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Date:   Sun, 3 May 2020 00:21:54 +0530
From:   Syed Nayyar Waris <syednwaris@gmail.com>
To:     akpm@linux-foundation.org
Cc:     andriy.shevchenko@linux.intel.com, vilhelm.gray@gmail.com,
        linus.walleij@linaro.org, bgolaszewski@baylibre.com,
        michal.simek@xilinx.com, linux-gpio@vger.kernel.org,
        linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org
Subject: [PATCH v4 4/4] gpio: xilinx: Utilize for_each_set_clump macro
Message-ID: <366a64f80ee9fe1c644ea038ac112ead9766d5c8.1588443578.git.syednwaris@gmail.com>
References: <cover.1588443578.git.syednwaris@gmail.com>
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This patch reimplements the xgpio_set_multiple function in
drivers/gpio/gpio-xilinx.c to use the new for_each_set_clump macro.
Instead of looping for each bit in xgpio_set_multiple
function, now we can check each channel at a time and save cycles.

Cc: Linus Walleij <linus.walleij@linaro.org>
Cc: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Cc: Michal Simek <michal.simek@xilinx.com>
Signed-off-by: Syed Nayyar Waris <syednwaris@gmail.com>
Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
---
Changes in v4:
 - Minor change: Hardcode value for better code readability.

Changes in v3:
 - No change.

Changes in v2:
 - No change.

 drivers/gpio/gpio-xilinx.c | 64 ++++++++++++++++++++------------------
 1 file changed, 34 insertions(+), 30 deletions(-)

diff --git a/drivers/gpio/gpio-xilinx.c b/drivers/gpio/gpio-xilinx.c
index 67f9f82e0db0..67c5eeaf1bb9 100644
--- a/drivers/gpio/gpio-xilinx.c
+++ b/drivers/gpio/gpio-xilinx.c
@@ -136,39 +136,43 @@ static void xgpio_set(struct gpio_chip *gc, unsigned int gpio, int val)
 static void xgpio_set_multiple(struct gpio_chip *gc, unsigned long *mask,
 			       unsigned long *bits)
 {
-	unsigned long flags;
+	unsigned long flags[2];
 	struct xgpio_instance *chip = gpiochip_get_data(gc);
-	int index = xgpio_index(chip, 0);
-	int offset, i;
-
-	spin_lock_irqsave(&chip->gpio_lock[index], flags);
-
-	/* Write to GPIO signals */
-	for (i = 0; i < gc->ngpio; i++) {
-		if (*mask == 0)
-			break;
-		/* Once finished with an index write it out to the register */
-		if (index !=  xgpio_index(chip, i)) {
-			xgpio_writereg(chip->regs + XGPIO_DATA_OFFSET +
-				       index * XGPIO_CHANNEL_OFFSET,
-				       chip->gpio_state[index]);
-			spin_unlock_irqrestore(&chip->gpio_lock[index], flags);
-			index =  xgpio_index(chip, i);
-			spin_lock_irqsave(&chip->gpio_lock[index], flags);
-		}
-		if (__test_and_clear_bit(i, mask)) {
-			offset =  xgpio_offset(chip, i);
-			if (test_bit(i, bits))
-				chip->gpio_state[index] |= BIT(offset);
-			else
-				chip->gpio_state[index] &= ~BIT(offset);
-		}
+	u32 *const state = chip->gpio_state;
+	unsigned int *const width = chip->gpio_width;
+	const unsigned long state_size = 32;
+	const unsigned long total_state_bits = state_size * 2;
+	unsigned long offset, clump;
+	size_t index;
+
+	DECLARE_BITMAP(old, 64);
+	DECLARE_BITMAP(new, 64);
+	DECLARE_BITMAP(changed, 64);
+
+	spin_lock_irqsave(&chip->gpio_lock[0], flags[0]);
+	spin_lock_irqsave(&chip->gpio_lock[1], flags[1]);
+
+	bitmap_set_value(old, state[0], 0, width[0]);
+	bitmap_set_value(old, state[1], width[0], width[1]);
+	bitmap_replace(new, old, bits, mask, gc->ngpio);
+
+	bitmap_set_value(old, state[0], 0, state_size);
+	bitmap_set_value(old, state[1], state_size, state_size);
+	state[0] = bitmap_get_value(new, 0, width[0]);
+	state[1] = bitmap_get_value(new, width[0], width[1]);
+	bitmap_set_value(new, state[0], 0, state_size);
+	bitmap_set_value(new, state[1], state_size, state_size);
+	bitmap_xor(changed, old, new, total_state_bits);
+
+	for_each_set_clump(offset, clump, changed, total_state_bits, state_size) {
+		index = offset / state_size;
+		xgpio_writereg(chip->regs + XGPIO_DATA_OFFSET +
+				index * XGPIO_CHANNEL_OFFSET,
+				state[index]);
 	}
 
-	xgpio_writereg(chip->regs + XGPIO_DATA_OFFSET +
-		       index * XGPIO_CHANNEL_OFFSET, chip->gpio_state[index]);
-
-	spin_unlock_irqrestore(&chip->gpio_lock[index], flags);
+	spin_unlock_irqrestore(&chip->gpio_lock[1], flags[1]);
+	spin_unlock_irqrestore(&chip->gpio_lock[0], flags[0]);
 }
 
 /**
-- 
2.26.2