[PATCH v4 5/6] dt-bindings: display: add Unisoc's mipi dsi controller bindings
Maxime Ripard
maxime at cerno.tech
Wed Apr 21 09:38:33 UTC 2021
Hi,
On Mon, Apr 19, 2021 at 12:33:42AM +0800, Kevin Tang wrote:
> Maxime Ripard <maxime at cerno.tech> 于2021年4月15日周四 下午4:42写道：
> >
> > On Fri, Apr 09, 2021 at 08:23:19AM +0800, Kevin Tang wrote:
> > > Maxime Ripard <maxime at cerno.tech> 于2021年4月7日周三 下午6:46写道：
> > >
> > > > On Wed, Mar 31, 2021 at 09:49:14AM +0800, Kevin Tang wrote:
> > > > > Hi Maxime,
> > > > >
> > > > > Maxime Ripard <maxime at cerno.tech> 于2021年3月24日周三 下午7:13写道：
> > > > >
> > > > > > On Mon, Feb 22, 2021 at 09:28:21PM +0800, Kevin Tang wrote:
> > > > > > > From: Kevin Tang <kevin.tang at unisoc.com>
> > > > > > >
> > > > > > > Adds MIPI DSI Controller
> > > > > > > support for Unisoc's display subsystem.
> > > > > > >
> > > > > > > Cc: Orson Zhai <orsonzhai at gmail.com>
> > > > > > > Cc: Chunyan Zhang <zhang.lyra at gmail.com>
> > > > > > > Signed-off-by: Kevin Tang <kevin.tang at unisoc.com>
> > > > > > > Reviewed-by: Rob Herring <robh at kernel.org>
> > > > > > > ---
> > > > > > > .../display/sprd/sprd,sharkl3-dsi-host.yaml | 102
> > > > ++++++++++++++++++
> > > > > > > 1 file changed, 102 insertions(+)
> > > > > > > create mode 100644
> > > > > >
> > > > Documentation/devicetree/bindings/display/sprd/sprd,sharkl3-dsi-host.yaml
> > > > > > >
> > > > > > > diff --git
> > > > > >
> > > > a/Documentation/devicetree/bindings/display/sprd/sprd,sharkl3-dsi-host.yaml
> > > > > >
> > > > b/Documentation/devicetree/bindings/display/sprd/sprd,sharkl3-dsi-host.yaml
> > > > > > > new file mode 100644
> > > > > > > index 000000000..d439f688f
> > > > > > > --- /dev/null
> > > > > > > +++
> > > > > >
> > > > b/Documentation/devicetree/bindings/display/sprd/sprd,sharkl3-dsi-host.yaml
> > > > > > > @@ -0,0 +1,102 @@
> > > > > > > +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> > > > > > > +%YAML 1.2
> > > > > > > +---
> > > > > > > +$id:
> > > > > > http://devicetree.org/schemas/display/sprd/sprd,sharkl3-dsi-host.yaml#
> > > > > > > +$schema: http://devicetree.org/meta-schemas/core.yaml#
> > > > > > > +
> > > > > > > +title: Unisoc MIPI DSI Controller
> > > > > > > +
> > > > > > > +maintainers:
> > > > > > > + - Kevin Tang <kevin.tang at unisoc.com>
> > > > > > > +
> > > > > > > +properties:
> > > > > > > + compatible:
> > > > > > > + const: sprd,sharkl3-dsi-host
> > > > > > > +
> > > > > > > + reg:
> > > > > > > + maxItems: 1
> > > > > > > +
> > > > > > > + interrupts:
> > > > > > > + maxItems: 2
> > > > > > > +
> > > > > > > + clocks:
> > > > > > > + minItems: 1
> > > > > > > +
> > > > > > > + clock-names:
> > > > > > > + items:
> > > > > > > + - const: clk_src_96m
> > > > > > > +
> > > > > > > + power-domains:
> > > > > > > + maxItems: 1
> > > > > > > +
> > > > > > > + ports:
> > > > > > > + type: object
> > > > > > > +
> > > > > > > + properties:
> > > > > > > + "#address-cells":
> > > > > > > + const: 1
> > > > > > > +
> > > > > > > + "#size-cells":
> > > > > > > + const: 0
> > > > > > > +
> > > > > > > + port at 0:
> > > > > > > + type: object
> > > > > > > + description:
> > > > > > > + A port node with endpoint definitions as defined in
> > > > > > > +
> > > > Documentation/devicetree/bindings/media/video-interfaces.txt.
> > > > > > > + That port should be the input endpoint, usually coming
> > > > from
> > > > > > > + the associated DPU.
> > > > > > > + port at 1:
> > > > > > > + type: object
> > > > > > > + description:
> > > > > > > + A port node with endpoint definitions as defined in
> > > > > > > +
> > > > Documentation/devicetree/bindings/media/video-interfaces.txt.
> > > > > > > + That port should be the output endpoint, usually output to
> > > > > > > + the associated panel.
> > > > > >
> > > > > > The DSI generic binding asks that peripherals that are controlled
> > > > > > through a DCS be a subnode of the MIPI-DSI bus, not through a port
> > > > > > endpoint.
> > > > > >
> > > > > Our DSI controller don't support DCS now...
> > > >
> > > > I'm not sure I follow you, you mentionned in the patch 4 that you were
> > > > testing for a device to be in command mode, how would that work without
> > > > DCS support?
> > > >
> > > Sorry, I see DCS as DSC, pls ignore my previous comments.
> > >
> > > dsi input node is display controller and dsi output node is panel,
> > > I still don't understand what it has to do with dcs? and it seems that
> > > other vendors also like this.
> > >
> > > can you help provide some cases?
> >
> > So the device tree is a tree organized through which bus controls which
> > device: Your DSI controller is accessed through a memory-mapped region
> > and is thus a child node of the main bus (I guess?) and then, since the
> > DSI panel is going to be controlled through the DSI controller and
> > MIPI-DCS, it needs to be a child of the display controller.
> Yeah, access DSI controller registers is through AHB bus.
>
> I'm a little confused, DSI panel node should be a child of the display
> controller?
If they are controlled through DSI, yes.
> I found a lot of cases are organized like this, we also do like it.
> https://elixir.bootlin.com/linux/v5.11.15/source/arch/arm/boot/dts/tegra114-dalmore.dts#L48
>
> >
> > This is exactly what is being described here:
> > https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/devicetree/bindings/display/mipi-dsi-bus.txt#n42
> >
> > The second port is thus not needed at all
> Yeah, dsi_out port is no need, should be detele.
> Besides, I also have a question, if out dsi-phy is separate driver(eg,
> dphy have it's own bus)
> dsi_out port should be "dphy_in"?
You could argue both, but phys are usually represented through the phys property.
Maxime
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