diff mbox series

[v6] gpio/mpc8xxx: change irq handler from chained to normal

Message ID 20190927031551.20074-1-hui.song_1@nxp.com (mailing list archive)
State New, archived
Headers show
Series [v6] gpio/mpc8xxx: change irq handler from chained to normal | expand

Commit Message

Hui Song Sept. 27, 2019, 3:15 a.m. UTC 
From: Song Hui <hui.song_1@nxp.com>

More than one gpio controllers can share one interrupt, change the
driver to request shared irq.

While this will work, it will mess up userspace accounting of the number
of interrupts per second in tools such as vmstat.  The reason is that
for every GPIO interrupt, /proc/interrupts records the count against GIC
interrupt 68 or 69, as well as the GPIO itself.  So, for every GPIO
interrupt, the total number of interrupts that the system has seen
increments by two

Signed-off-by: Laurentiu Tudor <Laurentiu.Tudor@nxp.com>
Signed-off-by: Alex Marginean <alexandru.marginean@nxp.com>
Signed-off-by: Song Hui <hui.song_1@nxp.com>
---
 Changes in v6:
	- change request_irq to devm_request_irq and add commit message
 Changes in v5:
	- add traverse every bit function.
 Changes in v4:
	- convert 'pr_err' to 'dev_err'.
 Changes in v3:
	- update the patch description.
 Changes in v2:
	- delete the compatible of ls1088a.

 drivers/gpio/gpio-mpc8xxx.c | 31 ++++++++++++++++++++-----------
 1 file changed, 20 insertions(+), 11 deletions(-)

Comments

Linus Walleij Oct. 3, 2019, 10:19 a.m. UTC | #1 
On Fri, Sep 27, 2019 at 5:26 AM Hui Song <hui.song_1@nxp.com> wrote:

> From: Song Hui <hui.song_1@nxp.com>
>
> More than one gpio controllers can share one interrupt, change the
> driver to request shared irq.
>
> While this will work, it will mess up userspace accounting of the number
> of interrupts per second in tools such as vmstat.  The reason is that
> for every GPIO interrupt, /proc/interrupts records the count against GIC
> interrupt 68 or 69, as well as the GPIO itself.  So, for every GPIO
> interrupt, the total number of interrupts that the system has seen
> increments by two
>
> Signed-off-by: Laurentiu Tudor <Laurentiu.Tudor@nxp.com>
> Signed-off-by: Alex Marginean <alexandru.marginean@nxp.com>
> Signed-off-by: Song Hui <hui.song_1@nxp.com>
> ---
>  Changes in v6:
>         - change request_irq to devm_request_irq and add commit message

There is some build error on the patch, can you look into it?

Yours,
Linus Walleij
diff mbox series

Patch

diff --git a/drivers/gpio/gpio-mpc8xxx.c b/drivers/gpio/gpio-mpc8xxx.c
index 16a47de..f0be284 100644
--- a/drivers/gpio/gpio-mpc8xxx.c
+++ b/drivers/gpio/gpio-mpc8xxx.c
@@ -22,6 +22,7 @@ 
 #include <linux/irq.h>
 #include <linux/gpio/driver.h>
 #include <linux/bitops.h>
+#include <linux/interrupt.h>
 
 #define MPC8XXX_GPIO_PINS	32
 
@@ -127,20 +128,20 @@  static int mpc8xxx_gpio_to_irq(struct gpio_chip *gc, unsigned offset)
 		return -ENXIO;
 }
 
-static void mpc8xxx_gpio_irq_cascade(struct irq_desc *desc)
+static irqreturn_t mpc8xxx_gpio_irq_cascade(int irq, void *data)
 {
-	struct mpc8xxx_gpio_chip *mpc8xxx_gc = irq_desc_get_handler_data(desc);
-	struct irq_chip *chip = irq_desc_get_chip(desc);
+	struct mpc8xxx_gpio_chip *mpc8xxx_gc = data;
 	struct gpio_chip *gc = &mpc8xxx_gc->gc;
 	unsigned int mask;
+	int i;
 
 	mask = gc->read_reg(mpc8xxx_gc->regs + GPIO_IER)
 		& gc->read_reg(mpc8xxx_gc->regs + GPIO_IMR);
-	if (mask)
+	for_each_set_bit(i, &mask, 32)
 		generic_handle_irq(irq_linear_revmap(mpc8xxx_gc->irq,
-						     32 - ffs(mask)));
-	if (chip->irq_eoi)
-		chip->irq_eoi(&desc->irq_data);
+						     31 - i));
+
+	return IRQ_HANDLED;
 }
 
 static void mpc8xxx_irq_unmask(struct irq_data *d)
@@ -388,8 +389,8 @@  static int mpc8xxx_probe(struct platform_device *pdev)
 
 	ret = gpiochip_add_data(gc, mpc8xxx_gc);
 	if (ret) {
-		pr_err("%pOF: GPIO chip registration failed with status %d\n",
-		       np, ret);
+		dev_err(&pdev->dev, "%pOF: GPIO chip registration failed with status %d\n",
+			np, ret);
 		goto err;
 	}
 
@@ -409,8 +410,16 @@  static int mpc8xxx_probe(struct platform_device *pdev)
 	if (devtype->gpio_dir_in_init)
 		devtype->gpio_dir_in_init(gc);
 
-	irq_set_chained_handler_and_data(mpc8xxx_gc->irqn,
-					 mpc8xxx_gpio_irq_cascade, mpc8xxx_gc);
+	ret = devm_request_irq(&pdev->dev, mpc8xxx_gc->irqn,
+			       mpc8xxx_gpio_irq_cascade,
+			       IRQF_NO_THREAD | IRQF_SHARED, "gpio-cascade",
+			       mpc8xxx_gc);
+	if (ret) {
+		dev_err(&pdev->dev, "%s: failed to devm_request_irq(%d), ret = %d\n",
+			np->full_name, mpc8xxx_gc->irqn, ret);
+		goto err;
+	}
+
 	return 0;
 err:
 	iounmap(mpc8xxx_gc->regs);