linux-kernel - Re: [RFC 1/2] clk: Allow overriding generic ops for clocks

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Message-id: <1416903050.5023.28.camel@AMDC1943>
Date:	Tue, 25 Nov 2014 09:10:50 +0100
From:	Krzysztof Kozlowski <k.kozlowski@...sung.com>
To:	Mike Turquette <mturquette@...aro.org>
Cc:	Sylwester Nawrocki <s.nawrocki@...sung.com>,
	Tomasz Figa <tomasz.figa@...il.com>,
	Kukjin Kim <kgene@...nel.org>, linux-kernel@...r.kernel.org,
	linux-samsung-soc@...r.kernel.org,
	linux-arm-kernel@...ts.infradead.org,
	Javier Martinez Canillas <javier.martinez@...labora.co.uk>,
	Vivek Gautam <gautam.vivek@...sung.com>,
	Kevin Hilman <khilman@...nel.org>
Subject: Re: [RFC 1/2] clk: Allow overriding generic ops for clocks

On pon, 2014-11-24 at 17:34 -0800, Mike Turquette wrote:
> Quoting Krzysztof Kozlowski (2014-11-24 07:18:31)
> > For clocks depending on some other clock domain one may want to perform
> > specific ops before actual enable/disable of gate clock. Allow such case
> > by accepting supplied ops in new exported function:
> > clk_register_gate_ops().
> 
> If you are not going to use the gate_ops, why use the gate clock at all?
> You can create a platform-specific clock type which uses the ops you
> specify.

Actually I want to use gate_ops (and as much as possible from current
code) but I need to encapsulate gate_ops calls in other enable/disable
of other clock. In 2nd patch:
 
+static int audss_clk_gate_enable(struct clk_hw *hw)
+{
+       int ret;
+
+       if (!IS_ERR(pll_in))
+               clk_prepare_enable(pll_in);
+       ret = clk_gate_ops.enable(hw);
+       if (!IS_ERR(pll_in))
+               clk_disable_unprepare(pll_in);
+
+       return ret;
+}

Other idea is to add some kind of dependency between clocks... but
wait... there is already parent-child dependency. However these audss
clocks need two parents :) 

Best regards,
Krzysztof

> 
> Regards,
> Mike
> 
> > 
> > Signed-off-by: Krzysztof Kozlowski <k.kozlowski@...sung.com>
> > ---
> >  drivers/clk/clk-gate.c       | 16 +++++++++++++---
> >  include/linux/clk-provider.h |  5 +++++
> >  2 files changed, 18 insertions(+), 3 deletions(-)
> > 
> > diff --git a/drivers/clk/clk-gate.c b/drivers/clk/clk-gate.c
> > index 51fd87fb7ba6..51802af2d9e7 100644
> > --- a/drivers/clk/clk-gate.c
> > +++ b/drivers/clk/clk-gate.c
> > @@ -117,11 +117,12 @@ EXPORT_SYMBOL_GPL(clk_gate_ops);
> >   * @bit_idx: which bit in the register controls gating of this clock
> >   * @clk_gate_flags: gate-specific flags for this clock
> >   * @lock: shared register lock for this clock
> > + * @ops: clk_ops to use for this clock
> >   */
> > -struct clk *clk_register_gate(struct device *dev, const char *name,
> > +struct clk *clk_register_gate_ops(struct device *dev, const char *name,
> >                 const char *parent_name, unsigned long flags,
> >                 void __iomem *reg, u8 bit_idx,
> > -               u8 clk_gate_flags, spinlock_t *lock)
> > +               u8 clk_gate_flags, spinlock_t *lock, const struct clk_ops *ops)
> >  {
> >         struct clk_gate *gate;
> >         struct clk *clk;
> > @@ -142,7 +143,7 @@ struct clk *clk_register_gate(struct device *dev, const char *name,
> >         }
> >  
> >         init.name = name;
> > -       init.ops = &clk_gate_ops;
> > +       init.ops = ops;
> >         init.flags = flags | CLK_IS_BASIC;
> >         init.parent_names = (parent_name ? &parent_name: NULL);
> >         init.num_parents = (parent_name ? 1 : 0);
> > @@ -161,4 +162,13 @@ struct clk *clk_register_gate(struct device *dev, const char *name,
> >  
> >         return clk;
> >  }
> > +EXPORT_SYMBOL_GPL(clk_register_gate_ops);
> > +
> > +struct clk *clk_register_gate(struct device *dev, const char *name,
> > +               const char *parent_name, unsigned long flags,
> > +               void __iomem *reg, u8 bit_idx,
> > +               u8 clk_gate_flags, spinlock_t *lock)
> > +{
> > +       return clk_register_gate_ops(dev, name, parent_name, flags, reg, bit_idx, clk_gate_flags, lock, &clk_gate_ops);
> > +}
> >  EXPORT_SYMBOL_GPL(clk_register_gate);
> > diff --git a/include/linux/clk-provider.h b/include/linux/clk-provider.h
> > index be21af149f11..6cfc77a9f339 100644
> > --- a/include/linux/clk-provider.h
> > +++ b/include/linux/clk-provider.h
> > @@ -290,11 +290,16 @@ struct clk_gate {
> >  #define CLK_GATE_HIWORD_MASK           BIT(1)
> >  
> >  extern const struct clk_ops clk_gate_ops;
> > +struct clk *clk_register_gate_ops(struct device *dev, const char *name,
> > +               const char *parent_name, unsigned long flags,
> > +               void __iomem *reg, u8 bit_idx,
> > +               u8 clk_gate_flags, spinlock_t *lock, const struct clk_ops *ops);
> >  struct clk *clk_register_gate(struct device *dev, const char *name,
> >                 const char *parent_name, unsigned long flags,
> >                 void __iomem *reg, u8 bit_idx,
> >                 u8 clk_gate_flags, spinlock_t *lock);
> >  
> > +
> >  struct clk_div_table {
> >         unsigned int    val;
> >         unsigned int    div;
> > -- 
> > 1.9.1
> > 

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