gpio: max3191x: utilize the for_each_set_clump8 macro

Replace verbose implementation in get_multiple callback with
for_each_set_clump8 macro to simplify code and improve clarity.

Link: http://lkml.kernel.org/r/c2b1ed62caf6fce6e5681809a50c05ce6acdf2a6.1570641097.git.vilhelm.gray@gmail.comSigned-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Mathias Duckeck <m.duckeck@kunbus.de>
Cc: Lukas Wunner <lukas@wunner.de>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Geert Uytterhoeven <geert+renesas@glider.be>
Cc: Linus Walleij <linus.walleij@linaro.org>
Cc: Masahiro Yamada <yamada.masahiro@socionext.com>
Cc: Morten Hein Tiljeset <morten.tiljeset@prevas.dk>
Cc: Phil Reid <preid@electromag.com.au>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Sean Nyekjaer <sean.nyekjaer@prevas.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/gpio/gpio-max3191x.c

@@ -31,6 +31,7 @@
  */
 
 #include <linux/bitmap.h>
+#include <linux/bitops.h>
 #include <linux/crc8.h>
 #include <linux/gpio/consumer.h>
 #include <linux/gpio/driver.h>
@@ -232,16 +233,20 @@ static int max3191x_get_multiple(struct gpio_chip *gpio, unsigned long *mask,
 				 unsigned long *bits)
 {
 	struct max3191x_chip *max3191x = gpiochip_get_data(gpio);
-	int ret, bit = 0, wordlen = max3191x_wordlen(max3191x);
+	const unsigned int wordlen = max3191x_wordlen(max3191x);
+	int ret;
+	unsigned long bit;
+	unsigned long gpio_mask;
+	unsigned long in;
 
 	mutex_lock(&max3191x->lock);
 	ret = max3191x_readout_locked(max3191x);
 	if (ret)
 		goto out_unlock;
 
-	while ((bit = find_next_bit(mask, gpio->ngpio, bit)) != gpio->ngpio) {
+	bitmap_zero(bits, gpio->ngpio);
+	for_each_set_clump8(bit, gpio_mask, mask, gpio->ngpio) {
 		unsigned int chipnum = bit / MAX3191X_NGPIO;
-		unsigned long in, shift, index;
 
 		if (max3191x_chip_is_faulting(max3191x, chipnum)) {
 			ret = -EIO;
@@ -249,12 +254,8 @@ static int max3191x_get_multiple(struct gpio_chip *gpio, unsigned long *mask,
 		}
 
 		in = ((u8 *)max3191x->xfer.rx_buf)[chipnum * wordlen];
-		shift = round_down(bit % BITS_PER_LONG, MAX3191X_NGPIO);
-		index = bit / BITS_PER_LONG;
-		bits[index] &= ~(mask[index] & (0xff << shift));
-		bits[index] |= mask[index] & (in << shift); /* copy bits */
-
-		bit = (chipnum + 1) * MAX3191X_NGPIO; /* go to next chip */
+		in &= gpio_mask;
+		bitmap_set_value8(bits, in, bit);
 	}
 
 out_unlock: