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path: root/drivers/gpio/gpio-mcp23s08.c
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Diffstat (limited to 'drivers/gpio/gpio-mcp23s08.c')
-rw-r--r--drivers/gpio/gpio-mcp23s08.c65
1 files changed, 60 insertions, 5 deletions
diff --git a/drivers/gpio/gpio-mcp23s08.c b/drivers/gpio/gpio-mcp23s08.c
index bdb6923..2a57d024 100644
--- a/drivers/gpio/gpio-mcp23s08.c
+++ b/drivers/gpio/gpio-mcp23s08.c
@@ -270,8 +270,10 @@ mcp23s08_direction_output(struct gpio_chip *chip, unsigned offset, int value)
static irqreturn_t mcp23s08_irq(int irq, void *data)
{
struct mcp23s08 *mcp = data;
- int intcap, intf, i;
+ int intcap, intf, i, gpio, gpio_orig, intcap_mask;
unsigned int child_irq;
+ bool intf_set, intcap_changed, gpio_bit_changed,
+ defval_changed, gpio_set;
mutex_lock(&mcp->lock);
if (mcp_read(mcp, MCP_INTF, &intf) < 0) {
@@ -287,14 +289,67 @@ static irqreturn_t mcp23s08_irq(int irq, void *data)
}
mcp->cache[MCP_INTCAP] = intcap;
+
+ /* This clears the interrupt(configurable on S18) */
+ if (mcp_read(mcp, MCP_GPIO, &gpio) < 0) {
+ mutex_unlock(&mcp->lock);
+ return IRQ_HANDLED;
+ }
+ gpio_orig = mcp->cache[MCP_GPIO];
+ mcp->cache[MCP_GPIO] = gpio;
mutex_unlock(&mcp->lock);
+ if (mcp->cache[MCP_INTF] == 0) {
+ /* There is no interrupt pending */
+ return IRQ_HANDLED;
+ }
+
+ dev_dbg(mcp->chip.parent,
+ "intcap 0x%04X intf 0x%04X gpio_orig 0x%04X gpio 0x%04X\n",
+ intcap, intf, gpio_orig, gpio);
for (i = 0; i < mcp->chip.ngpio; i++) {
- if ((BIT(i) & mcp->cache[MCP_INTF]) &&
- ((BIT(i) & intcap & mcp->irq_rise) ||
- (mcp->irq_fall & ~intcap & BIT(i)) ||
- (BIT(i) & mcp->cache[MCP_INTCON]))) {
+ /* We must check all of the inputs on the chip,
+ * otherwise we may not notice a change on >=2 pins.
+ *
+ * On at least the mcp23s17, INTCAP is only updated
+ * one byte at a time(INTCAPA and INTCAPB are
+ * not written to at the same time - only on a per-bank
+ * basis).
+ *
+ * INTF only contains the single bit that caused the
+ * interrupt per-bank. On the mcp23s17, there is
+ * INTFA and INTFB. If two pins are changed on the A
+ * side at the same time, INTF will only have one bit
+ * set. If one pin on the A side and one pin on the B
+ * side are changed at the same time, INTF will have
+ * two bits set. Thus, INTF can't be the only check
+ * to see if the input has changed.
+ */
+
+ intf_set = BIT(i) & mcp->cache[MCP_INTF];
+ if (i < 8 && intf_set)
+ intcap_mask = 0x00FF;
+ else if (i >= 8 && intf_set)
+ intcap_mask = 0xFF00;
+ else
+ intcap_mask = 0x00;
+
+ intcap_changed = (intcap_mask &
+ (BIT(i) & mcp->cache[MCP_INTCAP])) !=
+ (intcap_mask & (BIT(i) & gpio_orig));
+ gpio_set = BIT(i) & mcp->cache[MCP_GPIO];
+ gpio_bit_changed = (BIT(i) & gpio_orig) !=
+ (BIT(i) & mcp->cache[MCP_GPIO]);
+ defval_changed = (BIT(i) & mcp->cache[MCP_INTCON]) &&
+ ((BIT(i) & mcp->cache[MCP_GPIO]) !=
+ (BIT(i) & mcp->cache[MCP_DEFVAL]));
+
+ if (((gpio_bit_changed || intcap_changed) &&
+ (BIT(i) & mcp->irq_rise) && gpio_set) ||
+ ((gpio_bit_changed || intcap_changed) &&
+ (BIT(i) & mcp->irq_fall) && !gpio_set) ||
+ defval_changed) {
child_irq = irq_find_mapping(mcp->chip.irqdomain, i);
handle_nested_irq(child_irq);
}
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