linux-kernel - [RESEND PATCH v4 7/8] gpio: pci-idio-16: Utilize for_each_set

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Message-Id: <4ec0716fc3bcad6d0d90598ebd08b753cc354738.1538441919.git.vilhelm.gray@gmail.com>
Date:   Tue,  2 Oct 2018 10:16:00 +0900
From:   William Breathitt Gray <vilhelm.gray@...il.com>
To:     linus.walleij@...aro.org, akpm@...ux-foundation.org
Cc:     linux-gpio@...r.kernel.org, linux-arch@...r.kernel.org,
        linux-kernel@...r.kernel.org, andriy.shevchenko@...ux.intel.com,
        linux@...musvillemoes.dk,
        William Breathitt Gray <vilhelm.gray@...il.com>
Subject: [RESEND PATCH v4 7/8] gpio: pci-idio-16: 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-pci-idio-16.c | 67 +++++++++++----------------------
 1 file changed, 21 insertions(+), 46 deletions(-)

diff --git a/drivers/gpio/gpio-pci-idio-16.c b/drivers/gpio/gpio-pci-idio-16.c
index 25d16b2af1c3..6d748c6e59cb 100644
--- a/drivers/gpio/gpio-pci-idio-16.c
+++ b/drivers/gpio/gpio-pci-idio-16.c
@@ -109,44 +109,20 @@ static int idio_16_gpio_get_multiple(struct gpio_chip *chip,
 {
 	struct idio_16_gpio *const idio16gpio = gpiochip_get_data(chip);
 	size_t i;
-	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;
+	size_t word;
+	unsigned int offset;
 	void __iomem *ports[] = {
 		&idio16gpio->reg->out0_7, &idio16gpio->reg->out8_15,
 		&idio16gpio->reg->in0_7, &idio16gpio->reg->in8_15,
 	};
+	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 = ioread8(ports[i]);
-
-		/* store acquired bits at respective bits array offset */
-		bits[word_index] |= port_state << word_offset;
+		bits[word] |= port_state << offset;
 	}
 
 	return 0;
@@ -186,30 +162,29 @@ static void idio_16_gpio_set_multiple(struct gpio_chip *chip,
 	unsigned long *mask, unsigned long *bits)
 {
 	struct idio_16_gpio *const idio16gpio = gpiochip_get_data(chip);
+	size_t i;
+	size_t word;
+	unsigned int offset;
+	void __iomem *ports[] = {
+		&idio16gpio->reg->out0_7, &idio16gpio->reg->out8_15,
+	};
+	unsigned int iomask;
+	unsigned int bitmask;
 	unsigned long flags;
 	unsigned int out_state;
 
-	raw_spin_lock_irqsave(&idio16gpio->lock, flags);
+	for_each_set_clump(i, word, offset, mask, ARRAY_SIZE(ports), 8) {
+		iomask = mask[word] >> offset;
+		bitmask = iomask & (bits[word] >> offset);
 
-	/* process output lines 0-7 */
-	if (*mask & 0xFF) {
-		out_state = ioread8(&idio16gpio->reg->out0_7) & ~*mask;
-		out_state |= *mask & *bits;
-		iowrite8(out_state, &idio16gpio->reg->out0_7);
-	}
+		raw_spin_lock_irqsave(&idio16gpio->lock, flags);
 
-	/* shift to next output line word */
-	*mask >>= 8;
+		out_state = ioread8(ports[i]) & ~iomask;
+		out_state |= bitmask;
+		iowrite8(out_state, ports[i]);
 
-	/* process output lines 8-15 */
-	if (*mask & 0xFF) {
-		*bits >>= 8;
-		out_state = ioread8(&idio16gpio->reg->out8_15) & ~*mask;
-		out_state |= *mask & *bits;
-		iowrite8(out_state, &idio16gpio->reg->out8_15);
+		raw_spin_unlock_irqrestore(&idio16gpio->lock, flags);
 	}
-
-	raw_spin_unlock_irqrestore(&idio16gpio->lock, flags);
 }
 
 static void idio_16_irq_ack(struct irq_data *data)
-- 
2.19.0