Re: [PATCH 5/7] net: phy: at803x: add support for configuring SmartEEE

[Oleksij Rempel <linux@rempel-privat.de>]

Am 10.07.23 um 12:10 schrieb Ahmad Fatoum:
> On 10.07.23 08:36, Marco Felsch wrote:
>> This commit port Linux commit:
>>
>> | commit 390b4cad81484124db2b676ed20a265adc032bae
>> | Author: Russell King <rmk+kernel@armlinux.org.uk>
>> | Date:   Thu Jan 14 10:45:49 2021 +0000
>> |
>> |     net: phy: at803x: add support for configuring SmartEEE
>> |
>> |     SmartEEE for the atheros phy was deemed buggy by Freescale and commits
>> |     were added to disable it for their boards.
>> |
>> |     In initial testing, SolidRun found that the default settings were
>> |     causing disconnects but by increasing the Tw buffer time we could allow
>> |     enough time for all parts of the link to come out of a low power state
>> |     and function properly without causing a disconnect. This allows us to
>> |     have functional power savings of between 300 and 400mW, rather than
>> |     disabling the feature altogether.
>> |
>> |     This commit adds support for disabling SmartEEE and configuring the Tw
>> |     parameters for 1G and 100M speeds.
>> |
>> |     Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
>> |     Signed-off-by: Jakub Kicinski <kuba@kernel.org>
>>
>> I slightly adapted the at803x_config_init() as well to be more in line
>> with the Linux code base.
>>
>> Signed-off-by: Marco Felsch <m.felsch@pengutronix.de>
>
> Same question as in follow-up commit: Can't we just disable it unconditionally?

Most of PHYs with EEE support have EEE advertisement register on the same offset. I would recommend
to create a common function for all PHYs drivers to clear all EEE advertising bits and call it the
PHY framework. EEE should be never advertised by barebox. As a side effect, if Atheros PHY do not
advertise EEE, SmartEEE will not be activated.

--
Regards,
Oleksij