gpio: zynq: Report gpio direction at boot

commit 6169005ceb8c715582eca70df3912cd2b351ede2 upstream

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@collins.com>
Tested-by: Michal Simek <michal.simek@xilinx.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Cc: stable <stable@vger.kernel.org> # 4.19
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/drivers/gpio/gpio-zynq.c b/drivers/gpio/gpio-zynq.c
index a9238fb..5dec961 100644 (file)
--- a/drivers/gpio/gpio-zynq.c
+++ b/drivers/gpio/gpio-zynq.c
@@ -358,6 +358,28 @@ static int zynq_gpio_dir_out(struct gpio_chip *chip, unsigned int pin,
 }
 
 /**
+ * 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
  *
@@ -829,6 +851,7 @@ 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;