spi: use is_power_of_2 instead of hweight32 in spi_nor_write()

hweight32 is a somewhat expensive way to check for power-of-2. Use the
is_power_of_2 helper, which does the standard and cheap idiom
foo&(foo-1)==0.

add/remove: 0/0 grow/shrink: 0/1 up/down: 0/-96 (-96)
Function                                     old     new   delta
spi_nor_write                                388     292     -96

Signed-off-by: Rasmus Villemoes <rasmus.villemoes@prevas.dk>
Acked-by: Vignesh Raghavendra <vigneshr@ti.com>
Acked-by: Jagan Teki <jagan@amarulasolutions.com>

diff --git a/drivers/mtd/spi/spi-nor-core.c b/drivers/mtd/spi/spi-nor-core.c
index 7b6ad49..3bf8ddf 100644 (file)
--- a/drivers/mtd/spi/spi-nor-core.c
+++ b/drivers/mtd/spi/spi-nor-core.c
@@ -1246,11 +1246,8 @@ static int spi_nor_write(struct mtd_info *mtd, loff_t to, size_t len,
                 * If page_size is a power of two, the offset can be quickly
                 * calculated with an AND operation. On the other cases we
                 * need to do a modulus operation (more expensive).
-                * Power of two numbers have only one bit set and we can use
-                * the instruction hweight32 to detect if we need to do a
-                * modulus (do_div()) or not.
                 */
-               if (hweight32(nor->page_size) == 1) {
+               if (is_power_of_2(nor->page_size)) {
                        page_offset = addr & (nor->page_size - 1);
                } else {
                        u64 aux = addr;