Merge branch 'irq/gpio-immutable' of git://git.kernel.org/pub/scm/linux/kernel/git/maz/arm-platforms into gpio/for-next

This pulls in changes improving the handling of immutable irqchips in core
gpiolib and several drivers.

4 files changed, 75 insertions, 21 deletions

diff --git a/drivers/gpio/TODO b/drivers/gpio/TODO
index b8b1473a5b1e..f87ff3fa8a53 100644
--- a/drivers/gpio/TODO
+++ b/drivers/gpio/TODO
@@ -178,3 +178,22 @@ discussed but the idea is to provide a low-level access point
 for debugging and hacking and to expose all lines without the
 need of any exporting. Also provide ample ammunition to shoot
 oneself in the foot, because this is debugfs after all.
+
+
+Moving over to immutable irq_chip structures
+
+Most of the gpio chips implementing interrupt support rely on gpiolib
+intercepting some of the irq_chip callbacks, preventing the structures
+from being made read-only and forcing duplication of structures that
+should otherwise be unique.
+
+The solution is to call into the gpiolib code when needed (resource
+management, enable/disable or unmask/mask callbacks), and to let the
+core code know about that by exposing a flag (IRQCHIP_IMMUTABLE) in
+the irq_chip structure. The irq_chip structure can then be made unique
+and const.
+
+A small number of drivers have been converted (pl061, tegra186, msm,
+amd, apple), and can be used as examples of how to proceed with this
+conversion. Note that drivers using the generic irqchip framework
+cannot be converted yet, but watch this space!
diff --git a/drivers/gpio/gpio-pl061.c b/drivers/gpio/gpio-pl061.c
index 4ecab700f23f..6464056cb6ae 100644
--- a/drivers/gpio/gpio-pl061.c
+++ b/drivers/gpio/gpio-pl061.c
@@ -52,7 +52,6 @@ struct pl061 {
 
 	void __iomem		*base;
 	struct gpio_chip	gc;
-	struct irq_chip		irq_chip;
 	int			parent_irq;
 
 #ifdef CONFIG_PM
@@ -241,6 +240,8 @@ static void pl061_irq_mask(struct irq_data *d)
 	gpioie = readb(pl061->base + GPIOIE) & ~mask;
 	writeb(gpioie, pl061->base + GPIOIE);
 	raw_spin_unlock(&pl061->lock);
+
+	gpiochip_disable_irq(gc, d->hwirq);
 }
 
 static void pl061_irq_unmask(struct irq_data *d)
@@ -250,6 +251,8 @@ static void pl061_irq_unmask(struct irq_data *d)
 	u8 mask = BIT(irqd_to_hwirq(d) % PL061_GPIO_NR);
 	u8 gpioie;
 
+	gpiochip_enable_irq(gc, d->hwirq);
+
 	raw_spin_lock(&pl061->lock);
 	gpioie = readb(pl061->base + GPIOIE) | mask;
 	writeb(gpioie, pl061->base + GPIOIE);
@@ -283,6 +286,24 @@ static int pl061_irq_set_wake(struct irq_data *d, unsigned int state)
 	return irq_set_irq_wake(pl061->parent_irq, state);
 }
 
+static void pl061_irq_print_chip(struct irq_data *data, struct seq_file *p)
+{
+	struct gpio_chip *gc = irq_data_get_irq_chip_data(data);
+
+	seq_printf(p, dev_name(gc->parent));
+}
+
+static const struct irq_chip pl061_irq_chip = {
+	.irq_ack		= pl061_irq_ack,
+	.irq_mask		= pl061_irq_mask,
+	.irq_unmask		= pl061_irq_unmask,
+	.irq_set_type		= pl061_irq_type,
+	.irq_set_wake		= pl061_irq_set_wake,
+	.irq_print_chip		= pl061_irq_print_chip,
+	.flags			= IRQCHIP_IMMUTABLE,
+	GPIOCHIP_IRQ_RESOURCE_HELPERS,
+};
+
 static int pl061_probe(struct amba_device *adev, const struct amba_id *id)
 {
 	struct device *dev = &adev->dev;
@@ -315,13 +336,6 @@ static int pl061_probe(struct amba_device *adev, const struct amba_id *id)
 	/*
 	 * irq_chip support
 	 */
-	pl061->irq_chip.name = dev_name(dev);
-	pl061->irq_chip.irq_ack	= pl061_irq_ack;
-	pl061->irq_chip.irq_mask = pl061_irq_mask;
-	pl061->irq_chip.irq_unmask = pl061_irq_unmask;
-	pl061->irq_chip.irq_set_type = pl061_irq_type;
-	pl061->irq_chip.irq_set_wake = pl061_irq_set_wake;
-
 	writeb(0, pl061->base + GPIOIE); /* disable irqs */
 	irq = adev->irq[0];
 	if (!irq)
@@ -329,7 +343,7 @@ static int pl061_probe(struct amba_device *adev, const struct amba_id *id)
 	pl061->parent_irq = irq;
 
 	girq = &pl061->gc.irq;
-	girq->chip = &pl061->irq_chip;
+	gpio_irq_chip_set_chip(girq, &pl061_irq_chip);
 	girq->parent_handler = pl061_irq_handler;
 	girq->num_parents = 1;
 	girq->parents = devm_kcalloc(dev, 1, sizeof(*girq->parents),
diff --git a/drivers/gpio/gpio-tegra186.c b/drivers/gpio/gpio-tegra186.c
index 031fe105b58e..84c4f1e9fb0c 100644
--- a/drivers/gpio/gpio-tegra186.c
+++ b/drivers/gpio/gpio-tegra186.c
@@ -80,7 +80,6 @@ struct tegra_gpio_soc {
 
 struct tegra_gpio {
 	struct gpio_chip gpio;
-	struct irq_chip intc;
 	unsigned int num_irq;
 	unsigned int *irq;
 
