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;
MIME-Version: 1.0
References: <20221018-clk-range-checks-fixes-v3-0-9a1358472d52@cerno.tech> <20221018-clk-range-checks-fixes-v3-34-9a1358472d52@cerno.tech>
In-Reply-To: <20221018-clk-range-checks-fixes-v3-34-9a1358472d52@cerno.tech>
From:   Linus Walleij <linus.walleij@linaro.org>
Date:   Tue, 4 Apr 2023 15:44:25 +0200
Message-ID: <CACRpkdYcHaUBG1qFVb=mi40SyEp=VyYzPmxNn-Zrmpqs1QH+kQ@mail.gmail.com>
Subject: Re: [PATCH v3 34/65] clk: ux500: prcmu: Add a determine_rate hook
To:     Maxime Ripard <maxime@cerno.tech>
Cc:     Michael Turquette <mturquette@baylibre.com>,
        Stephen Boyd <sboyd@kernel.org>,
        =?UTF-8?Q?Andreas_F=C3=A4rber?= <afaerber@suse.de>,
        Manivannan Sadhasivam <mani@kernel.org>,
        Nicolas Ferre <nicolas.ferre@microchip.com>,
        Alexandre Belloni <alexandre.belloni@bootlin.com>,
        Claudiu Beznea <claudiu.beznea@microchip.com>,
        Max Filippov <jcmvbkbc@gmail.com>,
        Charles Keepax <ckeepax@opensource.cirrus.com>,
        Richard Fitzgerald <rf@opensource.cirrus.com>,
        Maxime Coquelin <mcoquelin.stm32@gmail.com>,
        Alexandre Torgue <alexandre.torgue@foss.st.com>,
        Luca Ceresoli <luca.ceresoli@bootlin.com>,
        David Lechner <david@lechnology.com>,
        Sekhar Nori <nsekhar@ti.com>, Abel Vesa <abelvesa@kernel.org>,
        Shawn Guo <shawnguo@kernel.org>,
        Sascha Hauer <s.hauer@pengutronix.de>,
        Pengutronix Kernel Team <kernel@pengutronix.de>,
        Fabio Estevam <festevam@gmail.com>,
        NXP Linux Team <linux-imx@nxp.com>,
        Matthias Brugger <matthias.bgg@gmail.com>,
        Geert Uytterhoeven <geert+renesas@glider.be>,
        Dinh Nguyen <dinguyen@kernel.org>,
        Peter De Schrijver <pdeschrijver@nvidia.com>,
        Prashant Gaikwad <pgaikwad@nvidia.com>,
        Thierry Reding <thierry.reding@gmail.com>,
        Jonathan Hunter <jonathanh@nvidia.com>,
        Ulf Hansson <ulf.hansson@linaro.org>,
        David Airlie <airlied@gmail.com>,
        Daniel Vetter <daniel@ffwll.ch>, Vinod Koul <vkoul@kernel.org>,
        Kishon Vijay Abraham I <kishon@kernel.org>,
        Alessandro Zummo <a.zummo@towertech.it>,
        Chen-Yu Tsai <wens@csie.org>,
        Jernej Skrabec <jernej.skrabec@gmail.com>,
        Samuel Holland <samuel@sholland.org>,
        Liam Girdwood <lgirdwood@gmail.com>,
        Mark Brown <broonie@kernel.org>,
        Jaroslav Kysela <perex@perex.cz>,
        Takashi Iwai <tiwai@suse.com>,
        Paul Cercueil <paul@crapouillou.net>,
        Orson Zhai <orsonzhai@gmail.com>,
        Baolin Wang <baolin.wang@linux.alibaba.com>,
        Chunyan Zhang <zhang.lyra@gmail.com>,
        linux-clk@vger.kernel.org, linux-kernel@vger.kernel.org,
        AngeloGioacchino Del Regno 
        <angelogioacchino.delregno@collabora.com>,
        linux-arm-kernel@lists.infradead.org,
        linux-actions@lists.infradead.org, patches@opensource.cirrus.com,
        linux-stm32@st-md-mailman.stormreply.com,
        linux-mediatek@lists.infradead.org,
        linux-renesas-soc@vger.kernel.org, linux-tegra@vger.kernel.org,
        dri-devel@lists.freedesktop.org, linux-phy@lists.infradead.org,
        linux-rtc@vger.kernel.org, linux-sunxi@lists.linux.dev,
        alsa-devel@alsa-project.org, linux-mips@vger.kernel.org
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable
Precedence: bulk

On Tue, Apr 4, 2023 at 2:45=E2=80=AFPM Maxime Ripard <maxime@cerno.tech> wr=
ote:

> The UX500 PRCMU "clkout" clock implements a mux with a set_parent hook,
> but doesn't provide a determine_rate implementation.
>
> This is a bit odd, since set_parent() is there to, as its name implies,
> change the parent of a clock. However, the most likely candidate to
> trigger that parent change is a call to clk_set_rate(), with
> determine_rate() figuring out which parent is the best suited for a
> given rate.

Not even that.

The parent is selected from the second cell of the device tree
specifier, and the divisor from the third cell. See:
Documentation/devicetree/bindings/clock/stericsson,u8500-clks.yaml

So this definitely does not reparent.

Yours,
Linus Walleij