linux-kernel - RE: [PATCH 2/2] PCI: amd-mdb: Add support for PCIe RP PERST# signal

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Message-ID:
 <DM4PR12MB6158433474E7875ADF92ACA3CDA92@DM4PR12MB6158.namprd12.prod.outlook.com>
Date: Fri, 4 Apr 2025 07:07:51 +0000
From: "Musham, Sai Krishna" <sai.krishna.musham@....com>
To: Krzysztof Kozlowski <krzk@...nel.org>
CC: "bhelgaas@...gle.com" <bhelgaas@...gle.com>, "lpieralisi@...nel.org"
	<lpieralisi@...nel.org>, "kw@...ux.com" <kw@...ux.com>,
	"manivannan.sadhasivam@...aro.org" <manivannan.sadhasivam@...aro.org>,
	"robh@...nel.org" <robh@...nel.org>, "krzk+dt@...nel.org"
	<krzk+dt@...nel.org>, "conor+dt@...nel.org" <conor+dt@...nel.org>,
	"cassel@...nel.org" <cassel@...nel.org>, "linux-pci@...r.kernel.org"
	<linux-pci@...r.kernel.org>, "devicetree@...r.kernel.org"
	<devicetree@...r.kernel.org>, "linux-kernel@...r.kernel.org"
	<linux-kernel@...r.kernel.org>, "Simek, Michal" <michal.simek@....com>,
	"Gogada, Bharat Kumar" <bharat.kumar.gogada@....com>, "Havalige, Thippeswamy"
	<thippeswamy.havalige@....com>
Subject: RE: [PATCH 2/2] PCI: amd-mdb: Add support for PCIe RP PERST# signal

[AMD Official Use Only - AMD Internal Distribution Only]

Hi Krzysztof,

> -----Original Message-----
> From: Krzysztof Kozlowski <krzk@...nel.org>
> Sent: Wednesday, March 26, 2025 1:53 PM
> To: Musham, Sai Krishna <sai.krishna.musham@....com>
> Cc: bhelgaas@...gle.com; lpieralisi@...nel.org; kw@...ux.com;
> manivannan.sadhasivam@...aro.org; robh@...nel.org; krzk+dt@...nel.org;
> conor+dt@...nel.org; cassel@...nel.org; linux-pci@...r.kernel.org;
> devicetree@...r.kernel.org; linux-kernel@...r.kernel.org; Simek, Michal
> <michal.simek@....com>; Gogada, Bharat Kumar
> <bharat.kumar.gogada@....com>; Havalige, Thippeswamy
> <thippeswamy.havalige@....com>
> Subject: Re: [PATCH 2/2] PCI: amd-mdb: Add support for PCIe RP PERST# signal
>
> Caution: This message originated from an External Source. Use proper caution
> when opening attachments, clicking links, or responding.
>
>
> On Wed, Mar 26, 2025 at 09:45:07AM +0530, Sai Krishna Musham wrote:
> > Add PERST# signal handling via I2C GPIO expander for AMD Versal2 MDB
> > PCIe Root Port.
> >
> > Signed-off-by: Sai Krishna Musham <sai.krishna.musham@....com>
> > ---
> >  drivers/pci/controller/dwc/pcie-amd-mdb.c | 20 ++++++++++++++++++++
> >  1 file changed, 20 insertions(+)
> >
> > diff --git a/drivers/pci/controller/dwc/pcie-amd-mdb.c
> > b/drivers/pci/controller/dwc/pcie-amd-mdb.c
> > index 4eb2a4e8189d..4eea53e9e197 100644
> > --- a/drivers/pci/controller/dwc/pcie-amd-mdb.c
> > +++ b/drivers/pci/controller/dwc/pcie-amd-mdb.c
> > @@ -18,6 +18,7 @@
> >  #include <linux/resource.h>
> >  #include <linux/types.h>
> >
> > +#include "../../pci.h"
> >  #include "pcie-designware.h"
> >
> >  #define AMD_MDB_TLP_IR_STATUS_MISC           0x4C0
> > @@ -408,6 +409,7 @@ static int amd_mdb_add_pcie_port(struct amd_mdb_pcie
> *pcie,
> >       struct dw_pcie *pci = &pcie->pci;
> >       struct dw_pcie_rp *pp = &pci->pp;
> >       struct device *dev = &pdev->dev;
> > +     struct gpio_desc *reset_gpio;
> >       int err;
> >
> >       pcie->slcr = devm_platform_ioremap_resource_byname(pdev,
> > "slcr"); @@ -426,6 +428,24 @@ static int amd_mdb_add_pcie_port(struct
> > amd_mdb_pcie *pcie,
> >
> >       pp->ops = &amd_mdb_pcie_host_ops;
> >
> > +     /* Request the GPIO for PCIe reset signal and assert */
> > +     reset_gpio = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_HIGH);
> > +     if (IS_ERR(reset_gpio)) {
> > +             if (PTR_ERR(reset_gpio) == -EPROBE_DEFER)
> > +                     return -EPROBE_DEFER;
> > +             dev_err(dev, "Failed to request reset GPIO\n");
>
> Do not open-code dev_err_probe.
>

Thank you for reviewing. Sure, I will use dev_err_probe in next patch.

> Best regards,
> Krzysztof

Regards,
Sai Krishna