linux-kernel - Re: [PATCHv4 1/2] PCI: fu740: fix finding GPIOs

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Message-ID: <20220223205129.GA148800@bhelgaas>
Date:   Wed, 23 Feb 2022 14:51:29 -0600
From:   Bjorn Helgaas <helgaas@...nel.org>
To:     Ben Dooks <ben.dooks@...ethink.co.uk>
Cc:     paul.walmsley@...ive.com, greentime.hu@...ive.com,
        lorenzo.pieralisi@....com, robh@...nel.org, kw@...ux.com,
        bhelgaas@...gle.com, linux-pci@...r.kernel.org,
        linux-kernel@...r.kernel.org, linux-riscv@...ts.infradead.org
Subject: Re: [PATCHv4 1/2] PCI: fu740: fix finding GPIOs

On Mon, Feb 21, 2022 at 09:03:46PM +0000, Ben Dooks wrote:
> The calls to devm_gpiod_get_optional() have the -gpios at the end of
> the name but the GPIO core code is already adding the suffix during
> the lookup. This means the PCIe driver is not finding the necessary
> reset or power lines to allow initialisation of the PCIe.
> 
> This bug has not been noticed as if U-Boot has setup the GPIO lines
> for the hardware when it does the PCIe initialisation (either by
> booting from PCIe or user command to access PCIe) then the PCIe
> will work in Linux. The U-Boot as supplied by SiFive does not by
> default initialise any PCIe component.

Lorenzo, if you apply this, would you mind s/fix/Fix/ in the subject?
Or maybe even update to "Drop redundant '-gpios' from DT GPIO lookup"?

> Signed-off-by: Ben Dooks <ben.dooks@...ethink.co.uk>
> ---
>  drivers/pci/controller/dwc/pcie-fu740.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/pci/controller/dwc/pcie-fu740.c b/drivers/pci/controller/dwc/pcie-fu740.c
> index 00cde9a248b5..842b7202b96e 100644
> --- a/drivers/pci/controller/dwc/pcie-fu740.c
> +++ b/drivers/pci/controller/dwc/pcie-fu740.c
> @@ -259,11 +259,11 @@ static int fu740_pcie_probe(struct platform_device *pdev)
>  		return PTR_ERR(afp->mgmt_base);
>  
>  	/* Fetch GPIOs */
> -	afp->reset = devm_gpiod_get_optional(dev, "reset-gpios", GPIOD_OUT_LOW);
> +	afp->reset = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_LOW);
>  	if (IS_ERR(afp->reset))
>  		return dev_err_probe(dev, PTR_ERR(afp->reset), "unable to get reset-gpios\n");
>  
> -	afp->pwren = devm_gpiod_get_optional(dev, "pwren-gpios", GPIOD_OUT_LOW);
> +	afp->pwren = devm_gpiod_get_optional(dev, "pwren", GPIOD_OUT_LOW);
>  	if (IS_ERR(afp->pwren))
>  		return dev_err_probe(dev, PTR_ERR(afp->pwren), "unable to get pwren-gpios\n");
>  
> -- 
> 2.34.1
>