[ARM] Orion edge GPIO IRQ support

This patch adds support for Orion edge sensitive GPIO IRQs.

Signed-off-by: Tzachi Perelstein <tzachi@marvell.com>
Signed-off-by: Nicolas Pitre <nico@marvell.com>
CC: Thomas Gleixner <tglx@linutronix.de>

diff --git a/arch/arm/mach-orion/gpio.c b/arch/arm/mach-orion/gpio.c
index 0418f5b..d5f00c8 100644 (file)
--- a/arch/arm/mach-orion/gpio.c
+++ b/arch/arm/mach-orion/gpio.c
@@ -93,7 +93,7 @@ int gpio_get_value(unsigned pin)
        int val, mask = 1 << pin;
 
        if (orion_read(GPIO_IO_CONF) & mask)
-               val = orion_read(GPIO_DATA_IN);
+               val = orion_read(GPIO_DATA_IN) ^ orion_read(GPIO_IN_POL);
        else
                val = orion_read(GPIO_OUT);
 

diff --git a/arch/arm/mach-orion/irq.c b/arch/arm/mach-orion/irq.c
index 585a0fb..df7e12a 100644 (file)
--- a/arch/arm/mach-orion/irq.c
+++ b/arch/arm/mach-orion/irq.c
@@ -19,22 +19,66 @@
 
 /*****************************************************************************
  * Orion GPIO IRQ
+ *
+ * GPIO_IN_POL register controlls whether GPIO_DATA_IN will hold the same
+ * value of the line or the opposite value.
+ *
+ * Level IRQ handlers: DATA_IN is used directly as cause register.
+ *                     Interrupt are masked by LEVEL_MASK registers.
+ * Edge IRQ handlers:  Change in DATA_IN are latched in EDGE_CAUSE.
+ *                     Interrupt are masked by EDGE_MASK registers.
+ * Both-edge handlers: Similar to regular Edge handlers, but also swaps
+ *                     the polarity to catch the next line transaction.
+ *                     This is a race condition that might not perfectly
+ *                     work on some use cases.
+ *
+ * Every eight GPIO lines are grouped (OR'ed) before going up to main
+ * cause register.
+ *
+ *                    EDGE  cause    mask
+ *        data-in   /--------| |-----| |----\
+ *     -----| |-----                         ---- to main cause reg
+ *           X      \----------------| |----/
+ *        polarity    LEVEL          mask
+ *
  ****************************************************************************/
+static void orion_gpio_irq_ack(u32 irq)
+{
+       int pin = irq_to_gpio(irq);
+       if (irq_desc[irq].status & IRQ_LEVEL)
+               /*
+                * Mask bit for level interrupt
+                */
+               orion_clrbits(GPIO_LEVEL_MASK, 1 << pin);
+       else
+               /*
+                * Clear casue bit for egde interrupt
+                */
+               orion_clrbits(GPIO_EDGE_CAUSE, 1 << pin);
+}
+
 static void orion_gpio_irq_mask(u32 irq)
 {
        int pin = irq_to_gpio(irq);
-       orion_clrbits(GPIO_LEVEL_MASK, 1 << pin);
+       if (irq_desc[irq].status & IRQ_LEVEL)
+               orion_clrbits(GPIO_LEVEL_MASK, 1 << pin);
+       else
+               orion_clrbits(GPIO_EDGE_MASK, 1 << pin);
 }
 
 static void orion_gpio_irq_unmask(u32 irq)
 {
        int pin = irq_to_gpio(irq);
-       orion_setbits(GPIO_LEVEL_MASK, 1 << pin);
+       if (irq_desc[irq].status & IRQ_LEVEL)
+               orion_setbits(GPIO_LEVEL_MASK, 1 << pin);
+       else
+               orion_setbits(GPIO_EDGE_MASK, 1 << pin);
 }
 
 static int orion_gpio_set_irq_type(u32 irq, u32 type)
 {
        int pin = irq_to_gpio(irq);
+       struct irq_desc *desc;
 
        if ((orion_read(GPIO_IO_CONF) & (1 << pin)) == 0) {
                printk(KERN_ERR "orion_gpio_set_irq_type failed "
@@ -42,24 +86,56 @@ static int orion_gpio_set_irq_type(u32 irq, u32 type)
                return -EINVAL;
        }
 
