[PATCH v2 0/2] PCI: imx6: Add a method to handle CLKREQ# override
Manivannan Sadhasivam
mani at kernel.org
Sat Sep 20 00:34:29 PDT 2025
On Wed, Sep 17, 2025 at 05:37:49PM +0800, Richard Zhu wrote:
> The CLKREQ# is an open drain, active low signal that is driven low by
> the card to request reference clock.
>
> But the CLKREQ# maybe reserved on some old device, compliant with CEM
> r3.0 or before. Thus, this signal wouldn't be driven low by these old
> devices.
>
> Since the reference clock controlled by CLKREQ# may be required by i.MX
> PCIe host too. To make sure this clock is ready even when the CLKREQ#
> isn't driven low by the card(e.x old cards described above), force
> CLKREQ# override active low for i.MX PCIe host during initialization.
>
> The CLKREQ# override can be cleared safely when supports-clkreq is
> present and PCIe link is up later. Because the CLKREQ# would be driven
> low by the card in this case.
>
> Main changes in v2:
> - Update the commit message, and collect the reviewed-by tag.
>
> [PATCH v2 1/2] PCI: dwc: Invoke post_init in dw_pcie_resume_noirq()
> [PATCH v2 2/2] PCI: imx6: Add a method to handle CLKREQ# override
>
Patch 2 is not applying on top of 6.17-rc1. Please fix it and resend the series
(along with the CEM 4.0 citation suggested by Bjorn).
- Mani
--
மணிவண்ணன் சதாசிவம்
More information about the linux-arm-kernel
mailing list