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>
---
drivers/net/can/spi/mcp251x.c | 16 ++++++++++------
1 file changed, 10 insertions(+), 6 deletions(-)
diff --git a/drivers/net/can/spi/mcp251x.c b/drivers/net/can/spi/mcp251x.c
index ec5c64006a16f703bc816983765584c5f3ac76e8..7545497d14b46c6388f3976c2bf7b9a99e959c1e 100644
--- a/drivers/net/can/spi/mcp251x.c
+++ b/drivers/net/can/spi/mcp251x.c
@@ -530,8 +530,8 @@ static int mcp251x_gpio_get_multiple(struct gpio_chip *chip,
return 0;
}
-static void mcp251x_gpio_set(struct gpio_chip *chip, unsigned int offset,
- int value)
+static int mcp251x_gpio_set(struct gpio_chip *chip, unsigned int offset,
+ int value)
{
struct mcp251x_priv *priv = gpiochip_get_data(chip);
u8 mask, val;
@@ -545,9 +545,11 @@ static void mcp251x_gpio_set(struct gpio_chip *chip, unsigned int offset,
priv->reg_bfpctrl &= ~mask;
priv->reg_bfpctrl |= val;
+
+ return 0;
}
-static void
+static int
mcp251x_gpio_set_multiple(struct gpio_chip *chip,
unsigned long *maskp, unsigned long *bitsp)
{
@@ -561,7 +563,7 @@ mcp251x_gpio_set_multiple(struct gpio_chip *chip,
val = FIELD_PREP(BFPCTRL_BFS_MASK, val);
if (!mask)
- return;
+ return 0;
mutex_lock(&priv->mcp_lock);
mcp251x_write_bits(priv->spi, BFPCTRL, mask, val);
@@ -569,6 +571,8 @@ mcp251x_gpio_set_multiple(struct gpio_chip *chip,
priv->reg_bfpctrl &= ~mask;
priv->reg_bfpctrl |= val;
+
+ return 0;
}
static void mcp251x_gpio_restore(struct spi_device *spi)
@@ -594,8 +598,8 @@ static int mcp251x_gpio_setup(struct mcp251x_priv *priv)
gpio->get_direction = mcp251x_gpio_get_direction;
gpio->get = mcp251x_gpio_get;
gpio->get_multiple = mcp251x_gpio_get_multiple;
- gpio->set = mcp251x_gpio_set;
- gpio->set_multiple = mcp251x_gpio_set_multiple;
+ gpio->set_rv = mcp251x_gpio_set;
+ gpio->set_multiple_rv = mcp251x_gpio_set_multiple;
gpio->base = -1;
gpio->ngpio = ARRAY_SIZE(mcp251x_gpio_names);
gpio->names = mcp251x_gpio_names;
--
2.48.1On 10/06/2025 at 21:37, Bartosz Golaszewski wrote:
> 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>
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
This does not match the address with which you sent the patch: brgl@bgdev.pl
> ---
> drivers/net/can/spi/mcp251x.c | 16 ++++++++++------
> 1 file changed, 10 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/net/can/spi/mcp251x.c b/drivers/net/can/spi/mcp251x.c
> index ec5c64006a16f703bc816983765584c5f3ac76e8..7545497d14b46c6388f3976c2bf7b9a99e959c1e 100644
> --- a/drivers/net/can/spi/mcp251x.c
> +++ b/drivers/net/can/spi/mcp251x.c
> @@ -530,8 +530,8 @@ static int mcp251x_gpio_get_multiple(struct gpio_chip *chip,
> return 0;
> }
>
> -static void mcp251x_gpio_set(struct gpio_chip *chip, unsigned int offset,
> - int value)
> +static int mcp251x_gpio_set(struct gpio_chip *chip, unsigned int offset,
> + int value)
> {
> struct mcp251x_priv *priv = gpiochip_get_data(chip);
> u8 mask, val;
> @@ -545,9 +545,11 @@ static void mcp251x_gpio_set(struct gpio_chip *chip, unsigned int offset,
>
> priv->reg_bfpctrl &= ~mask;
> priv->reg_bfpctrl |= val;
> +
> + return 0;
mcp251x_gpio_set() calls mcp251x_write_bits() which calls mcp251x_spi_write()
which can fail.
