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Subject[PATCH v2 01/16] gpio: Implement tighter IRQ chip integration
Date
From: Thierry Reding <treding@nvidia.com>

Currently GPIO drivers are required to a GPIO chip and the corresponding
IRQ chip separately, which can result in a lot of boilerplate. Introduce
a new struct gpio_irq_chip, embedded in a struct gpio_chip, that drivers
can fill in if they want the GPIO core to automatically register the IRQ
chip associated with a GPIO chip.

Signed-off-by: Thierry Reding <treding@nvidia.com>
---
drivers/gpio/gpiolib.c | 146 +++++++++++++++++++++++++++++++++++++++++++-
include/linux/gpio/driver.h | 64 +++++++++++++++++++
2 files changed, 207 insertions(+), 3 deletions(-)

diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index eb80dac4e26a..b34d9cbd5809 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -72,6 +72,7 @@ static LIST_HEAD(gpio_lookup_list);
LIST_HEAD(gpio_devices);

static void gpiochip_free_hogs(struct gpio_chip *chip);
+static int gpiochip_add_irqchip(struct gpio_chip *gpiochip);
static void gpiochip_irqchip_remove(struct gpio_chip *gpiochip);
static int gpiochip_irqchip_init_valid_mask(struct gpio_chip *gpiochip);
static void gpiochip_irqchip_free_valid_mask(struct gpio_chip *gpiochip);
@@ -1260,6 +1261,10 @@ int gpiochip_add_data(struct gpio_chip *chip, void *data)
if (status)
goto err_remove_from_list;

+ status = gpiochip_add_irqchip(chip);
+ if (status)
+ goto err_remove_chip;
+
status = of_gpiochip_add(chip);
if (status)
goto err_remove_chip;
@@ -1626,8 +1631,8 @@ EXPORT_SYMBOL_GPL(gpiochip_set_nested_irqchip);
* gpiochip by assigning the gpiochip as chip data, and using the irqchip
* stored inside the gpiochip.
*/
-static int gpiochip_irq_map(struct irq_domain *d, unsigned int irq,
- irq_hw_number_t hwirq)
+int gpiochip_irq_map(struct irq_domain *d, unsigned int irq,
+ irq_hw_number_t hwirq)
{
struct gpio_chip *chip = d->host_data;

@@ -1655,8 +1660,9 @@ static int gpiochip_irq_map(struct irq_domain *d, unsigned int irq,

return 0;
}
+EXPORT_SYMBOL_GPL(gpiochip_irq_map);

-static void gpiochip_irq_unmap(struct irq_domain *d, unsigned int irq)
+void gpiochip_irq_unmap(struct irq_domain *d, unsigned int irq)
{
struct gpio_chip *chip = d->host_data;

@@ -1665,6 +1671,7 @@ static void gpiochip_irq_unmap(struct irq_domain *d, unsigned int irq)
irq_set_chip_and_handler(irq, NULL, NULL);
irq_set_chip_data(irq, NULL);
}
+EXPORT_SYMBOL_GPL(gpiochip_irq_unmap);

static const struct irq_domain_ops gpiochip_domain_ops = {
.map = gpiochip_irq_map,
@@ -1705,6 +1712,124 @@ static int gpiochip_to_irq(struct gpio_chip *chip, unsigned offset)
return irq_create_mapping(chip->irqdomain, offset);
}

