pinctrl: bcm2835: Add support for wake-up interrupts

Leverage the IRQCHIP_MASK_ON_SUSPEND flag in order to avoid having to
specifically treat the GPIO interrupts during suspend and resume, and
simply implement an irq_set_wake() callback that is responsible for
enabling the parent wake-up interrupt as a wake-up interrupt.

To avoid allocating unnecessary resources for other chips, the wake-up
interrupts are only initialized if we have a brcm,bcm7211-gpio
compatibility string.

Signed-off-by: Florian Fainelli <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Linus Walleij <[e-mail]>

drivers/pinctrl/bcm/pinctrl-bcm2835.c

···
 #include <linux/irq.h>
 #include <linux/irqdesc.h>
 #include <linux/init.h>
+#include <linux/interrupt.h>
 #include <linux/of_address.h>
 #include <linux/of.h>
 #include <linux/of_irq.h>
···
 struct bcm2835_pinctrl {
 	struct device *dev;
 	void __iomem *base;
+	int *wake_irq;
 
 	/* note: locking assumes each bank will have its own unsigned long */
 	unsigned long enabled_irq_map[BCM2835_NUM_BANKS];
···
 	chained_irq_exit(host_chip, desc);
 }
 
+static irqreturn_t bcm2835_gpio_wake_irq_handler(int irq, void *dev_id)
+{
+	return IRQ_HANDLED;
+}
+
 static inline void __bcm2835_gpio_irq_config(struct bcm2835_pinctrl *pc,
 	unsigned reg, unsigned offset, bool enable)
 {
···
 	bcm2835_gpio_set_bit(pc, GPEDS0, gpio);
 }
 
+static int bcm2835_gpio_irq_set_wake(struct irq_data *data, unsigned int on)
+{
+	struct gpio_chip *chip = irq_data_get_irq_chip_data(data);
+	struct bcm2835_pinctrl *pc = gpiochip_get_data(chip);
+	unsigned gpio = irqd_to_hwirq(data);
+	unsigned int irqgroup;
+	int ret = -EINVAL;
+
+	if (!pc->wake_irq)
+		return ret;
+
+	if (gpio <= 27)
+		irqgroup = 0;
+	else if (gpio >= 28 && gpio <= 45)
+		irqgroup = 1;
+	else if (gpio >= 46 && gpio <= 57)
+		irqgroup = 2;
+	else
+		return ret;
+
+	if (on)
+		ret = enable_irq_wake(pc->wake_irq[irqgroup]);
+	else
+		ret = disable_irq_wake(pc->wake_irq[irqgroup]);
+
+	return ret;
+}
+
 static struct irq_chip bcm2835_gpio_irq_chip = {
 	.name = MODULE_NAME,
 	.irq_enable = bcm2835_gpio_irq_enable,
···
 	.irq_ack = bcm2835_gpio_irq_ack,
 	.irq_mask = bcm2835_gpio_irq_disable,
 	.irq_unmask = bcm2835_gpio_irq_enable,
+	.irq_set_wake = bcm2835_gpio_irq_set_wake,
+	.flags = IRQCHIP_MASK_ON_SUSPEND,
 };
 
 static int bcm2835_pctl_get_groups_count(struct pinctrl_dev *pctldev)
···
 	struct resource iomem;
 	int err, i;
 	const struct of_device_id *match;
+	int is_7211 = 0;
 
 	BUILD_BUG_ON(ARRAY_SIZE(bcm2835_gpio_pins) != BCM2711_NUM_GPIOS);
 	BUILD_BUG_ON(ARRAY_SIZE(bcm2835_gpio_groups) != BCM2711_NUM_GPIOS);
···
 		return -EINVAL;
 
 	pdata = match->data;
+	is_7211 = of_device_is_compatible(np, "brcm,bcm7211-gpio");
 
 	pc->gpio_chip = *pdata->gpio_chip;
 	pc->gpio_chip.parent = dev;
···
 				     GFP_KERNEL);
 	if (!girq->parents)
 		return -ENOMEM;
+
+	if (is_7211) {
+		pc->wake_irq = devm_kcalloc(dev, BCM2835_NUM_IRQS,
+					    sizeof(*pc->wake_irq),
+					    GFP_KERNEL);
+		if (!pc->wake_irq)
+			return -ENOMEM;
+	}
+
 	/*
 	 * Use the same handler for all groups: this is necessary
 	 * since we use one gpiochip to cover all lines - the
···
 	 * bank that was firing the IRQ and look up the per-group
 	 * and bank data.
 	 */
-	for (i = 0; i < BCM2835_NUM_IRQS; i++)
+	for (i = 0; i < BCM2835_NUM_IRQS; i++) {
+		int len;
+		char *name;
+
 		girq->parents[i] = irq_of_parse_and_map(np, i);
+		if (!is_7211)
+			continue;
+
+		/* Skip over the all banks interrupts */
+		pc->wake_irq[i] = irq_of_parse_and_map(np, i +
+						       BCM2835_NUM_IRQS + 1);
+
+		len = strlen(dev_name(pc->dev)) + 16;
+		name = devm_kzalloc(pc->dev, len, GFP_KERNEL);
+		if (!name)
+			return -ENOMEM;
+
+		snprintf(name, len, "%s:bank%d", dev_name(pc->dev), i);
+
+		/* These are optional interrupts */
+		err = devm_request_irq(dev, pc->wake_irq[i],
+				       bcm2835_gpio_wake_irq_handler,
+				       IRQF_SHARED, name, pc);
+		if (err)
+			dev_warn(dev, "unable to request wake IRQ %d\n",
+				 pc->wake_irq[i]);
+	}
+
 	girq->default_type = IRQ_TYPE_NONE;
 	girq->handler = handle_level_irq;