On Thu, Jan 10, 2019 at 12:05 AM Sascha Hauer <s.hauer@xxxxxxxxxxxxxx> wrote:
>
> On Tue, Jan 08, 2019 at 11:12:05PM -0800, Andrey Smirnov wrote:
> > Port of a Linux commit bde4a5a00e761f55be92f62378cf5024ced79ee3
> >
> > Some designs implement reset GPIO via a GPIO expander connected to a
> > peripheral bus. One such example would be i.MX7 Sabre board where said
> > GPIO is provided by SPI shift register connected to a bitbanged SPI bus.
> > To support such designs, allow reset GPIO request to defer probing of the
> > driver.
> >
> > Signed-off-by: Andrey Smirnov <andrew.smirnov@xxxxxxxxx>
> > Signed-off-by: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
> > Reviewed-by: Lucas Stach <l.stach@xxxxxxxxxxxxxx>
> > Cc: yurovsky@xxxxxxxxx
> > Cc: Fabio Estevam <fabio.estevam@xxxxxxx>
> > Cc: Dong Aisheng <dongas86@xxxxxxxxx>
> > Cc: linux-arm-kernel@xxxxxxxxxxxxxxxxxxx
> >
> > Signed-off-by: Andrey Smirnov <andrew.smirnov@xxxxxxxxx>
> > ---
> > drivers/pci/pci-imx6.c | 9 ++++++---
> > 1 file changed, 6 insertions(+), 3 deletions(-)
> >
> > diff --git a/drivers/pci/pci-imx6.c b/drivers/pci/pci-imx6.c
> > index 6471f95b6..517c6bef8 100644
> > --- a/drivers/pci/pci-imx6.c
> > +++ b/drivers/pci/pci-imx6.c
> > @@ -562,8 +562,8 @@ static const struct dw_pcie_host_ops imx6_pcie_host_ops = {
> > .host_init = imx6_pcie_host_init,
> > };
> >
> > -static int __init imx6_add_pcie_port(struct imx6_pcie *imx6_pcie,
> > - struct device_d *dev)
> > +static int imx6_add_pcie_port(struct imx6_pcie *imx6_pcie,
> > + struct device_d *dev)
> > {
> > struct dw_pcie *pci = imx6_pcie->pci;
> > struct pcie_port *pp = &pci->pp;
> > @@ -581,7 +581,7 @@ static int __init imx6_add_pcie_port(struct imx6_pcie *imx6_pcie,
> > return 0;
> > }
> >
> > -static int __init imx6_pcie_probe(struct device_d *dev)
> > +static int imx6_pcie_probe(struct device_d *dev)
> > {
> > struct resource *iores;
> > struct dw_pcie *pci;
> > @@ -606,6 +606,9 @@ static int __init imx6_pcie_probe(struct device_d *dev)
> >
> > /* Fetch GPIOs */
> > imx6_pcie->reset_gpio = of_get_named_gpio(np, "reset-gpio", 0);
> > + if (imx6_pcie->reset_gpio == -EPROBE_DEFER)
> > + return imx6_pcie->reset_gpio;
>
> Normally probe function run only once in barebox and in that case I do
> not care about loosing memory. When doing probe deferral here we loose a
> private data struct with each deferred probe here.
>
> Before returning -EPROBE_DEFER Here we already claimed a iomem resource using
> dev_request_mem_resource() which will fail during next probe, so I
> believe this patch doesn't work.
>
Yeah, it just happens to be that in Barebox 74164 GPIO driver gets
probed before PCIe, so this patch isn't strictly needed on i.MX7
(unlike on Linux). The simplest solution, I think, would be to move
GPIO request before dev_request_mem_resource(), which is my plan for
v2. If you'd rather this patch be dropped, since, technically things
are working without it, let me know.
Thanks,
Andrey Smirnov
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