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Subject[PATCH 4.19 17/52] gpio: zynq: Report gpio direction at boot
Date
From: Brandon Maier <Brandon.Maier@collins.com>

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>
---
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 a9238fb150131..5dec96155814b 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
@@ -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;

--
2.20.1


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