From: Marc Zyngier <maz@xxxxxxxxxx>
The core gpiolib code is able to deal with multiple interrupt parents
for a single gpio irqchip. It however only allows a single piece
of data to be conveyed to all flow handlers (either the gpio_chip
or some other, driver-specific data).
This means that drivers have to go through some interesting dance
to find the correct context, something that isn't great in interrupt
context (see aebdc8abc9db86e2bd33070fc2f961012fff74b4 for a prime
example).
Instead, offer an optional way for a pinctrl/gpio driver to provide
an array of pointers which gets used to provide the correct context
to the flow handler.
Signed-off-by: Marc Zyngier <maz@xxxxxxxxxx>
---
drivers/gpio/gpiolib.c | 9 +++++++--
include/linux/gpio/driver.h | 19 +++++++++++++++++--
2 files changed, 24 insertions(+), 4 deletions(-)
diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index d1b9b721218f..abfbf546d159 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -1534,9 +1534,14 @@ static int gpiochip_add_irqchip(struct gpio_chip *gc,
}
if (gc->irq.parent_handler) {
- void *data = gc->irq.parent_handler_data ?: gc;
-
for (i = 0; i < gc->irq.num_parents; i++) {
+ void *data;
+
+ if (gc->irq.per_parent_data)
+ data = gc->irq.parent_handler_data_array[i];
+ else
+ data = gc->irq.parent_handler_data ?: gc;
+
/*
* The parent IRQ chip is already using the chip_data
* for this IRQ chip, so our callbacks simply use the
diff --git a/include/linux/gpio/driver.h b/include/linux/gpio/driver.h
index a0f9901dcae6..a673a359e20b 100644
--- a/include/linux/gpio/driver.h
+++ b/include/linux/gpio/driver.h
@@ -168,11 +168,18 @@ struct gpio_irq_chip {
/**
* @parent_handler_data:
+ * @parent_handler_data_array:
*
* Data associated, and passed to, the handler for the parent
- * interrupt.
+ * interrupt. Can either be a single pointer if @per_parent_data
+ * is false, or an array of @num_parents pointers otherwise. If
+ * @per_parent_data is true, @parent_handler_data_array cannot be
+ * NULL.
*/
- void *parent_handler_data;
+ union {
+ void *parent_handler_data;
+ void **parent_handler_data_array;
+ };
/**
* @num_parents:
@@ -203,6 +210,14 @@ struct gpio_irq_chip {
*/
bool threaded;
+ /**
+ * @per_parent_data:
+ *
+ * True if parent_handler_data_array describes a @num_parents
+ * sized array to be used as parent data.
+ */
+ bool per_parent_data;
+
/**
* @init_hw: optional routine to initialize hardware before
* an IRQ chip will be added. This is quite useful when
--
2.17.1
