1. Patchew
  2. linux
  3. [PATCH 0/5] powerpc: convert board-file GPIO chips to using new value setters
  4. View patch

[PATCH 2/5] powerpc: 83xx/gpio: use new line value setter callbacks

Bartosz Golaszewski posted 5 patches 8 months, 2 weeks ago
There is a newer version of this series
[PATCH 2/5] powerpc: 83xx/gpio: use new line value setter callbacks
Posted by Bartosz Golaszewski 8 months, 2 weeks ago 
From: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

struct gpio_chip now has callbacks for setting line values that return
an integer, allowing to indicate failures. Convert the driver to using
them.

Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
---
 arch/powerpc/platforms/83xx/mcu_mpc8349emitx.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/arch/powerpc/platforms/83xx/mcu_mpc8349emitx.c b/arch/powerpc/platforms/83xx/mcu_mpc8349emitx.c
index 4d8fa9ed1a67..d4ba6dbb86b2 100644
--- a/arch/powerpc/platforms/83xx/mcu_mpc8349emitx.c
+++ b/arch/powerpc/platforms/83xx/mcu_mpc8349emitx.c
@@ -92,7 +92,7 @@ static void mcu_power_off(void)
 	mutex_unlock(&mcu->lock);
 }
 
-static void mcu_gpio_set(struct gpio_chip *gc, unsigned int gpio, int val)
+static int mcu_gpio_set(struct gpio_chip *gc, unsigned int gpio, int val)
 {
 	struct mcu *mcu = gpiochip_get_data(gc);
 	u8 bit = 1 << (4 + gpio);
@@ -105,6 +105,8 @@ static void mcu_gpio_set(struct gpio_chip *gc, unsigned int gpio, int val)
 
 	i2c_smbus_write_byte_data(mcu->client, MCU_REG_CTRL, mcu->reg_ctrl);
 	mutex_unlock(&mcu->lock);
+
+	return 0;
 }
 
 static int mcu_gpio_dir_out(struct gpio_chip *gc, unsigned int gpio, int val)
@@ -123,7 +125,7 @@ static int mcu_gpiochip_add(struct mcu *mcu)
 	gc->can_sleep = 1;
 	gc->ngpio = MCU_NUM_GPIO;
 	gc->base = -1;
-	gc->set = mcu_gpio_set;
+	gc->set_rv = mcu_gpio_set;
 	gc->direction_output = mcu_gpio_dir_out;
 	gc->parent = dev;
 

-- 
2.45.2
Re: [PATCH 2/5] powerpc: 83xx/gpio: use new line value setter callbacks
Posted by Christophe Leroy 7 months, 3 weeks ago 

Le 08/04/2025 à 09:21, Bartosz Golaszewski a écrit :
> From: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
> 
> struct gpio_chip now has callbacks for setting line values that return
> an integer, allowing to indicate failures. Convert the driver to using
> them.
> 
> Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
> ---
>   arch/powerpc/platforms/83xx/mcu_mpc8349emitx.c | 6 ++++--
>   1 file changed, 4 insertions(+), 2 deletions(-)
> 
> diff --git a/arch/powerpc/platforms/83xx/mcu_mpc8349emitx.c b/arch/powerpc/platforms/83xx/mcu_mpc8349emitx.c
> index 4d8fa9ed1a67..d4ba6dbb86b2 100644
> --- a/arch/powerpc/platforms/83xx/mcu_mpc8349emitx.c
> +++ b/arch/powerpc/platforms/83xx/mcu_mpc8349emitx.c
> @@ -92,7 +92,7 @@ static void mcu_power_off(void)
>   	mutex_unlock(&mcu->lock);
>   }
>   
> -static void mcu_gpio_set(struct gpio_chip *gc, unsigned int gpio, int val)
> +static int mcu_gpio_set(struct gpio_chip *gc, unsigned int gpio, int val)
>   {
>   	struct mcu *mcu = gpiochip_get_data(gc);
>   	u8 bit = 1 << (4 + gpio);
> @@ -105,6 +105,8 @@ static void mcu_gpio_set(struct gpio_chip *gc, unsigned int gpio, int val)
>   
>   	i2c_smbus_write_byte_data(mcu->client, MCU_REG_CTRL, mcu->reg_ctrl);
>   	mutex_unlock(&mcu->lock);
> +
> +	return 0;

i2c_smbus_write_byte_data() can fail, why not return the value returned 
by i2c_smbus_write_byte_data() ?

