[PATCH 2/2] ARM: mx5/mx53_evk: Remove unneeded gpio_set_value call
Julia Lawall
julia at diku.dk
Wed Mar 16 05:15:35 EDT 2011
I'll see if I can incorporate the use of gpio_request_one in my rule.
julia
On Wed, 16 Mar 2011, Uwe Kleine-König wrote:
> [added some people to Cc:]
>
> Hello Julia,
>
> On Tue, Mar 15, 2011 at 11:19:53AM +0100, Julia Lawall wrote:
> > On Tue, 15 Mar 2011, Uwe Kleine-König wrote:
> >
> > > On Tue, Mar 15, 2011 at 10:41:37AM +0100, Julia Lawall wrote:
> > > > I tried the following
> > > >
> > > > @@
> > > > expression E1,E2;
> > > > @@
> > > >
> > > > gpio_direction_output(E1,E2);
> > > > ...
> > > > - gpio_set_value(E1,E2);
> > > >
> > > > and found occurrences in 15 files. In some cases there seems to be some
> > > > delay before the call to gpio_set_value. Does that have any impacton
> > > > whether it is needed?
> > > gpio_direction_output(E1,E2) implies gpio_set_value(E1,E2), so unless
> > > there is a gpio_set_value(E1,!E2) before gpio_set_value(E1,E2) is a
> > > noop.
> > >
> > > I still don't know how to work with coccinelle, so if you point me to a
> > > concrete location I can be more specific.
> >
> > OK. I have changed the semantic patch to the following:
> >
> > @@
> > expression E1,E2,E3;
> > @@
> >
> > gpio_direction_output(E1,E2);
> > ... when != gpio_set_value(E1,E3)
> > - gpio_set_value(E1,E2);
> >
> > Now it doesn't do all the cases where there is an earlier set ofr some
> > other value. The patch I obtain is below. This only concerns 5 files.
> > I haven't checked the result at all.
> Thanks. So here comes the check.
>
> > diff -u -p a/arch/arm/mach-mx5/board-mx51_babbage.c b/arch/arm/mach-mx5/board-mx51_babbage.c
> > --- a/arch/arm/mach-mx5/board-mx51_babbage.c 2011-02-19 08:28:51.000000000 +0100
> > +++ b/arch/arm/mach-mx5/board-mx51_babbage.c 2011-03-15 11:17:03.000000000 +0100
> > @@ -218,7 +218,6 @@ static inline void babbage_usbhub_reset(
> >
> > /* USB HUB RESET - De-assert USB HUB RESET_N */
> > msleep(1);
> > - gpio_set_value(BABBAGE_USB_HUB_RESET, 0);
> > msleep(1);
> > gpio_set_value(BABBAGE_USB_HUB_RESET, 1);
> > }
> This function is a bit confusing:
>
> /* Bring USB hub out of reset */
> ret = gpio_request(BABBAGE_USB_HUB_RESET, "GPIO1_7");
> if (ret) {
> ...
> return;
> }
> gpio_direction_output(BABBAGE_USB_HUB_RESET, 0);
> /* USB HUB RESET - De-assert USB HUB RESET_N */
> msleep(1);
> gpio_set_value(BABBAGE_USB_HUB_RESET, 0);
> msleep(1);
> gpio_set_value(BABBAGE_USB_HUB_RESET, 1);
>
> IMHO the comments are misleading. I'd suggest:
>
> ret = gpio_request_one(BABBAGE_USB_HUB_RESET,
> GPIOF_DIR_OUT | GPIOF_INIT_LOW, "USB hub reset#");
> if (ret) {
> pr_err("failed to request gpio for USB hub reset#: %d\n", ret);
> return;
> }
> msleep(2);
> gpio_set_value(BABBAGE_USB_HUB_RESET, 1);
>
> Fabio?
