[SRU][Xenial][PATCH 1/3] gpiolib: Make it possible to exclude GPIOs from IRQ domain
Phidias Chiang
phidias.chiang at canonical.com
Wed Oct 19 06:45:23 UTC 2016
From: Mika Westerberg <mika.westerberg at linux.intel.com>
BugLink: http://bugs.launchpad.net/bugs/1620979
When using GPIO irqchip helpers to setup irqchip for a gpiolib based
driver, it is not possible to select which GPIOs to add to the IRQ domain.
Instead it just adds all GPIOs which is not always desired. For example
there might be GPIOs that for some reason cannot generated normal
interrupts at all.
To support this we add a flag irq_need_valid_mask to struct gpio_chip. When
this flag is set the core allocates irq_valid_mask that holds one bit for
each GPIO the chip has. By default all bits are set but drivers can
manipulate this using set_bit() and clear_bit() accordingly.
Then when gpiochip_irqchip_add() is called, this mask is checked and all
GPIOs with bit is set are added to the IRQ domain created for the GPIO
chip.
Suggested-by: Linus Walleij <linus.walleij at linaro.org>
Signed-off-by: Mika Westerberg <mika.westerberg at linux.intel.com>
Signed-off-by: Linus Walleij <linus.walleij at linaro.org>
(cherry picked from commit 79b804cb6af4f128b2c53f0887c02537a7eb5824)
Signed-off-by: Phidias Chiang <phidias.chiang at canonical.com>
---
Documentation/gpio/driver.txt | 6 ++++
drivers/gpio/gpiolib.c | 66 +++++++++++++++++++++++++++++++++++++++++--
include/linux/gpio/driver.h | 6 ++++
3 files changed, 75 insertions(+), 3 deletions(-)
diff --git a/Documentation/gpio/driver.txt b/Documentation/gpio/driver.txt
index 12a6194..cc58807 100644
--- a/Documentation/gpio/driver.txt
+++ b/Documentation/gpio/driver.txt
@@ -165,6 +165,12 @@ symbol:
to the container using container_of().
(See Documentation/driver-model/design-patterns.txt)
+ If there is a need to exclude certain GPIOs from the IRQ domain, one can
+ set .irq_need_valid_mask of the gpiochip before gpiochip_add_data() is
+ called. This allocates .irq_valid_mask with as many bits set as there are
+ GPIOs in the chip. Drivers can exclude GPIOs by clearing bits from this
+ mask. The mask must be filled in before gpiochip_irqchip_add() is called.
+
* gpiochip_set_chained_irqchip(): sets up a chained irq handler for a
gpio_chip from a parent IRQ and passes the struct gpio_chip* as handler
data. (Notice handler data, since the irqchip data is likely used by the
diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index 06d345b..bee7963 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -55,6 +55,8 @@ LIST_HEAD(gpio_chips);
static void gpiochip_free_hogs(struct gpio_chip *chip);
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);
static inline void desc_set_label(struct gpio_desc *d, const char *label)
@@ -355,6 +357,10 @@ int gpiochip_add(struct gpio_chip *chip)
if (status)
goto err_remove_from_list;
+ status = gpiochip_irqchip_init_valid_mask(chip);
+ if (status)
+ goto err_remove_from_list;
+
status = of_gpiochip_add(chip);
if (status)
goto err_remove_chip;
@@ -375,6 +381,7 @@ err_remove_chip:
acpi_gpiochip_remove(chip);
gpiochip_free_hogs(chip);
of_gpiochip_remove(chip);
+ gpiochip_irqchip_free_valid_mask(chip);
err_remove_from_list:
spin_lock_irqsave(&gpio_lock, flags);
list_del(&chip->list);
@@ -481,6 +488,40 @@ static struct gpio_chip *find_chip_by_name(const char *name)
* The following is irqchip helper code for gpiochips.