@@ -372,6 +371,8 @@ static void tegra186_irq_mask(struct irq_data *data)
 	value = readl(base + TEGRA186_GPIO_ENABLE_CONFIG);
 	value &= ~TEGRA186_GPIO_ENABLE_CONFIG_INTERRUPT;
 	writel(value, base + TEGRA186_GPIO_ENABLE_CONFIG);
+
+	gpiochip_disable_irq(&gpio->gpio, data->hwirq);
 }
 
 static void tegra186_irq_unmask(struct irq_data *data)
@@ -385,6 +386,8 @@ static void tegra186_irq_unmask(struct irq_data *data)
 	if (WARN_ON(base == NULL))
 		return;
 
+	gpiochip_enable_irq(&gpio->gpio, data->hwirq);
+
 	value = readl(base + TEGRA186_GPIO_ENABLE_CONFIG);
 	value |= TEGRA186_GPIO_ENABLE_CONFIG_INTERRUPT;
 	writel(value, base + TEGRA186_GPIO_ENABLE_CONFIG);
@@ -456,6 +459,24 @@ static int tegra186_irq_set_wake(struct irq_data *data, unsigned int on)
 	return 0;
 }
 
+static void tegra186_irq_print_chip(struct irq_data *data, struct seq_file *p)
+{
+	struct gpio_chip *gc = irq_data_get_irq_chip_data(data);
+
+	seq_printf(p, dev_name(gc->parent));
+}
+
+static const struct irq_chip tegra186_gpio_irq_chip = {
+	.irq_ack		= tegra186_irq_ack,
+	.irq_mask		= tegra186_irq_mask,
+	.irq_unmask		= tegra186_irq_unmask,
+	.irq_set_type		= tegra186_irq_set_type,
+	.irq_set_wake		= tegra186_irq_set_wake,
+	.irq_print_chip		= tegra186_irq_print_chip,
+	.flags			= IRQCHIP_IMMUTABLE,
+	GPIOCHIP_IRQ_RESOURCE_HELPERS,
+};
+
 static void tegra186_gpio_irq(struct irq_desc *desc)
 {
 	struct tegra_gpio *gpio = irq_desc_get_handler_data(desc);
@@ -760,15 +781,8 @@ static int tegra186_gpio_probe(struct platform_device *pdev)
 	gpio->gpio.of_xlate = tegra186_gpio_of_xlate;
 #endif /* CONFIG_OF_GPIO */
 
-	gpio->intc.name = dev_name(&pdev->dev);
-	gpio->intc.irq_ack = tegra186_irq_ack;
-	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 = tegra186_irq_set_wake;
-
 	irq = &gpio->gpio.irq;
-	irq->chip = &gpio->intc;
+	gpio_irq_chip_set_chip(irq, &tegra186_gpio_irq_chip);
 	irq->fwnode = of_node_to_fwnode(pdev->dev.of_node);
 	irq->child_to_parent_hwirq = tegra186_gpio_child_to_parent_hwirq;
 	irq->populate_parent_alloc_arg = tegra186_gpio_populate_parent_fwspec;
diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index 2e18fef3847e..721a8a92d4a6 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -1417,19 +1417,21 @@ static int gpiochip_to_irq(struct gpio_chip *gc, unsigned int offset)
 	return irq_create_mapping(domain, offset);
 }
 
-static int gpiochip_irq_reqres(struct irq_data *d)
+int gpiochip_irq_reqres(struct irq_data *d)
 {
 	struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
 
 	return gpiochip_reqres_irq(gc, d->hwirq);
 }
+EXPORT_SYMBOL(gpiochip_irq_reqres);
 
-static void gpiochip_irq_relres(struct irq_data *d)
+void gpiochip_irq_relres(struct irq_data *d)
 {
 	struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
 
 	gpiochip_relres_irq(gc, d->hwirq);
 }
+EXPORT_SYMBOL(gpiochip_irq_relres);
 
 static void gpiochip_irq_mask(struct irq_data *d)
 {
@@ -1469,6 +1471,11 @@ static void gpiochip_set_irq_hooks(struct gpio_chip *gc)
 {
 	struct irq_chip *irqchip = gc->irq.chip;
 
+	if (irqchip->flags & IRQCHIP_IMMUTABLE)
+		return;
+
+	chip_warn(gc, "not an immutable chip, please consider fixing it!\n");
+
 	if (!irqchip->irq_request_resources &&
 	    !irqchip->irq_release_resources) {
 		irqchip->irq_request_resources = gpiochip_irq_reqres;
@@ -1627,7 +1634,7 @@ static void gpiochip_irqchip_remove(struct gpio_chip *gc)
 		irq_domain_remove(gc->irq.domain);
 	}
 
-	if (irqchip) {
+	if (irqchip && !(irqchip->flags & IRQCHIP_IMMUTABLE)) {
 		if (irqchip->irq_request_resources == gpiochip_irq_reqres) {
 			irqchip->irq_request_resources = NULL;
 			irqchip->irq_release_resources = NULL;