diff mbox

[2/7] gpiolib: support monitoring mockup devices

Message ID 1485358461-24070-3-git-send-email-bgolaszewski@baylibre.com
State New
Headers show

Commit Message

Bartosz Golaszewski Jan. 25, 2017, 3:34 p.m. UTC 
Add a new flag to struct gpio_chip indicating that the chip doesn't
model a real device. When setting up the line event queue, check if
a device is a mockup chip and don't actually request the interrupt.

This way we can monitor mockup GPIOs.

Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
---
 drivers/gpio/gpiolib.c      | 27 +++++++++++++++++----------
 include/linux/gpio/driver.h |  4 ++++
 2 files changed, 21 insertions(+), 10 deletions(-)

Comments

Linus Walleij Jan. 31, 2017, 1:23 p.m. UTC | #1 
On Wed, Jan 25, 2017 at 4:34 PM, Bartosz Golaszewski
<bgolaszewski@baylibre.com> wrote:

> Add a new flag to struct gpio_chip indicating that the chip doesn't
> model a real device. When setting up the line event queue, check if
> a device is a mockup chip and don't actually request the interrupt.
>
> This way we can monitor mockup GPIOs.
>
> Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>

Hm. I'm not so happy about adding code that gets compiled into every
system on the planet but is only used for testing with the mockup driver.

Atleast it should be #ifdef:ed (one of the few cases when we should
do that).

But I would prefer if there was some more elegant way. Like getting
a mockup irqchip! But I don't know how hard that is indeed.

Yours,
Linus Walleij
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diff mbox

Patch

diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index 6722579..19b4b8b 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -735,6 +735,7 @@  static irqreturn_t lineevent_irq_thread(int irq, void *p)
 
 static int lineevent_create(struct gpio_device *gdev, void __user *ip)
 {
+	struct gpio_chip *chip = gdev->chip;
 	struct gpioevent_request eventreq;
 	struct lineevent_state *le;
 	struct gpio_desc *desc;
@@ -807,7 +808,8 @@  static int lineevent_create(struct gpio_device *gdev, void __user *ip)
 		goto out_free_desc;
 
 	le->irq = gpiod_to_irq(desc);
-	if (le->irq <= 0) {
+	/* Mockup gpiochips don't have to support this. */
+	if (le->irq <= 0 && !chip->mockup) {
 		ret = -ENODEV;
 		goto out_free_desc;
 	}
@@ -823,15 +825,20 @@  static int lineevent_create(struct gpio_device *gdev, void __user *ip)
 	init_waitqueue_head(&le->wait);
 	mutex_init(&le->read_lock);
 
-	/* Request a thread to read the events */
-	ret = request_threaded_irq(le->irq,
-			NULL,
-			lineevent_irq_thread,
-			irqflags,
-			le->label,
-			le);
-	if (ret)
-		goto out_free_desc;
+	if (!chip->mockup) {
+		/*
+		 * Request a thread to read the events unless we're dealing
+		 * with a mockup gpiochip.
+		 */
+		ret = request_threaded_irq(le->irq,
+				NULL,
+				lineevent_irq_thread,
+				irqflags,
+				le->label,
+				le);
+		if (ret)
+			goto out_free_desc;
+	}
 
 	fd = get_unused_fd_flags(O_RDONLY | O_CLOEXEC);
 	if (fd < 0) {
diff --git a/include/linux/gpio/driver.h b/include/linux/gpio/driver.h
index e973fab..912eae1 100644
--- a/include/linux/gpio/driver.h
+++ b/include/linux/gpio/driver.h
@@ -82,6 +82,9 @@  enum single_ended_mode {
  *	implies that if the chip supports IRQs, these IRQs need to be threaded
  *	as the chip access may sleep when e.g. reading out the IRQ status
  *	registers.
+ * @mockup: if set, the flag signifies that this gpiochip does not model a
+ *      real device; this can affect the way the chip is handled internally
+ *      by gpiolib.
  * @read_reg: reader function for generic GPIO
  * @write_reg: writer function for generic GPIO
  * @pin2mask: some generic GPIO controllers work with the big-endian bits
@@ -166,6 +169,7 @@  struct gpio_chip {
 	u16			ngpio;
 	const char		*const *names;
 	bool			can_sleep;
+	bool			mockup;
 
 #if IS_ENABLED(CONFIG_GPIO_GENERIC)
 	unsigned long (*read_reg)(void __iomem *reg);