drv:gn412x_gpio: add request/free methods

We do not want any GPIO usage to overwrite a bypass mode Signed-off-by: Federico Vaga <federico.vaga@cern.ch>

drv:gn412x_gpio: add request/free methods
We do not want any GPIO usage to overwrite a bypass mode Signed-off-by: Federico Vaga <federico.vaga@cern.ch>
bcfc4f6d · Federico Vaga · 085d0e85 · bcfc4f6d
Commit bcfc4f6d authored Jun 06, 2019 by Federico Vaga
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gn412x-gpio.c kernel/gn412x-gpio.c +21 -0

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--- a/kernel/gn412x-gpio.c
+++ b/kernel/gn412x-gpio.c
@@ -49,6 +49,25 @@ static void gn412x_gpio_reg_write(struct gpio_chip *chip,
 	gn412x_iowrite32(gn412x, regval, reg);
 }

+static int gn412x_gpio_request(struct gpio_chip *chip, unsigned offset)
+{
+	int val;
+
+	val = gn412x_gpio_reg_read(chip, GNGPIO_BYPASS_MODE, offset);
+	if (val) {
+		dev_err(chip->dev, "%s GPIO %d is in BYPASS mode\n",
+			chip->label, offset);
+		return -EBUSY;
+	}
+
+	return 0;
+}
+
+static void gn412x_gpio_free(struct gpio_chip *chip, unsigned offset)
+{
+	/* set it as input to avoid to drive anything */
+	gn412x_gpio_reg_write(chip, GNGPIO_DIRECTION_MODE, offset, 1);
+}

 static int gn412x_gpio_get_direction(struct gpio_chip *chip,
 				     unsigned offset)
@@ -92,6 +111,8 @@ int gn412x_gpio_init(struct gn412x_dev *gn412x)
 	memset(&gn412x->gpiochip, 0, sizeof(gn412x->gpiochip));
 	gn412x->gpiochip.label = "gn412x-gpio";
 	gn412x->gpiochip.owner = THIS_MODULE;
+	gn412x->gpiochip.request = gn412x_gpio_request;
+	gn412x->gpiochip.free = gn412x_gpio_free;
 	gn412x->gpiochip.get_direction = gn412x_gpio_get_direction,
 	gn412x->gpiochip.direction_input = gn412x_gpio_direction_input,
 	gn412x->gpiochip.direction_output = gn412x_gpio_direction_output,