Bill Gatliff reported the following bug when using the irq_chip
facility of the pca953x driver on a PPC platform:
BUG: scheduling while atomic: insmod/1530/0x00000002
He traced it back to an i2c transaction in pca953x_irq_set_type(),
which can be called with interrupt disabled (from __setup_irq()). As
the i2c controller can sleep while sending a message, this qualifies
as a bad idea.
This patch moves the i2c transaction to pca953x_irq_bus_sync_unlock(),
where it is actually safe to send an i2c message.
Signed-off-by: Marc Zyngier <[email protected]>
Reported-by: Bill Gatliff <[email protected]>
Cc: Eric Miao <[email protected]>
Cc: Andrew Morton <[email protected]>
---
drivers/gpio/pca953x.c | 14 +++++++++++++-
1 files changed, 13 insertions(+), 1 deletions(-)
diff --git a/drivers/gpio/pca953x.c b/drivers/gpio/pca953x.c
index 7d521e1..d407d84 100644
--- a/drivers/gpio/pca953x.c
+++ b/drivers/gpio/pca953x.c
@@ -252,6 +252,18 @@ static void pca953x_irq_bus_lock(unsigned int irq)
static void pca953x_irq_bus_sync_unlock(unsigned int irq)
{
struct pca953x_chip *chip = get_irq_chip_data(irq);
+ uint16_t new_irqs;
+ uint16_t level;
+
+ /* Look for any newly setup interrupt */
+ new_irqs = chip->irq_trig_fall | chip->irq_trig_raise;
+ new_irqs &= ~chip->reg_direction;
+
+ while(new_irqs) {
+ level = __ffs(new_irqs);
+ pca953x_gpio_direction_input(&chip->gpio_chip, level);
+ new_irqs &= ~(1 << level);
+ }
mutex_unlock(&chip->irq_lock);
}
@@ -278,7 +290,7 @@ static int pca953x_irq_set_type(unsigned int irq, unsigned int type)
else
chip->irq_trig_raise &= ~mask;
- return pca953x_gpio_direction_input(&chip->gpio_chip, level);
+ return 0;
}
static struct irq_chip pca953x_irq_chip = {
--
1.7.0.6