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From: "Shradha Todi" <shradha.t@samsung.com>
To: "'Manivannan Sadhasivam'" <manivannan.sadhasivam@linaro.org>
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	<pankaj.dubey@samsung.com>
In-Reply-To: <20240120150303.GB5405@thinkpad>
Subject: RE: [PATCH v3 1/2] clk: Provide managed helper to get and enable
 bulk clocks
Date: Wed, 24 Jan 2024 12:23:15 +0530
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	<20240120150303.GB5405@thinkpad>


> -----Original Message-----
> From: Manivannan Sadhasivam <manivannan.sadhasivam=40linaro.org>
> Sent: 20 January 2024 20:33
> To: Shradha Todi <shradha.t=40samsung.com>
> Cc: linux-clk=40vger.kernel.org; linux-kernel=40vger.kernel.org; linux-
> pci=40vger.kernel.org; linux-arm-kernel=40lists.infradead.org; linux-sams=
ung-
> soc=40vger.kernel.org; mturquette=40baylibre.com; sboyd=40kernel.org;
> jingoohan1=40gmail.com; lpieralisi=40kernel.org; kw=40linux.com; robh=40k=
ernel.org;
> bhelgaas=40google.com; krzysztof.kozlowski=40linaro.org;
> alim.akhtar=40samsung.com; linux=40armlinux.org.uk;
> m.szyprowski=40samsung.com
> Subject: Re: =5BPATCH v3 1/2=5D clk: Provide managed helper to get and en=
able bulk
> clocks
>=20
> On Wed, Jan 10, 2024 at 04:31:14PM +0530, Shradha Todi wrote:
> > Provide a managed devm_clk_bulk* wrapper to get and enable all bulk
> > clocks in order to simplify drivers that keeps all clocks enabled for
> > the time of driver operation.
> >
> > Suggested-by: Marek Szyprowski <m.szyprowski=40samsung.com>
> > Signed-off-by: Shradha Todi <shradha.t=40samsung.com>
> > ---
> >  drivers/clk/clk-devres.c =7C 41
> ++++++++++++++++++++++++++++++++++++++++
> >  include/linux/clk.h      =7C 25 ++++++++++++++++++++++++
> >  2 files changed, 66 insertions(+)
> >
> > diff --git a/drivers/clk/clk-devres.c b/drivers/clk/clk-devres.c index
> > 4fb4fd4b06bd..05b0ff4bc1d4 100644
> > --- a/drivers/clk/clk-devres.c
> > +++ b/drivers/clk/clk-devres.c
> > =40=40 -102,6 +102,7 =40=40
> EXPORT_SYMBOL_GPL(devm_clk_get_optional_enabled);
> >  struct clk_bulk_devres =7B
> >  	struct clk_bulk_data *clks;
> >  	int num_clks;
> > +	void (*exit)(int num_clks, const struct clk_bulk_data *clks);
> >  =7D;
> >
> >  static void devm_clk_bulk_release(struct device *dev, void *res) =40=
=40
> > -182,6 +183,46 =40=40 int __must_check devm_clk_bulk_get_all(struct dev=
ice
> > *dev,  =7D  EXPORT_SYMBOL_GPL(devm_clk_bulk_get_all);
> >
> > +static void devm_clk_bulk_release_all_enabled(struct device *dev,
> > +void *res) =7B
> > +	struct clk_bulk_devres *devres =3D res;
> > +
> > +	if (devres->exit)
> > +		devres->exit(devres->num_clks, devres->clks);
> > +
> > +	clk_bulk_put_all(devres->num_clks, devres->clks); =7D
> > +
> > +int __must_check devm_clk_bulk_get_all_enabled(struct device *dev,
> > +				  struct clk_bulk_data **clks, int *num_clks)
>=20
> What is the user supposed to do with =22num_clks=22 when you are already =
handling
> the enable part?
>=20

Since the initial clk_bulk_get_all was returning the num_clks value, the th=
ought was to maintain this
as the user might want to have a check in their driver whether x number of =
clocks were successfully
retrieved and enabled.

