[PATCH v2 1/2] gpio: dwapb: Add support for 1 interrupt per port A GPIO

[Phil Edworthy]

The DesignWare GPIO IP can be configured for either 1 interrupt or 1
per GPIO in port A, but the driver currently only supports 1 interrupt.
See the DesignWare DW_apb_gpio Databook description of the
'GPIO_INTR_IO' parameter.

This change allows the driver to work with up to 32 interrupts, it will
get as many interrupts as specified in the DT 'interrupts' property.
It doesn't do anything clever with the different interrupts, it just calls
the same handler used for single interrupt hardware.

Signed-off-by: Phil Edworthy <phil.edworthy@xxxxxxxxxxx>
---
v2:
 - Replaced interrupt-mask DT prop with support for the interrupts-extended
   prop. This means replacing the call to irq_of_parse_and_map() with calls
   to of_irq_parse_one() and irq_create_of_mapping().

Note: There are a few *code* lines over 80 chars, but this is just guidance,
   right? Especially as there are already some lines over 80 chars.
---
 .../devicetree/bindings/gpio/snps-dwapb-gpio.txt   |  9 ++++-
 drivers/gpio/gpio-dwapb.c                          | 43 +++++++++++++++++-----
 include/linux/platform_data/gpio-dwapb.h           |  3 +-
 3 files changed, 43 insertions(+), 12 deletions(-)

diff --git a/Documentation/devicetree/bindings/gpio/snps-dwapb-gpio.txt b/Documentation/devicetree/bindings/gpio/snps-dwapb-gpio.txt
index 4a75da7..3c1118b 100644
--- a/Documentation/devicetree/bindings/gpio/snps-dwapb-gpio.txt
+++ b/Documentation/devicetree/bindings/gpio/snps-dwapb-gpio.txt
@@ -26,8 +26,13 @@ controller.
   the second encodes the triger flags encoded as described in
   Documentation/devicetree/bindings/interrupt-controller/interrupts.txt
 - interrupt-parent : The parent interrupt controller.
-- interrupts : The interrupt to the parent controller raised when GPIOs
-  generate the interrupts.
+- interrupts : The interrupts to the parent controller raised when GPIOs
+  generate the interrupts. If the controller provides one combined interrupt
+  for all GPIOs, specify a single interrupt. If the controller provides one
+  interrupt for each GPIO, provide a list of interrupts that correspond to each
+  of the GPIO pins. When specifying multiple interrupts, if any are unconnected,
+  use the interrupts-extended property to specify the interrupts and set the
+  interrupt controller handle for unused interrupts to 0.
 - snps,nr-gpios : The number of pins in the port, a single cell.
 - resets : Reset line for the controller.
 
diff --git a/drivers/gpio/gpio-dwapb.c b/drivers/gpio/gpio-dwapb.c
index 226977f..3273504 100644
--- a/drivers/gpio/gpio-dwapb.c
+++ b/drivers/gpio/gpio-dwapb.c
@@ -441,14 +441,19 @@ static void dwapb_configure_irqs(struct dwapb_gpio *gpio,
 	irq_gc->chip_types[1].handler = handle_edge_irq;
 
 	if (!pp->irq_shared) {
-		irq_set_chained_handler_and_data(pp->irq, dwapb_irq_handler,
-						 gpio);
+		int i;
+
+		for (i = 0; i < pp->ngpio; i++) {
+			if (pp->irq[i])
+				irq_set_chained_handler_and_data(pp->irq[i],
+						dwapb_irq_handler, gpio);
+		}
 	} else {
 		/*
 		 * Request a shared IRQ since where MFD would have devices
 		 * using the same irq pin
 		 */
-		err = devm_request_irq(gpio->dev, pp->irq,
+		err = devm_request_irq(gpio->dev, pp->irq[0],
 				       dwapb_irq_handler_mfd,
 				       IRQF_SHARED, "gpio-dwapb-mfd", gpio);
 		if (err) {
@@ -524,7 +529,7 @@ static int dwapb_gpio_add_port(struct dwapb_gpio *gpio,
 	if (pp->idx == 0)
 		port->gc.set_config = dwapb_gpio_set_config;
 
-	if (pp->irq)
+	if (pp->has_irq)
 		dwapb_configure_irqs(gpio, port, pp);
 
 	err = gpiochip_add_data(&port->gc, port);
@@ -535,7 +540,7 @@ static int dwapb_gpio_add_port(struct dwapb_gpio *gpio,
 		port->is_registered = true;
 
 	/* Add GPIO-signaled ACPI event support */
-	if (pp->irq)
+	if (pp->has_irq)
 		acpi_gpiochip_request_interrupts(&port->gc);
 
 	return err;
@@ -601,13 +606,33 @@ dwapb_gpio_get_pdata(struct device *dev)
 		if (dev->of_node && pp->idx == 0 &&
 			fwnode_property_read_bool(fwnode,
 						  "interrupt-controller")) {
-			pp->irq = irq_of_parse_and_map(to_of_node(fwnode), 0);
-			if (!pp->irq)
+			struct device_node *np = to_of_node(fwnode);
+			struct of_phandle_args oirq;
+			unsigned int j;
+
+			/*
+			 * The IP has configuration options to allow a single
+			 * combined interrupt or one per gpio. If one per gpio,
+			 * some might not be used.
+			 */
+			for (j = 0; j < pp->ngpio; j++) {
+				if (of_irq_parse_one(np, j, &oirq))
+					continue;
+
+				pp->irq[j] = irq_create_of_mapping(&oirq);
+				if (pp->irq[j])
+					pp->has_irq = true;
+			}
+
+			if (!pp->has_irq)
 				dev_warn(dev, "no irq for port%d\n", pp->idx);
 		}
 
-		if (has_acpi_companion(dev) && pp->idx == 0)
-			pp->irq = platform_get_irq(to_platform_device(dev), 0);
+		if (has_acpi_companion(dev) && pp->idx == 0) {
+			pp->irq[0] = platform_get_irq(to_platform_device(dev), 0);
+			if (pp->irq[0])
+				pp->has_irq = true;
+		}
 
 		pp->irq_shared	= false;
 		pp->gpio_base	= -1;
diff --git a/include/linux/platform_data/gpio-dwapb.h b/include/linux/platform_data/gpio-dwapb.h
index 2dc7f4a..5a52d69 100644
--- a/include/linux/platform_data/gpio-dwapb.h
+++ b/include/linux/platform_data/gpio-dwapb.h
@@ -19,7 +19,8 @@ struct dwapb_port_property {
 	unsigned int	idx;
 	unsigned int	ngpio;
 	unsigned int	gpio_base;
-	unsigned int	irq;
+	unsigned int	irq[32];
+	bool		has_irq;
 	bool		irq_shared;
 };
 
-- 
2.7.4