RE: [PATCH 08/09] ARM: s3c2440: gta02: Request usb pullup pin beforeusing it

From: Kukjin Kim
Date: Mon Feb 28 2011 - 05:44:34 EST


Lars-Peter Clausen wrote:
>
> On 02/28/2011 07:16 AM, Kukjin Kim wrote:
> > Lars-Peter Clausen wrote:
> >>
> >> Request the gpio pin used to control the usb pullup before using it to
> > avoid
> >> a
> >> runtime warning about an auto-requested gpio.
> >>
> >> Signed-off-by: Lars-Peter Clausen <lars@xxxxxxxxxx>
> >> ---
> >> arch/arm/mach-s3c2440/mach-gta02.c | 17 +++++++++++++++--
> >> 1 files changed, 15 insertions(+), 2 deletions(-)
> >>
> >> diff --git a/arch/arm/mach-s3c2440/mach-gta02.c
> > b/arch/arm/mach-s3c2440/mach-
> >> gta02.c
> >> index 1396639..94456fa 100644
> >> --- a/arch/arm/mach-s3c2440/mach-gta02.c
> >> +++ b/arch/arm/mach-s3c2440/mach-gta02.c
> >> @@ -451,11 +451,11 @@ static void gta02_udc_command(enum
s3c2410_udc_cmd_e
> >> cmd)
> >> switch (cmd) {
> >> case S3C2410_UDC_P_ENABLE:
> >> pr_debug("%s S3C2410_UDC_P_ENABLE\n", __func__);
> >> - gpio_direction_output(GTA02_GPIO_USB_PULLUP, 1);
> >> + gpio_set_value(GTA02_GPIO_USB_PULLUP, 1);
> >
> > How about following instead?
> > gpio_request(GTA02_GPIO_USB_PULLUP, "USB_PULLUP");
> > gpio_direction_output(GTA02_GPIO_USB_PULLUP, 1);
> > gpio_free(GTA02_GPIO_USB_PULLUP);
> >
>
> I don't think that is a good idea. This gpio should really be reserved for
> the
> udc driver. If it is freed again, it could be requested from someone else
> which
> could lead to undefined behaviour.
>
Yes right, but I mean the board designer already knows the usage of
regarding GPIOs on his board.
So why do we really need gpio_request for it?...

Thanks.

Best regards,
Kgene.
--
Kukjin Kim <kgene.kim@xxxxxxxxxxx>, Senior Engineer,
SW Solution Development Team, Samsung Electronics Co., Ltd.

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