| Message ID | CACRpkdbr9-hsFzPvOpwiVg=X=avx8fb14HhWWXNda7gGZaM2Gg@mail.gmail.com |
|---|---|
| State | New |
| Headers | show |
> Linus Walleij <linus.walleij@linaro.org> hat am 15. März 2017 um 09:46 geschrieben: > > > On Tue, Mar 14, 2017 at 9:09 PM, Stefan Wahren <stefan.wahren@i2se.com> wrote: > >> Linus Walleij <linus.walleij@linaro.org> hat am 14. März 2017 um 15:39 geschrieben: > > >> If you want to do it statically, at boot time: > >> Just add some NOOP function (i.e. a function that result in > >> zero register writes or anything) named "videocore-reserved" or > >> something to the driver in drivers/pinctrl/bcm/pinctrl-bcm2835.c, > >> make it applicable to the affected pins, making it possible > >> to create a state that will combine the function "videocore-reserved" > >> with these pins, resulting in them being exclusively used for > >> that. > > > > If you speak of a NOOP function, do you mean a "dummy" pin function > > which is configured by the device tree? Like extending the "brcm,function" > > property from the existing binding? > > No, a function for videocore defined by the driver in > drivers/pinctrl/bcm/pinctrl-bcm2835.c > and then used by the device tree. > > Looking at the BCM2835 syntax (hope I get it right), in the end you should > be able to do this: > > videocore: videocore { > brcm,pins = <12, 13, 14, 15, 16, 17, 18, 19, 20>; > brcm,function = <BCM2835_FSEL_VIDEOCORE>; > }; > > So BCM2835_FSEL_VIDEOCORE need to be defined in the > DT include and made available as a muxing option inside the driver, with > the effect that nothing really happens when you select it. > > The point is that the pinctrl core will then regard the pin as taken > (this can be verified in debugfs) and then no other function can go > in and use the pin by mistake. > > Something like this: > > From d188c03c1fba7d1223c1dafcb8b977e383298ef4 Mon Sep 17 00:00:00 2001 > From: Linus Walleij <linus.walleij@linaro.org> > Date: Wed, 15 Mar 2017 09:45:37 +0100 > Subject: [PATCH] Stab at videocore function > > Signed-off-by: Linus Walleij <linus.walleij@linaro.org> Again, thanks a lot Stefan > > Yours, > Linus Walleij -- To unsubscribe from this list: send the line "unsubscribe linux-gpio" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/drivers/pinctrl/bcm/pinctrl-bcm2835.c b/drivers/pinctrl/bcm/pinctrl-bcm2835.c index 85d009112864..213ca5117bd3 100644 --- a/drivers/pinctrl/bcm/pinctrl-bcm2835.c +++ b/drivers/pinctrl/bcm/pinctrl-bcm2835.c @@ -41,6 +41,7 @@ #include <linux/slab.h> #include <linux/spinlock.h> #include <linux/types.h> +#include <dt-bindings/pinctrl/bcm2835.h> #define MODULE_NAME "pinctrl-bcm2835" #define BCM2835_NUM_GPIOS 54 @@ -226,6 +227,9 @@ enum bcm2835_fsel { BCM2835_FSEL_MASK = 0x7, }; +/* This function can no be configured in the hardware register */ +#define BCM2835_FSEL_VIDEOCORE 8 + static const char * const bcm2835_functions[BCM2835_FSEL_COUNT] = { [BCM2835_FSEL_GPIO_IN] = "gpio_in", [BCM2835_FSEL_GPIO_OUT] = "gpio_out", @@ -235,6 +239,7 @@ static const char * const bcm2835_functions[BCM2835_FSEL_COUNT] = { [BCM2835_FSEL_ALT3] = "alt3", [BCM2835_FSEL_ALT4] = "alt4", [BCM2835_FSEL_ALT5] = "alt5", + [BCM2835_FSEL_VIDEOCORE] = "videocore", }; static const char * const irq_type_names[] = { @@ -879,6 +884,10 @@ static int bcm2835_pmx_set(struct pinctrl_dev *pctldev, { struct bcm2835_pinctrl *pc = pinctrl_dev_get_drvdata(pctldev); + /* This pin is set as used by the videocore - do nothing */ + if (func_selector == BCM2835_FSEL_VIDEOCORE) + return 0; + bcm2835_pinctrl_fsel_set(pc, group_selector, func_selector); return 0; diff --git a/include/dt-bindings/pinctrl/bcm2835.h b/include/dt-bindings/pinctrl/bcm2835.h index e4e4fdf5d38f..2de2a2eb2fbc 100644 --- a/include/dt-bindings/pinctrl/bcm2835.h +++ b/include/dt-bindings/pinctrl/bcm2835.h @@ -23,6 +23,7 @@ #define BCM2835_FSEL_ALT1 5 #define BCM2835_FSEL_ALT2 6 #define BCM2835_FSEL_ALT3 7 +#define BCM2835_FSEL_VIDEOCORE 8 /* brcm,pull property */ #define BCM2835_PUD_OFF 0