pinctrl: mcp23s08: Implement gpio bulk functions

To speed up some usecases implement reading and writing several IO lines
at once.
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Link: https://lore.kernel.org/r/20230324164957.485924-3-u.kleine-koenig@pengutronix.deSigned-off-by: Linus Walleij <linus.walleij@linaro.org>

drivers/pinctrl/pinctrl-mcp23s08.c

@@ -307,6 +307,28 @@ static int mcp23s08_get(struct gpio_chip *chip, unsigned offset)
 	return status;
 }
 
+static int mcp23s08_get_multiple(struct gpio_chip *chip,
+				 unsigned long *mask, unsigned long *bits)
+{
+	struct mcp23s08 *mcp = gpiochip_get_data(chip);
+	unsigned int status;
+	int ret;
+
+	mutex_lock(&mcp->lock);
+
+	/* REVISIT reading this clears any IRQ ... */
+	ret = mcp_read(mcp, MCP_GPIO, &status);
+	if (ret < 0)
+		status = 0;
+	else {
+		mcp->cached_gpio = status;
+		*bits = status;
+	}
+
+	mutex_unlock(&mcp->lock);
+	return ret;
+}
+
 static int __mcp23s08_set(struct mcp23s08 *mcp, unsigned mask, bool value)
 {
 	return mcp_update_bits(mcp, MCP_OLAT, mask, value ? mask : 0);
@@ -322,6 +344,16 @@ static void mcp23s08_set(struct gpio_chip *chip, unsigned offset, int value)
 	mutex_unlock(&mcp->lock);
 }
 
+static void mcp23s08_set_multiple(struct gpio_chip *chip,
+				  unsigned long *mask, unsigned long *bits)
+{
+	struct mcp23s08	*mcp = gpiochip_get_data(chip);
+
+	mutex_lock(&mcp->lock);
+	mcp_update_bits(mcp, MCP_OLAT, *mask, *bits);
+	mutex_unlock(&mcp->lock);
+}
+
 static int
 mcp23s08_direction_output(struct gpio_chip *chip, unsigned offset, int value)
 {
@@ -546,8 +578,10 @@ int mcp23s08_probe_one(struct mcp23s08 *mcp, struct device *dev,
 
 	mcp->chip.direction_input = mcp23s08_direction_input;
 	mcp->chip.get = mcp23s08_get;
+	mcp->chip.get_multiple = mcp23s08_get_multiple;
 	mcp->chip.direction_output = mcp23s08_direction_output;
 	mcp->chip.set = mcp23s08_set;
+	mcp->chip.set_multiple = mcp23s08_set_multiple;
 
 	mcp->chip.base = base;
 	mcp->chip.can_sleep = true;