On Fri, Sep 28, 2012 at 5:41 AM, Jingoo Han <jg1.han@xxxxxxxxxxx> wrote:
> On Thursday, September 27, 2012 10:45 PM Sylwester Nawrocki wrote
>>
>> Hi,
>>
>> Cc: devicetree-discuss@xxxxxxxxxxxxxxxx
>>
>> On 09/24/2012 09:36 PM, Ajay Kumar wrote:
>> > This patch enables device tree based discovery support for DP driver.
>> > The driver is modified to handle platform data in both the cases:
>> > with DT and non-DT.
>> > Documentation is also added for the DT bindings.
>> >
>> > DP-PHY should be regarded as a seperate device node while
>> > being passed from device tree list, and device node for
>> > DP should contain DP-PHY as child node with property name "dp-phy"
>> > associated with it.
>> >
>> > Signed-off-by: Ajay Kumar<ajaykumar.rs@xxxxxxxxxxx>
>> > ---
>> > .../devicetree/bindings/video/exynos_dp.txt | 83 ++++++++++
>> > drivers/video/exynos/exynos_dp_core.c | 168 ++++++++++++++++++--
>> > drivers/video/exynos/exynos_dp_core.h | 2 +
>> > 3 files changed, 239 insertions(+), 14 deletions(-)
>> > create mode 100644 Documentation/devicetree/bindings/video/exynos_dp.txt
>> >
>> > diff --git a/Documentation/devicetree/bindings/video/exynos_dp.txt
>> b/Documentation/devicetree/bindings/video/exynos_dp.txt
>> > new file mode 100644
>> > index 0000000..c27f892
>> > --- /dev/null
>> > +++ b/Documentation/devicetree/bindings/video/exynos_dp.txt
>> > @@ -0,0 +1,83 @@
>> > +Exynos Displayport driver should configure the displayport interface
>>
>> Don't we need a whitespace between 'display' and 'port' ?
>
> Either 'display port' or 'DisplayPort' is commonly used.
> For clarity, display port would be better.
Ok. I will change it.
>>
>> > +based on the type of panel connected to it.
>> > +
>> > +We use two nodes:
>> > + -dptx_phy node
>> > + -display-port-controller node
>> > +
>> > +For the dp-phy initialization, we use a dptx_phy node.
>> > +Required properties for dptx_phy:
>> > + -compatible:
>> > + Should be "samsung,dp-phy".
>> > + -samsung,dptx_phy_reg:
>> > + Base address of DP PHY register.
>>
>> Couldn't just 'reg' be used for this one ?
>>
>> > + -samsung,enable_bit:
>> > + The bit used to enable/disable DP PHY.
>>
>> Is this the bit mask or the bit index ? In the code it's used as
>> a bitmask. But from description it is not clear whether it is
>> an index or a mask. Is it different across various SoCs ?
>>
>> Perhaps it's better to name it samsung,enable_mask (in case some
>> SoC need more than one bit) ?
>
> It's the bit mask.
> It is different across various SoCs.
> OK, enable_mask would be better.
Ok. I will change it.
>>
>> > +
>> > +For the Panel initialization, we read data from display-port-controller node.
>> > +Required properties for display-port-controller:
>> > + -compatible:
>> > + Should be "samsung,exynos5-dp".
>> > + -reg:
>> > + physical base address of the controller and length
>> > + of memory mapped region.
>> > + -interrupts:
>> > + Internet combiner values.
>>
>> what? :)
>
> Ajay: Please, fix it.
My bad :(...I will fix it.
>>
>> > + -interrupt-parent:
>> > + Address of Interrupt combiner node.
>> > + -dp_phy:
>> > + Address of dptx_phy node.
>>
>> "A phandle to dptx_phy node" ?
>
> Yes, you're right.
>
> Ajay: Please, replace 'Address of dptx_phy node'
> with 'phandle of dptx_phy node'.
Ok.
>>
>> > + -samsung,color_space:
>> > + input video data format.
>> > + COLOR_RGB = 0, COLOR_YCBCR422 = 1, COLOR_YCBCR444 = 2
>>
>> Can this be changed at run time ?
>
> No, it is not changeable.
> It's a default setting according to eDP panel.
