From: Conor Dooley <conor@kernel.org>
To: Svyatoslav Ryhel <clamor95@gmail.com>
Cc: Andrzej Hajda <andrzej.hajda@intel.com>,
Neil Armstrong <neil.armstrong@linaro.org>,
Robert Foss <rfoss@kernel.org>,
Laurent Pinchart <Laurent.pinchart@ideasonboard.com>,
Jonas Karlman <jonas@kwiboo.se>,
Jernej Skrabec <jernej.skrabec@gmail.com>,
Maarten Lankhorst <maarten.lankhorst@linux.intel.com>,
Maxime Ripard <mripard@kernel.org>,
Thomas Zimmermann <tzimmermann@suse.de>,
David Airlie <airlied@gmail.com>, Simona Vetter <simona@ffwll.ch>,
Rob Herring <robh@kernel.org>,
Krzysztof Kozlowski <krzk+dt@kernel.org>,
Conor Dooley <conor+dt@kernel.org>,
dri-devel@lists.freedesktop.org, devicetree@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH v1 1/2] dt-bindings: display: bridge: Document Solomon SSD2825
Date: Tue, 18 Feb 2025 17:09:29 +0000 [thread overview]
Message-ID: <20250218-thinly-passcode-f659d81cd5a4@spud> (raw)
In-Reply-To: <CAPVz0n1CpoAFvwwvoTOFQu4mgg57jCwS5W4GXCiUZ3eLEAdwZA@mail.gmail.com>
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On Fri, Feb 14, 2025 at 08:29:22AM +0200, Svyatoslav Ryhel wrote:
> чт, 13 лют. 2025 р. о 22:34 Conor Dooley <conor@kernel.org> пише:
> >
> > On Thu, Feb 13, 2025 at 03:56:04PM +0200, Svyatoslav Ryhel wrote:
> > > Add bindings for Solomon SSD2825 MIPI master bridge chip that connects an
> > > application processor with traditional parallel LCD interface and an LCD
> > > driver with MIPI slave interface. The SSD2825 supports both parallel RGB
> > > interface and serial SPI interface.
> > >
> > > Signed-off-by: Svyatoslav Ryhel <clamor95@gmail.com>
> > > ---
> > > .../display/bridge/solomon,ssd2825.yaml | 140 ++++++++++++++++++
> > > 1 file changed, 140 insertions(+)
> > > create mode 100644 Documentation/devicetree/bindings/display/bridge/solomon,ssd2825.yaml
> > >
> > > diff --git a/Documentation/devicetree/bindings/display/bridge/solomon,ssd2825.yaml b/Documentation/devicetree/bindings/display/bridge/solomon,ssd2825.yaml
> > > new file mode 100644
> > > index 000000000000..cd7ff971495c
> > > --- /dev/null
> > > +++ b/Documentation/devicetree/bindings/display/bridge/solomon,ssd2825.yaml
> > > @@ -0,0 +1,140 @@
> > > +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> > > +%YAML 1.2
> > > +---
> > > +$id: http://devicetree.org/schemas/display/bridge/solomon,ssd2825.yaml#
> > > +$schema: http://devicetree.org/meta-schemas/core.yaml#
> > > +
> > > +title: Solomon SSD2825 RGB to MIPI-DSI bridge
> > > +
> > > +maintainers:
> > > + - Svyatoslav Ryhel <clamor95@gmail.com>
> > > +
> > > +allOf:
> > > + - $ref: /schemas/spi/spi-peripheral-props.yaml#
> > > +
> > > +properties:
> > > + compatible:
> > > + const: solomon,ssd2825
> > > +
> > > + reg:
> > > + maxItems: 1
> > > +
> > > + reset-gpios: true
> > > +
> > > + dvdd-supply:
> > > + description: Regulator for 1.2V digital power supply.
> > > +
> > > + avdd-supply:
> > > + description: Regulator for 1.2V analog power supply.
> > > +
> > > + vddio-supply:
> > > + description: Regulator for 1.8V IO power supply.
> > > +
> > > + spi-max-frequency:
> > > + maximum: 1000000
> > > +
> > > + spi-cpha: true
> > > + spi-cpol: true
> >
> > Should these be required? Supplies should really be required too, since
> > the device probably cannot function without them?
> >
>
> No, since spi-* define mode in which device works. If both are present
> it is mode 3, if none it is mode 0.
>
> About supplies, device cannot work without power supply obviously, but
> often exact supplies are not known and I would like to not enforce
> someone to add random regulators just because they are mandatory.
If the device doesn't work without the supplies, the supplies should be
mandatory in the binding.
>
> > > + clocks:
> > > + maxItems: 1
> > > +
> > > + clock-names:
> > > + const: tx_clk
> >
> > Drop the _clk, since this cannot be anything else! clock-names isn't
> > really useful when you have just one, so I'd be inclined to say remove
> > it entirely...
> >
>
> TX_CLK is the name which datasheet refers to hence I have included
> clock name solely to have clear link between datasheet clock
> references and clock used here.
I think people will be able to make the leap between "tx_clk" and "tx".
>
> > > + solomon,hs-zero-delay-ns:
> > > + description:
> > > + HS zero delay period
> > > + default: 133
> > > +
> > > + solomon,hs-prep-delay-ns:
> > > + description:
> > > + HS prep delay period
> > > + default: 40
> >
> > Do these two have limits? Use maximum/minimum to set them if so.
> > Cheers,
> > Conor.
> >
>
> Datasheet does not specify limits actually, only defaults. I will try
> to calculate boundaries.
Hmm, that's interesting. I see in your driver that the eventual value
gets converted down to a u8? That should at least impose some sort of
limits I guess.
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next prev parent reply other threads:[~2025-02-18 17:09 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-02-13 13:56 [PATCH v1 0/2] drm: bridge: add ssd2825 RGB/DSI bridge support Svyatoslav Ryhel
2025-02-13 13:56 ` [PATCH v1 1/2] dt-bindings: display: bridge: Document Solomon SSD2825 Svyatoslav Ryhel
2025-02-13 20:34 ` Conor Dooley
2025-02-14 6:29 ` Svyatoslav Ryhel
2025-02-18 17:09 ` Conor Dooley [this message]
2025-02-13 13:56 ` [PATCH v1 2/2] drm: bridge: Add support for Solomon SSD2825 RGB/DSI bridge Svyatoslav Ryhel
2025-02-13 16:05 ` Dmitry Baryshkov
2025-02-13 16:08 ` Svyatoslav Ryhel
2025-02-15 3:48 ` kernel test robot
2025-02-15 8:31 ` kernel test robot
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