> > +=7B
> > +	struct clk_bulk_devres *devres;
> > +	int ret;
> > +
> > +	devres =3D devres_alloc(devm_clk_bulk_release_all_enabled,
> > +			      sizeof(*devres), GFP_KERNEL);
> > +	if (=21devres)
> > +		return -ENOMEM;
> > +
> > +	ret =3D clk_bulk_get_all(dev, &devres->clks);
> > +	if (ret > 0) =7B
> > +		*clks =3D devres->clks;
> > +		devres->num_clks =3D ret;
> > +		*num_clks =3D ret;
> > +		devres_add(dev, devres);
>=20
> If you move the statements inside this condition to the end of this funct=
ion, you
> could get rid of the exit() callback and directly use
> clk_bulk_disable_unprepare() in devm_clk_bulk_release_all_enabled().
>=20

Okay=21 I will change this in the next patchset as suggested

> > +	=7D else =7B
> > +		devres_free(devres);
> > +		return ret;
> > +	=7D
> > +
> > +	ret =3D clk_bulk_prepare_enable(devres->num_clks, *clks);
> > +	if (=21ret)
> > +		devres->exit =3D clk_bulk_disable_unprepare;
>=20
> Here you can just do clk_bulk_put_all() and devres_free() directly becaus=
e you
> know that the driver won't proceed after this error.
>=20
> - Mani
>=20

Thanks for the review, Mani. Will change this as suggested=21

> > +
> > +	return ret;
> > +=7D
> > +EXPORT_SYMBOL_GPL(devm_clk_bulk_get_all_enabled);
> > +
> >  static int devm_clk_match(struct device *dev, void *res, void *data)
> > =7B
> >  	struct clk **c =3D res;
> > diff --git a/include/linux/clk.h b/include/linux/clk.h index
> > 1ef013324237..bf3e9bee5754 100644
> > --- a/include/linux/clk.h
> > +++ b/include/linux/clk.h
> > =40=40 -438,6 +438,24 =40=40 int __must_check
> > devm_clk_bulk_get_optional(struct device *dev, int num_clks,  int
> __must_check devm_clk_bulk_get_all(struct device *dev,
> >  				       struct clk_bulk_data **clks);
> >
> > +/**
> > + * devm_clk_bulk_get_all_enabled - managed get multiple clk consumers =
and
> > + *					enable all clk
> > + * =40dev: device for clock =22consumer=22
> > + * =40clks: pointer to the clk_bulk_data table of consumer
> > + * =40num_clks: out parameter to store the number of clk_bulk_data
> > + *
> > + * Returns success (0) or negative errno.
> > + *
> > + * This helper function allows drivers to get several clk
> > + * consumers and enable all of them in one operation with management.
> > + * The clks will automatically be disabled and freed when the device
> > + * is unbound.
> > + */
> > +
> > +int __must_check devm_clk_bulk_get_all_enabled(struct device *dev,
> > +				struct clk_bulk_data **clks, int *num_clks);
> > +
> >  /**
> >   * devm_clk_get - lookup and obtain a managed reference to a clock pro=
ducer.
> >   * =40dev: device for clock =22consumer=22
> > =40=40 -960,6 +978,13 =40=40 static inline int __must_check
> devm_clk_bulk_get_all(struct device *dev,
> >  	return 0;
> >  =7D
> >
> > +static inline int __must_check devm_clk_bulk_get_all_enabled(struct de=
vice
> *dev,
> > +				struct clk_bulk_data **clks, int *num_clks) =7B
> > +
> > +	return 0;
> > +=7D
> > +
> >  static inline struct clk *devm_get_clk_from_child(struct device *dev,
> >  				struct device_node *np, const char *con_id)  =7B
> > --
> > 2.17.1
> >
>=20
> --
> =E0=AE=AE=E0=AE=A3=E0=AE=BF=E0=AE=B5=E0=AE=A3=E0=AF=8D=E0=AE=A3=E0=AE=A9=
=E0=AF=8D=20=E0=AE=9A=E0=AE=A4=E0=AE=BE=E0=AE=9A=E0=AE=BF=E0=AE=B5=E0=AE=AE=
=E0=AF=8D=0D=0A=0D=0A