gpio: dwapb: Add support for 1 interrupt per port A GPIO

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.

ACPI companion code provided by Hoan Tran <hotran@apm.com>. This was tested
on X-Gene by Hoan.
Signed-off-by: Phil Edworthy <phil.edworthy@renesas.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Acked-by: Lee Jones <lee.jones@linaro.org>
Acked-by: Hoan Tran <hotran@apm.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

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.
 

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 +606,36 @@ 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);
+			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++) {
+				int irq = of_irq_get(np, j);
+				if (irq < 0)
+					continue;
+
+				pp->irq[j] = irq;
+				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) {
+			unsigned int j;
+
+			for (j = 0; j < pp->ngpio; j++) {
+				pp->irq[j] = platform_get_irq(to_platform_device(dev), j);
+				if (pp->irq[j])
+					pp->has_irq = true;
+			}
+		}
 
 		pp->irq_shared	= false;
 		pp->gpio_base	= -1;

drivers/mfd/intel_quark_i2c_gpio.c

@@ -233,7 +233,8 @@ static int intel_quark_gpio_setup(struct pci_dev *pdev, struct mfd_cell *cell)
 	pdata->properties->idx		= 0;
 	pdata->properties->ngpio	= INTEL_QUARK_MFD_NGPIO;
 	pdata->properties->gpio_base	= INTEL_QUARK_MFD_GPIO_BASE;
-	pdata->properties->irq		= pdev->irq;
+	pdata->properties->irq[0]	= pdev->irq;
+	pdata->properties->has_irq	= true;
 	pdata->properties->irq_shared	= true;
 
 	cell->platform_data = pdata;

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;
 };