For this change to really make sense, the return value of mcp251x_spi_write()
should be propagated all the way around.
> }
>
> -static void
> +static int
> mcp251x_gpio_set_multiple(struct gpio_chip *chip,
> unsigned long *maskp, unsigned long *bitsp)
> {
> @@ -561,7 +563,7 @@ mcp251x_gpio_set_multiple(struct gpio_chip *chip,
> val = FIELD_PREP(BFPCTRL_BFS_MASK, val);
>
> if (!mask)
> - return;
> + return 0;
>
> mutex_lock(&priv->mcp_lock);
> mcp251x_write_bits(priv->spi, BFPCTRL, mask, val);
> @@ -569,6 +571,8 @@ mcp251x_gpio_set_multiple(struct gpio_chip *chip,
>
> priv->reg_bfpctrl &= ~mask;
> priv->reg_bfpctrl |= val;
> +
> + return 0;
Same as above.
> }
>
> static void mcp251x_gpio_restore(struct spi_device *spi)
> @@ -594,8 +598,8 @@ static int mcp251x_gpio_setup(struct mcp251x_priv *priv)
> gpio->get_direction = mcp251x_gpio_get_direction;
> gpio->get = mcp251x_gpio_get;
> gpio->get_multiple = mcp251x_gpio_get_multiple;
> - gpio->set = mcp251x_gpio_set;
> - gpio->set_multiple = mcp251x_gpio_set_multiple;
> + gpio->set_rv = mcp251x_gpio_set;
> + gpio->set_multiple_rv = mcp251x_gpio_set_multiple;
> gpio->base = -1;
> gpio->ngpio = ARRAY_SIZE(mcp251x_gpio_names);
> gpio->names = mcp251x_gpio_names;
>
Yours sincerely,
Vincent Mailhol
On Tue, Jun 10, 2025 at 3:55 PM Vincent Mailhol
<mailhol.vincent@wanadoo.fr> wrote:
>
> On 10/06/2025 at 21:37, Bartosz Golaszewski wrote:
> > 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>
> ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
>
> This does not match the address with which you sent the patch: brgl@bgdev.pl
>
> > ---
> > drivers/net/can/spi/mcp251x.c | 16 ++++++++++------
> > 1 file changed, 10 insertions(+), 6 deletions(-)
> >
> > diff --git a/drivers/net/can/spi/mcp251x.c b/drivers/net/can/spi/mcp251x.c
> > index ec5c64006a16f703bc816983765584c5f3ac76e8..7545497d14b46c6388f3976c2bf7b9a99e959c1e 100644
> > --- a/drivers/net/can/spi/mcp251x.c
> > +++ b/drivers/net/can/spi/mcp251x.c
> > @@ -530,8 +530,8 @@ static int mcp251x_gpio_get_multiple(struct gpio_chip *chip,
> > return 0;
> > }
> >
> > -static void mcp251x_gpio_set(struct gpio_chip *chip, unsigned int offset,
> > - int value)
> > +static int mcp251x_gpio_set(struct gpio_chip *chip, unsigned int offset,
> > + int value)
> > {
> > struct mcp251x_priv *priv = gpiochip_get_data(chip);
> > u8 mask, val;
> > @@ -545,9 +545,11 @@ static void mcp251x_gpio_set(struct gpio_chip *chip, unsigned int offset,
> >
> > priv->reg_bfpctrl &= ~mask;
> > priv->reg_bfpctrl |= val;
> > +
> > + return 0;
>
> mcp251x_gpio_set() calls mcp251x_write_bits() which calls mcp251x_spi_write()
> which can fail.
>
> For this change to really make sense, the return value of mcp251x_spi_write()
> should be propagated all the way around.
>
I don't know this code so I followed the example of the rest of the
codebase where the result of this function is never checked - even in
functions that do return values. I didn't know the reason for this and
so didn't want to break anything as I have no means of testing it.
Can you confirm that you really want the result to be checked here?
