[PATCH v3 2/2] gpio/omap: auto request GPIO as input if used as IRQ via DT

[Javier Martinez Canillas <javier.martinez@xxxxxxxxxxxxxxx>]

When an OMAP GPIO is used as an IRQ line, a call to gpio_request()
has to be made to initialize the OMAP GPIO bank before a driver
request the IRQ. Otherwise the call to request_irq() fails.

Drives should not be aware of this neither care wether an IRQ line
is a GPIO or not. They should just request the IRQ and this has to
be handled by the irq_chip driver.

With the current OMAP GPIO DT binding, if we define:

    gpio6: gpio@49058000 {
    	   compatible = "ti,omap3-gpio";
	   reg = <0x49058000 0x200>;
	   interrupts = <34>;
	   ti,hwmods = "gpio6";
	   gpio-controller;
	   #gpio-cells = <2>;
	   interrupt-controller;
	   #interrupt-cells = <2>;
    };

	   interrupt-parent = <&gpio6>;
           interrupts = <16 8>;

The GPIO is correctly mapped as an IRQ but a call to gpio_request()
is never made. Since a call to the custom IRQ domain .map function
handler is made for each GPIO used as an IRQ, the GPIO can be setup
and configured as input there automatically.

Signed-off-by: Javier Martinez Canillas <javier.martinez@xxxxxxxxxxxxxxx>
---

Changes since v2:
 - Only make the call to gpio_request_one() conditional in the DT
   case as suggested by Grant Likely.

Changes since v1:
  - Split the irq domain mapping function handler and the GPIO
    request in two different patches.

 drivers/gpio/gpio-omap.c |   11 +++++++++++
 1 files changed, 11 insertions(+), 0 deletions(-)

diff --git a/drivers/gpio/gpio-omap.c b/drivers/gpio/gpio-omap.c
index 42f04ff..98848c9 100644
--- a/drivers/gpio/gpio-omap.c
+++ b/drivers/gpio/gpio-omap.c
@@ -1090,6 +1090,8 @@ static int omap_gpio_irq_map(struct irq_domain *d, unsigned int virq,
 			     irq_hw_number_t hwirq)
 {
 	struct gpio_bank *bank = d->host_data;
+	int gpio;
+	int ret;
 
 	if (!bank)
 		return -EINVAL;
@@ -1104,6 +1106,15 @@ static int omap_gpio_irq_map(struct irq_domain *d, unsigned int virq,
 		set_irq_flags(virq, IRQF_VALID);
 	}
 
+	if (of_have_populated_dt()) {
+		gpio = irq_to_gpio(bank, hwirq);
+		ret = gpio_request_one(gpio, GPIOF_IN, NULL);
+		if (ret) {
+			dev_err(bank->dev, "Could not request GPIO%d\n", gpio);
+			return ret;
+		}
+	}
+
 	return 0;
 }
 
-- 
1.7.7.6

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