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Subject[PATCH 1/2] gpio: eic: Add edge trigger emulation for EIC
Date
The Spreadtrum debounce EIC and latch EIC can not support edge trigger,
but most GPIO users (like gpio-key driver) only use the edge trigger,
thus the EIC driver need add some support to emulate the edge trigger
to satisfy this requirement.

Signed-off-by: Baolin Wang <baolin.wang@linaro.org>
---
drivers/gpio/gpio-eic-sprd.c | 73 ++++++++++++++++++++++++++++++++++++++++++
1 file changed, 73 insertions(+)

diff --git a/drivers/gpio/gpio-eic-sprd.c b/drivers/gpio/gpio-eic-sprd.c
index de7dd93..e0d6a0a 100644
--- a/drivers/gpio/gpio-eic-sprd.c
+++ b/drivers/gpio/gpio-eic-sprd.c
@@ -300,6 +300,7 @@ static int sprd_eic_irq_set_type(struct irq_data *data, unsigned int flow_type)
struct gpio_chip *chip = irq_data_get_irq_chip_data(data);
struct sprd_eic *sprd_eic = gpiochip_get_data(chip);
u32 offset = irqd_to_hwirq(data);
+ int state;

switch (sprd_eic->type) {
case SPRD_EIC_DEBOUNCE:
@@ -310,6 +311,17 @@ static int sprd_eic_irq_set_type(struct irq_data *data, unsigned int flow_type)
case IRQ_TYPE_LEVEL_LOW:
sprd_eic_update(chip, offset, SPRD_EIC_DBNC_IEV, 0);
break;
+ case IRQ_TYPE_EDGE_RISING:
+ case IRQ_TYPE_EDGE_FALLING:
+ case IRQ_TYPE_EDGE_BOTH:
+ state = sprd_eic_get(chip, offset);
+ if (state)
+ sprd_eic_update(chip, offset,
+ SPRD_EIC_DBNC_IEV, 0);
+ else
+ sprd_eic_update(chip, offset,
+ SPRD_EIC_DBNC_IEV, 1);
+ break;
default:
return -ENOTSUPP;
}
@@ -324,6 +336,17 @@ static int sprd_eic_irq_set_type(struct irq_data *data, unsigned int flow_type)
case IRQ_TYPE_LEVEL_LOW:
sprd_eic_update(chip, offset, SPRD_EIC_LATCH_INTPOL, 1);
break;
+ case IRQ_TYPE_EDGE_RISING:
+ case IRQ_TYPE_EDGE_FALLING:
+ case IRQ_TYPE_EDGE_BOTH:
+ state = sprd_eic_get(chip, offset);
+ if (state)
+ sprd_eic_update(chip, offset,
+ SPRD_EIC_LATCH_INTPOL, 0);
+ else
+ sprd_eic_update(chip, offset,
+ SPRD_EIC_LATCH_INTPOL, 1);
+ break;
default:
return -ENOTSUPP;
}
@@ -405,6 +428,55 @@ static int sprd_eic_irq_set_type(struct irq_data *data, unsigned int flow_type)
return 0;
}

+static void sprd_eic_toggle_trigger(struct gpio_chip *chip, unsigned int irq,
+ unsigned int offset)
+{
+ struct sprd_eic *sprd_eic = gpiochip_get_data(chip);
+ struct irq_data *data = irq_get_irq_data(irq);
+ u32 trigger = irqd_get_trigger_type(data);
+ int state, post_state;
+
+ /*
+ * The debounce EIC and latch EIC can only support level trigger, so we
+ * can toggle the level trigger to emulate the edge trigger.
+ */
+ if ((sprd_eic->type != SPRD_EIC_DEBOUNCE &&
+ sprd_eic->type != SPRD_EIC_LATCH) ||
+ !(trigger & IRQ_TYPE_EDGE_BOTH))
+ return;
+
+ sprd_eic_irq_mask(data);
+ state = sprd_eic_get(chip, offset);
+
+retry:
+ switch (sprd_eic->type) {
+ case SPRD_EIC_DEBOUNCE:
+ if (state)
+ sprd_eic_update(chip, offset, SPRD_EIC_DBNC_IEV, 0);
+ else
+ sprd_eic_update(chip, offset, SPRD_EIC_DBNC_IEV, 1);
+ break;
+ case SPRD_EIC_LATCH:
+ if (state)
+ sprd_eic_update(chip, offset, SPRD_EIC_LATCH_INTPOL, 0);
+ else
+ sprd_eic_update(chip, offset, SPRD_EIC_LATCH_INTPOL, 1);
+ break;
+ default:
+ sprd_eic_irq_unmask(data);
+ return;
+ }
+
+ post_state = sprd_eic_get(chip, offset);
+ if (state != post_state) {
+ dev_warn(chip->parent, "EIC level was changed.\n");
+ state = post_state;
+ goto retry;
+ }
+
+ sprd_eic_irq_unmask(data);
+}
+
static int sprd_eic_match_chip_by_type(struct gpio_chip *chip, void *data)
{
enum sprd_eic_type type = *(enum sprd_eic_type *)data;
@@ -448,6 +520,7 @@ static void sprd_eic_handle_one_type(struct gpio_chip *chip)
bank * SPRD_EIC_PER_BANK_NR + n);

generic_handle_irq(girq);
+ sprd_eic_toggle_trigger(chip, girq, n);
}
}
}
--
1.7.9.5
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