Re: [Resend Patch v6] driver/clk/clk-si5338: Add common clock framework driver for si5338

[York Sun <yorksun@freescale.com>]

On 10/16/2015 02:31 PM, Stephen Boyd wrote:
> On 10/16, York Sun wrote:
>>
>>
>> On 10/09/2015 05:09 PM, Stephen Boyd wrote:
>>> On 10/09, York Sun wrote:
>>>> +/*
>>>> + * To support multiple si5338 chips, we cannot use devm_clk_get because
>>>> + * each chip has its own clock sources. If device tree is not used,
>>>> + * platform driver should provide these clocks. Let the clocks be freed
>>>> + * automatically when device is unbound. We implement our own devm_of_clk_get.
>>>> + */
>>>> +static void devm_of_clk_release(struct device *dev, void *res)
>>>> +{
>>>> +	clk_put(*(struct clk **)res);
>>>> +}
>>>> +
>>>> +static struct clk *devm_of_clk_get(struct device *dev, struct device_node *np,
>>>
>>> What is this? I don't get it at all.
>>
>> Maybe you can help me on this.
>> We have two ways to get parent clock. One is from device tree, the other is from
>> platform data. When the clock is from platform data, the consumer gets the clock
>> and passes it. The clock will be put by the consumer as well. When the parent
>> clock comes from device tree, what I am trying to do is to call of_clk_get(),
>> without worrying about to call clk_put() later when the driver is removed, so I
>> don't have to know where the parent clock data came from.
>>
> 
> This driver should always use clk_get() then. If the mode is
> device tree, clk_get() will lookup the clock in DT and get it
> from there. If the mode is platform data, then we'll fallback to
> the clkdev method of clk_get(), which will look for a clk_lookup
> created for the device calling clk_get() + the connection id that
> was provided by the lookup creator. This driver should always
> call clk_put() on the clock when it's done with it, regardless of
> DT vs. platform data.
> 

For the platform data mode, I think it is up to the consumer to get and put the
parent clocks. The current code is to pass (struct clk *) pointers as parent
clocks. Are you suggesting to pass the name of parent clocks?

York