linux-kernel - [RESEND PATCH v4 3/3] gpio: xilinx: Utilize generic bitmap_get_value and _set

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Date:   Fri, 2 Apr 2021 22:07:36 +0530
From:   Syed Nayyar Waris <syednwaris@...il.com>
To:     bgolaszewski@...libre.com
Cc:     andriy.shevchenko@...ux.intel.com, vilhelm.gray@...il.com,
        michal.simek@...inx.com, arnd@...db.de, rrichter@...vell.com,
        linus.walleij@...aro.org, bgolaszewski@...libre.com,
        yamada.masahiro@...ionext.com, akpm@...ux-foundation.org,
        rui.zhang@...el.com, daniel.lezcano@...aro.org,
        amit.kucheria@...durent.com, linux-arch@...r.kernel.org,
        linux-gpio@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org, linux-pm@...r.kernel.org
Subject: [RESEND PATCH v4 3/3] gpio: xilinx: Utilize generic bitmap_get_value
 and _set_value

This patch reimplements the xgpio_set_multiple() function in
drivers/gpio/gpio-xilinx.c to use the new generic functions:
bitmap_get_value() and bitmap_set_value(). The code is now simpler
to read and understand. Moreover, instead of looping for each bit
in xgpio_set_multiple() function, now we can check each channel at
a time and save cycles.

Cc: Bartosz Golaszewski <bgolaszewski@...libre.com>
Cc: Michal Simek <michal.simek@...inx.com>
Signed-off-by: Syed Nayyar Waris <syednwaris@...il.com>
Acked-by: William Breathitt Gray <vilhelm.gray@...il.com>
---
 drivers/gpio/gpio-xilinx.c | 52 +++++++++++++++++++-------------------
 1 file changed, 26 insertions(+), 26 deletions(-)

diff --git a/drivers/gpio/gpio-xilinx.c b/drivers/gpio/gpio-xilinx.c
index b411d3156e0b..512198250b02 100644
--- a/drivers/gpio/gpio-xilinx.c
+++ b/drivers/gpio/gpio-xilinx.c
@@ -18,6 +18,7 @@
 #include <linux/of_platform.h>
 #include <linux/pm_runtime.h>
 #include <linux/slab.h>
+#include "gpiolib.h"
 
 /* Register Offset Definitions */
 #define XGPIO_DATA_OFFSET   (0x0)	/* Data register  */
@@ -161,35 +162,34 @@ static void xgpio_set_multiple(struct gpio_chip *gc, unsigned long *mask,
 {
 	unsigned long flags;
 	struct xgpio_instance *chip = gpiochip_get_data(gc);
-	int index = xgpio_index(chip, 0);
-	int offset, i;
 
-	spin_lock_irqsave(&chip->gpio_lock, flags);
+	u32 *state = chip->gpio_state;
+	unsigned int *width = chip->gpio_width;
+	DECLARE_BITMAP(old, 64);
+	DECLARE_BITMAP(new, 64);
+	DECLARE_BITMAP(changed, 64);
 
-	/* 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, flags);
-			index =  xgpio_index(chip, i);
-			spin_lock_irqsave(&chip->gpio_lock, 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);
-		}
-	}
+	spin_lock_irqsave(&chip->gpio_lock, flags);
 
-	xgpio_writereg(chip->regs + XGPIO_DATA_OFFSET +
-		       index * XGPIO_CHANNEL_OFFSET, chip->gpio_state[index]);
+	/* Copy initial value of state bits into 'old' contiguously */
+	bitmap_set_value(old, 64, state[0], width[0], 0);
+	bitmap_set_value(old, 64, state[1], width[1], width[0]);
+	/* Copy value from 'old' into 'new' with mask applied */
+	bitmap_replace(new, old, bits, mask, gc->ngpio);
+
+	bitmap_from_arr32(old, state, 64);
+	/* Update 'state' */
+	state[0] = bitmap_get_value(new, 0, width[0]);
+	state[1] = bitmap_get_value(new, width[0], width[1]);
+	bitmap_from_arr32(new, state, 64);
+	/* XOR operation sets only changed bits */
+	bitmap_xor(changed, old, new, 64);
+
+	if (((u32 *)changed)[0])
+		xgpio_writereg(chip->regs + XGPIO_DATA_OFFSET, state[0]);
+	if (((u32 *)changed)[1])
+		xgpio_writereg(chip->regs + XGPIO_DATA_OFFSET +
+			XGPIO_CHANNEL_OFFSET, state[1]);
 
 	spin_unlock_irqrestore(&chip->gpio_lock, flags);
 }
-- 
2.29.0