powerpc: Add interrupt support to mpc8xxx_gpio

Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>
Acked-by: Anton Vorontsov <avorontsov@ru.mvista.com>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>

2 files changed, 168 insertions, 1 deletions

diff --git a/Documentation/powerpc/dts-bindings/fsl/8xxx_gpio.txt b/Documentation/powerpc/dts-bindings/fsl/8xxx_gpio.txt
index d015dcec4011..b0019eb5330e 100644
--- a/Documentation/powerpc/dts-bindings/fsl/8xxx_gpio.txt
+++ b/Documentation/powerpc/dts-bindings/fsl/8xxx_gpio.txt
@@ -11,7 +11,7 @@ Required properties:
   83xx, "fsl,mpc8572-gpio" for 85xx and "fsl,mpc8610-gpio" for 86xx.
 - #gpio-cells : Should be two. The first cell is the pin number and the
   second cell is used to specify optional parameters (currently unused).
- - interrupts : Interrupt mapping for GPIO IRQ (currently unused).
+ - interrupts : Interrupt mapping for GPIO IRQ.
  - interrupt-parent : Phandle for the interrupt controller that
    services interrupts for this device.
 - gpio-controller : Marks the port as GPIO controller.
@@ -38,3 +38,23 @@ Example of gpio-controller nodes for a MPC8347 SoC:
 
 See booting-without-of.txt for details of how to specify GPIO
 information for devices.
+
+To use GPIO pins as interrupt sources for peripherals, specify the
+GPIO controller as the interrupt parent and define GPIO number +
+trigger mode using the interrupts property, which is defined like
+this:
+
+interrupts = <number trigger>, where:
+ - number: GPIO pin (0..31)
+ - trigger: trigger mode:
+        2 = trigger on falling edge
+        3 = trigger on both edges
+
+Example of device using this is:
+
+        funkyfpga@0 {
+                compatible = "funky-fpga";
+                ...
+                interrupts = <4 3>;
+                interrupt-parent = <&gpio1>;
+        };
diff --git a/arch/powerpc/sysdev/mpc8xxx_gpio.c b/arch/powerpc/sysdev/mpc8xxx_gpio.c
index 6478eb10691a..83f519655fac 100644
--- a/arch/powerpc/sysdev/mpc8xxx_gpio.c
+++ b/arch/powerpc/sysdev/mpc8xxx_gpio.c
@@ -16,6 +16,7 @@
 #include <linux/of_gpio.h>
 #include <linux/gpio.h>
 #include <linux/slab.h>
+#include <linux/irq.h>
 
 #define MPC8XXX_GPIO_PINS       32
 
@@ -35,6 +36,7 @@ struct mpc8xxx_gpio_chip {
          * open drain mode safely
          */
         u32 data;
+        struct irq_host *irq;
 };
 
 static inline u32 mpc8xxx_gpio2mask(unsigned int gpio)
@@ -128,12 +130,136 @@ static int mpc8xxx_gpio_dir_out(struct gpio_chip *gc, unsigned int gpio, int val
         return 0;
 }
 
