linux-kernel - [PATCH v3 4/8] gpio: 104-idi-48: Utilize for_each_set

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Message-Id: <49e61fc62ad34928ae05eaa77d757070636aefb8.1526397764.git.vilhelm.gray@gmail.com>
Date:   Tue, 15 May 2018 11:50:39 -0400
From:   William Breathitt Gray <vilhelm.gray@...il.com>
To:     linus.walleij@...aro.org
Cc:     linux-gpio@...r.kernel.org, linux-arch@...r.kernel.org,
        linux-kernel@...r.kernel.org,
        William Breathitt Gray <vilhelm.gray@...il.com>
Subject: [PATCH v3 4/8] gpio: 104-idi-48: Utilize for_each_set_clump macro

Replace verbose implementation in get_multiple/set_multiple callbacks
with for_each_set_clump macro to simplify code and improve clarity.

Signed-off-by: William Breathitt Gray <vilhelm.gray@...il.com>
---
 drivers/gpio/gpio-104-idi-48.c | 32 ++++----------------------------
 1 file changed, 4 insertions(+), 28 deletions(-)

diff --git a/drivers/gpio/gpio-104-idi-48.c b/drivers/gpio/gpio-104-idi-48.c
index 2c9738adb3a6..f8de5560174f 100644
--- a/drivers/gpio/gpio-104-idi-48.c
+++ b/drivers/gpio/gpio-104-idi-48.c
@@ -94,41 +94,17 @@ static int idi_48_gpio_get_multiple(struct gpio_chip *chip, unsigned long *mask,
 {
 	struct idi_48_gpio *const idi48gpio = gpiochip_get_data(chip);
 	size_t i;
+	size_t word;
+	unsigned int offset;
 	static const size_t ports[] = { 0, 1, 2, 4, 5, 6 };
-	const unsigned int gpio_reg_size = 8;
-	unsigned int bits_offset;
-	size_t word_index;
-	unsigned int word_offset;
-	unsigned long word_mask;
-	const unsigned long port_mask = GENMASK(gpio_reg_size - 1, 0);
 	unsigned long port_state;
 
 	/* clear bits array to a clean slate */
 	bitmap_zero(bits, chip->ngpio);
 
-	/* get bits are evaluated a gpio port register at a time */
-	for (i = 0; i < ARRAY_SIZE(ports); i++) {
-		/* gpio offset in bits array */
-		bits_offset = i * gpio_reg_size;
-
-		/* word index for bits array */
-		word_index = BIT_WORD(bits_offset);
-
-		/* gpio offset within current word of bits array */
-		word_offset = bits_offset % BITS_PER_LONG;
-
-		/* mask of get bits for current gpio within current word */
-		word_mask = mask[word_index] & (port_mask << word_offset);
-		if (!word_mask) {
-			/* no get bits in this port so skip to next one */
-			continue;
-		}
-
-		/* read bits from current gpio port */
+	for_each_set_clump(i, word, offset, mask, ARRAY_SIZE(ports), 8) {
 		port_state = inb(idi48gpio->base + ports[i]);
-
-		/* store acquired bits at respective bits array offset */
-		bits[word_index] |= port_state << word_offset;
+		bits[word] |= port_state << offset;
 	}
 
 	return 0;
-- 
2.17.0