+       desc = irq_desc + irq;
+
        switch (type) {
        case IRQT_HIGH:
+               desc->handle_irq = handle_level_irq;
+               desc->status |= IRQ_LEVEL;
                orion_clrbits(GPIO_IN_POL, (1 << pin));
                break;
        case IRQT_LOW:
+               desc->handle_irq = handle_level_irq;
+               desc->status |= IRQ_LEVEL;
+               orion_setbits(GPIO_IN_POL, (1 << pin));
+               break;
+       case IRQT_RISING:
+               desc->handle_irq = handle_edge_irq;
+               desc->status &= ~IRQ_LEVEL;
+               orion_clrbits(GPIO_IN_POL, (1 << pin));
+               break;
+       case IRQT_FALLING:
+               desc->handle_irq = handle_edge_irq;
+               desc->status &= ~IRQ_LEVEL;
                orion_setbits(GPIO_IN_POL, (1 << pin));
                break;
+       case IRQT_BOTHEDGE:
+               desc->handle_irq = handle_edge_irq;
+               desc->status &= ~IRQ_LEVEL;
+               /*
+                * set initial polarity based on current input level
+                */
+               if ((orion_read(GPIO_IN_POL) ^ orion_read(GPIO_DATA_IN))
+                   & (1 << pin))
+                       orion_setbits(GPIO_IN_POL, (1 << pin)); /* falling */
+               else
+                       orion_clrbits(GPIO_IN_POL, (1 << pin)); /* rising */
+
+               break;
        default:
                printk(KERN_ERR "failed to set irq=%d (type=%d)\n", irq, type);
                return -EINVAL;
        }
 
+       desc->status &= ~IRQ_TYPE_SENSE_MASK;
+       desc->status |= type & IRQ_TYPE_SENSE_MASK;
+
        return 0;
 }
 
 static struct irq_chip orion_gpio_irq_chip = {
        .name           = "Orion-IRQ-GPIO",
-       .ack            = orion_gpio_irq_mask,
+       .ack            = orion_gpio_irq_ack,
        .mask           = orion_gpio_irq_mask,
        .unmask         = orion_gpio_irq_unmask,
        .set_type       = orion_gpio_set_irq_type,
@@ -67,24 +143,24 @@ static struct irq_chip orion_gpio_irq_chip = {
 
 static void orion_gpio_irq_handler(unsigned int irq, struct irq_desc *desc)
 {
-       int i;
-       u32 cause, shift;
+       u32 cause, offs, pin;
 
        BUG_ON(irq < IRQ_ORION_GPIO_0_7 || irq > IRQ_ORION_GPIO_24_31);
-       shift = (irq - IRQ_ORION_GPIO_0_7) * 8;
-       cause = orion_read(GPIO_EDGE_CAUSE) & orion_read(GPIO_LEVEL_MASK);
-       cause &= (0xff << shift);
-
-       for (i = shift; i < shift + 8; i++) {
-               if (cause & (1 << i)) {
-                       int gpio_irq = i + IRQ_ORION_GPIO_START;
-                       if (gpio_irq > 0) {
-                               desc = irq_desc + gpio_irq;
-                               desc_handle_irq(gpio_irq, desc);
-                       } else {
-                               printk(KERN_ERR "orion_gpio_irq_handler error, "
-                                               "invalid irq %d\n", gpio_irq);
+       offs = (irq - IRQ_ORION_GPIO_0_7) * 8;
+       cause = (orion_read(GPIO_DATA_IN) & orion_read(GPIO_LEVEL_MASK)) |
+               (orion_read(GPIO_EDGE_CAUSE) & orion_read(GPIO_EDGE_MASK));
+
+       for (pin = offs; pin < offs + 8; pin++) {
+               if (cause & (1 << pin)) {
+                       irq = gpio_to_irq(pin);
+                       desc = irq_desc + irq;
+                       if ((desc->status & IRQ_TYPE_SENSE_MASK) == IRQT_BOTHEDGE) {
+                               /* Swap polarity (race with GPIO line) */
+                               u32 polarity = orion_read(GPIO_IN_POL);
+                               polarity ^= 1 << pin;
+                               orion_write(GPIO_IN_POL, polarity);
                        }
+                       desc_handle_irq(irq, desc);
                }
        }
 }
@@ -92,19 +168,24 @@ static void orion_gpio_irq_handler(unsigned int irq, struct irq_desc *desc)
 static void __init orion_init_gpio_irq(void)
 {
        int i;
+       struct irq_desc *desc;
 
        /*
         * Mask and clear GPIO IRQ interrupts
         */
        orion_write(GPIO_LEVEL_MASK, 0x0);
+       orion_write(GPIO_EDGE_MASK, 0x0);
        orion_write(GPIO_EDGE_CAUSE, 0x0);
 
        /*
-        * Register chained level handlers for GPIO IRQs
+        * Register chained level handlers for GPIO IRQs by default.
+        * User can use set_type() if he wants to use edge types handlers.
         */
        for (i = IRQ_ORION_GPIO_START; i < NR_IRQS; i++) {
                set_irq_chip(i, &orion_gpio_irq_chip);
                set_irq_handler(i, handle_level_irq);
+               desc = irq_desc + i;
+               desc->status |= IRQ_LEVEL;
                set_irq_flags(i, IRQF_VALID);
        }
        set_irq_chained_handler(IRQ_ORION_GPIO_0_7, orion_gpio_irq_handler);