[PATCH v6 2/4] drivers: irqchip: Add STM32 external interrupts support

Alexandre TORGUE
2016-09-20T16:03:12Z

The STM32 external interrupt controller consists of edge detectors that
generate interrupts requests or wake-up events.

Each line can be independently configured as interrupt or wake-up source,
and triggers either on rising, falling or both edges. Each line can also
be masked independently.

Signed-off-by: Maxime Coquelin <mcoquelin.stm32@gmail.com>
Signed-off-by: Alexandre TORGUE <alexandre.torgue@st.com>

diff --git a/drivers/irqchip/Kconfig b/drivers/irqchip/Kconfig
index 7f87289..bc62d1f 100644
--- a/drivers/irqchip/Kconfig
+++ b/drivers/irqchip/Kconfig
@@ -264,3 +264,7 @@ config EZNPS_GIC
select IRQ_DOMAIN
help
Support the EZchip NPS400 global interrupt controller
+
+config STM32_EXTI
+ bool
+ select IRQ_DOMAIN
diff --git a/drivers/irqchip/Makefile b/drivers/irqchip/Makefile
index 4c203b6..96383b2 100644
--- a/drivers/irqchip/Makefile
+++ b/drivers/irqchip/Makefile
@@ -71,3 +71,4 @@ obj-$(CONFIG_MVEBU_ODMI) += irq-mvebu-odmi.o
obj-$(CONFIG_LS_SCFG_MSI) += irq-ls-scfg-msi.o
obj-$(CONFIG_EZNPS_GIC) += irq-eznps.o
obj-$(CONFIG_ARCH_ASPEED) += irq-aspeed-vic.o
+obj-$(CONFIG_STM32_EXTI) += irq-stm32-exti.o
diff --git a/drivers/irqchip/irq-stm32-exti.c b/drivers/irqchip/irq-stm32-exti.c
new file mode 100644
index 0000000..491568c
--- /dev/null
+++ b/drivers/irqchip/irq-stm32-exti.c
@@ -0,0 +1,201 @@
+/*
+ * Copyright (C) Maxime Coquelin 2015
+ * Author: Maxime Coquelin <mcoquelin.stm32@gmail.com>
+ * License terms: GNU General Public License (GPL), version 2
+ */
+
+#include <linux/bitops.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/irq.h>
+#include <linux/irqchip.h>
+#include <linux/irqchip/chained_irq.h>
+#include <linux/irqdomain.h>
+#include <linux/of_address.h>
+#include <linux/of_irq.h>
+
+#define EXTI_IMR 0x0
+#define EXTI_EMR 0x4
+#define EXTI_RTSR 0x8
+#define EXTI_FTSR 0xc
+#define EXTI_SWIER 0x10
+#define EXTI_PR 0x14
+
+static void stm32_irq_handler(struct irq_desc *desc)
+{
+ struct irq_domain *domain = irq_desc_get_handler_data(desc);
+ struct irq_chip_generic *gc = domain->gc->gc[0];
+ struct irq_chip *chip = irq_desc_get_chip(desc);
+ unsigned long pending;
+ int n;
+
+ chained_irq_enter(chip, desc);
+
+ while ((pending = irq_reg_readl(gc, EXTI_PR))) {
+ for_each_set_bit(n, &pending, BITS_PER_LONG) {
+ generic_handle_irq(irq_find_mapping(domain, n));
+ irq_reg_writel(gc, BIT(n), EXTI_PR);
+ }
+ }
+
+ chained_irq_exit(chip, desc);
+}
+
+static int stm32_irq_set_type(struct irq_data *data, unsigned int type)
+{
+ struct irq_chip_generic *gc = irq_data_get_irq_chip_data(data);
+ int pin = data->hwirq;
+ u32 rtsr, ftsr;
+
+ irq_gc_lock(gc);
+
+ rtsr = irq_reg_readl(gc, EXTI_RTSR);
+ ftsr = irq_reg_readl(gc, EXTI_FTSR);
+
+ switch (type) {
+ case IRQ_TYPE_EDGE_RISING:
+ rtsr |= BIT(pin);
+ ftsr &= ~BIT(pin);
+ break;
+ case IRQ_TYPE_EDGE_FALLING:
+ rtsr &= ~BIT(pin);
+ ftsr |= BIT(pin);
+ break;
+ case IRQ_TYPE_EDGE_BOTH:
+ rtsr |= BIT(pin);
+ ftsr |= BIT(pin);
+ break;
+ default:
+ irq_gc_unlock(gc);
+ return -EINVAL;