>
> > @@ -234,7 +233,6 @@ static inline void babbage_fec_reset(voi
> > return;
> > }
> > gpio_direction_output(BABBAGE_FEC_PHY_RESET, 0);
> > - gpio_set_value(BABBAGE_FEC_PHY_RESET, 0);
> > msleep(1);
> > gpio_set_value(BABBAGE_FEC_PHY_RESET, 1);
> > }
> should use
> gpio_request_one(BABBAGE_FEC_PHY_RESET,
> GPIOF_DIR_OUT | GPIOF_INIT_LOW, "fec-phy-reset");
>
> > diff -u -p a/arch/arm/mach-mx5/board-mx53_evk.c b/arch/arm/mach-mx5/board-mx53_evk.c
> > --- a/arch/arm/mach-mx5/board-mx53_evk.c 2011-03-14 17:19:13.000000000 +0100
> > +++ b/arch/arm/mach-mx5/board-mx53_evk.c 2011-03-15 11:17:03.000000000 +0100
> > @@ -88,7 +88,6 @@ static inline void mx53_evk_fec_reset(vo
> > return;
> > }
> > gpio_direction_output(SMD_FEC_PHY_RST, 0);
> > - gpio_set_value(SMD_FEC_PHY_RST, 0);
> > msleep(1);
> > gpio_set_value(SMD_FEC_PHY_RST, 1);
> > }
> ditto
>
> > diff -u -p a/arch/arm/mach-omap2/board-omap3evm.c b/arch/arm/mach-omap2/board-omap3evm.c
> > --- a/arch/arm/mach-omap2/board-omap3evm.c 2011-03-14 17:19:13.000000000 +0100
> > +++ b/arch/arm/mach-omap2/board-omap3evm.c 2011-03-15 11:17:04.000000000 +0100
> > @@ -860,7 +860,6 @@ static void __init omap3_evm_init(void)
> > omap_mux_init_gpio(61, OMAP_PIN_INPUT_PULLUP);
> > gpio_request(OMAP3_EVM_EHCI_SELECT, "select EHCI port");
> > gpio_direction_output(OMAP3_EVM_EHCI_SELECT, 0);
> > - gpio_set_value(OMAP3_EVM_EHCI_SELECT, 0);
> >
> > /* setup EHCI phy reset config */
> > omap_mux_init_gpio(21, OMAP_PIN_INPUT_PULLUP);
> ditto
>
> > diff -u -p a/arch/arm/mach-omap2/board-omap4panda.c b/arch/arm/mach-omap2/board-omap4panda.c
> > --- a/arch/arm/mach-omap2/board-omap4panda.c 2011-03-14 17:19:13.000000000 +0100
> > +++ b/arch/arm/mach-omap2/board-omap4panda.c 2011-03-15 11:17:04.000000000 +0100
> > @@ -129,7 +129,6 @@ static void __init omap4_ehci_init(void)
> > }
> > gpio_export(GPIO_HUB_POWER, 0);
> > gpio_direction_output(GPIO_HUB_POWER, 0);
> > - gpio_set_value(GPIO_HUB_POWER, 0);
> Should use gpio_request_one, too. And IMHO gpio_export should only be
> called after the direction is set (which is an obsolete comment when
> gpio_request_one is used).
>
> > /* reset phy+hub */
> > ret = gpio_request(GPIO_HUB_NRESET, "hub_nreset");
> > @@ -139,7 +138,6 @@ static void __init omap4_ehci_init(void)
> > }
> > gpio_export(GPIO_HUB_NRESET, 0);
> > gpio_direction_output(GPIO_HUB_NRESET, 0);
> > - gpio_set_value(GPIO_HUB_NRESET, 0);
> > gpio_set_value(GPIO_HUB_NRESET, 1);
> >
> > usbhs_init(&usbhs_bdata);
> ditto
>
> > diff -u -p a/arch/arm/mach-pxa/am300epd.c b/arch/arm/mach-pxa/am300epd.c
> > --- a/arch/arm/mach-pxa/am300epd.c 2010-03-18 09:06:45.000000000 +0100
> > +++ b/arch/arm/mach-pxa/am300epd.c 2011-03-15 11:17:04.000000000 +0100
> > @@ -150,8 +150,6 @@ static int am300_init_gpio_regs(struct b
> > gpio_direction_output(i, 0);
> >
> > /* go into command mode */
> > - gpio_set_value(CFG_GPIO_PIN, 1);
> > - gpio_set_value(RST_GPIO_PIN, 0);
> > msleep(10);
> > gpio_set_value(RST_GPIO_PIN, 1);
> > msleep(10);
> This can probably make use of gpio_request_array.
>
> Best regards
> Uwe
>
> --
> Pengutronix e.K. | Uwe Kleine-König |
> Industrial Linux Solutions | http://www.pengutronix.de/ |
>
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