[PATCH] gpio: zynq: Report gpio direction at boot

[Brandon Maier <Brandon.Maier@xxxxxxxxxxx>]

The Zynq's gpios can be configured by the bootloader. But Linux will
erroneously report all gpios as inputs unless we implement
get_direction().

Signed-off-by: Brandon Maier <brandon.maier@xxxxxxxxxxxxxxxxxxx>
---
 drivers/gpio/gpio-zynq.c | 23 +++++++++++++++++++++++
 1 file changed, 23 insertions(+)

diff --git a/drivers/gpio/gpio-zynq.c b/drivers/gpio/gpio-zynq.c
index 3f5fcdd5a429..6bb914ef83c7 100644
--- a/drivers/gpio/gpio-zynq.c
+++ b/drivers/gpio/gpio-zynq.c
@@ -357,6 +357,28 @@ static int zynq_gpio_dir_out(struct gpio_chip *chip, unsigned int pin,
 	return 0;
 }
 
+/**
+ * zynq_gpio_get_direction - Read the direction of the specified GPIO pin
+ * @chip:	gpio_chip instance to be worked on
+ * @pin:	gpio pin number within the device
+ *
+ * This function returns the direction of the specified GPIO.
+ *
+ * Return: 0 for output, 1 for input
+ */
+static int zynq_gpio_get_direction(struct gpio_chip *chip, unsigned int pin)
+{
+	u32 reg;
+	unsigned int bank_num, bank_pin_num;
+	struct zynq_gpio *gpio = gpiochip_get_data(chip);
+
+	zynq_gpio_get_bank_pin(pin, &bank_num, &bank_pin_num, gpio);
+
+	reg = readl_relaxed(gpio->base_addr + ZYNQ_GPIO_DIRM_OFFSET(bank_num));
+
+	return !(reg & BIT(bank_pin_num));
+}
+
 /**
  * zynq_gpio_irq_mask - Disable the interrupts for a gpio pin
  * @irq_data:	per irq and chip data passed down to chip functions
@@ -827,6 +849,7 @@ static int zynq_gpio_probe(struct platform_device *pdev)
 	chip->free = zynq_gpio_free;
 	chip->direction_input = zynq_gpio_dir_in;
 	chip->direction_output = zynq_gpio_dir_out;
+	chip->get_direction = zynq_gpio_get_direction;
 	chip->base = of_alias_get_id(pdev->dev.of_node, "gpio");
 	chip->ngpio = gpio->p_data->ngpio;
 
-- 
2.19.0