[PATCH v3 2/2] pinctrl: stm32: Add level interrupt support to gpio irq chip

[Alexandre Torgue]

GPIO hardware block is directly linked to EXTI block but EXTI handles
external interrupts only on edge. To be able to handle GPIO interrupt on
level a "hack" is done in gpio irq chip: parent interrupt (exti irq chip)
is retriggered following interrupt type and gpio line value.

Signed-off-by: Alexandre Torgue <alexandre.torgue@xxxxxx>
Tested-by: Marek Vasut <marex@xxxxxxx>

diff --git a/drivers/pinctrl/stm32/pinctrl-stm32.c b/drivers/pinctrl/stm32/pinctrl-stm32.c
index 2d5e0435af0a..d330b30729a5 100644
--- a/drivers/pinctrl/stm32/pinctrl-stm32.c
+++ b/drivers/pinctrl/stm32/pinctrl-stm32.c
@@ -92,6 +92,7 @@ struct stm32_gpio_bank {
 	u32 bank_nr;
 	u32 bank_ioport_nr;
 	u32 pin_backup[STM32_GPIO_PINS_PER_BANK];
+	u8 irq_type[STM32_GPIO_PINS_PER_BANK];
 };
 
 struct stm32_pinctrl {
@@ -303,6 +304,46 @@ static const struct gpio_chip stm32_gpio_template = {
 	.get_direction		= stm32_gpio_get_direction,
 };
 
+void stm32_gpio_irq_eoi(struct irq_data *d)
+{
+	struct stm32_gpio_bank *bank = d->domain->host_data;
+	int level;
+
+	irq_chip_eoi_parent(d);
+
+	/* If level interrupt type then retrig */
+	level = stm32_gpio_get(&bank->gpio_chip, d->hwirq);
+	if ((level == 0 && bank->irq_type[d->hwirq] == IRQ_TYPE_LEVEL_LOW) ||
+	    (level == 1 && bank->irq_type[d->hwirq] == IRQ_TYPE_LEVEL_HIGH))
+		irq_chip_retrigger_hierarchy(d);
+};
+
+static int stm32_gpio_set_type(struct irq_data *d, unsigned int type)
+{
+	struct stm32_gpio_bank *bank = d->domain->host_data;
+	u32 parent_type;
+
+	switch (type) {
+	case IRQ_TYPE_EDGE_RISING:
+	case IRQ_TYPE_EDGE_FALLING:
+	case IRQ_TYPE_EDGE_BOTH:
+		parent_type = type;
+		break;
+	case IRQ_TYPE_LEVEL_HIGH:
+		parent_type = IRQ_TYPE_EDGE_RISING;
+		break;
+	case IRQ_TYPE_LEVEL_LOW:
+		parent_type = IRQ_TYPE_EDGE_FALLING;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	bank->irq_type[d->hwirq] = type;
+
+	return irq_chip_set_type_parent(d, parent_type);
+};
+
 static int stm32_gpio_irq_request_resources(struct irq_data *irq_data)
 {
 	struct stm32_gpio_bank *bank = irq_data->domain->host_data;
@@ -332,11 +373,11 @@ static void stm32_gpio_irq_release_resources(struct irq_data *irq_data)
 
 static struct irq_chip stm32_gpio_irq_chip = {
 	.name		= "stm32gpio",
-	.irq_eoi	= irq_chip_eoi_parent,
+	.irq_eoi	= stm32_gpio_irq_eoi,
 	.irq_ack	= irq_chip_ack_parent,
 	.irq_mask	= irq_chip_mask_parent,
 	.irq_unmask	= irq_chip_unmask_parent,
-	.irq_set_type	= irq_chip_set_type_parent,
+	.irq_set_type	= stm32_gpio_set_type,
 	.irq_set_wake	= irq_chip_set_wake_parent,
 	.irq_request_resources = stm32_gpio_irq_request_resources,
 	.irq_release_resources = stm32_gpio_irq_release_resources,
-- 
2.17.1