[PATCH v2 11/22] thunderbolt: Find Apple VSE capability during startup

[Joshua Peisach]

On Sun Sep 6, 2026 at 2:36 PM EDT, Sven Peter wrote:
> Only Apple Silicon host routers have the Apple vendor-specific extended
> capability. Look it up when the software connection manager starts and
> store its offset in the root switch.
>
> The Apple NHI driver can then use the stored offset when programming
> cable information without searching the router capabilities itself.
>
> Signed-off-by: Sven Peter <sven at kernel.org>
> ---
>  drivers/thunderbolt/tb.c      | 4 ++++
>  drivers/thunderbolt/tb.h      | 2 ++
>  drivers/thunderbolt/tb_regs.h | 1 +
>  3 files changed, 7 insertions(+)
>
> diff --git a/drivers/thunderbolt/tb.c b/drivers/thunderbolt/tb.c
> index bf1c192ec10a..d2832323cc36 100644
> --- a/drivers/thunderbolt/tb.c
> +++ b/drivers/thunderbolt/tb.c
> @@ -3025,6 +3025,10 @@ static int tb_start(struct tb *tb, bool reset)
>  		return dev_err_probe(tb->nhi->dev, PTR_ERR(tb->root_switch),
>  				     "failed to allocate host router\n");
>  
> +	ret = tb_switch_find_vse_cap(tb->root_switch, TB_VSE_CAP_APPLE);
> +	if (ret > 0)
> +		tb->root_switch->cap_vsec_apple = ret;
> +

Nitpick: I *think* based on the surrounding code that this can be
simplified to "if (ret)"

-Josh