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gpio: zynq: Report gpio direction at boot

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commit 6169005ceb 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>
This commit is contained in:
Brandon Maier 2020-02-10 10:18:26 -07:00 committed by Greg Kroah-Hartman
parent 4d905fc227
commit 1503649d8f
1 changed files with 23 additions and 0 deletions
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23
drivers/gpio/gpio-zynq.c
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@ -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;