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

Stanimir Varbanov
2015-02-11T09:19:55Z

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@mm-sol.com>
> написал:
>
>> Hi,
>>
>> On 02/11/2015 05:35 AM, Viresh Kumar wrote:
>>
>>> On 11 February 2015 at 00:31, Matwey V. Kornilov <matwey@sai.msu.ru>
>>> 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@sai.msu.ru>
>>>> ---
>>>> 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
>>
>>
>