Subject: Re: [PATCH net-next v8 2/9] i2c: designware: Add driver support for Wangxun 10Gb NIC

From: Jarkko Nikula <[email-masked]>
Date: Wed, 17 May 2023 11:49:03 +0300

On 5/15/23 12:24, [email-masked] wrote:
> Mon, May 15, 2023 at 02:31:53PM +0800, Jiawen Wu kirjoitti:
>> Wangxun 10Gb ethernet chip is connected to Designware I2C, to communicate
>> with SFP.
>>
>> Introduce the property "snps,i2c-platform" to match device data for Wangxun
>> in software node case. Since IO resource was mapped on the ethernet driver,
>> add a model quirk to get regmap from parent device.
>>
>> The exists IP limitations are dealt as workarounds:
>> - IP does not support interrupt mode, it works on polling mode.
>> - Additionally set FIFO depth address the chip issue.
> 
> ...
> 
>>   	dev->flags = (uintptr_t)device_get_match_data(&pdev->dev);
>> +	if (device_property_present(&pdev->dev, "snps,i2c-platform"))
>> +		dev->flags |= MODEL_WANGXUN_SP;
> 
> What I meant here is to use device_property_present() _iff_ you have decided to
> go with the _vendor-specific_ property name.
> 
> Otherwise it should be handled differently, i.e. with reading the actual value
> of that property. Hence it should correspond the model enum, which you need to
> declare in the Device Tree bindings before use.
> 
> So, either
> 
> 	if (device_property_present(&pdev->dev, "wx,..."))
> 		dev->flags |= MODEL_WANGXUN_SP;
> 
> or
> 
> 	if ((dev->flags & MODEL_MASK) == MODEL_NONE) {
> 	// you now have to distinguish that there is no model set in driver data
> 		u32 model;
> 
> 		ret = device_property_read_u32(dev, "snps,i2c-platform");
> 		if (ret) {
> 			...handle error...
> 		}
> 		dev->flags |= model
> 
I'm not a device tree expert but I wonder would it be possible somehow 
combine this and compatible properties in dw_i2c_of_match[]? They set 
model flag for MODEL_MSCC_OCELOT and MODEL_BAIKAL_BT1.

Then I'm thinking is "snps,i2c-platform" descriptive enough name for a 
model and does it confuse with "snps,designware-i2c" compatible property?