RE: [PATCH V8 05/13] PCI: imx6: Add support for parsing the reset property in new Root Port binding

[Sherry Sun]

> On Fri, Mar 13, 2026 at 10:08:15AM +0800, Sherry Sun wrote:
> > The current DT binding for pci-imx6 specifies the 'reset-gpios'
> > property in the host bridge node. However, the PERST# signal logically
> > belongs to individual Root Ports rather than the host bridge itself.
> > This becomes important when supporting PCIe KeyE connector and PCI
> > power control framework for pci-imx6 driver, which requires properties
> > to be specified in Root Port nodes.
> >
> > With the common Root Port parsing now handled in dw_pcie_host_init(),
> > update the reset GPIO handling to use the parsed port list from
> > bridge->ports. To maintain DT backwards compatibility, fallback to the
> > legacy method of parsing the host bridge node if the reset property is
> > not present in the Root Port node (indicated by an empty ports list).
> >
> > Signed-off-by: Sherry Sun <sherry.sun@xxxxxxx>
> > ---
> >  drivers/pci/controller/dwc/pci-imx6.c | 74
> > +++++++++++++++++++++------
> >  1 file changed, 59 insertions(+), 15 deletions(-)
> >
> > diff --git a/drivers/pci/controller/dwc/pci-imx6.c
> > b/drivers/pci/controller/dwc/pci-imx6.c
> > index 83beca5a1fc2..cb18e1579788 100644
> > --- a/drivers/pci/controller/dwc/pci-imx6.c
> > +++ b/drivers/pci/controller/dwc/pci-imx6.c
> > @@ -34,6 +34,7 @@
> >  #include <linux/pm_runtime.h>
> >
> >  #include "../../pci.h"
> > +#include "../pci-host-common.h"
> >  #include "pcie-designware.h"
> >
> >  #define IMX8MQ_GPR_PCIE_REF_USE_PAD		BIT(9)
> > @@ -150,7 +151,6 @@ struct imx_lut_data {
> >
> >  struct imx_pcie {
> >  	struct dw_pcie		*pci;
> > -	struct gpio_desc	*reset_gpiod;
> >  	struct clk_bulk_data	*clks;
> >  	int			num_clks;
> >  	bool			supports_clkreq;
> > @@ -1222,6 +1222,44 @@ static void imx_pcie_disable_device(struct
> pci_host_bridge *bridge,
> >  	imx_pcie_remove_lut(imx_pcie, pci_dev_id(pdev));  }
> >
> > +static int imx_pcie_parse_legacy_binding(struct imx_pcie *pcie) {
> > +	struct device *dev = pcie->pci->dev;
> > +	struct pci_host_bridge *bridge = pcie->pci->pp.bridge;
> > +	struct pci_host_port *port;
> > +	struct gpio_desc *reset;
> > +
> > +	if (!bridge) {
> > +		dev_err(dev, "Bridge not allocated yet\n");
> > +		return -EINVAL;
> > +	}
> > +
> > +	/*
> > +	 * For DT backward compatibility: if no Root Port nodes were parsed
> > +	 * (indicated by empty ports list), parse reset-gpios from the host
> > +	 * bridge node.
> > +	 */
> > +	if (!list_empty(&bridge->ports))
> 
> You should move this check and the comment to imx_pcie_host_init() and call
> imx_pcie_parse_legacy_binding() conditionally to make it clear that this is a
> fallback.
> 

Ok, thanks for the suggestion, will do this in V9.

Best Regards
Sherry

> - Mani
> 
> --
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