1 files changed, 63 insertions, 35 deletions

diff --git a/drivers/iio/industrialio-core.c b/drivers/iio/industrialio-core.c
index 3dccd6c3a889..8848f16c547b 100644
--- a/drivers/iio/industrialio-core.c
+++ b/drivers/iio/industrialio-core.c
@@ -408,6 +408,64 @@ static ssize_t iio_read_channel_info(struct device *dev,
 	}
 }
 
+/**
+ * iio_str_to_fixpoint() - Parse a fixed-point number from a string
+ * @str: The string to parse
+ * @fract_mult: Multiplier for the first decimal place, should be a power of 10
+ * @integer: The integer part of the number
+ * @fract: The fractional part of the number
+ *
+ * Returns 0 on success, or a negative error code if the string could not be
+ * parsed.
+ */
+int iio_str_to_fixpoint(const char *str, int fract_mult,
+	int *integer, int *fract)
+{
+	int i = 0, f = 0;
+	bool integer_part = true, negative = false;
+
+	if (str[0] == '-') {
+		negative = true;
+		str++;
+	} else if (str[0] == '+') {
+		str++;
+	}
+
+	while (*str) {
+		if ('0' <= *str && *str <= '9') {
+			if (integer_part) {
+				i = i * 10 + *str - '0';
+			} else {
+				f += fract_mult * (*str - '0');
+				fract_mult /= 10;
+			}
+		} else if (*str == '\n') {
+			if (*(str + 1) == '\0')
+				break;
+			else
+				return -EINVAL;
+		} else if (*str == '.' && integer_part) {
+			integer_part = false;
+		} else {
+			return -EINVAL;
+		}
+		str++;
+	}
+
+	if (negative) {
+		if (i)
+			i = -i;
+		else
+			f = -f;
+	}
+
+	*integer = i;
+	*fract = f;
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(iio_str_to_fixpoint);
+
 static ssize_t iio_write_channel_info(struct device *dev,
 				      struct device_attribute *attr,
 				      const char *buf,
@@ -415,8 +473,8 @@ static ssize_t iio_write_channel_info(struct device *dev,
 {
 	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
 	struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
-	int ret, integer = 0, fract = 0, fract_mult = 100000;
-	bool integer_part = true, negative = false;
+	int ret, fract_mult = 100000;
+	int integer, fract;
 
 	/* Assumes decimal - precision based on number of digits */
 	if (!indio_dev->info->write_raw)
@@ -435,39 +493,9 @@ static ssize_t iio_write_channel_info(struct device *dev,
 			return -EINVAL;
 		}
 
-	if (buf[0] == '-') {
-		negative = true;
-		buf++;
-	} else if (buf[0] == '+') {
-		buf++;
-	}
-
-	while (*buf) {
-		if ('0' <= *buf && *buf <= '9') {
-			if (integer_part)
-				integer = integer*10 + *buf - '0';
-			else {
-				fract += fract_mult*(*buf - '0');
-				fract_mult /= 10;
-			}
-		} else if (*buf == '\n') {
-			if (*(buf + 1) == '\0')
-				break;
-			else
-				return -EINVAL;
-		} else if (*buf == '.' && integer_part) {
-			integer_part = false;
-		} else {
-			return -EINVAL;
-		}
-		buf++;
-	}
-	if (negative) {
-		if (integer)
-			integer = -integer;
-		else
-			fract = -fract;
-	}
+	ret = iio_str_to_fixpoint(buf, fract_mult, &integer, &fract);
+	if (ret)
+		return ret;
 
 	ret = indio_dev->info->write_raw(indio_dev, this_attr->c,
 					 integer, fract, this_attr->address);