[PATCH 1/2] pinctrl: at91: Add set_multiple GPIO chip feature

[Alexander Stein]

This adds the callback for set_multiple.
As this controller has a separate set and clear register, we can't write
directly to PIO_ODSR as this would required a cached variable and would
race with at91_gpio_set.
So build masks for the PIO_SODR and PIO_CODR registers and write them
together.

Signed-off-by: Alexander Stein <alexanders83 at web.de>
---
This was tested by using an own test driver which uses
gpiod_set_array_cansleep to set multiple GPIOs at once.

 drivers/pinctrl/pinctrl-at91.c | 28 ++++++++++++++++++++++++++++
 1 file changed, 28 insertions(+)

diff --git a/drivers/pinctrl/pinctrl-at91.c b/drivers/pinctrl/pinctrl-at91.c
index f4cd0b9..a882523 100644
--- a/drivers/pinctrl/pinctrl-at91.c
+++ b/drivers/pinctrl/pinctrl-at91.c
@@ -1330,6 +1330,33 @@ static void at91_gpio_set(struct gpio_chip *chip, unsigned offset,
 	writel_relaxed(mask, pio + (val ? PIO_SODR : PIO_CODR));
 }
 
+static void at91_gpio_set_multiple(struct gpio_chip *chip,
+				      unsigned long *mask, unsigned long *bits)
+{
+	struct at91_gpio_chip *at91_gpio = to_at91_gpio_chip(chip);
+	void __iomem *pio = at91_gpio->regbase;
+	unsigned long set_mask;
+	unsigned long clear_mask;
+	size_t i;
+
+	set_mask = 0;
+	clear_mask = 0;
+
+	for (i = 0; i < chip->ngpio; i++) {
+		if (*mask == 0)
+			break;
+		if (__test_and_clear_bit(i, mask)) {
+			if (test_bit(i, bits))
+				set_mask |= BIT(i);
+			else
+				clear_mask |= BIT(i);
+		}
+	}
+
+	writel_relaxed(set_mask, pio + PIO_SODR);
+	writel_relaxed(clear_mask, pio + PIO_CODR);
+}
+
 static int at91_gpio_direction_output(struct gpio_chip *chip, unsigned offset,
 				int val)
 {
@@ -1692,6 +1719,7 @@ static struct gpio_chip at91_gpio_template = {
 	.get			= at91_gpio_get,
 	.direction_output	= at91_gpio_direction_output,
 	.set			= at91_gpio_set,
+	.set_multiple		= at91_gpio_set_multiple,
 	.dbg_show		= at91_gpio_dbg_show,
 	.can_sleep		= false,
 	.ngpio			= MAX_NB_GPIO_PER_BANK,
-- 
2.3.3