>   }
>   
>   static int mcu_gpio_dir_out(struct gpio_chip *gc, unsigned int gpio, int val)
> @@ -123,7 +125,7 @@ static int mcu_gpiochip_add(struct mcu *mcu)
>   	gc->can_sleep = 1;
>   	gc->ngpio = MCU_NUM_GPIO;
>   	gc->base = -1;
> -	gc->set = mcu_gpio_set;
> +	gc->set_rv = mcu_gpio_set;
>   	gc->direction_output = mcu_gpio_dir_out;
>   	gc->parent = dev;
>   
>
Re: [PATCH 2/5] powerpc: 83xx/gpio: use new line value setter callbacks
Posted by Bartosz Golaszewski 7 months, 3 weeks ago 
On Wed, Apr 30, 2025 at 7:33 PM Christophe Leroy
<christophe.leroy@csgroup.eu> wrote:
>
>
>
> Le 08/04/2025 à 09:21, Bartosz Golaszewski a écrit :
> > From: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
> >
> > struct gpio_chip now has callbacks for setting line values that return
> > an integer, allowing to indicate failures. Convert the driver to using
> > them.
> >
> > Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
> > ---
> >   arch/powerpc/platforms/83xx/mcu_mpc8349emitx.c | 6 ++++--
> >   1 file changed, 4 insertions(+), 2 deletions(-)
> >
> > diff --git a/arch/powerpc/platforms/83xx/mcu_mpc8349emitx.c b/arch/powerpc/platforms/83xx/mcu_mpc8349emitx.c
> > index 4d8fa9ed1a67..d4ba6dbb86b2 100644
> > --- a/arch/powerpc/platforms/83xx/mcu_mpc8349emitx.c
> > +++ b/arch/powerpc/platforms/83xx/mcu_mpc8349emitx.c
> > @@ -92,7 +92,7 @@ static void mcu_power_off(void)
> >       mutex_unlock(&mcu->lock);
> >   }
> >
> > -static void mcu_gpio_set(struct gpio_chip *gc, unsigned int gpio, int val)
> > +static int mcu_gpio_set(struct gpio_chip *gc, unsigned int gpio, int val)
> >   {
> >       struct mcu *mcu = gpiochip_get_data(gc);
> >       u8 bit = 1 << (4 + gpio);
> > @@ -105,6 +105,8 @@ static void mcu_gpio_set(struct gpio_chip *gc, unsigned int gpio, int val)
> >
> >       i2c_smbus_write_byte_data(mcu->client, MCU_REG_CTRL, mcu->reg_ctrl);
> >       mutex_unlock(&mcu->lock);
> > +
> > +     return 0;
>
> i2c_smbus_write_byte_data() can fail, why not return the value returned
> by i2c_smbus_write_byte_data() ?
>

The calls to i2c_smbus_write_byte_data() in this driver are
universally not checked. I cannot test it and wasn't sure if that's on
purpose so I decided to stay safe. Someone who has access to this
platform could potentially fix it across the file.

Bartosz

> >   }
> >
> >   static int mcu_gpio_dir_out(struct gpio_chip *gc, unsigned int gpio, int val)
> > @@ -123,7 +125,7 @@ static int mcu_gpiochip_add(struct mcu *mcu)
> >       gc->can_sleep = 1;
> >       gc->ngpio = MCU_NUM_GPIO;
> >       gc->base = -1;
> > -     gc->set = mcu_gpio_set;
> > +     gc->set_rv = mcu_gpio_set;
> >       gc->direction_output = mcu_gpio_dir_out;
> >       gc->parent = dev;
> >
> >
>
Re: [PATCH 2/5] powerpc: 83xx/gpio: use new line value setter callbacks
Posted by Christophe Leroy 7 months, 3 weeks ago 

Le 30/04/2025 à 19:37, Bartosz Golaszewski a écrit :
> On Wed, Apr 30, 2025 at 7:33 PM Christophe Leroy
> <christophe.leroy@csgroup.eu> wrote:
>>
>>
>>
>> Le 08/04/2025 à 09:21, Bartosz Golaszewski a écrit :
>>> From: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
>>>
>>> struct gpio_chip now has callbacks for setting line values that return
>>> an integer, allowing to indicate failures. Convert the driver to using
>>> them.
>>>
>>> Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
>>> ---
>>>    arch/powerpc/platforms/83xx/mcu_mpc8349emitx.c | 6 ++++--
>>>    1 file changed, 4 insertions(+), 2 deletions(-)
>>>
>>> diff --git a/arch/powerpc/platforms/83xx/mcu_mpc8349emitx.c b/arch/powerpc/platforms/83xx/mcu_mpc8349emitx.c
>>> index 4d8fa9ed1a67..d4ba6dbb86b2 100644
>>> --- a/arch/powerpc/platforms/83xx/mcu_mpc8349emitx.c
>>> +++ b/arch/powerpc/platforms/83xx/mcu_mpc8349emitx.c
>>> @@ -92,7 +92,7 @@ static void mcu_power_off(void)
>>>        mutex_unlock(&mcu->lock);
>>>    }
>>>
>>> -static void mcu_gpio_set(struct gpio_chip *gc, unsigned int gpio, int val)
>>> +static int mcu_gpio_set(struct gpio_chip *gc, unsigned int gpio, int val)
>>>    {
>>>        struct mcu *mcu = gpiochip_get_data(gc);
>>>        u8 bit = 1 << (4 + gpio);
>>> @@ -105,6 +105,8 @@ static void mcu_gpio_set(struct gpio_chip *gc, unsigned int gpio, int val)
>>>
>>>        i2c_smbus_write_byte_data(mcu->client, MCU_REG_CTRL, mcu->reg_ctrl);
>>>        mutex_unlock(&mcu->lock);
>>> +
>>> +     return 0;
>>
>> i2c_smbus_write_byte_data() can fail, why not return the value returned
>> by i2c_smbus_write_byte_data() ?
>>
> 
> The calls to i2c_smbus_write_byte_data() in this driver are
> universally not checked. I cannot test it and wasn't sure if that's on
> purpose so I decided to stay safe. Someone who has access to this
> platform could potentially fix it across the file.

