[alsa-devel] [PATCH] clk: x86: add "mclk" alias for Baytrail/Cherrytrail

[Pierre-Louis Bossart]

On 2/14/17 1:04 PM, Stephen Boyd wrote:
> On 02/12, Pierre-Louis Bossart wrote:
>> Due to timing requirements, TI and Conexant manage the audio
>> reference clock from their ASoC codec drivers using the "mclk"
>> string. This patch adds a default alias to "pmc_plt_clk_3" to
>> avoid Intel-specific tests in those codec drivers and use code
>> as-is.
>> "pmc_plt_clk_3" is used exclusively for audio on all known
>> Baytrail/CherryTrail designs and is e.g. routed on the MCLK
>> (pin 26) of the MinnowBoardMAX Turbot LSE connector.
>>
>> Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart at linux.intel.com>
>> ---
>>
>> Notes:
>>     This patch only applies on top of linux-next or clk-next, the
>>     previous clk-related patches are not yet merged in the audio
>>     trees
>>
>>  drivers/clk/x86/clk-pmc-atom.c | 2 ++
>>  1 file changed, 2 insertions(+)
>>
>> diff --git a/drivers/clk/x86/clk-pmc-atom.c b/drivers/clk/x86/clk-pmc-atom.c
>> index 2b60577..ba00d27 100644
>> --- a/drivers/clk/x86/clk-pmc-atom.c
>> +++ b/drivers/clk/x86/clk-pmc-atom.c
>> @@ -340,6 +340,8 @@ static int plt_clk_probe(struct platform_device *pdev)
>>
>>  	plt_clk_free_parent_names_loop(parent_names, data->nparents);
>>
>> +	clk_add_alias("mclk", dev_name(&pdev->dev), "pmc_plt_clk_3", NULL);
>> +
>
> This leaks an alias when the driver is removed. Honestly,
> clk_add_alias() doesn't work well because of that problem. Can
> you just add another lookup with the pointer you already have
> instead of passing a NULL device to do a global lookup?

This is a builtin driver that cannot be configured as a module, is the 
leaked alias problematic?
I don't mind trying something different but I am not familiar enough 
with the framework to understand what you are hinting at. Are you 
suggesting a change on the last parameter such as:

clk_add_alias("mclk", dev_name(&pdev->dev), "pmc_plt_clk_3", &pdev->dev)

Thanks!
-Pierre