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?
Bjorn
