gpio: tegra186: Implement wake event support

The GPIO controller doesn't have any controls to enable the system to
wake up from low power states based on activity on GPIO pins. An extra
hardware block that is part of the power management controller (PMC)
contains these controls. In order for the GPIO controller to be able
to cooperate with the PMC, obtain a reference to the PMC's IRQ domain
and make it a parent to the GPIO controller's IRQ domain. This way the
PMC gets an opportunity to program the additional registers required
to enable wakeup sources on suspend.

Based on additional work by Bitan Biswas <bbiswas@nvidia.com>.
Signed-off-by: Thierry Reding <treding@nvidia.com>
Link: https://lore.kernel.org/r/20191002144502.156393-2-thierry.reding@gmail.comSigned-off-by: Linus Walleij <linus.walleij@linaro.org>

drivers/gpio/Kconfig

@@ -539,6 +539,7 @@ config GPIO_TEGRA186
 	depends on ARCH_TEGRA_186_SOC || COMPILE_TEST
 	depends on OF_GPIO
 	select GPIOLIB_IRQCHIP
+	select IRQ_DOMAIN_HIERARCHY
 	help
 	  Say yes here to support GPIO pins on NVIDIA Tegra186 SoCs.
 

drivers/gpio/gpio-tegra186.c

@@ -53,6 +53,7 @@ struct tegra_gpio_soc {
 	const struct tegra_gpio_port *ports;
 	unsigned int num_ports;
 	const char *name;
+	unsigned int instance;
 };
 
 struct tegra_gpio {
@@ -327,7 +328,7 @@ static int tegra186_irq_set_type(struct irq_data *data, unsigned int type)
 	else
 		irq_set_handler_locked(data, handle_edge_irq);
 
-	return 0;
+	return irq_chip_set_type_parent(data, type);
 }
 
 static void tegra186_gpio_irq(struct irq_desc *desc)
@@ -367,39 +368,80 @@ static void tegra186_gpio_irq(struct irq_desc *desc)
 	chained_irq_exit(chip, desc);
 }
 
-static int tegra186_gpio_irq_domain_xlate(struct irq_domain *domain,
-					  struct device_node *np,
-					  const u32 *spec, unsigned int size,
-					  unsigned long *hwirq,
-					  unsigned int *type)
+static int tegra186_gpio_irq_domain_translate(struct irq_domain *domain,
+					      struct irq_fwspec *fwspec,
+					      unsigned long *hwirq,
+					      unsigned int *type)
 {
 	struct tegra_gpio *gpio = gpiochip_get_data(domain->host_data);
 	unsigned int port, pin, i, offset = 0;
 
-	if (size < 2)
+	if (WARN_ON(gpio->gpio.of_gpio_n_cells < 2))
+		return -EINVAL;
+
+	if (WARN_ON(fwspec->param_count < gpio->gpio.of_gpio_n_cells))
 		return -EINVAL;
 
-	port = spec[0] / 8;
-	pin = spec[0] % 8;
+	port = fwspec->param[0] / 8;
+	pin = fwspec->param[0] % 8;
 
-	if (port >= gpio->soc->num_ports) {
-		dev_err(gpio->gpio.parent, "invalid port number: %u\n", port);
+	if (port >= gpio->soc->num_ports)
 		return -EINVAL;
-	}
 
 	for (i = 0; i < port; i++)
 		offset += gpio->soc->ports[i].pins;
 
-	*type = spec[1] & IRQ_TYPE_SENSE_MASK;
+	*type = fwspec->param[1] & IRQ_TYPE_SENSE_MASK;
 	*hwirq = offset + pin;
 
 	return 0;
 }
 
-static const struct irq_domain_ops tegra186_gpio_irq_domain_ops = {
-	.map = gpiochip_irq_map,
-	.unmap = gpiochip_irq_unmap,
-	.xlate = tegra186_gpio_irq_domain_xlate,
+static void tegra186_gpio_populate_parent_fwspec(struct gpio_chip *chip,
+						 struct irq_fwspec *fwspec,
+						 unsigned int parent_hwirq,
+						 unsigned int parent_type)
+{
+	struct tegra_gpio *gpio = gpiochip_get_data(chip);
+
+	fwspec->param_count = 3;
+	fwspec->param[0] = gpio->soc->instance;
+	fwspec->param[1] = parent_hwirq;
+	fwspec->param[2] = parent_type;
+}
+
+static int tegra186_gpio_child_to_parent_hwirq(struct gpio_chip *chip,
+					       unsigned int hwirq,
+					       unsigned int type,
+					       unsigned int *parent_hwirq,
+					       unsigned int *parent_type)
+{
+	*parent_hwirq = chip->irq.child_offset_to_irq(chip, hwirq);
+	*parent_type = type;
+
+	return 0;
+}
+
+static unsigned int tegra186_gpio_child_offset_to_irq(struct gpio_chip *chip,
+						      unsigned int offset)
+{
+	struct tegra_gpio *gpio = gpiochip_get_data(chip);
+	unsigned int i;
+
+	for (i = 0; i < gpio->soc->num_ports; i++) {
+		if (offset < gpio->soc->ports[i].pins)
+			break;
+
+		offset -= gpio->soc->ports[i].pins;
+	}
+
+	return offset + i * 8;
+}
+
+static const struct of_device_id tegra186_pmc_of_match[] = {
+	{ .compatible = "nvidia,tegra186-pmc" },
+	{ .compatible = "nvidia,tegra194-pmc" },
+	{ /* sentinel */ }
 };
 
