From mboxrd@z Thu Jan 1 00:00:00 1970 From: Thierry Reding Subject: Re: [PATCH v3 4/6] DEV: CLK: add function to check the using clock name of driver. Date: Mon, 26 Nov 2018 16:26:37 +0100 Message-ID: <20181126152637.GB19710@ulmo> References: <20181125162118.GA5358@arx-s1> Reply-To: thierry.reding-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="7iMSBzlTiPOCCT2k" Return-path: Sender: linux-sunxi-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org Content-Disposition: inline In-Reply-To: <20181125162118.GA5358@arx-s1> List-Post: , List-Help: , List-Archive: , List-Unsubscribe: , To: Hao Zhang Cc: robh+dt-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org, mark.rutland-5wv7dgnIgG8@public.gmane.org, maxime.ripard-LDxbnhwyfcJBDgjK7y7TUQ@public.gmane.org, wens-jdAy2FN1RRM@public.gmane.org, mturquette-rdvid1DuHRBWk0Htik3J/w@public.gmane.org, sboyd-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org, linux-gpio-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org, linux-pwm-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-sunxi-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org List-Id: devicetree@vger.kernel.org --7iMSBzlTiPOCCT2k Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline On Mon, Nov 26, 2018 at 12:21:18AM +0800, Hao Zhang wrote: > In some situation we want to check clock whether is we want > and after the driver been probed use to change different clock source. > > Signed-off-by: Hao Zhang > --- > drivers/clk/clk.c | 6 ++++++ > include/linux/clk-provider.h | 1 + > 2 files changed, 7 insertions(+) This doesn't seem right. If you're going to change to to a different clock source anyway, why would you even want to know what it was set before that? Isn't that completely irrelevant? But if you really need this, perhaps a combination of clk_get() and clk_is_match() would be a better approach? Perhaps best to let Mike and Stephen share their feelings about this kind of API. > diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c > index d31055a..3d2c2cd 100644 > --- a/drivers/clk/clk.c > +++ b/drivers/clk/clk.c > @@ -3466,6 +3466,12 @@ static int devm_clk_hw_match(struct device *dev, void *res, void *data) > return hw == data; > } > > +bool devm_clk_name_match(struct clk *clk, const char *string) > +{ > + return match_string(&clk->con_id, 1, string) == 0; > +} > +EXPORT_SYMBOL_GPL(devm_clk_name_match); Also, there's nothing about this that would be device-managed, so the devm_ prefix on the function name is misleading. > /** > * devm_clk_unregister - resource managed clk_unregister() > * @clk: clock to unregister > diff --git a/include/linux/clk-provider.h b/include/linux/clk-provider.h > index 08b1aa7..5cd2eed 100644 > --- a/include/linux/clk-provider.h > +++ b/include/linux/clk-provider.h > @@ -764,6 +764,7 @@ struct clk *devm_clk_register(struct device *dev, struct clk_hw *hw); > int __must_check clk_hw_register(struct device *dev, struct clk_hw *hw); > int __must_check devm_clk_hw_register(struct device *dev, struct clk_hw *hw); > > +bool devm_clk_name_match(struct clk *clk, const char *string); > void clk_unregister(struct clk *clk); > void devm_clk_unregister(struct device *dev, struct clk *clk); You use this from clock consumers, so clk-provider.h is not the right place for it. Also, you'll want to add a dummy implementation for the case where CONFIG_COMMON_CLK is not set. Thierry --7iMSBzlTiPOCCT2k--