[PATCH v2 1/3] kernel: Provide a __pow10() function

[Florian Fainelli <f.fainelli@gmail.com>]

Provide a simple macro that can return the value of 10 raised to a
positive integer. We are going to use this in order to scale units from
firmware to HWMON.

Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
---
 include/linux/kernel.h | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/include/linux/kernel.h b/include/linux/kernel.h
index 2d14e21c16c0..62fc8bd84bc9 100644
--- a/include/linux/kernel.h
+++ b/include/linux/kernel.h
@@ -294,6 +294,17 @@ static inline u32 reciprocal_scale(u32 val, u32 ep_ro)
 	return (u32)(((u64) val * ep_ro) >> 32);
 }
 
+/* Return in f the value of 10 raise to the power x */
+#define __pow10(x, f)(					\
+{							\
+	typeof(x) __x = abs(x);				\
+	f = 1;						\
+	while (__x--)					\
+		f *= 10;				\
+	f;						\
+}							\
+)
+
 #if defined(CONFIG_MMU) && \
 	(defined(CONFIG_PROVE_LOCKING) || defined(CONFIG_DEBUG_ATOMIC_SLEEP))
 #define might_fault() __might_fault(__FILE__, __LINE__)
-- 
2.17.1