[PATCH 1/2] drm/exynos: hdmi: Add support for Exynos7 HDMI

[Ajay kumar]

On Wed, Mar 4, 2015 at 2:30 PM, Andrzej Hajda <a.hajda at samsung.com> wrote:
> On 03/02/2015 09:40 AM, Ajay kumar wrote:
>> Hi Andrej,
>>
>> On Fri, Feb 27, 2015 at 4:18 PM, Andrzej Hajda <a.hajda at samsung.com> wrote:
>>> Hi Ajay,
>>>
>>> Thanks for the patch.
>> Thanks for reviewing the patch.
>>
>>> On 02/26/2015 04:24 PM, Ajay Kumar wrote:
>>>> Modify the exynos HDMI driver to support Exynos7 HDMI 1.4.
>>>> * Add phy configs for Exynos7.
>>>> * Exynos7 has a different clock structure for HDMI,
>>>>   so introduce the new clocks.
>>>> * Add sysreg support to enable HDMI SYSREG on Exynos7.
>>>> * Exynos7 based boards need a DCDC_EN and LS_EN pins
>>>>   for powering up HDMI. Add support for that too.
>>>>
>>>> Signed-off-by: Ajay Kumar <ajaykumar.rs at samsung.com>
>>>> ---
>>>>  .../devicetree/bindings/video/exynos_hdmi.txt      |   21 +-
>>>>  drivers/gpu/drm/exynos/exynos_hdmi.c               |  252 ++++++++++++++++----
>>>>  drivers/gpu/drm/exynos/regs-hdmi.h                 |    4 +
>>>>  3 files changed, 231 insertions(+), 46 deletions(-)
>>>>
>>>> diff --git a/Documentation/devicetree/bindings/video/exynos_hdmi.txt b/Documentation/devicetree/bindings/video/exynos_hdmi.txt
>>>> index 1fd8cf9..bb22a60 100644
>>>> --- a/Documentation/devicetree/bindings/video/exynos_hdmi.txt
>>>> +++ b/Documentation/devicetree/bindings/video/exynos_hdmi.txt
>>>> @@ -6,6 +6,7 @@ Required properties:
>>>>       2) "samsung,exynos4210-hdmi"
>>>>       3) "samsung,exynos4212-hdmi"
>>>>       4) "samsung,exynos5420-hdmi"
>>>> +     5) "samsung,exynos7-hdmi"
>>> Why not "samsung,exynos7420-hdmi" ?
>>> What compatible will you use for Exynos7430 or higher chip number?
>> I will leave this decision to Inki Dae or Kukjin.
>>
>>>>  - reg: physical base address of the hdmi and length of memory mapped
>>>>       region.
>>>>  - interrupts: interrupt number to the cpu.
>>>> @@ -15,21 +16,33 @@ Required properties:
>>>>       c) optional flags and pull up/down.
>>>>  - clocks: list of clock IDs from SoC clock driver.
>>>>       a) hdmi: Gate of HDMI IP bus clock.
>>>> -     b) sclk_hdmi: Gate of HDMI special clock.
>>>> -     c) sclk_pixel: Pixel special clock, one of the two possible inputs of
>>>> +     HDMI clocks necessary for non exynos7:
>>>> +      b) sclk_hdmi: Gate of HDMI special clock.
>>>> +      c) sclk_pixel: Pixel special clock, one of the two possible inputs of
>>>>               HDMI clock mux.
>>>> -     d) sclk_hdmiphy: HDMI PHY clock output, one of two possible inputs of
>>>> +      d) sclk_hdmiphy: HDMI PHY clock output, one of two possible inputs of
>>>>               HDMI clock mux.
>>>> -     e) mout_hdmi: It is required by the driver to switch between the 2
>>>> +      e) mout_hdmi: It is required by the driver to switch between the 2
>>>>               parents i.e. sclk_pixel and sclk_hdmiphy. If hdmiphy is stable
>>>>               after configuration, parent is set to sclk_hdmiphy else
>>>>               sclk_pixel.
>>>> +     HDMI clocks necessary for Exynos7:
>>>> +      b) pclk_hdmiphy: Gate to HDMIPHY clock.
>>> According to specs there is also pclk_hdmi, why do you specify only this
>>> one?
>> Right, I have reused "hdmi" gating clock for pclk_hdmi. That is why I have
>> left "hdmi" clock as common for exynos7 and non-exynos7.
>
> IMO it would be better to use separate entry for pclk_hdmi.
Ok.

>>>> +      c) hdmi_pixel: Gate clock of MUX output for I_PIXEL_CLK.
>>>> +      d) hdmi_tmds: Gate clock of MUX output for I_TMDS_CLK.
>>> According to specs these clocks should be named i_pixel_clk and
>>> i_tmds_clk, shouldn't they?
>> I actually took these changes from an "internal" code(non-DRM).
>> The original author used these names, and I just carried the same names. :)
>>
>>>>  - clock-names: aliases as per driver requirements for above clock IDs:
>>>>       "hdmi", "sclk_hdmi", "sclk_pixel", "sclk_hdmiphy" and "mout_hdmi".
>>>>  - ddc: phandle to the hdmi ddc node
>>>>  - phy: phandle to the hdmi phy node
>>>>  - samsung,syscon-phandle: phandle for system controller node for PMU.
>>>>
>>>> +Only for Exynos7(when compatible = "samsung,exynos7-hdmi"):
>>>> +- samsung,sysreg-phandle: phandle for system controller node for SYSREG block.
>>>> +
>>>> +Optional properties:
>>>> +- dcdc-gpios: OF device-tree gpio specification for HDMI_DCDC_EN pin.
>>>> +- lsen-gpios: OF device-tree gpio specification for HDMI_LS_EN pin.
>>> What is purpose of these gpios?
>> These 2 GPIOs need to be enabled to powerup HDMI on exynos7-espresso board.
>> Other boards need not provide the GPIO.
>
> HDMI is internal IP of SoC, so it is rather not configurable via pins.
> Pin names suggests they are for DC-DC converter and level shifter, I guess
> these are for HDMI connector, not the HDMI IP, am I right?
Right, this is for HDMI connector.

> Maybe better option is to use pinctrl for these gpios, or use gpio
> regulator, hard
> to guess without documentation.
Why should I not use devm_gpiod_get_optional for these GPIOs?

Ajay