+/**
+ * gpiochip_add_irqchip() - adds an IRQ chip to a GPIO chip
+ * @gpiochip: the GPIO chip to add the IRQ chip to
+ */
+static int gpiochip_add_irqchip(struct gpio_chip *gpiochip)
+{
+ struct irq_chip *irqchip = gpiochip->irqchip;
+ const struct irq_domain_ops *ops;
+ struct device_node *np;
+ unsigned int type;
+ unsigned int i;
+
+ if (!irqchip)
+ return 0;
+
+ if (gpiochip->irq.parent_handler && gpiochip->can_sleep) {
+ chip_err(gpiochip, "you cannot have chained interrupts on a "
+ "chip that may sleep\n");
+ return -EINVAL;
+ }
+
+ type = gpiochip->irq_default_type;
+ np = gpiochip->parent->of_node;
+
+#ifdef CONFIG_OF_GPIO
+ /*
+ * If the gpiochip has an assigned OF node this takes precedence
+ * FIXME: get rid of this and use gpiochip->parent->of_node
+ * everywhere
+ */
+ if (gpiochip->of_node)
+ np = gpiochip->of_node;
+#endif
+
+ /*
+ * Specifying a default trigger is a terrible idea if DT or ACPI is
+ * used to configure the interrupts, as you may end up with
+ * conflicting triggers. Tell the user, and reset to NONE.
+ */
+ if (WARN(np && type != IRQ_TYPE_NONE,
+ "%s: Ignoring %u default trigger\n", np->full_name, type))
+ type = IRQ_TYPE_NONE;
+
+ if (has_acpi_companion(gpiochip->parent) && type != IRQ_TYPE_NONE) {
+ acpi_handle_warn(ACPI_HANDLE(gpiochip->parent),
+ "Ignoring %u default trigger\n", type);
+ type = IRQ_TYPE_NONE;
+ }
+
+ gpiochip->to_irq = gpiochip_to_irq;
+ gpiochip->irq_default_type = type;
+
+ if (gpiochip->irq.domain_ops)
+ ops = gpiochip->irq.domain_ops;
+ else
+ ops = &gpiochip_domain_ops;
+
+ gpiochip->irqdomain = irq_domain_add_simple(np, gpiochip->ngpio,
+ gpiochip->irq_base,
+ ops, gpiochip);
+ if (!gpiochip->irqdomain)
+ return -EINVAL;
+
+ /*
+ * It is possible for a driver to override this, but only if the
+ * alternative functions are both implemented.
+ */
+ if (!irqchip->irq_request_resources &&
+ !irqchip->irq_release_resources) {
+ irqchip->irq_request_resources = gpiochip_irq_reqres;
+ irqchip->irq_release_resources = gpiochip_irq_relres;
+ }
+
+ if (gpiochip->irq.parent_handler) {
+ void *data = gpiochip->irq.parent_handler_data ?: gpiochip;
+
+ for (i = 0; i < gpiochip->irq.num_parents; i++) {
+ /*
+ * The parent IRQ chip is already using the chip_data
+ * for this IRQ chip, so our callbacks simply use the
+ * handler_data.
+ */
+ irq_set_chained_handler_and_data(gpiochip->irq.parents[i],
+ gpiochip->irq.parent_handler,
+ data);
+ }
+
+ gpiochip->irq_nested = false;
+ } else {
+ gpiochip->irq_nested = true;
+ }
+
+ /*
+ * Prepare the mapping since the IRQ chip shall be orthogonal to any
+ * GPIO chip calls.
+ */
+ for (i = 0; i < gpiochip->ngpio; i++) {
+ unsigned int irq;
+
+ if (!gpiochip_irqchip_irq_valid(gpiochip, i))
+ continue;
+
+ irq = irq_create_mapping(gpiochip->irqdomain, i);
+ if (!irq) {
+ chip_err(gpiochip,
+ "failed to create IRQ mapping for GPIO#%u\n",
+ i);
+ continue;
+ }
+
+ irq_set_parent(irq, gpiochip->irq.map[i]);
+ }
+
+ acpi_gpiochip_request_interrupts(gpiochip);
+
+ return 0;
+}
+
/**
* gpiochip_irqchip_remove() - removes an irqchip added to a gpiochip
* @gpiochip: the gpiochip to remove the irqchip from
@@ -1722,6 +1847,16 @@ static void gpiochip_irqchip_remove(struct gpio_chip *gpiochip)
irq_set_handler_data(gpiochip->irq_chained_parent, NULL);
}

