[PATCH v12 4/4] gpio: xilinx: Utilize generic bitmap_get_value and _set_value

From: Syed Nayyar Waris
Date: Sun Oct 18 2020 - 17:42:14 EST


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@xxxxxxxxxxxx>
Cc: Michal Simek <michal.simek@xxxxxxxxxx>
Signed-off-by: Syed Nayyar Waris <syednwaris@xxxxxxxxx>
Signed-off-by: William Breathitt Gray <vilhelm.gray@xxxxxxxxx>
---
Changes in v12:
- Remove extra empty newline.

Changes in v11:
- Change variable name 'flag' to 'flags'.

Changes in v10:
- No change.

Changes in v9:
- Remove looping of 'for_each_set_clump' and instead process two
halves of a 64-bit bitmap separately or individually. Use normal spin_lock
call for second inner lock. And take the spin_lock_init call outside the 'if'
condition in the 'probe' function of driver.

Changes in v8:
- No change.

Changes in v7:
- No change.

Changes in v6:
- No change.

Changes in v5:
- Minor change: Inline values '32' and '64' in code for better
code readability.

Changes in v4:
- Minor change: Inline values '32' and '64' in code for better
code readability.

Changes in v3:
- No change.

Changes in v2:
- No change

drivers/gpio/gpio-xilinx.c | 65 +++++++++++++++++++-------------------
1 file changed, 32 insertions(+), 33 deletions(-)

diff --git a/drivers/gpio/gpio-xilinx.c b/drivers/gpio/gpio-xilinx.c
index 67f9f82e0db0..3ba1a993c85e 100644
--- a/drivers/gpio/gpio-xilinx.c
+++ b/drivers/gpio/gpio-xilinx.c
@@ -138,37 +138,37 @@ 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[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);
- }
- }
-
- xgpio_writereg(chip->regs + XGPIO_DATA_OFFSET +
- index * XGPIO_CHANNEL_OFFSET, chip->gpio_state[index]);
-
- spin_unlock_irqrestore(&chip->gpio_lock[index], flags);
+ u32 *const state = chip->gpio_state;
+ unsigned int *const width = chip->gpio_width;
+
+ DECLARE_BITMAP(old, 64);
+ DECLARE_BITMAP(new, 64);
+ DECLARE_BITMAP(changed, 64);
+
+ spin_lock_irqsave(&chip->gpio_lock[0], flags);
+ spin_lock(&chip->gpio_lock[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, 32);
+ bitmap_set_value(old, state[1], 32, 32);
+ 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, 32);
+ bitmap_set_value(new, state[1], 32, 32);
+ 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(&chip->gpio_lock[1]);
+ spin_unlock_irqrestore(&chip->gpio_lock[0], flags);
}

/**
@@ -292,6 +292,7 @@ static int xgpio_probe(struct platform_device *pdev)
chip->gpio_width[0] = 32;

spin_lock_init(&chip->gpio_lock[0]);
+ spin_lock_init(&chip->gpio_lock[1]);

if (of_property_read_u32(np, "xlnx,is-dual", &is_dual))
is_dual = 0;
@@ -313,8 +314,6 @@ static int xgpio_probe(struct platform_device *pdev)
if (of_property_read_u32(np, "xlnx,gpio2-width",
&chip->gpio_width[1]))
chip->gpio_width[1] = 32;
-
- spin_lock_init(&chip->gpio_lock[1]);
}

chip->gc.base = -1;
--
2.26.2