From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 3946E25F988; Mon, 22 Jun 2026 13:16:12 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1782134173; cv=none; b=SKxNpef5vt5xvf3VSpLFH5kS4gQrqVqm23QdkA2oSkhQ48+R+DjrR16NkpSmoTZ1hpWa9mosMENxGtljWG9GmgKweI8oYmhKcu13La2LqGqWLEOEboD6rSmMbgSi8zyyKBpFzpTh+/B0a9FBIV2zUMllj9TRkM7kIjFo/CL9g5k= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1782134173; c=relaxed/simple; bh=8lDXcn20mPRtH3kbeh0YUIpkuvxTrJakxs7O1Gu1DQI=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=V0nRDH7w2xWx5Ap4FGwq2DLwz7xYKy1beygJdk1WL2MPrYT3ZFJjE9z0FShZGNcnVn+zy8uzqJlOHolJ7nZYlIPy3UcjqswinL9VY1GEJWAIYJzg6lkqYqtQU0vQay8oVSofNaD2KsepwVW+yGoidtk6xGWkDF+BWYZGRTq8azI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=IA0VbonM; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="IA0VbonM" Received: by smtp.kernel.org (Postfix) with ESMTPSA id DEEEB1F000E9; Mon, 22 Jun 2026 13:16:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1782134171; bh=xKdZBYhzStO/Z8jg+KHo0lknzhp9aWoASlmT29VDKzU=; h=Date:Subject:To:Cc:References:From:In-Reply-To; b=IA0VbonMekQxUdhVX4XoSqzqppZ9OEp6d8BrQ85/aNurpZ3IN40pxZmcJMOpoz6Qx R7PGgBfyqd3EyEVDLYFsVH2LswJ8GD4Jhv9tsmsRWTyhnoKIX8M6Tdt0Zic2Rb6TnJ rW/5qjpGOlymzdUIX/YMZ14fTnBQUS62RzmShRt7xplryanaA0G/kD/0kD6FbDMQIh dkuc0gRKwkak515V7Up17Qizsd3ATWTmQti25uOY600ufDFmwY4LWHPTAwUbB5+7LX xPeUa6SDq2z5HVDKWlD44RUZK8OeUCjDPn/mQYCF55i4UlVaR8x5rR2ZIYeSr1VB0X zBRYxg8Hnueuw== Message-ID: <7aeccd3e-fb0a-4147-b76b-0cd019b1dfb0@kernel.org> Date: Mon, 22 Jun 2026 15:16:03 +0200 Precedence: bulk X-Mailing-List: devicetree@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 1/4] dt-bindings: brige: lt9611c: add port-select property for LT9611C To: Laurent Pinchart , Mohit Dsor Cc: Andrzej Hajda , Neil Armstrong , Robert Foss , Jonas Karlman , Jernej Skrabec , Luca Ceresoli , David Airlie , Simona Vetter , Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , Rob Herring , Krzysztof Kozlowski , Conor Dooley , Vinod Koul , dri-devel@lists.freedesktop.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, boss@oss.qualcomm.com, qc-display-maintainer@oss.qualcomm.com References: <20260611-lt9611-b4-send-v1-0-42abbcd3bb1e@oss.qualcomm.com> <20260611-lt9611-b4-send-v1-1-42abbcd3bb1e@oss.qualcomm.com> <20260611-burrowing-fervent-serpent-584cac@quoll> <20260622120801.GA3899757@killaraus.ideasonboard.com> From: Krzysztof Kozlowski Content-Language: en-US Autocrypt: addr=krzk@kernel.org; keydata= xsFNBFVDQq4BEAC6KeLOfFsAvFMBsrCrJ2bCalhPv5+KQF2PS2+iwZI8BpRZoV+Bd5kWvN79 cFgcqTTuNHjAvxtUG8pQgGTHAObYs6xeYJtjUH0ZX6ndJ33FJYf5V3yXqqjcZ30FgHzJCFUu JMp7PSyMPzpUXfU12yfcRYVEMQrmplNZssmYhiTeVicuOOypWugZKVLGNm0IweVCaZ/DJDIH gNbpvVwjcKYrx85m9cBVEBUGaQP6AT7qlVCkrf50v8bofSIyVa2xmubbAwwFA1oxoOusjPIE J3iadrwpFvsZjF5uHAKS+7wHLoW9hVzOnLbX6ajk5Hf8Pb1m+VH/E8bPBNNYKkfTtypTDUCj NYcd27tjnXfG+SDs/EXNUAIRefCyvaRG7oRYF3Ec+2RgQDRnmmjCjoQNbFrJvJkFHlPeHaeS