linux-kernel - [PATCH v17 13/14] gpio: max3191x: Utilize the for_each_set

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Date:   Wed,  9 Oct 2019 11:27:11 -0400
From:   William Breathitt Gray <vilhelm.gray@...il.com>
To:     linus.walleij@...aro.org, bgolaszewski@...libre.com,
        akpm@...ux-foundation.org
Cc:     linux-gpio@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-arch@...r.kernel.org, andriy.shevchenko@...ux.intel.com,
        linux@...musvillemoes.dk, yamada.masahiro@...ionext.com,
        linux-arm-kernel@...ts.infradead.org, linux-pm@...r.kernel.org,
        geert@...ux-m68k.org, preid@...ctromag.com.au, lukas@...ner.de,
        sean.nyekjaer@...vas.dk, morten.tiljeset@...vas.dk,
        William Breathitt Gray <vilhelm.gray@...il.com>,
        Mathias Duckeck <m.duckeck@...bus.de>
Subject: [PATCH v17 13/14] 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.

Cc: Mathias Duckeck <m.duckeck@...bus.de>
Cc: Lukas Wunner <lukas@...ner.de>
Signed-off-by: William Breathitt Gray <vilhelm.gray@...il.com>
---
 drivers/gpio/gpio-max3191x.c | 19 ++++++++++---------
 1 file changed, 10 insertions(+), 9 deletions(-)

diff --git a/drivers/gpio/gpio-max3191x.c b/drivers/gpio/gpio-max3191x.c
index 4b4b2ceb82fc..0242c6187bf5 100644
--- a/drivers/gpio/gpio-max3191x.c
+++ b/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:
-- 
2.23.0