>
>>
>> > + -samsung,dynamic_range:
>> > + dynamic range for input video data.
>> > + VESA = 0, CEA = 1
>>
>> Why is it in the device tree ? Shouldn't it be configurable at runtime ?
>> My apologies if this an obvious question, I don't have much experience
>> with DP.
>
> Same above.
>
>>
>> > + -samsung,ycbcr_coeff:
>> > + YCbCr co-efficients for input video.
>> > + COLOR_YCBCR601 = 0, COLOR_YCBCR709 = 1
>> > + -samsung,color_depth:
>> > + Bit per color component.
>>
>> "Number of bits per colour component" ? Also same remark as above.
>
> Same above.
>
>>
>> > + COLOR_6 = 0, COLOR_8 = 1, COLOR_10 = 2, COLOR_12 = 3
>> > + -samsung,link_rate:
>> > + link rates supportd by the panel.
>>
>> typo: supportd -> supported
> Ajay: Please fix it.
Ok.
>
>>
>> > + LINK_RATE_1_62GBPS = 0x6, LINK_RATE_2_70GBPS = 0x0A
>>
>> Is this really a property of a panel ? Why it is in the PHY node ?
>> Also I can see this is just a single property, so "link rates" is a bit
>> misleading.
>>
>
> Yes, It's a property of LCD panel.
> It is not in the 'PHY' node, but 'display-port-controller' node.
>
> Ajay: Please replace 'link rates' with 'link rate'.
Ok.
>> > + -samsung,lane_count:
>> > + number of lanes supported by the panel.
>> > + LANE_COUNT1 = 1, LANE_COUNT2 = 2, LANE_COUNT4 = 4
>>
>> What do these symbolic names are needed for ? Is lane_count a number or a
>> mask, is this really a _maximum_ number of lanes ? What are the valid values,
>> 1, 2 and 4 ? Or maybe 0x3 is also valid which would indicate that we can
>> use 1 or 2 data lanes ?
>>
>
> These symbolic names are defined in './include/video/exynos_dp.h'.
> It seems that Ajay used these definitions.
Yes. I referred include/video/exynos_dp.h.
> 'lane_count' is a number of used lanes of main link which transfer data
> streams as video. The number of lanes of Main Link is 1, 2, or 4 lanes.
> It is dependent on eDP panel.
>
>
>> > + -samsung,interlaced:
>> > + Interlace scan mode.
>> > + Progressive if defined, Interlaced if not defined
>>
>> Why do we need this in the device tree ? Is this really a default scan mode ?
>> Can it be the changed at runtime ?
>
> No, it is not changeable.
> It's a default setting according to eDP panel.
>
>>
>> > + -samsung,v_sync_polarity:
>> > + VSYNC polarity configuration.
>> > + High if defined, Low if not defined
>> > + -samsung,h_sync_polarity:
>> > + HSYNC polarity configuration.
>> > + High if defined, Low if not defined
>> > +
>> > +Example:
>> > +
>> > +SOC specific portion:
>> > + dptx_phy: dptx_phy@0x10040720 {
>> > + compatible = "samsung,dp-phy";
>> > + samsung,dptx_phy_reg =<0x10040720>;
>> > + samsung,enable_bit =<1>;
>> > + };
>> > +
>> > + display-port-controller {
>> > + compatible = "samsung,exynos5-dp";
>> > + reg =<0x145B0000 0x10000>;
>> > + interrupts =<10 3>;
>> > + interrupt-parent =<&combiner>;
>> > + dp_phy =<&dptx_phy>;
>>
>> Shouldn't it be "samsung,dp_phy" ?
>
> Do you mean this ? It is not working.
> + dp_phy = "samsung,dp_phy";
I din't get this.
What do I need to change here?
>>
>> > + };
>> > +
>> > +Board Specific portion:
>> > + display-port-controller {
>> > + samsung,color_space =<0>;
>> > + samsung,dynamic_range =<0>;
>> > + samsung,ycbcr_coeff =<0>;
>> > + samsung,color_depth =<1>;
>> > + samsung,link_rate =<0x0a>;
>> > + samsung,lane_count =<2>;
>> > + };
>>
>> --
>>
>> Regards,
>> Sylwester
>
Thanks and regards,
Ajay Kumar
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