Bart
On 10/06/2025 at 23:05, Bartosz Golaszewski wrote:
> On Tue, Jun 10, 2025 at 3:55 PM Vincent Mailhol
> <mailhol.vincent@wanadoo.fr> wrote:
>>
>> On 10/06/2025 at 21:37, Bartosz Golaszewski wrote:
>>> 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>
>> ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
>>
>> This does not match the address with which you sent the patch: brgl@bgdev.pl
>>
>>> ---
>>> drivers/net/can/spi/mcp251x.c | 16 ++++++++++------
>>> 1 file changed, 10 insertions(+), 6 deletions(-)
>>>
>>> diff --git a/drivers/net/can/spi/mcp251x.c b/drivers/net/can/spi/mcp251x.c
>>> index ec5c64006a16f703bc816983765584c5f3ac76e8..7545497d14b46c6388f3976c2bf7b9a99e959c1e 100644
>>> --- a/drivers/net/can/spi/mcp251x.c
>>> +++ b/drivers/net/can/spi/mcp251x.c
>>> @@ -530,8 +530,8 @@ static int mcp251x_gpio_get_multiple(struct gpio_chip *chip,
>>> return 0;
>>> }
>>>
>>> -static void mcp251x_gpio_set(struct gpio_chip *chip, unsigned int offset,
>>> - int value)
>>> +static int mcp251x_gpio_set(struct gpio_chip *chip, unsigned int offset,
>>> + int value)
>>> {
>>> struct mcp251x_priv *priv = gpiochip_get_data(chip);
>>> u8 mask, val;
>>> @@ -545,9 +545,11 @@ static void mcp251x_gpio_set(struct gpio_chip *chip, unsigned int offset,
>>>
>>> priv->reg_bfpctrl &= ~mask;
>>> priv->reg_bfpctrl |= val;
>>> +
>>> + return 0;
>>
>> mcp251x_gpio_set() calls mcp251x_write_bits() which calls mcp251x_spi_write()
>> which can fail.
>>
>> For this change to really make sense, the return value of mcp251x_spi_write()
>> should be propagated all the way around.
>>
>
> I don't know this code so I followed the example of the rest of the
> codebase where the result of this function is never checked - even in
> functions that do return values. I didn't know the reason for this and
> so didn't want to break anything as I have no means of testing it.
The return value of mcp251x_spi_write() is used in mcp251x_hw_reset(). In other
locations, mcp251x_spi_write() is only used in functions which return void, so
obviously, the return value is not checked.
> Can you confirm that you really want the result to be checked here?
That's the point of those new gpio setters, isn't it? If we do not check the
result, I do not understand the purpose of the migration.
Yours sincerely,
Vincent Mailhol
On Tue, Jun 10, 2025 at 5:48 PM Vincent Mailhol
<mailhol.vincent@wanadoo.fr> wrote:
>
> On 10/06/2025 at 23:05, Bartosz Golaszewski wrote:
> > On Tue, Jun 10, 2025 at 3:55 PM Vincent Mailhol
> > <mailhol.vincent@wanadoo.fr> wrote:
> >>
> >> On 10/06/2025 at 21:37, Bartosz Golaszewski wrote:
> >>> 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>
> >> ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
> >>
> >> This does not match the address with which you sent the patch: brgl@bgdev.pl
> >>
> >>> ---
> >>> drivers/net/can/spi/mcp251x.c | 16 ++++++++++------
> >>> 1 file changed, 10 insertions(+), 6 deletions(-)
> >>>
> >>> diff --git a/drivers/net/can/spi/mcp251x.c b/drivers/net/can/spi/mcp251x.c
> >>> index ec5c64006a16f703bc816983765584c5f3ac76e8..7545497d14b46c6388f3976c2bf7b9a99e959c1e 100644
> >>> --- a/drivers/net/can/spi/mcp251x.c
> >>> +++ b/drivers/net/can/spi/mcp251x.c
> >>> @@ -530,8 +530,8 @@ static int mcp251x_gpio_get_multiple(struct gpio_chip *chip,
> >>> return 0;
> >>> }
> >>>
> >>> -static void mcp251x_gpio_set(struct gpio_chip *chip, unsigned int offset,
> >>> - int value)
> >>> +static int mcp251x_gpio_set(struct gpio_chip *chip, unsigned int offset,
> >>> + int value)
> >>> {
> >>> struct mcp251x_priv *priv = gpiochip_get_data(chip);
> >>> u8 mask, val;
> >>> @@ -545,9 +545,11 @@ static void mcp251x_gpio_set(struct gpio_chip *chip, unsigned int offset,
> >>>
> >>> priv->reg_bfpctrl &= ~mask;
> >>> priv->reg_bfpctrl |= val;
> >>> +
> >>> + return 0;
> >>
> >> mcp251x_gpio_set() calls mcp251x_write_bits() which calls mcp251x_spi_write()
> >> which can fail.
