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gpio: eic: Add edge trigger emulation for EIC 

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>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
This commit is contained in:
Baolin Wang 2018-03-30 15:02:37 +08:00 committed by Linus Walleij
parent df42a02d45
commit 7bf0d7f622
1 changed files with 73 additions and 0 deletions
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73
drivers/gpio/gpio-eic-sprd.c
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@ -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);
}
}
}