On Tue, Aug 19, 2025 at 03:16:30PM GMT, Richard Zhu wrote:
> Enable the vaux regulator at probe time and keep it enabled for the
> entire PCIe controller lifecycle. This ensures support for outbound
> wake-up mechanism such as WAKE# signaling.
>
> Signed-off-by: Richard Zhu <hongxing.zhu@xxxxxxx>
> ---
> drivers/pci/controller/dwc/pci-imx6.c | 15 +++++++++++++++
> 1 file changed, 15 insertions(+)
>
> diff --git a/drivers/pci/controller/dwc/pci-imx6.c b/drivers/pci/controller/dwc/pci-imx6.c
> index 5a38cfaf989b1..1c1dce2d87e44 100644
> --- a/drivers/pci/controller/dwc/pci-imx6.c
> +++ b/drivers/pci/controller/dwc/pci-imx6.c
> @@ -159,6 +159,7 @@ struct imx_pcie {
> u32 tx_deemph_gen2_6db;
> u32 tx_swing_full;
> u32 tx_swing_low;
> + struct regulator *vaux;
> struct regulator *vpcie;
> struct regulator *vph;
> void __iomem *phy_base;
> @@ -1739,6 +1740,20 @@ static int imx_pcie_probe(struct platform_device *pdev)
> pci->max_link_speed = 1;
> of_property_read_u32(node, "fsl,max-link-speed", &pci->max_link_speed);
>
> + /*
> + * Refer to PCIe CEM r6.0, sec 2.3 WAKE# Signal, WAKE# signal is only
> + * asserted by the Add-in Card when all its functions are in D3Cold
> + * state and at least one of its functions is enabled for wakeup
> + * generation. The 3.3V auxiliary power (+3.3Vaux) must be present and
> + * used for wakeup process. Since the main power supply would be gated
> + * off to let Add-in Card to be in D3Cold, get the vaux and keep it
> + * enabled to power up WAKE# circuit for the entire PCIe controller
> + * lifecycle when WAKE# is supported.
> + */
This comment implies that the presence of Vaux is dependent on WAKE#. But there
is no such check present in the code. Maybe you are referring to the fact that
the platform will only supply Vaux if it intends to support WAKE#?
But I guess you can just drop the comment altogether and move it to patch
description.
- Mani
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