Hi Sascha, On Mon, Aug 03, 2020 at 10:22:22PM +0200, Sascha Hauer wrote: > Hi Oleksij, > > On Thu, Jul 23, 2020 at 12:33:23PM +0200, Oleksij Rempel wrote: > > Some boards provide a board version and/or ID coded by pull-up/down > > resistors connected to the gpio pins (or pins which can be multiplexed > > at some point as gpio). In this case every one implements own gpio id > > reader function. > > > > To avoid it, provide the common helper function to extract a value out > > of provided gpio array. > > > > Signed-off-by: Oleksij Rempel > > --- > > drivers/gpio/gpiolib.c | 28 ++++++++++++++++++++++++++++ > > include/gpio.h | 5 +++++ > > 2 files changed, 33 insertions(+) > > > > diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c > > index 27674af54c..2e9150d2ea 100644 > > --- a/drivers/gpio/gpiolib.c > > +++ b/drivers/gpio/gpiolib.c > > @@ -381,6 +381,34 @@ void gpio_free_array(const struct gpio *array, size_t num) > > } > > EXPORT_SYMBOL_GPL(gpio_free_array); > > > > +int gpio_array_to_id(const struct gpio *array, size_t num, u32 *val) > > +{ > > + u32 id = 0; > > + int ret, i; > > + > > + if (num > 32) > > + return -EOVERFLOW; > > + > > + ret = gpio_request_array(array, num); > > + if (ret) > > + return ret; > > This function expects an unrequested array and returns with the array > requested. This is at least inconsistent. fixed > > + > > + /* Wait untill logic level will be stable */ > > s/untill/until/ fixed > > + udelay(5); > > This delay looks rather arbitrary. Is it really necessary? The vendor reported that otherwise will not always read proper value. > > + for (i = 0; i < num; i++) { > > + ret = gpio_is_active(array[i].gpio); > > + if (ret < 0) > > + return ret; > > + > > + id |= ret << i; > > 'ret' is signed. Does this work when i == 31 ? yes, it works Regards, Oleksij -- Pengutronix e.K. | | Steuerwalder Str. 21 | http://www.pengutronix.de/ | 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 |