linux-kernel - [PATCH v3 6/8] gpio: ws16c48: Utilize for_each_set

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Message-Id: <bb6ec86ff81f5bd0104c3c138753ca19a3e2821e.1526397764.git.vilhelm.gray@gmail.com>
Date:   Tue, 15 May 2018 11:51:01 -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 6/8] gpio: ws16c48: 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-ws16c48.c | 66 +++++++++----------------------------
 1 file changed, 16 insertions(+), 50 deletions(-)

diff --git a/drivers/gpio/gpio-ws16c48.c b/drivers/gpio/gpio-ws16c48.c
index c7028eb0b8e1..625336376b5d 100644
--- a/drivers/gpio/gpio-ws16c48.c
+++ b/drivers/gpio/gpio-ws16c48.c
@@ -134,42 +134,19 @@ static int ws16c48_gpio_get_multiple(struct gpio_chip *chip,
 	unsigned long *mask, unsigned long *bits)
 {
 	struct ws16c48_gpio *const ws16c48gpio = gpiochip_get_data(chip);
-	const unsigned int gpio_reg_size = 8;
-	size_t i;
-	const size_t num_ports = chip->ngpio / gpio_reg_size;
-	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);
+	size_t port;
+	size_t word;
+	unsigned int offset;
+	const unsigned int port_size = 8;
+	const size_t num_ports = chip->ngpio / port_size;
 	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 < num_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 */
-		port_state = inb(ws16c48gpio->base + i);
-
-		/* store acquired bits at respective bits array offset */
-		bits[word_index] |= port_state << word_offset;
+	for_each_set_clump(port, word, offset, mask, num_ports, port_size) {
+		port_state = inb(ws16c48gpio->base + port);
+		bits[word] |= port_state << offset;
 	}
 
 	return 0;
@@ -203,26 +180,19 @@ static void ws16c48_gpio_set_multiple(struct gpio_chip *chip,
 	unsigned long *mask, unsigned long *bits)
 {
 	struct ws16c48_gpio *const ws16c48gpio = gpiochip_get_data(chip);
-	unsigned int i;
-	const unsigned int gpio_reg_size = 8;
-	unsigned int port;
+	size_t port;
+	size_t word;
+	unsigned int offset;
+	const unsigned int port_size = 8;
+	const size_t num_ports = chip->ngpio / port_size;
 	unsigned int iomask;
 	unsigned int bitmask;
 	unsigned long flags;
 
-	/* set bits are evaluated a gpio register size at a time */
-	for (i = 0; i < chip->ngpio; i += gpio_reg_size) {
-		/* no more set bits in this mask word; skip to the next word */
-		if (!mask[BIT_WORD(i)]) {
-			i = (BIT_WORD(i) + 1) * BITS_PER_LONG - gpio_reg_size;
-			continue;
-		}
-
-		port = i / gpio_reg_size;
-
+	for_each_set_clump(port, word, offset, mask, num_ports, port_size) {
 		/* mask out GPIO configured for input */
-		iomask = mask[BIT_WORD(i)] & ~ws16c48gpio->io_state[port];
-		bitmask = iomask & bits[BIT_WORD(i)];
+		iomask = (mask[word] >> offset) & ~ws16c48gpio->io_state[port];
+		bitmask = iomask & (bits[word] >> offset);
 
 		raw_spin_lock_irqsave(&ws16c48gpio->lock, flags);
 
@@ -232,10 +202,6 @@ static void ws16c48_gpio_set_multiple(struct gpio_chip *chip,
 		outb(ws16c48gpio->out_state[port], ws16c48gpio->base + port);
 
 		raw_spin_unlock_irqrestore(&ws16c48gpio->lock, flags);
-
-		/* prepare for next gpio register set */
-		mask[BIT_WORD(i)] >>= gpio_reg_size;
-		bits[BIT_WORD(i)] >>= gpio_reg_size;
 	}
 }
 
-- 
2.17.0