Hi,
On 5/27/2020 3:14 PM, Stephen Boyd wrote:
Quoting Maulik Shah (2020-05-23 10:11:10)
With 'commit 461c1a7d4733 ("gpiolib: override irq_enable/disable")' gpiolib
overrides irqchip's irq_enable and irq_disable callbacks. If irq_disable
callback is implemented then genirq takes unlazy path to disable irq.
Underlying irqchip may not want to implement irq_disable callback to lazy
disable irq when client drivers invokes disable_irq(). By overriding
irq_disable callback, gpiolib ends up always unlazy disabling IRQ.
Allow gpiolib to lazy disable IRQs by overriding irq_disable callback only
if irqchip implemented irq_disable. In cases where irq_disable is not
implemented irq_mask is overridden. Similarly override irq_enable callback
only if irqchip implemented irq_enable otherwise irq_unmask is overridden.
Fixes: 461c1a7d47 (gpiolib: override irq_enable/disable)
This isn't a proper Fixes line. Should have quotes
Fixes: 461c1a7d4733 ("gpiolib: override irq_enable/disable")
Thanks for pointing this, i will address in next revision.
Signed-off-by: Maulik Shah <mkshah@xxxxxxxxxxxxxx>
---
drivers/gpio/gpiolib.c | 55 +++++++++++++++++++++++++++++----------------
include/linux/gpio/driver.h | 13 +++++++++++
2 files changed, 49 insertions(+), 19 deletions(-)
diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index eaa0e20..3810cd0 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -2465,32 +2465,37 @@ static void gpiochip_irq_relres(struct irq_data *d)
gpiochip_relres_irq(gc, d->hwirq);
}
+static void gpiochip_irq_mask(struct irq_data *d)
+{
+ struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
+
+ if (gc->irq.irq_mask)
+ gc->irq.irq_mask(d);
+ gpiochip_disable_irq(gc, d->hwirq);
How does this work in the lazy case when I want to drive the GPIO? Say I
have a GPIO that is also an interrupt. The code would look like
struct gpio_desc *gpio = gpiod_get(...)
unsigned int girq = gpiod_to_irq(gpio)
request_irq(girq, ...);
disable_irq(girq);
gpiod_direction_output(gpio, 1);
In the lazy case genirq wouldn't call the mask function until the first
interrupt arrived on the GPIO line. If that never happened then wouldn't
we be blocked in gpiod_direction_output() when the test_bit() sees
FLAG_USED_AS_IRQ? Or do we need irqs to be released before driving
gpios?
The client driver can decide to unlazy disable IRQ with below API...
irq_set_status_flags(girq, IRQ_DISABLE_UNLAZY);
This will immediatly invoke mask function (unlazy disable) from genirq,
even though irq_disable is not implemented.
Thanks,
Maulik
+}
+
+static void gpiochip_irq_unmask(struct irq_data *d)
+{
+ struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
+
+ gpiochip_enable_irq(gc, d->hwirq);
+ if (gc->irq.irq_unmask)
+ gc->irq.irq_unmask(d);
+}
+
--
QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, hosted by The Linux Foundation