+ if (gpiochip->irqchip) {
+ struct gpio_irq_chip *irq = &gpiochip->irq;
+ unsigned int i;
+
+ for (i = 0; i < irq->num_parents; i++) {
+ irq_set_chained_handler(irq->parents[i], NULL);
+ irq_set_handler_data(irq->parents[i], NULL);
+ }
+ }
+
/* Remove all IRQ mappings and delete the domain */
if (gpiochip->irqdomain) {
for (offset = 0; offset < gpiochip->ngpio; offset++) {
@@ -1842,6 +1977,11 @@ EXPORT_SYMBOL_GPL(gpiochip_irqchip_add_key);

#else /* CONFIG_GPIOLIB_IRQCHIP */

+static inline int gpiochip_add_irqchip(struct gpio_chip *gpiochip)
+{
+ return 0;
+}
+
static void gpiochip_irqchip_remove(struct gpio_chip *gpiochip) {}
static inline int gpiochip_irqchip_init_valid_mask(struct gpio_chip *gpiochip)
{
diff --git a/include/linux/gpio/driver.h b/include/linux/gpio/driver.h
index c97f8325e8bf..6100b171817e 100644
--- a/include/linux/gpio/driver.h
+++ b/include/linux/gpio/driver.h
@@ -19,6 +19,58 @@ struct module;

#ifdef CONFIG_GPIOLIB

+#ifdef CONFIG_GPIOLIB_IRQCHIP
+/**
+ * struct gpio_irq_chip - GPIO interrupt controller
+ */
+struct gpio_irq_chip {
+ /**
+ * @domain_ops:
+ *
+ * Table of interrupt domain operations for this IRQ chip.
+ */
+ const struct irq_domain_ops *domain_ops;
+
+ /**
+ * @parent_handler:
+ *
+ * The interrupt handler for the GPIO chip's parent interrupts, may be
+ * NULL if the parent interrupts are nested rather than cascaded.
+ */
+ irq_flow_handler_t parent_handler;
+
+ /**
+ * @parent_handler_data:
+ *
+ * Data associated, and passed to, the handler for the parent
+ * interrupt.
+ */
+ void *parent_handler_data;
+
+ /**
+ * @num_parents:
+ *
+ * The number of interrupt parents of a GPIO chip.
+ */
+ unsigned int num_parents;
+
+ /**
+ * @parents:
+ *
+ * A list of interrupt parents of a GPIO chip. This is owned by the
+ * driver, so the core will only reference this list, not modify it.
+ */
+ unsigned int *parents;
+
+ /**
+ * @map:
+ *
+ * A list of interrupt parents for each line of a GPIO chip.
+ */
+ unsigned int *map;
+};
+#endif
+
/**
* struct gpio_chip - abstract a GPIO controller
* @label: a functional name for the GPIO device, such as a part
@@ -173,6 +225,14 @@ struct gpio_chip {
bool irq_need_valid_mask;
unsigned long *irq_valid_mask;
struct lock_class_key *lock_key;
+
+ /**
+ * @irq:
+ *
+ * Integrates interrupt chip functionality with the GPIO chip. Can be
+ * used to handle IRQs for most practical cases.
+ */
+ struct gpio_irq_chip irq;
#endif

#if defined(CONFIG_OF_GPIO)
@@ -264,6 +324,10 @@ int bgpio_init(struct gpio_chip *gc, struct device *dev,

#ifdef CONFIG_GPIOLIB_IRQCHIP

+int gpiochip_irq_map(struct irq_domain *d, unsigned int irq,
+ irq_hw_number_t hwirq);
+void gpiochip_irq_unmap(struct irq_domain *d, unsigned int irq);
+
void gpiochip_set_chained_irqchip(struct gpio_chip *gpiochip,
struct irq_chip *irqchip,
unsigned int parent_irq,
--
2.14.1
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