+ }
+
+ irq_reg_writel(gc, rtsr, EXTI_RTSR);
+ irq_reg_writel(gc, ftsr, EXTI_FTSR);
+
+ irq_gc_unlock(gc);
+
+ return 0;
+}
+
+static int stm32_irq_set_wake(struct irq_data *data, unsigned int on)
+{
+ struct irq_chip_generic *gc = irq_data_get_irq_chip_data(data);
+ int pin = data->hwirq;
+ u32 emr;
+
+ irq_gc_lock(gc);
+
+ emr = irq_reg_readl(gc, EXTI_EMR);
+ if (on)
+ emr |= BIT(pin);
+ else
+ emr &= ~BIT(pin);
+ irq_reg_writel(gc, emr, EXTI_EMR);
+
+ irq_gc_unlock(gc);
+
+ return 0;
+}
+
+static int stm32_exti_alloc(struct irq_domain *d, unsigned int virq,
+ unsigned int nr_irqs, void *data)
+{
+ struct irq_chip_generic *gc = d->gc->gc[0];
+ struct irq_fwspec *fwspec = data;
+ irq_hw_number_t hwirq;
+
+ hwirq = fwspec->param[0];
+
+ 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;
+}
+
+static void stm32_exti_free(struct irq_domain *d, unsigned int virq,
+ unsigned int nr_irqs)
+{
+ struct irq_data *data = irq_domain_get_irq_data(d, virq);
+
+ irq_domain_reset_irq_data(data);
+}
+
+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,
+};
+
+static int __init stm32_exti_init(struct device_node *node,
+ struct device_node *parent)
+{
+ unsigned int clr = IRQ_NOREQUEST | IRQ_NOPROBE | IRQ_NOAUTOEN;
+ int nr_irqs, nr_exti, ret, i;
+ struct irq_chip_generic *gc;
+ struct irq_domain *domain;
+ void *base;
+
+ base = of_iomap(node, 0);
+ if (!base) {
+ pr_err("%s: Unable to map registers\n", node->full_name);
+ return -ENOMEM;
+ }
+
+ /* Determine number of irqs supported */
+ writel_relaxed(~0UL, base + EXTI_RTSR);
+ nr_exti = fls(readl_relaxed(base + EXTI_RTSR));
+ writel_relaxed(0, base + EXTI_RTSR);
+
+ pr_info("%s: %d External IRQs detected\n", node->full_name, nr_exti);
+
+ domain = irq_domain_add_linear(node, nr_exti,
+ &irq_exti_domain_ops, NULL);
+ if (!domain) {
+ pr_err("%s: Could not register interrupt domain.\n",
+ node->name);
+ ret = -ENOMEM;
+ goto out_unmap;
+ }
+
+ ret = irq_alloc_domain_generic_chips(domain, nr_exti, 1, "exti",
+ handle_edge_irq, clr, 0, 0);
+ if (ret) {
+ pr_err("%s: Could not allocate generic interrupt chip.\n",
+ node->full_name);
+ goto out_free_domain;
+ }
+
+ gc = domain->gc->gc[0];
+ gc->reg_base = base;
+ gc->chip_types->type = IRQ_TYPE_EDGE_BOTH;
+ gc->chip_types->chip.name = gc->chip_types[0].chip.name;
+ gc->chip_types->chip.irq_ack = irq_gc_ack_set_bit;
+ gc->chip_types->chip.irq_mask = irq_gc_mask_clr_bit;
+ gc->chip_types->chip.irq_unmask = irq_gc_mask_set_bit;
+ gc->chip_types->chip.irq_set_type = stm32_irq_set_type;
+ gc->chip_types->chip.irq_set_wake = stm32_irq_set_wake;
+ gc->chip_types->regs.ack = EXTI_PR;
+ gc->chip_types->regs.mask = EXTI_IMR;
+ gc->chip_types->handler = handle_edge_irq;
+
+ nr_irqs = of_irq_count(node);
+ for (i = 0; i < nr_irqs; i++) {
+ unsigned int irq = irq_of_parse_and_map(node, i);
+
+ irq_set_handler_data(irq, domain);
+ irq_set_chained_handler(irq, stm32_irq_handler);
+ }
+
+ return 0;
+
+out_free_domain:
+ irq_domain_remove(domain);
+out_unmap:
+ iounmap(base);
+ return ret;
+}
+
+IRQCHIP_DECLARE(stm32_exti, "st,stm32-exti", stm32_exti_init);
--
1.9.1