2 files changed, 66 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);
diff --git a/include/linux/iio/iio.h b/include/linux/iio/iio.h
index adca93a999a7..da8c776ba0bd 100644
--- a/include/linux/iio/iio.h
+++ b/include/linux/iio/iio.h
@@ -620,6 +620,9 @@ static inline struct dentry *iio_get_debugfs_dentry(struct iio_dev *indio_dev)
 };
 #endif
 
+int iio_str_to_fixpoint(const char *str, int fract_mult, int *integer,
+        int *fract);
+
 /**
  * IIO_DEGREE_TO_RAD() - Convert degree to rad
  * @deg: A value in degree