Subject: [PATCH 1/2] PCI: imx6: Make reset-gpio optional

From: [email-masked] (Marek Vasut)
Date: Mon, 14 Oct 2013 02:44:48 +0200

Hello Han,

> On Saturday, October 12, 2013 6:29 PM, Marek Vasut wrote:
> > > On Fri, Oct 11, 2013 at 04:12:31AM +0200, Marek Vasut wrote:
> > > > Some boards do not have a PCIe reset GPIO. To avoid probe
> > > > failure on these boards, make the reset GPIO optional as
> > > > well.
> > > > 
> > > > Signed-off-by: Marek Vasut <[email-masked]>
> > > > Cc: Bjorn Helgaas <[email-masked]>
> > > > Cc: Frank Li <[email-masked]>
> > > > Cc: Richard Zhu <[email-masked]>
> > > > Cc: Sascha Hauer <[email-masked]>
> > > > Cc: Sean Cross <[email-masked]>
> > > > Cc: Shawn Guo <[email-masked]>
> > > > Cc: Tim Harvey <[email-masked]>
> > > > Cc: Yinghai Lu <[email-masked]>
> > > > ---
> > > > 
> > > >  drivers/pci/host/pci-imx6.c | 29 +++++++++++++++--------------
> > > >  1 file changed, 15 insertions(+), 14 deletions(-)
> > > > 
> > > > diff --git a/drivers/pci/host/pci-imx6.c
> > > > b/drivers/pci/host/pci-imx6.c index d3639aa..8e7adce 100644
> > > > --- a/drivers/pci/host/pci-imx6.c
> > > > +++ b/drivers/pci/host/pci-imx6.c
> > > > @@ -220,9 +220,12 @@ static int imx6_pcie_assert_core_reset(struct
> > > > pcie_port *pp)
> > > > 
> > > >  	regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR1,
> > > >  	
> > > >  			IMX6Q_GPR1_PCIE_REF_CLK_EN, 0 << 16);
> > > > 
> > > > -	gpio_set_value(imx6_pcie->reset_gpio, 0);
> > > > -	msleep(100);
> > > > -	gpio_set_value(imx6_pcie->reset_gpio, 1);
> > > > +	/* Some boards don't have PCIe reset GPIO. */
> > > > +	if (gpio_is_valid(imx6_pcie->reset_gpio)) {
> > > > +		gpio_set_value(imx6_pcie->reset_gpio, 0);
> > > > +		msleep(100);
> > > > +		gpio_set_value(imx6_pcie->reset_gpio, 1);
> > > > +	}
> > > > 
> > > >  	return 0;
> > > >  
> > > >  }
> > > > 
> > > > @@ -447,17 +450,15 @@ static int __init imx6_pcie_probe(struct
> > > > platform_device *pdev)
> > > > 
> > > >  	/* Fetch GPIOs */
> > > >  	imx6_pcie->reset_gpio = of_get_named_gpio(np, "reset-gpio", 0);
> > > > 
> > > > -	if (!gpio_is_valid(imx6_pcie->reset_gpio)) {
> > > > -		dev_err(&pdev->dev, "no reset-gpio defined\n");
> > > > -		ret = -ENODEV;
> > > > -	}
> > > 
> > > The 'reset-gpio' is documented as a required property in bindings doc
> > > Documentation/devicetree/bindings/pci/designware-pcie.txt.  You need
> > > to update bindings doc if you turn it into an optional property.
> > 
> > That's true, thanks for pointing it out!
> 
> +cc Kishon Vijay Abraham I, Pratyush Anand, Mohit KUMAR
> 
> Yes, right.
> "reset-gpio" property can be moved to an optional property.
> Also, the patch to fix 'Designware' part such as 'designware-pcie.txt'
> can be shared with other related people as below.
> 
>   - Samsung Exynos PCIe: Jingoo Han
>   - ST Spear PCIe: Pratyush Anand, Mohit KUMAR
>   - TI OMAP PCIe: Kishon Vijay Abraham I

I'm in the process of rebasing the patches on top of next 2013-10-10. Right now 
I'm getting a crash in __write_msi_msg() when my Intel "igb" reports "enabling 
bus mastering" . Any quick idea? Seems like this MSI support is new in the pcie-
designware.c .

I'll just start plumbing to see what it is.

Best regards,
Marek Vasut