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

[Alexandre Torgue]

This patch adds level interrupt support to gpio irq chip.

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>

diff --git a/drivers/pinctrl/stm32/pinctrl-stm32.c b/drivers/pinctrl/stm32/pinctrl-stm32.c
index 2d5e0435af0a..04e1b062c20e 100644
--- a/drivers/pinctrl/stm32/pinctrl-stm32.c
+++ b/drivers/pinctrl/stm32/pinctrl-stm32.c
@@ -89,6 +89,7 @@ struct stm32_gpio_bank {
 	struct pinctrl_gpio_range range;
 	struct fwnode_handle *fwnode;
 	struct irq_domain *domain;
+	u32 irq_type[STM32_GPIO_PINS_PER_BANK];
 	u32 bank_nr;
 	u32 bank_ioport_nr;
 	u32 pin_backup[STM32_GPIO_PINS_PER_BANK];
@@ -303,6 +304,48 @@ 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 line;
+
+	irq_chip_eoi_parent(d);
+
+	/* If level interrupt type then retrig */
+	line = stm32_gpio_get(&bank->gpio_chip, d->hwirq);
+	if ((line == 0 && bank->irq_type[d->hwirq] == IRQ_TYPE_LEVEL_LOW) ||
+	    (line == 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;
+
+	bank->irq_type[d->hwirq] = 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;
+	}
+
+	irq_chip_set_type_parent(d, parent_type);
+
+	return 0;
+};
+
 static int stm32_gpio_irq_request_resources(struct irq_data *irq_data)
 {
 	struct stm32_gpio_bank *bank = irq_data->domain->host_data;
@@ -332,11 +375,11 @@ 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