linux-kernel - RE: [PATCH 02/10] PCI: imx6: Add support for parsing the reset property in new Root Port binding

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Message-ID:
 <VI0PR04MB12114D934321FBE66469775DF9289A@VI0PR04MB12114.eurprd04.prod.outlook.com>
Date: Tue, 20 Jan 2026 02:33:48 +0000
From: Sherry Sun <sherry.sun@....com>
To: Frank Li <frank.li@....com>
CC: Hongxing Zhu <hongxing.zhu@....com>, "l.stach@...gutronix.de"
	<l.stach@...gutronix.de>, "bhelgaas@...gle.com" <bhelgaas@...gle.com>,
	"lpieralisi@...nel.org" <lpieralisi@...nel.org>, "kwilczynski@...nel.org"
	<kwilczynski@...nel.org>, "mani@...nel.org" <mani@...nel.org>,
	"robh@...nel.org" <robh@...nel.org>, "krzk+dt@...nel.org"
	<krzk+dt@...nel.org>, "conor+dt@...nel.org" <conor+dt@...nel.org>,
	"shawnguo@...nel.org" <shawnguo@...nel.org>, "s.hauer@...gutronix.de"
	<s.hauer@...gutronix.de>, "festevam@...il.com" <festevam@...il.com>,
	"kernel@...gutronix.de" <kernel@...gutronix.de>, "linux-pci@...r.kernel.org"
	<linux-pci@...r.kernel.org>, "devicetree@...r.kernel.org"
	<devicetree@...r.kernel.org>, "imx@...ts.linux.dev" <imx@...ts.linux.dev>,
	"linux-arm-kernel@...ts.infradead.org"
	<linux-arm-kernel@...ts.infradead.org>, "linux-kernel@...r.kernel.org"
	<linux-kernel@...r.kernel.org>
Subject: RE: [PATCH 02/10] PCI: imx6: Add support for parsing the reset
 property in new Root Port binding



> Subject: Re: [PATCH 02/10] PCI: imx6: Add support for parsing the reset
> property in new Root Port binding
> 
> On Mon, Jan 19, 2026 at 06:02:27PM +0800, Sherry Sun wrote:
> > DT binding allows specifying 'reset' property in both host bridge and
> > Root Port nodes, but specifying in the host bridge node is marked as
> > deprecated. So add support for parsing the new binding that uses
> > 'reset-gpios' property for PERST#.
> >
> > 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.
> >
> > Signed-off-by: Sherry Sun <sherry.sun@....com>
> > ---
> >  drivers/pci/controller/dwc/pci-imx6.c | 128
> > +++++++++++++++++++++++---
> >  1 file changed, 114 insertions(+), 14 deletions(-)
> >
> > diff --git a/drivers/pci/controller/dwc/pci-imx6.c
> > b/drivers/pci/controller/dwc/pci-imx6.c
> > index 1d8677d7de04..0592b24071bc 100644
> > --- a/drivers/pci/controller/dwc/pci-imx6.c
> > +++ b/drivers/pci/controller/dwc/pci-imx6.c
> > @@ -147,10 +147,15 @@ struct imx_lut_data {
> >  	u32 data2;
> >  };
> >
> > +
> > +static int imx_pcie_parse_ports(struct imx_pcie *pcie) {
> > +	struct device *dev = pcie->pci->dev;
> > +	struct imx_pcie_port *port, *tmp;
> > +	int ret = -ENOENT;
> > +
> > +	for_each_available_child_of_node_scoped(dev->of_node, of_port) {
> > +		if (!of_node_is_type(of_port, "pci"))
> > +			continue;
> > +		ret = imx_pcie_parse_port(pcie, of_port);
> > +		if (ret)
> > +			goto err_port_del;
> > +	}
> > +
> > +	return ret;
> > +
> > +err_port_del:
> > +	list_for_each_entry_safe(port, tmp, &pcie->ports, list)
> > +		list_del(&port->list);
> 
> you can call helper imx_pcie_delete_ports()

Sure, will fix in V2, thanks!

Best Regards
Sherry

> 
> Frank
> > +
> > +	return ret;
> > +}
> > +
> > +static int imx_pcie_parse_legacy_binding(struct imx_pcie *pcie) {
> > +	struct device *dev = pcie->pci->dev;
> > +	struct imx_pcie_port *port;
> > +	struct gpio_desc *reset;
> > +
> > +	reset = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_HIGH);
> > +	if (IS_ERR(reset))
> > +		return PTR_ERR(reset);
> > +
> > +	port = devm_kzalloc(dev, sizeof(*port), GFP_KERNEL);
> > +	if (!port)
> > +		return -ENOMEM;
> > +
> > +	port->reset = reset;
> > +	INIT_LIST_HEAD(&port->list);
> > +	list_add_tail(&port->list, &pcie->ports);
> > +
> > +	return 0;
> > +}
> > +
> > +static void imx_pcie_delete_ports(void *data) {
> > +	struct imx_pcie *pcie = data;
> > +	struct imx_pcie_port *port, *tmp;
> > +
> > +	list_for_each_entry_safe(port, tmp, &pcie->ports, list)
> > +		list_del(&port->list);
> > +}
> > +
> >  static int imx_pcie_probe(struct platform_device *pdev)  {
> >  	struct device *dev = &pdev->dev;
> > @@ -1656,6 +1742,8 @@ static int imx_pcie_probe(struct platform_device
> *pdev)
> >  	if (!pci)
> >  		return -ENOMEM;
> >
> > +	INIT_LIST_HEAD(&imx_pcie->ports);
> > +
> >  	pci->dev = dev;
> >  	pci->ops = &dw_pcie_ops;
> >
> > @@ -1684,12 +1772,24 @@ static int imx_pcie_probe(struct
> platform_device *pdev)
> >  			return PTR_ERR(imx_pcie->phy_base);
> >  	}
> >
> > -	/* Fetch GPIOs */
> > -	imx_pcie->reset_gpiod = devm_gpiod_get_optional(dev, "reset",
> GPIOD_OUT_HIGH);
> > -	if (IS_ERR(imx_pcie->reset_gpiod))
> > -		return dev_err_probe(dev, PTR_ERR(imx_pcie->reset_gpiod),
> > -				     "unable to get reset gpio\n");
> > -	gpiod_set_consumer_name(imx_pcie->reset_gpiod, "PCIe reset");
> > +	ret = imx_pcie_parse_ports(imx_pcie);
> > +	if (ret) {
> > +		if (ret != -ENOENT)
> > +			return dev_err_probe(dev, ret, "Failed to parse Root
> Port: %d\n",
> > +ret);
> > +
> > +		/*
> > +		 * In the case of properties not populated in Root Port node,
> > +		 * fallback to the legacy method of parsing the Host Bridge
> > +		 * node. This is to maintain DT backwards compatibility.
> > +		 */
> > +		ret = imx_pcie_parse_legacy_binding(imx_pcie);
> > +		if (ret)
> > +			return dev_err_probe(dev, ret, "Unable to get reset
> gpio: %d\n", ret);
> > +	}
> > +
> > +	ret = devm_add_action_or_reset(dev, imx_pcie_delete_ports,
> imx_pcie);
> > +	if (ret)
> > +		return ret;
> >
> >  	/* Fetch clocks */
> >  	imx_pcie->num_clks = devm_clk_bulk_get_all(dev, &imx_pcie->clks);
> > --
> > 2.37.1
> >