Re: [PATCH v4 2/9] drivers: irqchip: Add STM32 external interrupts support

[Jason Cooper]

On Tue, Sep 06, 2016 at 06:45:34PM +0200, Alexandre TORGUE wrote:
> 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@xxxxxxxxx>
> Signed-off-by: Alexandre TORGUE <alexandre.torgue@xxxxxx>
> 
> 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..763c17c
> --- /dev/null
> +++ b/drivers/irqchip/irq-stm32-exti.c
> @@ -0,0 +1,203 @@
> +/*
> + * Copyright (C) Maxime Coquelin 2015
> + * Author:  Maxime Coquelin <mcoquelin.stm32@xxxxxxxxx>
> + * 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/irqchip/chained_irq.h>

double paste?
double paste?

If there are no other critiques, I'll fix this up when I pull in patches
1 and 2.

thx,

Jason.

> +#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_get_irq_data(virq);
> +
> +	irq_gc_mask_clr_bit(data->parent_data);
> +	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
>