mxc: emulate GPIO interrupt on both-edges
MXC GPIO controller does not support generation of interrupts on both
edges. Emulate this mode in software by reconfiguring the irq trigger
polarity on each interrupt. This follows an example of
drivers/mfd/asic3.c.
Signed-off-by: Guennadi Liakhovetski <lg@denx.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
diff --git a/arch/arm/plat-mxc/gpio.c b/arch/arm/plat-mxc/gpio.c
index 89e9579..7506d96 100644
--- a/arch/arm/plat-mxc/gpio.c
+++ b/arch/arm/plat-mxc/gpio.c
@@ -64,6 +64,8 @@
_set_gpio_irqenable(&mxc_gpio_ports[gpio / 32], gpio & 0x1f, 1);
}
+static int mxc_gpio_get(struct gpio_chip *chip, unsigned offset);
+
static int gpio_set_irq_type(u32 irq, u32 type)
{
u32 gpio = irq_to_gpio(irq);
@@ -72,6 +74,7 @@
int edge;
void __iomem *reg = port->base;
+ port->both_edges &= ~(1 << (gpio & 31));
switch (type) {
case IRQ_TYPE_EDGE_RISING:
edge = GPIO_INT_RISE_EDGE;
@@ -79,13 +82,24 @@
case IRQ_TYPE_EDGE_FALLING:
edge = GPIO_INT_FALL_EDGE;
break;
+ case IRQ_TYPE_EDGE_BOTH:
+ val = mxc_gpio_get(&port->chip, gpio & 31);
+ if (val) {
+ edge = GPIO_INT_LOW_LEV;
+ pr_debug("mxc: set GPIO %d to low trigger\n", gpio);
+ } else {
+ edge = GPIO_INT_HIGH_LEV;
+ pr_debug("mxc: set GPIO %d to high trigger\n", gpio);
+ }
+ port->both_edges |= 1 << (gpio & 31);
+ break;
case IRQ_TYPE_LEVEL_LOW:
edge = GPIO_INT_LOW_LEV;
break;
case IRQ_TYPE_LEVEL_HIGH:
edge = GPIO_INT_HIGH_LEV;
break;
- default: /* this includes IRQ_TYPE_EDGE_BOTH */
+ default:
return -EINVAL;
}
@@ -98,6 +112,34 @@
return 0;
}
+static void mxc_flip_edge(struct mxc_gpio_port *port, u32 gpio)
+{
+ void __iomem *reg = port->base;
+ u32 bit, val;
+ int edge;
+
+ reg += GPIO_ICR1 + ((gpio & 0x10) >> 2); /* lower or upper register */
+ bit = gpio & 0xf;
+ val = __raw_readl(reg);
+ edge = (val >> (bit << 1)) & 3;
+ val &= ~(0x3 << (bit << 1));
+ switch (edge) {
+ case GPIO_INT_HIGH_LEV:
+ edge = GPIO_INT_LOW_LEV;
+ pr_debug("mxc: switch GPIO %d to low trigger\n", gpio);
+ break;
+ case GPIO_INT_LOW_LEV:
+ edge = GPIO_INT_HIGH_LEV;
+ pr_debug("mxc: switch GPIO %d to high trigger\n", gpio);
+ break;
+ default:
+ pr_err("mxc: invalid configuration for GPIO %d: %x\n",
+ gpio, edge);
+ return;
+ }
+ __raw_writel(val | (edge << (bit << 1)), reg);
+}
+
/* handle n interrupts in one status register */
static void mxc_gpio_irq_handler(struct mxc_gpio_port *port, u32 irq_stat)
{
@@ -105,11 +147,16 @@
gpio_irq_no = port->virtual_irq_start;
for (; irq_stat != 0; irq_stat >>= 1, gpio_irq_no++) {
+ u32 gpio = irq_to_gpio(gpio_irq_no);
if ((irq_stat & 1) == 0)
continue;
BUG_ON(!(irq_desc[gpio_irq_no].handle_irq));
+
+ if (port->both_edges & (1 << (gpio & 31)))
+ mxc_flip_edge(port, gpio);
+
irq_desc[gpio_irq_no].handle_irq(gpio_irq_no,
&irq_desc[gpio_irq_no]);
}