[PATCH RFT] gpio: mpc8xxx: Fixup setting gpio direction output

[PATCH RFT] gpio: mpc8xxx: Fixup setting gpio direction output

[Axel Lin]

For devtype with specific gpio_dir_out implementation, current code looks
wrong because below code sets both gc->direction_output and
mpc8xxx_gc->direction_output to the same function.

gc->direction_output = devtype->gpio_dir_out ?: gc->direction_output;
mpc8xxx_gc->direction_output = gc->direction_output;

Set mpc8xxx_gc->direction_output = gc->direction_output first to fix it.
This way mpc8xxx_gc->direction_output actually calls the standard
bgpio_dir_out() to update register.

Setting gc->direction_output to gc->direction_output looks strange.
This patch also slightly changes the code for better readability.

Fixes: commit 42178e2a1e42 ("drivers/gpio: Switch gpio-mpc8xxx to use gpio-generic")
Signed-off-by: Axel Lin <axel.lin@ingics.com>
---
Hi,
I don't have this h/w, please review and test if this patch works.
Thank,
Axel
 drivers/gpio/gpio-mpc8xxx.c | 11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/drivers/gpio/gpio-mpc8xxx.c b/drivers/gpio/gpio-mpc8xxx.c
index ecdb27a..0ed279a 100644
--- a/drivers/gpio/gpio-mpc8xxx.c
+++ b/drivers/gpio/gpio-mpc8xxx.c
@@ -344,11 +344,14 @@ static int mpc8xxx_probe(struct platform_device *pdev)
 	 */
 	mpc8xxx_irq_chip.irq_set_type = devtype->irq_set_type;
 
-	gc->direction_output = devtype->gpio_dir_out ?: gc->direction_output;
-	gc->get = devtype->gpio_get ?: gc->get;
-	gc->to_irq = mpc8xxx_gpio_to_irq;
-
 	mpc8xxx_gc->direction_output = gc->direction_output;
+	if (devtype->gpio_dir_out)
+		gc->direction_output = devtype->gpio_dir_out;
+
+	if (devtype->gpio_get)
+		gc->get = devtype->gpio_get;
+
+	gc->to_irq = mpc8xxx_gpio_to_irq;
 
 	ret = gpiochip_add_data(gc, mpc8xxx_gc);
 	if (ret) {
-- 
2.1.4

Re: [PATCH RFT] gpio: mpc8xxx: Fixup setting gpio direction output

[Linus Walleij]

On Thu, Feb 11, 2016 at 2:13 PM, Axel Lin <axel.lin@ingics.com> wrote:

> For devtype with specific gpio_dir_out implementation, current code looks
> wrong because below code sets both gc->direction_output and
> mpc8xxx_gc->direction_output to the same function.
>
> gc->direction_output = devtype->gpio_dir_out ?: gc->direction_output;
> mpc8xxx_gc->direction_output = gc->direction_output;
>
> Set mpc8xxx_gc->direction_output = gc->direction_output first to fix it.
> This way mpc8xxx_gc->direction_output actually calls the standard
> bgpio_dir_out() to update register.
>
> Setting gc->direction_output to gc->direction_output looks strange.
> This patch also slightly changes the code for better readability.
>
> Fixes: commit 42178e2a1e42 ("drivers/gpio: Switch gpio-mpc8xxx to use gpio-generic")
> Signed-off-by: Axel Lin <axel.lin@ingics.com>

Liu please comment on this patch.

Yours,
Linus Walleij

RE: [PATCH RFT] gpio: mpc8xxx: Fixup setting gpio direction output

[Gang Liu]

Hi, Axel,

Yes you are right.

Maybe we can make the change just like this:

+	mpc8xxx_gc->direction_output = gc->direction_output;
	gc->direction_output = devtype->gpio_dir_out ?: gc->direction_output;
	gc->get = devtype->gpio_get ?: gc->get;
	gc->to_irq = mpc8xxx_gpio_to_irq;

-	mpc8xxx_gc->direction_output = gc->direction_output;

Best Regards,
Liu Gang
-----Original Message-----
---
Hi,
I don't have this h/w, please review and test if this patch works.
Thank,
Axel
 drivers/gpio/gpio-mpc8xxx.c | 11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/drivers/gpio/gpio-mpc8xxx.c b/drivers/gpio/gpio-mpc8xxx.c index ecdb27a..0ed279a 100644
--- a/drivers/gpio/gpio-mpc8xxx.c
+++ b/drivers/gpio/gpio-mpc8xxx.c
@@ -344,11 +344,14 @@ static int mpc8xxx_probe(struct platform_device *pdev)
 	 */
 	mpc8xxx_irq_chip.irq_set_type = devtype->irq_set_type;
 
-	gc->direction_output = devtype->gpio_dir_out ?: gc->direction_output;
-	gc->get = devtype->gpio_get ?: gc->get;
-	gc->to_irq = mpc8xxx_gpio_to_irq;
-
 	mpc8xxx_gc->direction_output = gc->direction_output;
+	if (devtype->gpio_dir_out)
+		gc->direction_output = devtype->gpio_dir_out;
+
+	if (devtype->gpio_get)
+		gc->get = devtype->gpio_get;
+
+	gc->to_irq = mpc8xxx_gpio_to_irq;
 
 	ret = gpiochip_add_data(gc, mpc8xxx_gc);
 	if (ret) {
--
2.1.4