Hi Bjorn,
On Sat, 14 Jun 2025 at 00:01, Bjorn Helgaas <helgaas@xxxxxxxxxx> wrote:
> On Thu, Jun 12, 2025 at 03:16:45PM +0200, Geert Uytterhoeven wrote:
> > On Sat, 7 Jun 2025 at 21:46, Marek Vasut
> > <marek.vasut+renesas@xxxxxxxxxxx> wrote:
> > > Add the ability to enable optional slot clock into the pwrctrl driver.
> > > This is used to enable slot clock in split-clock topologies, where the
> > > PCIe host/controller supply and PCIe slot supply are not provided by
> > > the same clock. The PCIe host/controller clock should be described in
> > > the controller node as the controller clock, while the slot clock should
> > > be described in controller bridge/slot subnode.
> > >
> > > Example DT snippet:
> > > &pcicontroller {
> > > clocks = <&clk_dif 0>; /* PCIe controller clock */
> > >
> > > pci@0,0 {
> > > #address-cells = <3>;
> > > #size-cells = <2>;
> > > reg = <0x0 0x0 0x0 0x0 0x0>;
> > > compatible = "pciclass,0604";
> > > device_type = "pci";
> > > clocks = <&clk_dif 1>; /* PCIe slot clock */
> > > vpcie3v3-supply = <®_3p3v>;
> > > ranges;
> > > };
> > > };
> > >
> > > Example clock topology:
> > > ____________ ____________
> > > | PCIe host | | PCIe slot |
> > > | | | |
> > > | PCIe RX<|==================|>PCIe TX |
> > > | PCIe TX<|==================|>PCIe RX |
> > > | | | |
> > > | PCIe CLK<|======.. ..======|>PCIe CLK |
> > > '------------' || || '------------'
> > > || ||
> > > ____________ || ||
> > > | 9FGV0441 | || ||
> > > | | || ||
> > > | CLK DIF0<|======'' ||
> > > | CLK DIF1<|==========''
> > > | CLK DIF2<|
> > > | CLK DIF3<|
> > > '------------'
> > >
> > > Acked-by: Bartosz Golaszewski <bartosz.golaszewski@xxxxxxxxxx>
> > > Reviewed-by: Anand Moon <linux.amoon@xxxxxxxxx>
> > > Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@xxxxxxxxxx>
> > > Signed-off-by: Marek Vasut <marek.vasut+renesas@xxxxxxxxxxx>
> >
> > Reviewed-by: Geert Uytterhoeven <geert+renesas@xxxxxxxxx>
> >
> > Bartosz: Any chance you can apply this patch to an immutable branch,
> > so I can merge that before taking the other two patches?
> > The alternative is to postpone the DTS patches for one cycle.
>
> I applied this patch only to pci/pwrctrl for v6.17 and made a note
> that the commit should be immutable:
>
> 66db1d3cbdb0 ("PCI/pwrctrl: Add optional slot clock for PCI slots")
>
> We will likely add other pwrctrl patches to this branch during this
> cycle; I assume that will be OK as long as 66db1d3cbdb0 remains
> untouched, right?
Great, I will merge that branch, and will apply the DTS patches on top.
Thanks!
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
