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 65C1F289809; Wed, 13 Aug 2025 18:20:04 +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=1755109206; cv=none; b=k1FV6nRMNvIEkKvGHuL6qTmRzffRlQ3xLJx7KYdjKqkKP5N4aXnEPy1tKvQHP4aC+JOd+zx8YmNx0iH6LM0CpvfVtIS/nsUugRZZmXsjPp/VsSSbg/n5FFncsV7/R9aTURvQn3pOa/kHwr+jlwRicbmXTsRGh02B28gd89WYDrc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1755109206; c=relaxed/simple; bh=fx2taVZ5xjW8Do9nHaFsVYCdHcr+JOY5ZQch8MkH4BI=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=JzhrWGxD44o+IxK+Q6SuOmgMg4bQpTFj4gcrP8jAb3kaBOOrh4YuZ/D7sSWS9dS5vsrcYtB7LgvIlVPZExMFC4cIFyZtxBDbVZAfOTHBDgJscFD49c1LSkigafgKMJWoNqCIKHNMRcaPlyi3AZLOMPHltv5hFVn7oZauExP5DSg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=KvpBCAZv; 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="KvpBCAZv" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 813F4C4CEEF; Wed, 13 Aug 2025 18:19:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1755109204; bh=fx2taVZ5xjW8Do9nHaFsVYCdHcr+JOY5ZQch8MkH4BI=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=KvpBCAZv+uSlob2VReCQpMJE9J4RjQU7GmjcREdhPTpNa5BhMj+hdfFj1NLn3S2fv bmcuoq3rY0B9WFIQXbFKsoEyemNG8usUQsNniNzNgiHWXn/b57MxI5QPPurr9Zt6fY yICPkAPBznwoeFHxd3auZvwvH3o9ATcxm9VqSbmUGYF6HIG3FUa5EH2PRxE/BZ+q89 GAUOYAsllld0KCzTeeiJoD/IqNYJofcEu76FuSbQ7nt5IRwFKF6FDUUTOAhAOYHakH 6VkWSH97LPe9i4m0zr17O1uNwhU/02xo1Nf4Qe5ZtjxhALaWD2Az8yRUBIPrK0DKsQ sYkDcJedwsCtw== Message-ID: Date: Wed, 13 Aug 2025 20:19:57 +0200 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [RFC PATCH 2/3] drm/imagination: fix clock control on the J722S To: Michael Walle , Frank Binns , Matt Coster , Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , David Airlie , Simona Vetter , Rob Herring , Krzysztof Kozlowski , Conor Dooley , Nishanth Menon , Vignesh Raghavendra , Tero Kristo Cc: dri-devel@lists.freedesktop.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Stephan Gerhold , Abel Vesa , Bjorn Andersson , Konrad Dybcio , Stephen Boyd References: <20250716134717.4085567-1-mwalle@kernel.org> <20250716134717.4085567-3-mwalle@kernel.org> From: Krzysztof Kozlowski Content-Language: en-US Autocrypt: addr=krzk@kernel.org; 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charset=UTF-8 Content-Transfer-Encoding: 7bit On 16/07/2025 15:47, Michael Walle wrote: > The J722S won't let you set the clock frequency if there is no device > using it. Thus, the assigned-clocks property won't work per se. > > As a workaround, set the clock again during the probing of the driver. > > Signed-off-by: Michael Walle > --- > drivers/gpu/drm/imagination/pvr_device.c | 9 +++++++++ > 1 file changed, 9 insertions(+) > > diff --git a/drivers/gpu/drm/imagination/pvr_device.c b/drivers/gpu/drm/imagination/pvr_device.c > index 8b9ba4983c4c..e7a7cc1bdf93 100644 > --- a/drivers/gpu/drm/imagination/pvr_device.c > +++ b/drivers/gpu/drm/imagination/pvr_device.c > @@ -16,6 +16,7 @@ > > #include > #include > +#include > #include > #include > #include > @@ -641,6 +642,14 @@ pvr_device_init(struct pvr_device *pvr_dev) > if (err) > return err; > > + /* Set any 'assigned-clocks' properties again. This is a workaround for > + * the clock handling on k3 platforms. There, one cannot set the clock > + * frequency until there is at least one (enabled) user if it. > + */ > + err = of_clk_set_defaults(drm_dev->dev->of_node, true); > + if (err) > + return err; +Cc Abel, Bjorn, Konrad, Stephan G. and Stephen B., Interesting stuff. This touches a bit similar problems we have (and had) for Qualcomm Display PHYs, where assigned-clock-parents were called too early - before the block (PHY) is being enabled. The workaround we implemented so far was - last patch hook in: https://web.git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=80dd5911cbfdc2f6ae904341d41a7a8bd8cc546c I know Stephan G. is working on something better, so probably he will Cc you once this is ready. Best regards, Krzysztof