Subject: [PATCH 1/3] clk: composite: Add fixed-rate support

From: [email-masked] (Emilio López)
Date: Tue, 09 Apr 2013 13:04:20 -0300

Hi Gregory,

El 09/04/13 12:41, Gregory CLEMENT escribi?:
> On 04/09/2013 03:48 PM, Emilio L?pez wrote:
>> This patchset adds fixed-rate support to the composite clock, allowing
>> us to register gatable oscillators.
>>
>> Signed-off-by: Emilio L??pez <[email-masked]>
>> ---
>>  drivers/clk/clk-composite.c  | 57 ++++++++++++++++++++++++++++++++++++++++----
>>  include/linux/clk-provider.h |  6 +++++
>>  2 files changed, 59 insertions(+), 4 deletions(-)
>>
>> diff --git a/drivers/clk/clk-composite.c b/drivers/clk/clk-composite.c
>> index 097dee4..5416e1d 100644
>> --- a/drivers/clk/clk-composite.c
>> +++ b/drivers/clk/clk-composite.c
>> @@ -43,8 +43,8 @@ static int clk_composite_set_parent(struct clk_hw *hw, u8 index)
>>  	return mux_ops->set_parent(mux_hw, index);
>>  }
>>  
>> -static unsigned long clk_composite_recalc_rate(struct clk_hw *hw,
>> -					    unsigned long parent_rate)
>> +static unsigned long clk_composite_recalc_rate_div(struct clk_hw *hw,
>> +						   unsigned long parent_rate)
>>  {
>>  	struct clk_composite *composite = to_clk_composite(hw);
>>  	const struct clk_ops *div_ops = composite->div_ops;
>> @@ -55,6 +55,18 @@ static unsigned long clk_composite_recalc_rate(struct clk_hw *hw,
>>  	return div_ops->recalc_rate(div_hw, parent_rate);
>>  }
>>  
>> +static unsigned long clk_composite_recalc_rate_fixed(struct clk_hw *hw,
>> +						     unsigned long parent_rate)
>> +{
>> +	struct clk_composite *composite = to_clk_composite(hw);
>> +	const struct clk_ops *fixed_ops = composite->fixed_ops;
>> +	struct clk_hw *fixed_hw = composite->fixed_hw;
>> +
>> +	fixed_hw->clk = hw->clk;
>> +
>> +	return fixed_ops->recalc_rate(fixed_hw, parent_rate);
>> +}
>> +
>>  static long clk_composite_round_rate(struct clk_hw *hw, unsigned long rate,
>>  				  unsigned long *prate)
>>  {
>> @@ -112,11 +124,12 @@ static void clk_composite_disable(struct clk_hw *hw)
>>  	gate_ops->disable(gate_hw);
>>  }
>>  
>> -struct clk *clk_register_composite(struct device *dev, const char *name,
>> +static struct clk *_clk_register_composite(struct device *dev, const char *name,
>>  			const char **parent_names, int num_parents,
>>  			struct clk_hw *mux_hw, const struct clk_ops *mux_ops,
>>  			struct clk_hw *div_hw, const struct clk_ops *div_ops,
>>  			struct clk_hw *gate_hw, const struct clk_ops *gate_ops,
>> +			struct clk_hw *fixed_hw, const struct clk_ops *fixed_ops,
>>  			unsigned long flags)
>>  {
>>  	struct clk *clk;
>> @@ -158,7 +171,7 @@ struct clk *clk_register_composite(struct device *dev, const char *name,
>>  
>>  		composite->div_hw = div_hw;
>>  		composite->div_ops = div_ops;
>> -		clk_composite_ops->recalc_rate = clk_composite_recalc_rate;
>> +		clk_composite_ops->recalc_rate = clk_composite_recalc_rate_div;
>>  		clk_composite_ops->round_rate = clk_composite_round_rate;
>>  		clk_composite_ops->set_rate = clk_composite_set_rate;
>>  	}
>> @@ -177,6 +190,17 @@ struct clk *clk_register_composite(struct device *dev, const char *name,
>>  		clk_composite_ops->disable = clk_composite_disable;
>>  	}
>>  
>> +	if (fixed_hw && fixed_ops) {
>> +		if (!fixed_ops->recalc_rate) {
>> +			clk = ERR_PTR(-EINVAL);
>> +			goto err;
>> +		}
>> +
>> +		composite->fixed_hw = fixed_hw;
>> +		composite->fixed_ops = fixed_ops;
>> +		clk_composite_ops->recalc_rate = clk_composite_recalc_rate_fixed;
>> +	}
>> +
>>  	init.ops = clk_composite_ops;
>>  	composite->hw.init = &init;
>>  
>> @@ -193,9 +217,34 @@ struct clk *clk_register_composite(struct device *dev, const char *name,
>>  	if (composite->gate_hw)
>>  		composite->gate_hw->clk = clk;
>>  
>> +	if (composite->fixed_hw)
>> +		composite->fixed_hw->clk = clk;
>> +
>>  	return clk;
>>  
>>  err:
>>  	kfree(composite);
>>  	return clk;
>>  }
>> +
>> +struct clk *clk_register_composite(struct device *dev, const char *name,
>> +			const char **parent_names, int num_parents,
>> +			struct clk_hw *mux_hw, const struct clk_ops *mux_ops,
>> +			struct clk_hw *div_hw, const struct clk_ops *div_ops,
>> +			struct clk_hw *gate_hw, const struct clk_ops *gate_ops,
>> +			unsigned long flags)
>> +{
>> +	return _clk_register_composite(dev, name, parent_names, num_parents,
>> +				       mux_hw, mux_ops, div_hw, div_ops,
>> +				       gate_hw, gate_ops, NULL, NULL, flags);
>> +}
>> +
>> +struct clk *clk_register_gatable_osc(struct device *dev, const char *name,
>> +			struct clk_hw *fixed_hw, const struct clk_ops *fixed_ops,
>> +			struct clk_hw *gate_hw, const struct clk_ops *gate_ops,
>> +			unsigned long flags)
>> +{
>> +	return _clk_register_composite(dev, name, NULL, 0, NULL, NULL,
>> +				       NULL, NULL, gate_hw, gate_ops,
>> +				       fixed_hw, fixed_ops, flags);
>> +}
> 
> I think you should remove all this chunk, and made your change in
> clk_register_composite() instead of using _clk_register_composite(). I don't
> think it is a good thing that each kind of composition was declared here.
> 
> The way you composed your clock should be done by each driver.
> 
> I understand that you didn't want to break the existing driver, but in this case
> it is better to do the modification in the driver to follow the new API.
> The change is pretty trivial and can be automated by using spatch aka semantic patch
> aka coccinelle. But as this API is very new you could also do it by hand, however I
> didn't find any occurrences of this function in the branches clk-next or clk-for-3.10.
> I only found one occurrence in  the  in patch "clk: tegra30: Convert clk out to
> composite clk" from Prashant Gaikwad. Unfortunately I didn't find a tree with this
> commit applied.

Originally I thought of doing it that way, but I couldn't find any
actual usage of clk-composite, so I played it safe and avoided breaking
the API. If there are no patches queued for 3.10 using it and Prashant
agrees, I will rename _clk_register_composite -> clk_register_composite
and drop the wrappers.

@Prashant: are there any patches queued for 3.10 using this API?