gpio: sa1100: implement get_direction method

Allow gpiolib to read back the current IO direction configuration by
implementing the .get_direction callback. This, in part, allows
debugfs to report the complete true hardware state rather than the
software state.

Signed-off-by: Russell King <[e-mail]>
Signed-off-by: Linus Walleij <[e-mail]>

drivers/gpio/gpio-sa1100.c

···
 	writel_relaxed(BIT(offset), sa1100_gpio_chip(chip)->membase + reg);
 }
 
+static int sa1100_get_direction(struct gpio_chip *chip, unsigned offset)
+{
+	void __iomem *gpdr = sa1100_gpio_chip(chip)->membase + R_GPDR;
+
+	return !(readl_relaxed(gpdr) & BIT(offset));
+}
+
 static int sa1100_direction_input(struct gpio_chip *chip, unsigned offset)
 {
 	void __iomem *gpdr = sa1100_gpio_chip(chip)->membase + R_GPDR;
···
 static struct sa1100_gpio_chip sa1100_gpio_chip = {
 	.chip = {
 		.label			= "gpio",
+		.get_direction		= sa1100_get_direction,
 		.direction_input	= sa1100_direction_input,
 		.direction_output	= sa1100_direction_output,
 		.set			= sa1100_gpio_set,