+static int mpc8xxx_gpio_to_irq(struct gpio_chip *gc, unsigned offset)
+{
+        struct of_mm_gpio_chip *mm = to_of_mm_gpio_chip(gc);
+        struct mpc8xxx_gpio_chip *mpc8xxx_gc = to_mpc8xxx_gpio_chip(mm);
+
+        if (mpc8xxx_gc->irq && offset < MPC8XXX_GPIO_PINS)
+                return irq_create_mapping(mpc8xxx_gc->irq, offset);
+        else
+                return -ENXIO;
+}
+
+static void mpc8xxx_gpio_irq_cascade(unsigned int irq, struct irq_desc *desc)
+{
+        struct mpc8xxx_gpio_chip *mpc8xxx_gc = get_irq_desc_data(desc);
+        struct of_mm_gpio_chip *mm = &mpc8xxx_gc->mm_gc;
+        unsigned int mask;
+
+        mask = in_be32(mm->regs + GPIO_IER) & in_be32(mm->regs + GPIO_IMR);
+        if (mask)
+                generic_handle_irq(irq_linear_revmap(mpc8xxx_gc->irq,
+                                                     32 - ffs(mask)));
+}
+
+static void mpc8xxx_irq_unmask(unsigned int virq)
+{
+        struct mpc8xxx_gpio_chip *mpc8xxx_gc = get_irq_chip_data(virq);
+        struct of_mm_gpio_chip *mm = &mpc8xxx_gc->mm_gc;
+        unsigned long flags;
+
+        spin_lock_irqsave(&mpc8xxx_gc->lock, flags);
+
+        setbits32(mm->regs + GPIO_IMR, mpc8xxx_gpio2mask(virq_to_hw(virq)));
+
+        spin_unlock_irqrestore(&mpc8xxx_gc->lock, flags);
+}
+
+static void mpc8xxx_irq_mask(unsigned int virq)
+{
+        struct mpc8xxx_gpio_chip *mpc8xxx_gc = get_irq_chip_data(virq);
+        struct of_mm_gpio_chip *mm = &mpc8xxx_gc->mm_gc;
+        unsigned long flags;
+
+        spin_lock_irqsave(&mpc8xxx_gc->lock, flags);
+
+        clrbits32(mm->regs + GPIO_IMR, mpc8xxx_gpio2mask(virq_to_hw(virq)));
+
+        spin_unlock_irqrestore(&mpc8xxx_gc->lock, flags);
+}
+
+static void mpc8xxx_irq_ack(unsigned int virq)
+{
+        struct mpc8xxx_gpio_chip *mpc8xxx_gc = get_irq_chip_data(virq);
+        struct of_mm_gpio_chip *mm = &mpc8xxx_gc->mm_gc;
+
+        out_be32(mm->regs + GPIO_IER, mpc8xxx_gpio2mask(virq_to_hw(virq)));
+}
+
+static int mpc8xxx_irq_set_type(unsigned int virq, unsigned int flow_type)
+{
+        struct mpc8xxx_gpio_chip *mpc8xxx_gc = get_irq_chip_data(virq);
+        struct of_mm_gpio_chip *mm = &mpc8xxx_gc->mm_gc;
+        unsigned long flags;
+
+        switch (flow_type) {
+        case IRQ_TYPE_EDGE_FALLING:
+                spin_lock_irqsave(&mpc8xxx_gc->lock, flags);
+                setbits32(mm->regs + GPIO_ICR,
+                          mpc8xxx_gpio2mask(virq_to_hw(virq)));
+                spin_unlock_irqrestore(&mpc8xxx_gc->lock, flags);
+                break;
+
+        case IRQ_TYPE_EDGE_BOTH:
+                spin_lock_irqsave(&mpc8xxx_gc->lock, flags);
+                clrbits32(mm->regs + GPIO_ICR,
+                          mpc8xxx_gpio2mask(virq_to_hw(virq)));
+                spin_unlock_irqrestore(&mpc8xxx_gc->lock, flags);
+                break;
+
+        default:
+                return -EINVAL;
+        }
+
+        return 0;
+}
+
+static struct irq_chip mpc8xxx_irq_chip = {
+        .name           = "mpc8xxx-gpio",
+        .unmask         = mpc8xxx_irq_unmask,
+        .mask           = mpc8xxx_irq_mask,
+        .ack            = mpc8xxx_irq_ack,
+        .set_type       = mpc8xxx_irq_set_type,
+};
+
+static int mpc8xxx_gpio_irq_map(struct irq_host *h, unsigned int virq,
+                                irq_hw_number_t hw)
+{
+        set_irq_chip_data(virq, h->host_data);
+        set_irq_chip_and_handler(virq, &mpc8xxx_irq_chip, handle_level_irq);
+        set_irq_type(virq, IRQ_TYPE_NONE);
+
+        return 0;
+}
+
+static int mpc8xxx_gpio_irq_xlate(struct irq_host *h, struct device_node *ct,
+                                  const u32 *intspec, unsigned int intsize,
+                                  irq_hw_number_t *out_hwirq,
+                                  unsigned int *out_flags)
+
+{
+        /* interrupt sense values coming from the device tree equal either
+         * EDGE_FALLING or EDGE_BOTH
+         */
+        *out_hwirq = intspec[0];
+        *out_flags = intspec[1];
+
+        return 0;
+}
+
+static struct irq_host_ops mpc8xxx_gpio_irq_ops = {
+        .map    = mpc8xxx_gpio_irq_map,
+        .xlate  = mpc8xxx_gpio_irq_xlate,
+};
+
 static void __init mpc8xxx_add_controller(struct device_node *np)
 {
         struct mpc8xxx_gpio_chip *mpc8xxx_gc;
         struct of_mm_gpio_chip *mm_gc;
         struct of_gpio_chip *of_gc;
         struct gpio_chip *gc;
+        unsigned hwirq;
         int ret;
 
         mpc8xxx_gc = kzalloc(sizeof(*mpc8xxx_gc), GFP_KERNEL);
@@ -158,11 +284,32 @@ static void __init mpc8xxx_add_controller(struct device_node *np)
         else
                 gc->get = mpc8xxx_gpio_get;
         gc->set = mpc8xxx_gpio_set;
+        gc->to_irq = mpc8xxx_gpio_to_irq;
 
         ret = of_mm_gpiochip_add(np, mm_gc);
         if (ret)
                 goto err;
 
+        hwirq = irq_of_parse_and_map(np, 0);
+        if (hwirq == NO_IRQ)
+                goto skip_irq;
+
+        mpc8xxx_gc->irq =
+                irq_alloc_host(np, IRQ_HOST_MAP_LINEAR, MPC8XXX_GPIO_PINS,
+                               &mpc8xxx_gpio_irq_ops, MPC8XXX_GPIO_PINS);
+        if (!mpc8xxx_gc->irq)
+                goto skip_irq;
+
+        mpc8xxx_gc->irq->host_data = mpc8xxx_gc;
+
+        /* ack and mask all irqs */
+        out_be32(mm_gc->regs + GPIO_IER, 0xffffffff);
+        out_be32(mm_gc->regs + GPIO_IMR, 0);
+
+        set_irq_data(hwirq, mpc8xxx_gc);
+        set_irq_chained_handler(hwirq, mpc8xxx_gpio_irq_cascade);
+
+skip_irq:
         return;
 
 err: