irqchip: renesas-intc-irqpin: r8a7779 IRLM setup support

Add r8a7779 specific support for IRLM bit configuration
in the INTC-IRQPIN driver. Without this code we need
special workaround code in arch/arm/mach-shmobile.

The IRLM bit for the INTC hardware exists on various
older SH-based SoCs and is used to select between two
modes for the external interrupt pins IRQ0 to IRQ3:

IRLM = 0: (default from reset on r8a7779)
In this mode the pins IRQ0 to IRQ3 are used together
to give a value between 0 and 15 to the SoC. External
logic is required for masking. This mode is not
supported by the INTC-IRQPIN driver.

IRLM = 1: (needs this patch or configuration elsewhere)
In this mode IRQ0 to IRQ3 operate as 4 individual
external interrupt pins. In this mode the SMSC ethernet
chip can be used via IRQ1 on r8a7779 Marzen. This mode
is the only supported mode by the INTC-IRQPIN driver.

For this patch to work the r8a7779 DTS needs to pass
the ICR0 register as the last register bank.

Signed-off-by: Magnus Damm <damm+renesas@opensource.se>
Cc: Magnus Damm <magnus.damm@gmail.com>
Cc: horms@verge.net.au
Cc: jason@lakedaemon.net
Link: http://lkml.kernel.org/r/20141203121803.5936.35881.sendpatchset@w520
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

2 files changed, 46 insertions, 9 deletions

diff --git a/Documentation/devicetree/bindings/interrupt-controller/renesas,intc-irqpin.txt b/Documentation/devicetree/bindings/interrupt-controller/renesas,intc-irqpin.txt
index c73acd0..4f7946a 100644
--- a/Documentation/devicetree/bindings/interrupt-controller/renesas,intc-irqpin.txt
+++ b/Documentation/devicetree/bindings/interrupt-controller/renesas,intc-irqpin.txt
@@ -9,6 +9,11 @@ Required properties:
     - "renesas,intc-irqpin-r8a7778" (R-Car M1A)
     - "renesas,intc-irqpin-r8a7779" (R-Car H1)
     - "renesas,intc-irqpin-sh73a0" (SH-Mobile AG5)
+
+- reg: Base address and length of each register bank used by the external
+  IRQ pins driven by the interrupt controller hardware module. The base
+  addresses, length and number of required register banks varies with soctype.
+
 - #interrupt-cells: has to be <2>: an interrupt index and flags, as defined in
   interrupts.txt in this directory
 
diff --git a/drivers/irqchip/irq-renesas-intc-irqpin.c b/drivers/irqchip/irq-renesas-intc-irqpin.c
index 078cac5..9a0767b 100644
--- a/drivers/irqchip/irq-renesas-intc-irqpin.c
+++ b/drivers/irqchip/irq-renesas-intc-irqpin.c
@@ -30,6 +30,7 @@
 #include <linux/err.h>
 #include <linux/slab.h>
 #include <linux/module.h>
+#include <linux/of_device.h>
 #include <linux/platform_data/irq-renesas-intc-irqpin.h>
 #include <linux/pm_runtime.h>
 
@@ -40,7 +41,9 @@
 #define INTC_IRQPIN_REG_SOURCE 2 /* INTREQnn */
 #define INTC_IRQPIN_REG_MASK 3 /* INTMSKnn */
 #define INTC_IRQPIN_REG_CLEAR 4 /* INTMSKCLRnn */
-#define INTC_IRQPIN_REG_NR 5
+#define INTC_IRQPIN_REG_NR_MANDATORY 5
+#define INTC_IRQPIN_REG_IRLM 5 /* ICR0 with IRLM bit (optional) */
+#define INTC_IRQPIN_REG_NR 6
 
 /* INTC external IRQ PIN hardware register access:
  *
@@ -82,6 +85,10 @@ struct intc_irqpin_priv {
 	u8 shared_irq_mask;
 };
 
+struct intc_irqpin_irlm_config {
+	unsigned int irlm_bit;
+};
+
 static unsigned long intc_irqpin_read32(void __iomem *iomem)
 {
 	return ioread32(iomem);
@@ -345,10 +352,23 @@ static struct irq_domain_ops intc_irqpin_irq_domain_ops = {
 	.xlate  = irq_domain_xlate_twocell,
 };
 
+static const struct intc_irqpin_irlm_config intc_irqpin_irlm_r8a7779 = {
+	.irlm_bit = 23, /* ICR0.IRLM0 */
+};
+
+static const struct of_device_id intc_irqpin_dt_ids[] = {
+	{ .compatible = "renesas,intc-irqpin", },
+	{ .compatible = "renesas,intc-irqpin-r8a7779",
+	  .data = &intc_irqpin_irlm_r8a7779 },
+	{},
+};
+MODULE_DEVICE_TABLE(of, intc_irqpin_dt_ids);
+
 static int intc_irqpin_probe(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
 	struct renesas_intc_irqpin_config *pdata = dev->platform_data;
+	const struct of_device_id *of_id;
 	struct intc_irqpin_priv *p;
 	struct intc_irqpin_iomem *i;
 	struct resource *io[INTC_IRQPIN_REG_NR];
@@ -391,10 +411,11 @@ static int intc_irqpin_probe(struct platform_device *pdev)
 	pm_runtime_enable(dev);
 	pm_runtime_get_sync(dev);
 
-	/* get hold of manadatory IOMEM */
+	/* get hold of register banks */
+	memset(io, 0, sizeof(io));
 	for (k = 0; k < INTC_IRQPIN_REG_NR; k++) {
 		io[k] = platform_get_resource(pdev, IORESOURCE_MEM, k);
-		if (!io[k]) {
+		if (!io[k] && k < INTC_IRQPIN_REG_NR_MANDATORY) {
 			dev_err(dev, "not enough IOMEM resources\n");
 			ret = -EINVAL;
 			goto err0;
@@ -422,6 +443,10 @@ static int intc_irqpin_probe(struct platform_device *pdev)
 	for (k = 0; k < INTC_IRQPIN_REG_NR; k++) {
 		i = &p->iomem[k];
 
+		/* handle optional registers */
+		if (!io[k])
+			continue;
+
 		switch (resource_size(io[k])) {
 		case 1:
 			i->width = 8;
@@ -448,6 +473,19 @@ static int intc_irqpin_probe(struct platform_device *pdev)
 		}
 	}
 
+	/* configure "individual IRQ mode" where needed */
+	of_id = of_match_device(intc_irqpin_dt_ids, dev);
+	if (of_id && of_id->data) {
+		const struct intc_irqpin_irlm_config *irlm_config = of_id->data;
+
+		if (io[INTC_IRQPIN_REG_IRLM])
+			intc_irqpin_read_modify_write(p, INTC_IRQPIN_REG_IRLM,
+						      irlm_config->irlm_bit,
+						      1, 1);
+		else
+			dev_warn(dev, "unable to select IRLM mode\n");
+	}
+
 	/* mask all interrupts using priority */
 	for (k = 0; k < p->number_of_irqs; k++)
 		intc_irqpin_mask_unmask_prio(p, k, 1);
@@ -550,12 +588,6 @@ static int intc_irqpin_remove(struct platform_device *pdev)
 	return 0;
 }
 
-static const struct of_device_id intc_irqpin_dt_ids[] = {
-	{ .compatible = "renesas,intc-irqpin", },
-	{},
-};
-MODULE_DEVICE_TABLE(of, intc_irqpin_dt_ids);
-
 static struct platform_driver intc_irqpin_device_driver = {
 	.probe		= intc_irqpin_probe,
 	.remove		= intc_irqpin_remove,