[PATCH v3 4/6] thermal: sun8i: add syscon register access code

[Krzysztof Kozlowski]

On 28/11/2023 08:50, Chen-Yu Tsai wrote:
> On Tue, Nov 28, 2023 at 3:43 PM Krzysztof Kozlowski
> <krzysztof.kozlowski at linaro.org> wrote:
>>
>> On 28/11/2023 01:58, Andre Przywara wrote:
>>>
>>> +static struct regmap *sun8i_ths_get_syscon_regmap(struct device_node *node)
>>> +{
>>> +     struct device_node *syscon_node;
>>> +     struct platform_device *syscon_pdev;
>>> +     struct regmap *regmap = NULL;
>>> +
>>> +     syscon_node = of_parse_phandle(node, "syscon", 0);
>>
>> Nope. For the 100th time, this cannot be generic.
>>
>>> +     if (!syscon_node)
>>> +             return ERR_PTR(-ENODEV);
>>> +
>>> +     syscon_pdev = of_find_device_by_node(syscon_node);
>>> +     if (!syscon_pdev) {
>>> +             /* platform device might not be probed yet */
>>> +             regmap = ERR_PTR(-EPROBE_DEFER);
>>> +             goto out_put_node;
>>> +     }
>>> +
>>> +     /* If no regmap is found then the other device driver is at fault */
>>> +     regmap = dev_get_regmap(&syscon_pdev->dev, NULL);
>>> +     if (!regmap)
>>> +             regmap = ERR_PTR(-EINVAL);
>>
>> Aren't you open-coding existing API to get regmap from syscon?
> 
> Not really. This is to get a regmap exported by the device. Syscon's regmap
> is not tied to the device at all.

I am talking about open-coding existing API. Look at syscon.h.

> 
> With this scheme a device to could export just enough registers for the
> consumer to use, instead of the whole address range.
> 
> We do this in the R40 clock controller as well, which has some bits that
> tweak the ethernet controllers RGMII delay...

Not related.

> 
> 
> ChenYu

Best regards,
Krzysztof