Re: [PATCH] net: add regs attribute to phy device for user diagnose

[David Miller <davem@davemloft.net>]

From: Florian Fainelli <f.fainelli@gmail.com>
Date: Mon, 16 Jan 2017 12:22:16 -0800

> On 01/16/2017 04:59 AM, yuan linyu wrote:
>> On 日, 2017-01-15 at 18:21 +0100, Andrew Lunn wrote:
>>> On Sun, Jan 15, 2017 at 09:51:03AM +0800, yuan linyu wrote:
>>>>  
>>>> I hope user/developer can read this attribute file "regs" to do
>>>> a full check of all registers value, and they can write any register
>>>> inside PHY through this file.
>>> Since this is intended for debug, it should not be sysfs, but debugfs.
>> agree,
>>> However, in general, Linux does not allow user space to peek and poke
>>> device registers. Can you point me at examples where i can do the same
>>> to my GPU? SATA controller? Ethernet controller, I2C temperature
>>> sensor? Any device?
>> we can read registers of ethernet controller(memory register accessed) through devmem or ethtool
> 
> So why not add support in ethtool for reading PHY registers if you need
> it? There are handful of PHY "things" in ethtool, such as reading
> counters, configuring downshift etc., adding support for dumping
> registers does not sound out of space.

Agreed.