irqchip/stm32: Optimizes and cleans up stm32-exti irq_domain

- In stm32_exti_alloc function, discards irq_domain_set_info
  with handle_simple_irq. This overwrite the setting defined while init
  of generic chips. Exti controller manages edge irq type.
- Removes acking in chained irq handler as this is done by
  irq_chip itself inside handle_edge_irq
- removes unneeded irq_domain_ops.xlate callback

Acked-by: Ludovic Barre <ludovic.barre@st.com>
Tested-by: Ludovic Barre <ludovic.barre@st.com>
Signed-off-by: Radoslaw Pietrzyk <radoslaw.pietrzyk@gmail.com>
Signed-off-by: Ludovic Barre <ludovic.barre@st.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

drivers/irqchip/irq-stm32-exti.c

@@ -79,13 +79,6 @@ static unsigned long stm32_exti_pending(struct irq_chip_generic *gc)
 	return irq_reg_readl(gc, stm32_bank->pr_ofst);
 }
 
-static void stm32_exti_irq_ack(struct irq_chip_generic *gc, u32 mask)
-{
-	const struct stm32_exti_bank *stm32_bank = gc->private;
-
-	irq_reg_writel(gc, mask, stm32_bank->pr_ofst);
-}
-
 static void stm32_irq_handler(struct irq_desc *desc)
 {
 	struct irq_domain *domain = irq_desc_get_handler_data(desc);
@@ -106,7 +99,6 @@ static void stm32_irq_handler(struct irq_desc *desc)
 			for_each_set_bit(n, &pending, IRQS_PER_BANK) {
 				virq = irq_find_mapping(domain, irq_base + n);
 				generic_handle_irq(virq);
-				stm32_exti_irq_ack(gc, BIT(n));
 			}
 		}
 	}
@@ -176,16 +168,12 @@ static int stm32_irq_set_wake(struct irq_data *data, unsigned int on)
 static int stm32_exti_alloc(struct irq_domain *d, unsigned int virq,
 			    unsigned int nr_irqs, void *data)
 {
-	struct irq_chip_generic *gc;
 	struct irq_fwspec *fwspec = data;
 	irq_hw_number_t hwirq;
 
 	hwirq = fwspec->param[0];
-	gc = irq_get_domain_generic_chip(d, hwirq);
 
 	irq_map_generic_chip(d, virq, hwirq);
-	irq_domain_set_info(d, virq, hwirq, &gc->chip_types->chip, gc,
-			    handle_simple_irq, NULL, NULL);
 
 	return 0;
 }
@@ -200,7 +188,6 @@ static void stm32_exti_free(struct irq_domain *d, unsigned int virq,
 
 struct irq_domain_ops irq_exti_domain_ops = {
 	.map	= irq_map_generic_chip,
-	.xlate	= irq_domain_xlate_onetwocell,
 	.alloc  = stm32_exti_alloc,
 	.free	= stm32_exti_free,
 };