Dear Shawn Guo, > Apart from my comments below, we really need to know Rob and Grant's > opinion on this. Hm ... so why don't you actually write per-board driver ? :-) That'd handle every single board very well, you'd configure the GPIOs there, every single additional necessary thing that has to be configured would sink there too etc. > On Mon, May 21, 2012 at 05:23:52PM +0800, Richard Zhao wrote: > > Sometimes, boards have gpios that don't own by any driver or owner > > by a generic driver that don't like hacks. Such gpios is normally > > output and need setup once on boot. So I introduce the config-on-boot > > gpios. > > > > Signed-off-by: Richard Zhao <richard.zhao@xxxxxxxxxxxxx> > > Cc: Shawn Guo <shawn.guo@xxxxxxxxxx> > > Cc: Rob Herring <rob.herring@xxxxxxxxxxx> > > Cc: Grant Likely <grant.likely@xxxxxxxxxxxx> > > --- > > > > arch/arm/boot/dts/imx6q-sabrelite.dts | 7 ++++++ > > arch/arm/mach-imx/mach-imx6q.c | 35 > > +++++++++++++++++++++++++++++++++ 2 files changed, 42 insertions(+), 0 > > deletions(-) > > > > diff --git a/arch/arm/boot/dts/imx6q-sabrelite.dts > > b/arch/arm/boot/dts/imx6q-sabrelite.dts index e0ec929..1dd2261 100644 > > --- a/arch/arm/boot/dts/imx6q-sabrelite.dts > > +++ b/arch/arm/boot/dts/imx6q-sabrelite.dts > > @@ -17,6 +17,13 @@ > > > > model = "Freescale i.MX6 Quad SABRE Lite Board"; > > compatible = "fsl,imx6q-sabrelite", "fsl,imx6q"; > > > > + config-on-boot { > > + output-gpios = < > > + &gpio3 22 0>; /* vbus reset */ > > + output-gpio-values = < > > + 1>; /* vbus reset */ > > + }; > > + > > So it looks like something not specific to imx board but generic to > other boards. If so, we may need to come up with a generic binding > document for this. > > Is this only used to configure output pin? Will there be any pin that > needs to be configured as input but not owned by any driver? Hopefully > not. > > > memory { > > > > reg = <0x10000000 0x40000000>; > > > > }; > > > > diff --git a/arch/arm/mach-imx/mach-imx6q.c > > b/arch/arm/mach-imx/mach-imx6q.c index b47e98b..577cf19 100644 > > --- a/arch/arm/mach-imx/mach-imx6q.c > > +++ b/arch/arm/mach-imx/mach-imx6q.c > > @@ -19,6 +19,7 @@ > > > > #include <linux/irqdomain.h> > > #include <linux/of.h> > > #include <linux/of_address.h> > > > > +#include <linux/of_gpio.h> > > > > #include <linux/of_irq.h> > > #include <linux/of_platform.h> > > #include <linux/pinctrl/machine.h> > > > > @@ -113,6 +114,38 @@ static void __init imx6q_sabrelite_init(void) > > > > imx6q_sabrelite_cko1_setup(); > > > > } > > > > +static void __init imx6q_config_on_boot(void) > > Do you intend to make this function non-gpio-config only. Otherwise, > we may need to have "gpio" in the function name, as well as the > "config-on-boot" node name. > > Also, if we define the binding as generic one, we may need to find a > common place to implement the function. > > > +{ > > + struct device_node *np; > > + struct property *pp; > > + int cnt, len, i; > > + int gpio; > > + > > + np = of_find_node_by_path("/config-on-boot"); > > + if (!np) > > + return; > > + cnt = of_gpio_named_count(np, "output-gpios"); > > + pp = of_find_property(np, "output-gpio-values", &len); > > + if (!pp || cnt != len / sizeof(u32)) { > > + pr_err("Invalid config-on-boot gpios!\n"); > > + of_node_put(np); > > + return; > > + } > > + for (i = 0; i < cnt; i++) { > > + gpio = of_get_named_gpio(np, "output-gpios", i); > > + if (gpio_is_valid(gpio)) > > + gpio_request_one(gpio, GPIOF_OUT_INIT_HIGH, > > + "config-on-boot"); > > So all the gpios will use the same name. > > And doesn't the reset generally need a pulse or edge signal, e.g. pull > down for a msec and pull up? > > Regards, > Shawn > > > + } > > + > > + of_node_put(np); > > +} > > + > > +static void __init imx6q_post_populate(void) > > +{ > > + imx6q_config_on_boot(); > > +} > > + > > > > static void __init imx6q_init_machine(void) > > { > > > > /* > > > > @@ -126,6 +159,8 @@ static void __init imx6q_init_machine(void) > > > > of_platform_populate(NULL, of_default_bus_match_table, NULL, NULL); > > > > + imx6q_post_populate(); > > + > > > > imx6q_pm_init(); > > > > } Best regards, Marek Vasut -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html