iio: core: added support for IIO_VAL_INT

BugLink: https://bugs.launchpad.net/bugs/1676356

Added core support for IIO_VAL_INT in write_raw_get_fmt function.
Signed-off-by: Sean Nyekjaer <sean.nyekjaer@prevas.dk>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
(cherry picked from commit f47dff32)
Signed-off-by: Shrirang Bagul <shrirang.bagul@canonical.com>
Acked-by: Stefan Bader <stefan.bader@canonical.com>
Acked-by: Tim Gardner <tim.gardner@canonical.com>
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>

drivers/iio/industrialio-core.c

@@ -510,6 +510,12 @@ int iio_str_to_fixpoint(const char *str, int fract_mult,
 	int i = 0, f = 0;
 	bool integer_part = true, negative = false;
 
+	if (fract_mult == 0) {
+		*fract = 0;
+
+		return kstrtoint(str, 0, integer);
+	}
+
 	if (str[0] == '-') {
 		negative = true;
 		str++;
@@ -569,6 +575,9 @@ static ssize_t iio_write_channel_info(struct device *dev,
 	if (indio_dev->info->write_raw_get_fmt)
 		switch (indio_dev->info->write_raw_get_fmt(indio_dev,
 			this_attr->c, this_attr->address)) {
+		case IIO_VAL_INT:
+			fract_mult = 0;
+			break;
 		case IIO_VAL_INT_PLUS_MICRO:
 			fract_mult = 100000;
 			break;