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Message-ID: <25fbf4763c28af4c73162dec254af6111e05461b.camel@pengutronix.de>
Subject: Re: [PATCH v8 2/5] PCI: dwc: rockchip: reset core at driver probe
From:   Philipp Zabel <p.zabel@pengutronix.de>
To:     Peter Geis <pgwipeout@gmail.com>,
        Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>,
        Rob Herring <robh@kernel.org>,
        Krzysztof =?UTF-8?Q?Wilczy=C5=84ski?= <kw@linux.com>,
        Bjorn Helgaas <bhelgaas@google.com>,
        Heiko Stuebner <heiko@sntech.de>
Cc:     linux-rockchip@lists.infradead.org, Marc Zyngier <maz@kernel.org>,
        linux-pci@vger.kernel.org, devicetree@vger.kernel.org,
        linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org
Date:   Mon, 25 Apr 2022 11:20:50 +0200
In-Reply-To: <20220423152403.1681222-3-pgwipeout@gmail.com>
References: <20220423152403.1681222-1-pgwipeout@gmail.com>
         <20220423152403.1681222-3-pgwipeout@gmail.com>
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Hi Peter,

On Sa, 2022-04-23 at 11:24 -0400, Peter Geis wrote:
> The PCIe controller is in an unknown state at driver probe. This can
> lead to undesireable effects when the driver attempts to configure the
> controller.
> 
> Prevent issues in the future by resetting the core during probe.
> 
> Signed-off-by: Peter Geis <pgwipeout@gmail.com>
> ---
>  drivers/pci/controller/dwc/pcie-dw-rockchip.c | 22 +++++++------------
>  1 file changed, 8 insertions(+), 14 deletions(-)
> 
> diff --git a/drivers/pci/controller/dwc/pcie-dw-rockchip.c b/drivers/pci/controller/dwc/pcie-dw-rockchip.c
> index c9b341e55cbb..d67ed811e752 100644
> --- a/drivers/pci/controller/dwc/pcie-dw-rockchip.c
> +++ b/drivers/pci/controller/dwc/pcie-dw-rockchip.c
> @@ -152,7 +152,13 @@ static int rockchip_pcie_resource_get(struct platform_device *pdev,
>  	if (IS_ERR(rockchip->rst_gpio))
>  		return PTR_ERR(rockchip->rst_gpio);
> 
> -	return 0;
> +	rockchip->rst = devm_reset_control_array_get_exclusive(&pdev->dev);
> +	if (IS_ERR(rockchip->rst))
> +		return dev_err_probe(&pdev->dev, PTR_ERR(rockchip->rst),
> +				     "failed to get reset lines\n");
> +
> +	return reset_control_assert(rockchip->rst);

This makes "rockchip_pcie_resource_get" a bit of a misnomer, maybe move
this out into rockchip_pcie_probe()?

> +

Superfluous whitespace.

regards
Philipp