linux-kernel - Re: [PATCH v3 1/2] clk: Provide managed helper to get and enable bulk clocks

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Date: Wed, 24 Jan 2024 14:13:13 +0530
From: 'Manivannan Sadhasivam' <manivannan.sadhasivam@...aro.org>
To: Shradha Todi <shradha.t@...sung.com>
Cc: linux-clk@...r.kernel.org, linux-kernel@...r.kernel.org,
	linux-pci@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
	linux-samsung-soc@...r.kernel.org, mturquette@...libre.com,
	sboyd@...nel.org, jingoohan1@...il.com, lpieralisi@...nel.org,
	kw@...ux.com, robh@...nel.org, bhelgaas@...gle.com,
	krzysztof.kozlowski@...aro.org, alim.akhtar@...sung.com,
	linux@...linux.org.uk, m.szyprowski@...sung.com,
	pankaj.dubey@...sung.com
Subject: Re: [PATCH v3 1/2] clk: Provide managed helper to get and enable
 bulk clocks

On Wed, Jan 24, 2024 at 12:23:15PM +0530, Shradha Todi wrote:
> 
> 
> > -----Original Message-----
> > From: Manivannan Sadhasivam <manivannan.sadhasivam@...aro.org>
> > Sent: 20 January 2024 20:33
> > To: Shradha Todi <shradha.t@...sung.com>
> > Cc: linux-clk@...r.kernel.org; linux-kernel@...r.kernel.org; linux-
> > pci@...r.kernel.org; linux-arm-kernel@...ts.infradead.org; linux-samsung-
> > soc@...r.kernel.org; mturquette@...libre.com; sboyd@...nel.org;
> > jingoohan1@...il.com; lpieralisi@...nel.org; kw@...ux.com; robh@...nel.org;
> > bhelgaas@...gle.com; krzysztof.kozlowski@...aro.org;
> > alim.akhtar@...sung.com; linux@...linux.org.uk;
> > m.szyprowski@...sung.com
> > Subject: Re: [PATCH v3 1/2] clk: Provide managed helper to get and enable bulk
> > clocks
> > 
> > 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@...sung.com>
> > > Signed-off-by: Shradha Todi <shradha.t@...sung.com>
> > > ---
> > >  drivers/clk/clk-devres.c | 41
> > ++++++++++++++++++++++++++++++++++++++++
> > >  include/linux/clk.h      | 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
> > > @@ -102,6 +102,7 @@
> > EXPORT_SYMBOL_GPL(devm_clk_get_optional_enabled);
> > >  struct clk_bulk_devres {
> > >  	struct clk_bulk_data *clks;
> > >  	int num_clks;
> > > +	void (*exit)(int num_clks, const struct clk_bulk_data *clks);
> > >  };
> > >
> > >  static void devm_clk_bulk_release(struct device *dev, void *res) @@
> > > -182,6 +183,46 @@ int __must_check devm_clk_bulk_get_all(struct device
> > > *dev,  }  EXPORT_SYMBOL_GPL(devm_clk_bulk_get_all);
> > >
> > > +static void devm_clk_bulk_release_all_enabled(struct device *dev,
> > > +void *res) {
> > > +	struct clk_bulk_devres *devres = res;
> > > +
> > > +	if (devres->exit)
> > > +		devres->exit(devres->num_clks, devres->clks);
> > > +
> > > +	clk_bulk_put_all(devres->num_clks, devres->clks); }
> > > +
> > > +int __must_check devm_clk_bulk_get_all_enabled(struct device *dev,
> > > +				  struct clk_bulk_data **clks, int *num_clks)
> > 
> > What is the user supposed to do with "num_clks" when you are already handling
> > the enable part?
> > 
> 
> Since the initial clk_bulk_get_all was returning the num_clks value, the thought 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.
> 

IIUC, the returned clock count is only used for enabling or disabling the
clocks later. Since you are already handling it inside this API, I do not see a
necessity to return the count.

- Mani

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