Re: [PATCHv2 1/2] pci: spear: Use platform_driver_probe instead of platform_driver_register

[Stanimir Varbanov]

please don't top posting.

On 02/11/2015 10:38 AM, Matwey V. Kornilov wrote:
> It sounds reasonable, but does current implementation support deferring?

yes, it uses deferred probe see devm_phy_get() and devm_clk_get() calls 
in .probe and how the returned values are checked.

> Struct  spear13xx_pcie_driver just dissapears from memory after init.

IMO this is expected because spear13xx_pcie_driver is annotated as 
__initdata.

The proper solution was pointed by Kumar below, but we also need to 
remove the __init from dw_pcie_host_init() which is called from driver 
.probe.

> 11.02.2015 11:18 пользователь "Stanimir Varbanov" <svarbanov@xxxxxxxxxx>
> написал:
>
> > Hi,
> >
> > On 02/11/2015 05:35 AM, Viresh Kumar wrote:
> >
> > > On 11 February 2015 at 00:31, Matwey V. Kornilov <matwey@xxxxxxxxxx>
> > > wrote:
> > >
> > > > Use platform_driver_probe instead of platform_driver_register
> > > > because the former allows us to use probe function placed into __init
> > > > section
> > > > and the driver itself is not support hotplugging (yet?).
> > > >
> > > > Signed-off-by: Matwey V. Kornilov <matwey@xxxxxxxxxx>
> > > > ---
> > > > Changes from v1:
> > > >    - Use platform_driver_probe instead of platform_driver_register to
> > > > make linker happy.ven after it is used
> > > >
> > > >    drivers/pci/host/pcie-spear13xx.c | 3 +--
> > > >    1 file changed, 1 insertion(+), 2 deletions(-)
> > > >
> > > > diff --git a/drivers/pci/host/pcie-spear13xx.c b/drivers/pci/host/pcie-
> > > > spear13xx.c
> > > > index 866465f..51e1344 100644
> > > > --- a/drivers/pci/host/pcie-spear13xx.c
> > > > +++ b/drivers/pci/host/pcie-spear13xx.c
> > > > @@ -371,7 +371,6 @@ static const struct of_device_id
> > > > spear13xx_pcie_of_match[] = {
> > > >    MODULE_DEVICE_TABLE(of, spear13xx_pcie_of_match);
> > > >
> > > >    static struct platform_driver spear13xx_pcie_driver __initdata = {
> > > > -       .probe          = spear13xx_pcie_probe,
> > > >           .driver = {
> > > >                   .name   = "spear-pcie",
> > > >                   .of_match_table = of_match_ptr(spear13xx_pcie_
> > > > of_match),
> > > > @@ -382,7 +381,7 @@ static struct platform_driver spear13xx_pcie_driver
> > > > __initdata = {
> > > >
> > > >    static int __init spear13xx_pcie_init(void)
> > > >    {
> > > > -       return platform_driver_register(&spear13xx_pcie_driver);
> > > > +       return platform_driver_probe(&spear13xx_pcie_driver,
> > > > spear13xx_pcie_probe);
> > > >    }
> > > >    module_init(spear13xx_pcie_init);
> > >
> > > The problem here is that the driver is never registered. And we might
> > > never
> > > see it in sysfs. Probably a better solution would be to just remove all
> > > __init
> > > parts from this driver. Let it take space even after it is used. And
> > > don't care
> > > about it.
> > >
> > > Sorry was busy in a conference and couldn't reply to your earlier mail on
> > > this.
> >
> > Using platform_driver_probe() prevents deferred probe which is problem
> > because you get phy, clocks from probe, and these calls could return
> > EPROBE_DEFFER.
> >
> > Also dw_pcie_host_init() called from spear13xx_add_pcie_port() is
> > annotated as __init. I wanted send a patch which removes __init from
> > dw_pcie_host_init() but I haven't time, yet.
> >
> > regards,
> > Stan
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