From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 5CEF41B0F06; Mon, 25 Nov 2024 15:07:02 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1732547222; cv=none; b=XX9+hwSao+Lh9Nkvllci3Xjn6cwsDCape3rZc+R1NWZ0HC1eiaBRxBqjUkV8wxNxg9lHfl0w6c03VbQwQSDoeYzSPhSrn2NtEY3Z2n/ktFa+WdipnNNcnfQ2NJ5YdPNQQx3xJuKyvSWgDMN+iWXOrZFF3EY5M6+qN78qJovAx18= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1732547222; c=relaxed/simple; bh=GuYBNacdFjyx0Mbh71rlmpj4hWJscIplgCjbtQear9M=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=HF/9zDOwAB+DCa5D1RImun9627zP65z3V7dJ1RuvBjqYHRpvyFfiOk862Dyalf7y9zf+k7ibzYjK1ZVh0KAm3Ra1O+xWElVvxriXXoW++3OyUlNdG66+73j4fs2TJRu0aFDDRn0zH3v8EKpnQQYaDo4dIrPrEZVSZ03OsGsoTtM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=s0txlxm5; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="s0txlxm5" Received: by smtp.kernel.org (Postfix) with ESMTPSA id F2476C4CECE; Mon, 25 Nov 2024 15:06:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1732547221; bh=GuYBNacdFjyx0Mbh71rlmpj4hWJscIplgCjbtQear9M=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=s0txlxm5DH7fkuXmCbMHdJjxanaPqrwHzWGzZFXZW6E3BhyPVe58RB2DouMmfP/fJ OFcdUjnR+J/qci2PU1eM0AdDDgy27trkSXLLjSkoGWwotkFDNuikqRJEIFUK/gjHGb C3DyokQDGuXRqaI09iTwTNFSDSEDJfO5/a1/lLdGuEgUapgYTgrUHJoRbLX9YgrujE fTS1L1lz9/SoGJ736FeA+QURaeAYtMr6IfT8iaGnUpL0oG2wpMTeoJd0FW9RO8GsVR brIRceOMBJhYYZGeKoMW4qE7aM6mkHrKWcUAcxuIE6ix1cHoSRKZpAynk1TVe9VYEA SWwCO+v5GusKA== Message-ID: Date: Mon, 25 Nov 2024 16:06:54 +0100 Precedence: bulk X-Mailing-List: asahi@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 3/5] gpu: drm: adp: Add a backlight driver for the Summit LCD To: Nick Chan , fnkl.kernel@gmail.com, Hector Martin , Sven Peter , Alyssa Rosenzweig , Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , David Airlie , Simona Vetter , Rob Herring , Krzysztof Kozlowski , Conor Dooley , Neil Armstrong , Jessica Zhang , asahi@lists.linux.dev Cc: linux-arm-kernel@lists.infradead.org, dri-devel@lists.freedesktop.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org References: <20241124-adpdrm-v1-0-3191d8e6e49a@gmail.com> <20241124-adpdrm-v1-3-3191d8e6e49a@gmail.com> <3a6fb7fd-eb3d-428b-a37c-f04d81e7fbd0@gmail.com> From: Krzysztof Kozlowski Content-Language: en-US Autocrypt: addr=krzk@kernel.org; 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charset=UTF-8 Content-Transfer-Encoding: 7bit On 25/11/2024 16:03, Nick Chan wrote: >>> +static int summit_probe(struct mipi_dsi_device *dsi) >>> +{ >>> + struct backlight_properties props = { 0 }; >>> + struct device *dev = &dsi->dev; >>> + struct summit_data *panel; >>> + >>> + panel = devm_kzalloc(dev, sizeof(*panel), GFP_KERNEL); >>> + if (!panel) >>> + return -ENOMEM; >>> + >>> + mipi_dsi_set_drvdata(dsi, panel); >>> + panel->dsi = dsi; >>> + >>> + int ret = device_property_read_u32(dev, "max-brightness", &props.max_brightness); >> That's an undocumented property, which suggests you did not test your DTS. > > Actually, testing the DTS would not have caught this issue. For more > context, If you mean that property is not in your DTS, then right, it would not be caught. But otherwise it would. Anyway, I pointed out testing as helping tool for your development, just like building with clang W=1 will spare you some review comments or bugs. > all summit panels found in touch bar have a max brightness of 255, but the > summit panel in Apple A11 devices like the iPhone X is latter found to have > a max brightness of 2047. > > However, A11 cannot be properly supported right now due to not having a > driver > for the DART IOMMU. > > In the meantime, max-brightness could documented and be made required, > and the > default 255 brightness could be removed. BTW, max-brightness is a property of backlight, not panel, I think. Best regards, Krzysztof