 static int tegra186_gpio_probe(struct platform_device *pdev)
@@ -407,6 +449,7 @@ static int tegra186_gpio_probe(struct platform_device *pdev)
 	unsigned int i, j, offset;
 	struct gpio_irq_chip *irq;
 	struct tegra_gpio *gpio;
+	struct device_node *np;
 	struct resource *res;
 	char **names;
 	int err;
@@ -487,10 +530,15 @@ static int tegra186_gpio_probe(struct platform_device *pdev)
 	gpio->intc.irq_mask = tegra186_irq_mask;
 	gpio->intc.irq_unmask = tegra186_irq_unmask;
 	gpio->intc.irq_set_type = tegra186_irq_set_type;
+	gpio->intc.irq_set_wake = irq_chip_set_wake_parent;
 
 	irq = &gpio->gpio.irq;
 	irq->chip = &gpio->intc;
-	irq->domain_ops = &tegra186_gpio_irq_domain_ops;
+	irq->fwnode = of_node_to_fwnode(pdev->dev.of_node);
+	irq->child_to_parent_hwirq = tegra186_gpio_child_to_parent_hwirq;
+	irq->populate_parent_fwspec = tegra186_gpio_populate_parent_fwspec;
+	irq->child_offset_to_irq = tegra186_gpio_child_offset_to_irq;
+	irq->child_irq_domain_ops.translate = tegra186_gpio_irq_domain_translate;
 	irq->handler = handle_simple_irq;
 	irq->default_type = IRQ_TYPE_NONE;
 	irq->parent_handler = tegra186_gpio_irq;
@@ -498,6 +546,15 @@ static int tegra186_gpio_probe(struct platform_device *pdev)
 	irq->num_parents = gpio->num_irq;
 	irq->parents = gpio->irq;
 
+	np = of_find_matching_node(NULL, tegra186_pmc_of_match);
+	if (np) {
+		irq->parent_domain = irq_find_host(np);
+		of_node_put(np);
+
+		if (!irq->parent_domain)
+			return -EPROBE_DEFER;
+	}
+
 	irq->map = devm_kcalloc(&pdev->dev, gpio->gpio.ngpio,
 				sizeof(*irq->map), GFP_KERNEL);
 	if (!irq->map)
@@ -564,6 +621,7 @@ static const struct tegra_gpio_soc tegra186_main_soc = {
 	.num_ports = ARRAY_SIZE(tegra186_main_ports),
 	.ports = tegra186_main_ports,
 	.name = "tegra186-gpio",
+	.instance = 0,
 };
 
 #define TEGRA186_AON_GPIO_PORT(port, base, count, controller)	\
@@ -589,6 +647,7 @@ static const struct tegra_gpio_soc tegra186_aon_soc = {
 	.num_ports = ARRAY_SIZE(tegra186_aon_ports),
 	.ports = tegra186_aon_ports,
 	.name = "tegra186-gpio-aon",
+	.instance = 1,
 };
 
 #define TEGRA194_MAIN_GPIO_PORT(port, base, count, controller)	\
@@ -634,6 +693,7 @@ static const struct tegra_gpio_soc tegra194_main_soc = {
 	.num_ports = ARRAY_SIZE(tegra194_main_ports),
 	.ports = tegra194_main_ports,
 	.name = "tegra194-gpio",
+	.instance = 0,
 };
 
 #define TEGRA194_AON_GPIO_PORT(port, base, count, controller)	\
@@ -656,6 +716,7 @@ static const struct tegra_gpio_soc tegra194_aon_soc = {
 	.num_ports = ARRAY_SIZE(tegra194_aon_ports),
 	.ports = tegra194_aon_ports,
 	.name = "tegra194-gpio-aon",
+	.instance = 1,
 };
 
 static const struct of_device_id tegra186_gpio_of_match[] = {