*/
+static int gpiochip_irqchip_init_valid_mask(struct gpio_chip *gpiochip)
+{
+ int i;
+
+ if (!gpiochip->irq_need_valid_mask)
+ return 0;
+
+ gpiochip->irq_valid_mask = kcalloc(BITS_TO_LONGS(gpiochip->ngpio),
+ sizeof(long), GFP_KERNEL);
+ if (!gpiochip->irq_valid_mask)
+ return -ENOMEM;
+
+ /* Assume by default all GPIOs are valid */
+ for (i = 0; i < gpiochip->ngpio; i++)
+ set_bit(i, gpiochip->irq_valid_mask);
+
+ return 0;
+}
+
+static void gpiochip_irqchip_free_valid_mask(struct gpio_chip *gpiochip)
+{
+ kfree(gpiochip->irq_valid_mask);
+ gpiochip->irq_valid_mask = NULL;
+}
+
+static bool gpiochip_irqchip_irq_valid(const struct gpio_chip *gpiochip,
+ unsigned int offset)
+{
+ /* No mask means all valid */
+ if (likely(!gpiochip->irq_valid_mask))
+ return true;
+ return test_bit(offset, gpiochip->irq_valid_mask);
+}
+
/**
* gpiochip_set_chained_irqchip() - sets a chained irqchip to a gpiochip
* @gpiochip: the gpiochip to set the irqchip chain to
@@ -522,9 +563,12 @@ void gpiochip_set_chained_irqchip(struct gpio_chip *gpiochip,
}
/* Set the parent IRQ for all affected IRQs */
- for (offset = 0; offset < gpiochip->ngpio; offset++)
+ for (offset = 0; offset < gpiochip->ngpio; offset++) {
+ if (!gpiochip_irqchip_irq_valid(gpiochip, offset))
+ continue;
irq_set_parent(irq_find_mapping(gpiochip->irqdomain, offset),
parent_irq);
+ }
}
EXPORT_SYMBOL_GPL(gpiochip_set_chained_irqchip);
@@ -631,9 +675,12 @@ static void gpiochip_irqchip_remove(struct gpio_chip *gpiochip)
/* Remove all IRQ mappings and delete the domain */
if (gpiochip->irqdomain) {
- for (offset = 0; offset < gpiochip->ngpio; offset++)
+ for (offset = 0; offset < gpiochip->ngpio; offset++) {
+ if (!gpiochip_irqchip_irq_valid(gpiochip, offset))
+ continue;
irq_dispose_mapping(
irq_find_mapping(gpiochip->irqdomain, offset));
+ }
irq_domain_remove(gpiochip->irqdomain);
}
@@ -642,6 +689,8 @@ static void gpiochip_irqchip_remove(struct gpio_chip *gpiochip)
gpiochip->irqchip->irq_release_resources = NULL;
gpiochip->irqchip = NULL;
}
+
+ gpiochip_irqchip_free_valid_mask(gpiochip);
}
/**
@@ -677,6 +726,7 @@ int _gpiochip_irqchip_add(struct gpio_chip *gpiochip,
struct lock_class_key *lock_key)
{
struct device_node *of_node;
+ bool irq_base_set = false;
unsigned int offset;
unsigned irq_base = 0;
@@ -725,13 +775,17 @@ int _gpiochip_irqchip_add(struct gpio_chip *gpiochip,
* necessary to allocate descriptors for all IRQs.
*/
for (offset = 0; offset < gpiochip->ngpio; offset++) {
+ if (!gpiochip_irqchip_irq_valid(gpiochip, offset))
+ continue;
irq_base = irq_create_mapping(gpiochip->irqdomain, offset);
- if (offset == 0)
+ if (!irq_base_set) {
/*
* Store the base into the gpiochip to be used when
* unmapping the irqs.
*/
gpiochip->irq_base = irq_base;
+ irq_base_set = true;
+ }
}
acpi_gpiochip_request_interrupts(gpiochip);
@@ -743,6 +797,12 @@ EXPORT_SYMBOL_GPL(_gpiochip_irqchip_add);
#else /* CONFIG_GPIOLIB_IRQCHIP */
static void gpiochip_irqchip_remove(struct gpio_chip *gpiochip) {}
+static inline int gpiochip_irqchip_init_valid_mask(struct gpio_chip *gpiochip)
+{
+ return 0;
+}
+static inline void gpiochip_irqchip_free_valid_mask(struct gpio_chip *gpiochip)
+{ }
#endif /* CONFIG_GPIOLIB_IRQCHIP */
diff --git a/include/linux/gpio/driver.h b/include/linux/gpio/driver.h
index d1baebf..e3701c8 100644
--- a/include/linux/gpio/driver.h
+++ b/include/linux/gpio/driver.h
@@ -75,6 +75,10 @@ struct seq_file;
* initialization, provided by GPIO driver
* @irq_parent: GPIO IRQ chip parent/bank linux irq number,
* provided by GPIO driver
+ * @irq_need_valid_mask: If set core allocates @irq_valid_mask with all
+ * bits set to one
+ * @irq_valid_mask: If not %NULL holds bitmask of GPIOs which are valid to
+ * be included in IRQ domain of the chip
* @lock_key: per GPIO IRQ chip lockdep class
*
* A gpio_chip can help platforms abstract various sources of GPIOs so
@@ -138,6 +142,8 @@ struct gpio_chip {
irq_flow_handler_t irq_handler;
unsigned int irq_default_type;
int irq_parent;
+ bool irq_need_valid_mask;
+ unsigned long *irq_valid_mask;
struct lock_class_key *lock_key;
#endif
--
2.7.3
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