[U-Boot] [PATCH v2 1/2] core: add uclass_get_device_by_phandle_id() api

[Dr. Philipp Tomsich]

Kever,

> On 26 Feb 2018, at 04:07, Kever Yang <kever.yang at rock-chips.com> wrote:
> 
> Hi Simon,
> 
> 
> On 02/25/2018 11:54 PM, Simon Glass wrote:
>> Hi Kever,
>> 
>> On 23 February 2018 at 19:08, Kever Yang <kever.yang at rock-chips.com> wrote:
>>> Hi Simon,
>>> 
>>> 
>>> On 02/12/2018 10:35 PM, Simon Glass wrote:
>>>> Hi Kever,
>>>> 
>>>> On 8 February 2018 at 19:56, Kever Yang <kever.yang at rock-chips.com> wrote:
>>>>> Add api for who can not get phandle from a device property.
>>>> Can you please add a motivation to the commit message? It is not
>>>> obvious to me when this function would be used.
>>> Here is the example why I need this, see the dts node here:
>>> lvds at ff2e0000 {
>>>    ...
>>>    rockchip,grf = <&grf>;
>>>    port {
>>>        port at 0 {
>>>            endpoint at 0 {
>>>                remote-endpoint = <&vopl_out_lvds>;
>>>            }
>>>        }
>>>    }
>>> }
>>> 
>>> We can only get 'grf' udevice by uclass_get_device_by_phandle(),
>>> but we not able to get udevice 'vopl_out_lvds', other driver like
>>> rockchip pinctrl
>>> also need to get udevice by a phandle which is not one of direct property of
>>> another device node.
>> OK I see. This sort of info is useful in the commit message. It helps
>> to know two things about a patch:
>> 
>> - why it is needed
>> - what it does
>> 
>> In this case see rk_display_init() for how it handles the
>> 'remote-endpoint' property. I think it would be better to have
>> something like:
>> 
>> ofnode ofnode_lookup_phandle(ofnode node, const char *prop_name);
> Yes, this is enough for "remote-endpoint" case, but not for pinctrl case:
> 1199         pinctrl: pinctrl {
> 2095                 pwm0
> {                                                         
> 2096                         pwm0_pin: pwm0-pin
> {                                   
> 2097                                 rockchip,pins
> =                                
> 2098                                         <0 RK_PB7 RK_FUNC_1
> &pcfg_pull_none>;  
> 2099                        
> };                                                     
> 2100                 };    
> 
>    I think ofnode_lookup_phandle() still not able to find node for
> 'pcfg_pull_none’.

I had to convert rk_vop to livetree last week to fix a regression on HDMI for our
RK3399-Q7.  In doing so, I created some code to “walk the tree to find a parent
with a given uclass) … this had me introduce an new ofnode_get_parent() function.

Anatolij merged this on the weekend and it’s on Tom’s master already.

Best,
Philipp.

> 
> Thanks,
> - Kever
>> 
>> This should meet your needs without needing to decoding the phandle
>> property in the caller.
>> 
>> Regards,
>> Simon