[PATCH] PCI: kirin: Return -EPROBE_DEFER in case the gpio isn't ready

[PATCH] PCI: kirin: Return -EPROBE_DEFER in case the gpio isn't ready

[Bean Huo]

From: Bean Huo <beanhuo@micron.com>

PCI driver might be probed before the gpiochip, so, of_get_named_gpio()
can return -EPROBE_DEFER. And let kirin_pcie_probe() directly return
-ENODEV, which will result in the PCIe probe failure and the PCIe
will not be probed again after the gpiochip driver is loaded.

Fix the above issue by letting kirin_pcie_probe() return -EPROBE_DEFER in
such a case.

Fixes: 6e0832fa432e ("PCI: Collect all native drivers under drivers/pci/controller")
Signed-off-by: Bean Huo <beanhuo@micron.com>
---
 drivers/pci/controller/dwc/pcie-kirin.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/pci/controller/dwc/pcie-kirin.c b/drivers/pci/controller/dwc/pcie-kirin.c
index e496f51e0152..74b88d158072 100644
--- a/drivers/pci/controller/dwc/pcie-kirin.c
+++ b/drivers/pci/controller/dwc/pcie-kirin.c
@@ -507,8 +507,12 @@ static int kirin_pcie_probe(struct platform_device *pdev)
 
 	kirin_pcie->gpio_id_reset = of_get_named_gpio(dev->of_node,
 						      "reset-gpios", 0);
-	if (kirin_pcie->gpio_id_reset < 0)
+	if (kirin_pcie->gpio_id_reset == -EPROBE_DEFER) {
+		return -EPROBE_DEFER;
+	} else if (!gpio_is_valid(kirin_pcie->gpio_id_reset)) {
+		dev_err(dev, "unable to get a valid gpio pin\n");
 		return -ENODEV;
+	}
 
 	ret = kirin_pcie_power_on(kirin_pcie);
 	if (ret)
-- 
2.17.1

Re: [PATCH] PCI: kirin: Return -EPROBE_DEFER in case the gpio isn't ready

[Lorenzo Pieralisi]

On Fri, Sep 18, 2020 at 02:38:00PM +0200, Bean Huo wrote:
> From: Bean Huo <beanhuo@micron.com>
> 
> PCI driver might be probed before the gpiochip, so, of_get_named_gpio()
> can return -EPROBE_DEFER. And let kirin_pcie_probe() directly return
> -ENODEV, which will result in the PCIe probe failure and the PCIe
> will not be probed again after the gpiochip driver is loaded.
> 
> Fix the above issue by letting kirin_pcie_probe() return -EPROBE_DEFER in
> such a case.
> 
> Fixes: 6e0832fa432e ("PCI: Collect all native drivers under drivers/pci/controller")

This is certainly not the commit that triggered the issue so I would
remove it. Kirin maintainers are CC'ed, waiting for their ACK.

Lorenzo

> Signed-off-by: Bean Huo <beanhuo@micron.com>
> ---
>  drivers/pci/controller/dwc/pcie-kirin.c | 6 +++++-
>  1 file changed, 5 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/pci/controller/dwc/pcie-kirin.c b/drivers/pci/controller/dwc/pcie-kirin.c
> index e496f51e0152..74b88d158072 100644
> --- a/drivers/pci/controller/dwc/pcie-kirin.c
> +++ b/drivers/pci/controller/dwc/pcie-kirin.c
> @@ -507,8 +507,12 @@ static int kirin_pcie_probe(struct platform_device *pdev)
>  
>  	kirin_pcie->gpio_id_reset = of_get_named_gpio(dev->of_node,
>  						      "reset-gpios", 0);
> -	if (kirin_pcie->gpio_id_reset < 0)
> +	if (kirin_pcie->gpio_id_reset == -EPROBE_DEFER) {
> +		return -EPROBE_DEFER;
> +	} else if (!gpio_is_valid(kirin_pcie->gpio_id_reset)) {
> +		dev_err(dev, "unable to get a valid gpio pin\n");
>  		return -ENODEV;
> +	}
>  
>  	ret = kirin_pcie_power_on(kirin_pcie);
>  	if (ret)
> -- 
> 2.17.1
> 

Re: [PATCH] PCI: kirin: Return -EPROBE_DEFER in case the gpio isn't ready

[Bean Huo]

On Mon, 2020-09-21 at 12:22 +0100, Lorenzo Pieralisi wrote:
> > Fix the above issue by letting kirin_pcie_probe() return
> > -EPROBE_DEFER in
> > such a case.
> > 
> > Fixes: 6e0832fa432e ("PCI: Collect all native drivers under
> > drivers/pci/controller")
> 
> This is certainly not the commit that triggered the issue so I would
> remove it. Kirin maintainers are CC'ed, waiting for their ACK.
> 
> Lorenzo

Hi Lorenzo

Thanks very much for your reply. It is true this is a bug which was
introduced by the origin commit. It is ok  for me to remove this fix
tag.

Thanks, 
Bean

Re: [PATCH] PCI: kirin: Return -EPROBE_DEFER in case the gpio isn't ready

[Bean Huo]

seems the Hisilicon PCI driver maintainers are absent, however, we are
still using their old platform based on Kirin.

hi, Lorenzo
is it possible to take this patch without Hisilicon maintainter's ACK?

Thanks,
Bean

Re: [PATCH] PCI: kirin: Return -EPROBE_DEFER in case the gpio isn't ready

[Lorenzo Pieralisi]

On Sat, Sep 26, 2020 at 09:49:56AM +0200, Bean Huo wrote:
> seems the Hisilicon PCI driver maintainers are absent, however, we are
> still using their old platform based on Kirin.
> 
> hi, Lorenzo
> is it possible to take this patch without Hisilicon maintainter's ACK?

I applied it to pci/kirin, tentatively for v5.10.

Lorenzo

> Thanks,
> Bean
>