linux-kernel - Re: [PATCH v1] clk: Add devm_clk_{prepare,enable,prepare

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Date:   Mon, 25 Nov 2019 13:31:03 +0000
From:   Russell King - ARM Linux admin <linux@...linux.org.uk>
To:     Marc Gonzalez <marc.w.gonzalez@...e.fr>
Cc:     Stephen Boyd <sboyd@...nel.org>,
        Michael Turquette <mturquette@...libre.com>,
        linux-clk <linux-clk@...r.kernel.org>,
        Linux ARM <linux-arm-kernel@...ts.infradead.org>,
        LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v1] clk: Add devm_clk_{prepare,enable,prepare_enable}

On Mon, Nov 25, 2019 at 02:16:17PM +0100, Marc Gonzalez wrote:
> On 25/11/2019 13:52, Russell King - ARM Linux admin wrote:
> 
> > On Mon, Nov 25, 2019 at 01:46:51PM +0100, Marc Gonzalez wrote:
> > 
> >> On 15/07/2019 17:34, Marc Gonzalez wrote:
> >>
> >>> Provide devm variants for automatic resource release on device removal.
> >>> probe() error-handling is simpler, and remove is no longer required.
> >>>
> >>> Signed-off-by: Marc Gonzalez <marc.w.gonzalez@...e.fr>
> >>> ---
> >>>  Documentation/driver-model/devres.rst |  3 +++
> >>>  drivers/clk/clk.c                     | 24 ++++++++++++++++++++++++
> >>>  include/linux/clk.h                   |  8 ++++++++
> >>>  3 files changed, 35 insertions(+)
> >>>
> >>> diff --git a/Documentation/driver-model/devres.rst b/Documentation/driver-model/devres.rst
> >>> index 1b6ced8e4294..9357260576ef 100644
> >>> --- a/Documentation/driver-model/devres.rst
> >>> +++ b/Documentation/driver-model/devres.rst
> >>> @@ -253,6 +253,9 @@ CLOCK
> >>>    devm_clk_hw_register()
> >>>    devm_of_clk_add_hw_provider()
> >>>    devm_clk_hw_register_clkdev()
> >>> +  devm_clk_prepare()
> >>> +  devm_clk_enable()
> >>> +  devm_clk_prepare_enable()
> >>>  
> >>>  DMA
> >>>    dmaenginem_async_device_register()
> >>> diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
> >>> index c0990703ce54..5e85548357c0 100644
> >>> --- a/drivers/clk/clk.c
> >>> +++ b/drivers/clk/clk.c
> >>> @@ -914,6 +914,18 @@ int clk_prepare(struct clk *clk)
> >>>  }
> >>>  EXPORT_SYMBOL_GPL(clk_prepare);
> >>>  
> >>> +static void unprepare(void *clk)
> >>> +{
> >>> +	clk_unprepare(clk);
> >>> +}
> >>> +
> >>> +int devm_clk_prepare(struct device *dev, struct clk *clk)
> >>> +{
> >>> +	int rc = clk_prepare(clk);
> >>> +	return rc ? : devm_add_action_or_reset(dev, unprepare, clk);
> >>> +}
> >>> +EXPORT_SYMBOL_GPL(devm_clk_prepare);
> >>> +
> >>>  static void clk_core_disable(struct clk_core *core)
> >>>  {
> >>>  	lockdep_assert_held(&enable_lock);
> >>> @@ -1136,6 +1148,18 @@ int clk_enable(struct clk *clk)
> >>>  }
> >>>  EXPORT_SYMBOL_GPL(clk_enable);
> >>>  
> >>> +static void disable(void *clk)
> >>> +{
> >>> +	clk_disable(clk);
> >>> +}
> >>> +
> >>> +int devm_clk_enable(struct device *dev, struct clk *clk)
> >>> +{
> >>> +	int rc = clk_enable(clk);
> >>> +	return rc ? : devm_add_action_or_reset(dev, disable, clk);
> >>> +}
> >>> +EXPORT_SYMBOL_GPL(devm_clk_enable);
> >>> +
> >>>  static int clk_core_prepare_enable(struct clk_core *core)
> >>>  {
> >>>  	int ret;
> >>> diff --git a/include/linux/clk.h b/include/linux/clk.h
> >>> index 3c096c7a51dc..d09b5207e3f1 100644
> >>> --- a/include/linux/clk.h
> >>> +++ b/include/linux/clk.h
> >>> @@ -895,6 +895,14 @@ static inline void clk_restore_context(void) {}
> >>>  
> >>>  #endif
> >>>  
> >>> +int devm_clk_prepare(struct device *dev, struct clk *clk);
> >>> +int devm_clk_enable(struct device *dev, struct clk *clk);
> >>> +static inline int devm_clk_prepare_enable(struct device *dev, struct clk *clk)
> >>> +{
> >>> +	int rc = devm_clk_prepare(dev, clk);
> >>> +	return rc ? : devm_clk_enable(dev, clk);
> >>> +}
> >>> +
> >>>  /* clk_prepare_enable helps cases using clk_enable in non-atomic context. */
> >>>  static inline int clk_prepare_enable(struct clk *clk)
> >>>  {
> >>
> >> Thoughts? Comments?
> > 
> > These are part of the clk API rather than the CCF API, and belong in
> > drivers/clk/clk-devres.c.
> 
> I'm totally confused.
> 
> Are you saying that a hypothetical devm_clk_prepare() function should not be
> implemented in the same file as the "raw" clk_prepare() ?

The clk API and CCF are two different things.  I look after the clk API.
The CCF is an implementation of the clk API.  Do not introduce clk API
code in files that are CCF specific.

-- 
RMK's Patch system: https://www.armlinux.org.uk/developer/patches/
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