From mboxrd@z Thu Jan  1 00:00:00 1970
From: james.hogan@imgtec.com (James Hogan)
Date: Mon, 20 May 2013 10:13:11 +0100
Subject: [PATCH v3 2/4] clk: add support for clock reparent on set_rate
In-Reply-To: <20130520041508.GA27676@codeaurora.org>
References: <1368625263-23136-1-git-send-email-james.hogan@imgtec.com>
 <1368625263-23136-3-git-send-email-james.hogan@imgtec.com>
 <20130520041508.GA27676@codeaurora.org>
Message-ID: <5199E927.3080500@imgtec.com>
To: linux-arm-kernel@lists.infradead.org
List-Id: linux-arm-kernel.lists.infradead.org

On 20/05/13 05:15, Stephen Boyd wrote:
> Noticed another minor thing. I'm working on the set rate and
> parent at the same time op on top of this patch series. Hopefully
> have something soon.
> 
> On 05/15, James Hogan wrote:
>> @@ -1181,6 +1242,11 @@ static void clk_change_rate(struct clk *clk)
>>  
>>  	old_rate = clk->rate;
>>  
>> +	/* set parent */
>> +	if (clk->new_parent && clk->new_parent != clk->parent)
>> +		__clk_set_parent_no_recalc(clk, clk->new_parent,
>> +					   clk->new_parent_index);
>> +
> 
> This check here for new_parent != clk->parent ...
> 
>> @@ -1451,6 +1501,27 @@ static int __clk_set_parent(struct clk *clk, struct clk *parent, u8 p_index)
>>  	return 0;
>>  }
>>  
>> +static int __clk_set_parent_no_recalc(struct clk *clk, struct clk *parent,
>> +				      u8 p_index)
>> +{
>> +	int ret = 0;
>> +
>> +	if (clk->parent == parent)
>> +		goto out;
> 
> causes this to never be true, so we can probably drop it.
> 
>> +
>> +	/* only re-parent if the clock is not in use */
>> +	ret = __clk_set_parent(clk, parent, p_index);
>> +	if (ret)
>> +		goto out;
>> +
>> +	/* reparent, but don't propagate rate recalculation downstream */
>> +	clk_reparent(clk, parent);
>> +	clk_debug_reparent(clk, parent);
>> +
>> +out:
>> +	return ret;
>> +}
> 
> Also, we never check the return code so it's sort of useless.
> 

Hi Stephen,

Well spotted, and as you pointed it privately it can use
__clk_set_parent() instead of __clk_set_parent_no_recalc() now :)

Thanks
James