USB)     += phy-exynos5250-usb.o
>>>>> diff --git a/drivers/phy/phy-exynos-usb.c
>>>>> b/drivers/phy/phy-exynos-usb.c index d4a26df..172b774 100644
>>>>> --- a/drivers/phy/phy-exynos-usb.c
>>>>> +++ b/drivers/phy/phy-exynos-usb.c
>>>>> @@ -212,6 +212,10 @@ extern const struct uphy_config
>>>>> exynos4210_uphy_config;  extern const struct uphy_config
>>>>> exynos4212_uphy_config;  #endif
>>>>>
>>>>> +#ifdef CONFIG_PHY_EXYNOS5250_USB
>>>>> +extern const struct uphy_config exynos5250_uphy_config; #endif
>>>>> +
>>>>>  static const struct of_device_id exynos_uphy_of_match[] =
>> {  #ifdef
>>>>> CONFIG_PHY_EXYNOS4210_USB
>>>>>       {
>>>>> @@ -225,6 +229,12 @@ static const struct of_device_id
>> exynos_uphy_of_match[] = {
>>>>>               .data = &exynos4212_uphy_config,
>>>>>       },
>>>>>  #endif
>>>>> +#ifdef CONFIG_PHY_EXYNOS5250_USB
>>>>> +     {
>>>>> +             .compatible = "samsung,exynos5250-usbphy",
>>>>> +             .data = &exynos5250_uphy_config,
>>>>> +     },
>>>>> +#endif
>>>>>       { },
>>>>>  };
>>>>>
>>>>> diff --git a/drivers/phy/phy-exynos-usb.h
>>>>> b/drivers/phy/phy-exynos-usb.h index f45cb3c..a9febfa 100644
>>>>> --- a/drivers/phy/phy-exynos-usb.h
>>>>> +++ b/drivers/phy/phy-exynos-usb.h
>>>>> @@ -42,6 +42,7 @@ enum samsung_cpu_type {
>>>>>       TYPE_S3C64XX,
>>>>>       TYPE_EXYNOS4210,
>>>>>       TYPE_EXYNOS4212,
>>>>> +     TYPE_EXYNOS5250,
>>>>
>>>> No cpu types here.
>>>
>>> One question here.
>>> In case we move to single driver for Exynos4 SoCs (4210, 4212 and
>> 4412
>>> later) as well as S5PV210,
>>> there will be certain things changing from one SoC to another, how
>>> should we target that in case we don't have CPU types ?
>>> May be i am misinterpreting your suggestion ?
>>
>> We should be using the IP revision register or check for compatible
>> values.
>>
> 
> In case of this driver the compatible is checked. Maybe it is not as
> straight forward, but the choice is based on compatible value.
> Compatible is matched to an appropriate data entry in the of_device_id
> table. The data entry contains a cpu field which contains the information
> which PHY version we have. Maybe the "cpu" name is confusing and should be
> changed to something like "version" or "revision".

you don't have a revision register in the PHY IP which can be used?
> 
> For example:
> "samsung,exynos4212-usbphy" compatible is matched to exynos4212_uphy_config
> via data field of of_device_id, and the cpu field of exynos4212_uphy_config
> is equal to TYPE_EXYNOS4212.
> This way in the code all what is needed is to check the value of cpu field.
> It already got matched through the compatible.
> 
> Still, Tomasz Figa's idea sound good - using a boolean flag
> "has_mode_switch".

hmm, could be.

Thanks
Kishon
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