Re: [PATCH 2/5] phy: core: Define TBT phy_mode

[Konrad Dybcio]

On 5/18/26 2:25 PM, Dmitry Baryshkov wrote:
> On Mon, May 18, 2026 at 12:29:49PM +0200, Konrad Dybcio wrote:
>> From: Konrad Dybcio <konrad.dybcio@xxxxxxxxxxxxxxxx>
>>
>> There exist OS-accessible USB4 and Thunderbolt PHYs that need specific
>> configuration. Define a new phy_mode for them.
>>
>> Currently, USB4 and TBT3 are defined as submodes, because they're quite
>> distinct, most visibly in the electrical/analog aspects (slightly
>> different frequencies, timings, etc.). This results in a need to make
>> the PHY aware of the actual mode needed (at least in the Qualcomm
>> implementation, but I believe that'll be a general need).
>>
>> Newer versions of TBT are basically supersets of USB4 with higher
>> host-side requirements, so these are not defined. This can always be
>> changed as necessary.
>>
>> Signed-off-by: Konrad Dybcio <konrad.dybcio@xxxxxxxxxxxxxxxx>
>> ---
>>  include/linux/phy/phy-tbt.h | 14 ++++++++++++++
>>  include/linux/phy/phy.h     |  2 ++
>>  2 files changed, 16 insertions(+)
>>
>> diff --git a/include/linux/phy/phy-tbt.h b/include/linux/phy/phy-tbt.h
>> new file mode 100644
>> index 000000000000..5f48059814e1
>> --- /dev/null
>> +++ b/include/linux/phy/phy-tbt.h
>> @@ -0,0 +1,14 @@
>> +/* SPDX-License-Identifier: GPL-2.0 */
>> +/*
>> + * Copyright (c) Qualcomm Technologies, Inc. and/or its subsidiaries.
>> + */
>> +
>> +#ifndef __PHY_TBT_H_
>> +#define __PHY_TBT_H_
>> +
>> +enum tbt_phy_submode {
>> +	PHY_SUBMODE_TBT3,
>> +	PHY_SUBMODE_USB4,
> 
> Do we need TBT2 as a separate submode?

I would like to avoid extending that unless there's a user for it

Konrad