BosGY+XWKydnmsfY7SSnjAzLUGAFhLd/XDVpb1Een2XucPpKvt9ORF+48gy12FA5GduRLhQU vK4tU7ojoem/G23PcowM1CwPurC8sAVsQb9KmwTGh7rVz3ks3w/zfGBy3+WmLg++C2Wct6nM Pd8/6CBVjEWqD06/RjI2AnjIq5fSEH/BIfXXfC68nMp9BZoy3So4ZsbOlBmtAPvMYX6U8VwD TNeBxJu5Ex0Izf1NV9CzC3nNaFUYOY8KfN01X5SExAoVTr09ewARAQABzSVLcnp5c3p0b2Yg S296bG93c2tpIDxrcnprQGtlcm5lbC5vcmc+wsGPBBMBCgA5AhsDBgsJCAcDAgYVCAIJCgsE FgIDAQIeAQIXgBYhBJvQfg4MUfjVlne3VBuTQ307QWKbBQJp2mE8AAoJEBuTQ307QWKbeaIP /ihHTkTW4KsN/DQ945JJbyu5tI0J80Wue7QyyLPglyKfhgb5cLLNPpOC8cCIJsc7+W3i2P38 s2c1cOH6CYGE7E9ur3Vfme8NW2S2I/Z8VC7bZnzyS23wT17LrsdS/qCpx4o8U+pt/xdXDKph EGRYrIEmMpUWvyYzyYKGIe25FtaayIIKpq8eZYyFcp2f/sG5IkOW5uZzHPMPdcm87jU7fyuQ rAU2vx9r+ulUfQ/q9Z2roC/ode3l7t2pN7BCBCsUDp6JCrUyZrtT1e7EbA0ZRP3aOBNk2P2E DQOgJGjGdO5Yx2Y9LFtltu6JbsBJHi1syGRX3AtQYOMc4Y1WGoeZJmMlvKj2ZqqXNkcWi2DS IQEWB0uW6CqFsBBIMGDa+6OzdaVO/uAVXWDWml02Men3CILdI1MbVjoh8ECqYUY7OQ+JJvNN vnliuq5WM3Ghd3jg/LZZrxXjdIginRHFQCjIJYLKpLZWm1/iDFedcfzqRNYmTtqscdCNHW41 oT3Z7BmO9xwdjuwBS6nmS6JJwkbf5Ot2QR4pB/DRU7ZwjT1qHe+9r9gF32wXVQatHNGK/VVu sfwOnkdxCWkp/qb2gdQRmZh+SedStWshigH6sNfuHBloF/q+hjMRc8b2m326OZdrbSHwY1Sz vti8Hn7n8NjdHO9LKB7BIdjkA9DA5WsqOuVCzsFNBFVDXDQBEADNkrQYSREUL4D3Gws46JEo Z9HEQOKtkrwjrzlw/tCmqVzERRPvz2Xg8n7+HRCrgqnodIYoUh5WsU84N03KlLueMNsWLJBv BaubYN4JuJIdRr4dS4oyF1/fQAQPHh8Thpiz0SAZFx6iWKB7Qrz3OrGCjTPcW6eiOMheesVS 5hxietSmlin+SilmIAPZHx7n242u6kdHOh+/SyLImKn/dh9RzatVpUKbv34eP1wAGldWsRxb f3WP9pFNObSzI/Bo3kA89Xx2rO2roC+Gq4LeHvo7ptzcLcrqaHUAcZ3CgFG88CnA6z6lBZn0 WyewEcPOPdcUB2Q7D/NiUY+HDiV99rAYPJztjeTrBSTnHeSBPb+qn5ZZGQwIdUW9YegxWKvX XHTwB5eMzo/RB6vffwqcnHDoe0q7VgzRRZJwpi6aMIXLfeWZ5Wrwaw2zldFuO4Dt91pFzBSO IpeMtfgb/Pfe/a1WJ/GgaIRIBE+NUqckM+3zJHGmVPqJP/h2Iwv6nw8U+7Yyl6gUBLHFTg2h YnLFJI4Xjg+AX1hHFVKmvl3VBHIsBv0oDcsQWXqY+NaFahT0lRPjYtrTa1v3tem/JoFzZ4B0 p27K+qQCF2R96hVvuEyjzBmdq2esyE6zIqftdo4MOJho8uctOiWbwNNq2U9pPWmu4vXVFBYI GmpyNPYzRm0QPwARAQABwsF2BBgBCgAgAhsMFiEEm9B+DgxR+NWWd7dUG5NDfTtBYpsFAmna YUkACgkQG5NDfTtBYptX+BAApg32CkxwNucNEi8WfWA8oKkW0y8YDuY6ORMo9FWNGiT/OTy0 vyJrLocrpn86zwfjVp+eCrssPYh8eqJfnWqmYv6ACQtHPYzPZQ3mSo8H97Z01oUxITzCxpXm ZkLgPIqtDPcC2E3dPM/fVxcyowM8XsaMA9wcsaUYrta8toOq2b9tKcjleKMfMrm0gQ9u7wUc QbLkwj6TCLOwucb07GXzLTNF9PZmaDUpKAZjMjmrW+le+SFvQbhamx0rxLWPR0NWntXpbCn+ +ACch03p/JyTBVktxFsFyCt7pTPE1kEaeuXBTe/a2D9iQvRxRW19LvuO2e59/u1wYUiH/orz wbIC2S4dBsPAPihL3ztOU1yE86GPyQtSE0kU+/7snnLt4QGi6PChf3t5gnNjAzjUUovO8rgI c+5yN5heq5loYHgK6OQ9OlHzsPHO9e9MOQcKlFycs1pyijFGzDwdNUm/SchK8iWT2QApTx4A K9bCVaboTA2T77QYkRcRJYSsO1alGX0ome/hMLD1daXlkrNUp1HWa3K4iytLRXjCSIorWiGs n+q3krnpXu3TFkA8qtOFZMdnIiFuiq1yLT8hptsV5xh1TA2nsVvSYiaCr3q4s4BKjS/KrLDb qoxzw8ISjdUp4pA85vb6YLCmb39NgidD+7PmAr65lBNveIFynTgsja1rRQ4= In-Reply-To: <20260622120801.GA3899757@killaraus.ideasonboard.