Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
Date:   Mon, 7 Nov 2022 10:56:53 +0000
From:   Charles Keepax <ckeepax@opensource.cirrus.com>
To:     Maxime Ripard <maxime@cerno.tech>
CC:     Stephen Boyd <sboyd@kernel.org>,
        Maxime Coquelin <mcoquelin.stm32@gmail.com>,
        Chen-Yu Tsai <wens@csie.org>, Daniel Vetter <daniel@ffwll.ch>,
        Nicolas Ferre <nicolas.ferre@microchip.com>,
        Thierry Reding <thierry.reding@gmail.com>,
        Jaroslav Kysela <perex@perex.cz>,
        Shawn Guo <shawnguo@kernel.org>,
        Fabio Estevam <festevam@gmail.com>,
        Ulf Hansson <ulf.hansson@linaro.org>,
        Claudiu Beznea <claudiu.beznea@microchip.com>,
        Michael Turquette <mturquette@baylibre.com>,
        Dinh Nguyen <dinguyen@kernel.org>,
        Paul Cercueil <paul@crapouillou.net>,
        Chunyan Zhang <zhang.lyra@gmail.com>,
        Manivannan Sadhasivam <mani@kernel.org>,
        Andreas =?iso-8859-1?Q?F=E4rber?= <afaerber@suse.de>,
        Jonathan Hunter <jonathanh@nvidia.com>,
        Abel Vesa <abelvesa@kernel.org>,
        Alessandro Zummo <a.zummo@towertech.it>,
        Peter De Schrijver <pdeschrijver@nvidia.com>,
        Orson Zhai <orsonzhai@gmail.com>,
        Alexandre Torgue <alexandre.torgue@foss.st.com>,
        Prashant Gaikwad <pgaikwad@nvidia.com>,
        Liam Girdwood <lgirdwood@gmail.com>,
        Alexandre Belloni <alexandre.belloni@bootlin.com>,
        Samuel Holland <samuel@sholland.org>,
        Matthias Brugger <matthias.bgg@gmail.com>,
        Richard Fitzgerald <rf@opensource.cirrus.com>,
        Vinod Koul <vkoul@kernel.org>,
        NXP Linux Team <linux-imx@nxp.com>,
        Sekhar Nori <nsekhar@ti.com>,
        Kishon Vijay Abraham I <kishon@kernel.org>,
        Linus Walleij <linus.walleij@linaro.org>,
        Takashi Iwai <tiwai@suse.com>,
        David Airlie <airlied@gmail.com>,
        Luca Ceresoli <luca.ceresoli@bootlin.com>,
        Jernej Skrabec <jernej.skrabec@gmail.com>,
        Pengutronix Kernel Team <kernel@pengutronix.de>,
        Baolin Wang <baolin.wang@linux.alibaba.com>,
        David Lechner <david@lechnology.com>,
        Sascha Hauer <s.hauer@pengutronix.de>,
        Mark Brown <broonie@kernel.org>,
        Max Filippov <jcmvbkbc@gmail.com>,
        Geert Uytterhoeven <geert+renesas@glider.be>,
        <linux-stm32@st-md-mailman.stormreply.com>,
        <alsa-devel@alsa-project.org>,
        <linux-mediatek@lists.infradead.org>,
        <linux-phy@lists.infradead.org>, <linux-mips@vger.kernel.org>,
        <linux-renesas-soc@vger.kernel.org>,
        <linux-actions@lists.infradead.org>, <linux-clk@vger.kernel.org>,
        AngeloGioacchino Del Regno 
        <angelogioacchino.delregno@collabora.com>,
        <patches@opensource.cirrus.com>, <linux-tegra@vger.kernel.org>,
        <linux-rtc@vger.kernel.org>,
        <linux-arm-kernel@lists.infradead.org>,
        <linux-sunxi@lists.linux.dev>, <linux-kernel@vger.kernel.org>,
        <dri-devel@lists.freedesktop.org>
Subject: Re: [PATCH v2 65/65] clk: Warn if we register a mux without
 determine_rate
Message-ID: <20221107105653.GE10437@ediswmail.ad.cirrus.com>
References: <20221018-clk-range-checks-fixes-v2-0-f6736dec138e@cerno.tech>
 <20221018-clk-range-checks-fixes-v2-65-f6736dec138e@cerno.tech>
MIME-Version: 1.0
Content-Type: text/plain; charset="us-ascii"
Content-Disposition: inline
In-Reply-To: <20221018-clk-range-checks-fixes-v2-65-f6736dec138e@cerno.tech>
User-Agent: Mutt/1.5.21 (2010-09-15)
Precedence: bulk

On Fri, Nov 04, 2022 at 02:18:22PM +0100, Maxime Ripard wrote:
> The determine_rate hook allows to select the proper parent and its rate
> for a given clock configuration. On another hand, set_parent is there to
> change the parent of a mux.
> 
> Some clocks provide a set_parent hook but don't implement
> determine_rate. In such a case, set_parent is pretty much useless since
> the clock framework will always assume the current parent is to be used,
> and we will thus never change it.
> 
> This situation can be solved in two ways:
>   - either we don't need to change the parent, and we thus shouldn't
>     implement set_parent;
>   - or we don't want to change the parent, in this case we should set
>     CLK_SET_RATE_NO_REPARENT;
>   - or we're missing a determine_rate implementation.
> 
> The latter is probably just an oversight from the driver's author, and
> we should thus raise their awareness about the fact that the current
> state of the driver is confusing.
> 
> It's not clear at this point how many drivers are affected though, so
> let's make it a warning instead of an error for now.
> 

Commit message could probably use updated to make the new state
of the chain.

Thanks,
Charles