As far as I can see this function is called three times in this file.

First time is in mcu_power_off(), which must return void.
Second time is inside a forever loop in shutdown_thread_fn(), and I 
can't see what could be done with the returned value.

Last time is in the function you are changing. Wouldn't it make sense to 
take the value into account here ? IIUC it is the purpose of the change, 
isn't it ?

Christophe
Re: [PATCH 2/5] powerpc: 83xx/gpio: use new line value setter callbacks
Posted by Bartosz Golaszewski 7 months, 3 weeks ago 
On Wed, Apr 30, 2025 at 7:47 PM Christophe Leroy
<christophe.leroy@csgroup.eu> wrote:
>
>
>
> Le 30/04/2025 à 19:37, Bartosz Golaszewski a écrit :
> > On Wed, Apr 30, 2025 at 7:33 PM Christophe Leroy
> > <christophe.leroy@csgroup.eu> wrote:
> >>
> >>
> >>
> >> Le 08/04/2025 à 09:21, Bartosz Golaszewski a écrit :
> >>> From: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
> >>>
> >>> struct gpio_chip now has callbacks for setting line values that return
> >>> an integer, allowing to indicate failures. Convert the driver to using
> >>> them.
> >>>
> >>> Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
> >>> ---
> >>>    arch/powerpc/platforms/83xx/mcu_mpc8349emitx.c | 6 ++++--
> >>>    1 file changed, 4 insertions(+), 2 deletions(-)
> >>>
> >>> diff --git a/arch/powerpc/platforms/83xx/mcu_mpc8349emitx.c b/arch/powerpc/platforms/83xx/mcu_mpc8349emitx.c
> >>> index 4d8fa9ed1a67..d4ba6dbb86b2 100644
> >>> --- a/arch/powerpc/platforms/83xx/mcu_mpc8349emitx.c
> >>> +++ b/arch/powerpc/platforms/83xx/mcu_mpc8349emitx.c
> >>> @@ -92,7 +92,7 @@ static void mcu_power_off(void)
> >>>        mutex_unlock(&mcu->lock);
> >>>    }
> >>>
> >>> -static void mcu_gpio_set(struct gpio_chip *gc, unsigned int gpio, int val)
> >>> +static int mcu_gpio_set(struct gpio_chip *gc, unsigned int gpio, int val)
> >>>    {
> >>>        struct mcu *mcu = gpiochip_get_data(gc);
> >>>        u8 bit = 1 << (4 + gpio);
> >>> @@ -105,6 +105,8 @@ static void mcu_gpio_set(struct gpio_chip *gc, unsigned int gpio, int val)
> >>>
> >>>        i2c_smbus_write_byte_data(mcu->client, MCU_REG_CTRL, mcu->reg_ctrl);
> >>>        mutex_unlock(&mcu->lock);
> >>> +
> >>> +     return 0;
> >>
> >> i2c_smbus_write_byte_data() can fail, why not return the value returned
> >> by i2c_smbus_write_byte_data() ?
> >>
> >
> > The calls to i2c_smbus_write_byte_data() in this driver are
> > universally not checked. I cannot test it and wasn't sure if that's on
> > purpose so I decided to stay safe. Someone who has access to this
> > platform could potentially fix it across the file.
>
> As far as I can see this function is called three times in this file.
>
> First time is in mcu_power_off(), which must return void.
> Second time is inside a forever loop in shutdown_thread_fn(), and I
> can't see what could be done with the returned value.
>
> Last time is in the function you are changing. Wouldn't it make sense to
> take the value into account here ? IIUC it is the purpose of the change,
> isn't it ?
>
> Christophe
>

Sure, I can do it. The purpose is first and foremost to convert all
drivers so that we can drop the old callbacks but I see what you mean.

Bart

Patchew 2.1-devel-b67e4c2

© 2016 - 2025 Red Hat, Inc.