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 22/06/2026 14:08, Laurent Pinchart wrote: > On Mon, Jun 22, 2026 at 05:31:36PM +0530, Mohit Dsor wrote: >> On Thu, Jun 11, 2026 at 12:40:38PM +0200, Krzysztof Kozlowski wrote: >>> On Thu, Jun 11, 2026 at 02:44:56AM +0530, Mohit Dsor wrote: >>>> Add a new optional `lontium,port-select` property to describe the DSI >>>> input port configuration for the LT9611C variant, which supports >>>> single-port (A or B) and dual-port (A+B) operation. >>>> >>>> This property allows explicitly selecting the active DSI input port(s): >>>> 0 = port A (default) >>>> 1 = port B >>>> 2 = ports A and B (dual-port) >>>> >>>> Signed-off-by: Mohit Dsor >>>> --- >>>> .../devicetree/bindings/display/bridge/lontium,lt9611.yaml | 13 +++++++++++++ >>>> 1 file changed, 13 insertions(+) >>>> >>>> diff --git a/Documentation/devicetree/bindings/display/bridge/lontium,lt9611.yaml b/Documentation/devicetree/bindings/display/bridge/lontium,lt9611.yaml >>>> index e0821a63d9d7..77220f893bf8 100644 >>>> --- a/Documentation/devicetree/bindings/display/bridge/lontium,lt9611.yaml >>>> +++ b/Documentation/devicetree/bindings/display/bridge/lontium,lt9611.yaml >>>> @@ -41,6 +41,17 @@ properties: >>>> vcc-supply: >>>> description: Regulator for 3.3V IO power. >>>> >>>> + lontium,port-select: >>>> + $ref: /schemas/types.yaml#/definitions/uint32 >>>> + enum: [0, 1, 2] >>>> + default: 0 >>>> + description: | >>>> + Selects which DSI input port(s) the bridge uses. Only relevant for >>>> + the lontium,lt9611c compatible. >>>> + 0 = PORT_SELECT_A - single DSI port A (default) >>>> + 1 = PORT_SELECT_B - single DSI port B >>>> + 2 = PORT_SELECT_AB - dual DSI ports A and B >>> >>> Why graph is not enough? Seems exactly duplicating the graph ports. >>> >>> Best regards, >>> Krzysztof >>> >> Hi Krzysztof, >> >> Thanks for the review. >> >> The graph describes the physical connectivity between endpoints, >> however it does not fully capture the internal mode of operation of >> the LT9611C. This variant supports multiple functional configurations >> (single-port A, single-port B, or dual-port A+B), which affect how the >> hardware internally combines or selects DSI inputs. >> >> In particular: >> - The graph can describe connections to both ports, but it does not >> indicate whether the device should operate in single-port or dual-port >> aggregation mode. >> - For single-port use, both ports may be described in DT for board >> consistency, while the driver still needs to know which port is >> actively selected. >> - Dual-port mode requires explicit configuration even when both >> endpoints are present in the graph. > > If both modes of operation are possible on a given board, then it sounds > like the mode should be selected at runtime, not hardcoded in the device > tree. Yeah. Especially "while the driver still needs to know which port is actively selected" for a case when DT already clearly defines which ports are available, feels like 100% runtime decision, e.g. based on what is actually plugged into the connector. Best regards, Krzysztof