Re: [PATCH net-next 0/3] net: phy: motorcomm: Enable analog frontend DAC on yt8531S

[Yao Zi <me@ziyao.cc>]

On Mon, Aug 31, 2026 at 09:37:42AM +0200, Maxime Chevallier wrote:
> In the process of getting more stmmac boards to run tests on, I've
> acquired a nice and inexpensive YT6801 PCIe card, that can do
> 10/100/1000BaseT. It uses stmmac's PCI variant dwmac-motorcomm, as well
> as an integrated Motorcomm PHY (the YT8531S).
> 
> However while testing the card, I had link-up maybe once every 10
> reboots, and no traffic whatsoever. Comparing with the out-of-tree
> driver provided by Motorcomm, it was found that some Analog Frontend DAC
> needs a clock to be enabled, and indeed it fixed the issue.

As a side note, this operation was added between v1.0.30 and v1.031 of
the vendor driver, and we haven't observed similar issues with the
current YT8531S driver, so maybe this is a silicon issue only present in
later revisions of the chip.

If interested, you could find v1.028, v1.029, and v1.031 of the YT6801
driver here[1]. And REG_MII_EXT_AFE_CONTROL_CLKDAC_AON_POS was
introduced in this commit[2].

> As I don't know much about this device, this series implements the DAC
> CLK configuration in the YT8531S driver only for the integrated version,
> that uses the GMII interface.
> 
> I split that into 3 commits, the first 2 are splitting-out the YT8521
> and YT8531S config_init(). The third commit adds the DAC configuration.
> 
> This was tested on YT6801, which now reliably reports link up.
> 
> Maxime Chevallier (3):
>   net: phy: motorcomm: Split yt8521_config_init() page management
>   net: phy: motorcomm: Add a dedicated .config_init for YT8531S
>   net: phy: motorcomm: Enable analog frontend on YT8531S
> 
>  drivers/net/phy/motorcomm.c | 76 ++++++++++++++++++++++++++-----------
>  1 file changed, 54 insertions(+), 22 deletions(-)
> 
> -- 
> 2.55.0
> 

Regards,
Yao Zi

[1]: https://github.com/deepin-community/kernel/blob/linux-6.6.y/drivers/net/ethernet/motorcomm/yt6801/
[2]: https://github.com/deepin-community/kernel/commit/721c505713d104fe48a817e703936dfe583b8ae4