> >>
> >> For this change to really make sense, the return value of mcp251x_spi_write()
> >> should be propagated all the way around.
> >>
> >
> > I don't know this code so I followed the example of the rest of the
> > codebase where the result of this function is never checked - even in
> > functions that do return values. I didn't know the reason for this and
> > so didn't want to break anything as I have no means of testing it.
>
> The return value of mcp251x_spi_write() is used in mcp251x_hw_reset(). In other
> locations, mcp251x_spi_write() is only used in functions which return void, so
> obviously, the return value is not checked.
>
Wait, after a second look GPIO callbacks (including those that return
a value like request()) use mcp251x_write_bits() which has no return
value. It probably should propagate what mcp251x_spi_write() returns
but that's material for a different series. The goal of this one is to
use the new setters treewide and drop the old ones from struct
gpio_chip.
Bart
On 11/06/2025 at 01:05, Bartosz Golaszewski wrote:
> On Tue, Jun 10, 2025 at 5:48 PM Vincent Mailhol
> <mailhol.vincent@wanadoo.fr> wrote:
>>
>> On 10/06/2025 at 23:05, Bartosz Golaszewski wrote:
>>> On Tue, Jun 10, 2025 at 3:55 PM Vincent Mailhol
>>> <mailhol.vincent@wanadoo.fr> wrote:
>>>>
>>>> On 10/06/2025 at 21:37, Bartosz Golaszewski wrote:
>>>>> 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>
>>>> ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
>>>>
>>>> This does not match the address with which you sent the patch: brgl@bgdev.pl
>>>>
>>>>> ---
>>>>> drivers/net/can/spi/mcp251x.c | 16 ++++++++++------
>>>>> 1 file changed, 10 insertions(+), 6 deletions(-)
>>>>>
>>>>> diff --git a/drivers/net/can/spi/mcp251x.c b/drivers/net/can/spi/mcp251x.c
>>>>> index ec5c64006a16f703bc816983765584c5f3ac76e8..7545497d14b46c6388f3976c2bf7b9a99e959c1e 100644
>>>>> --- a/drivers/net/can/spi/mcp251x.c
>>>>> +++ b/drivers/net/can/spi/mcp251x.c
>>>>> @@ -530,8 +530,8 @@ static int mcp251x_gpio_get_multiple(struct gpio_chip *chip,
>>>>> return 0;
>>>>> }
>>>>>
>>>>> -static void mcp251x_gpio_set(struct gpio_chip *chip, unsigned int offset,
>>>>> - int value)
>>>>> +static int mcp251x_gpio_set(struct gpio_chip *chip, unsigned int offset,
>>>>> + int value)
>>>>> {
>>>>> struct mcp251x_priv *priv = gpiochip_get_data(chip);
>>>>> u8 mask, val;
>>>>> @@ -545,9 +545,11 @@ static void mcp251x_gpio_set(struct gpio_chip *chip, unsigned int offset,
>>>>>
>>>>> priv->reg_bfpctrl &= ~mask;
>>>>> priv->reg_bfpctrl |= val;
>>>>> +
>>>>> + return 0;
>>>>
>>>> mcp251x_gpio_set() calls mcp251x_write_bits() which calls mcp251x_spi_write()
>>>> which can fail.
>>>>
>>>> For this change to really make sense, the return value of mcp251x_spi_write()
>>>> should be propagated all the way around.
>>>>
>>>
>>> I don't know this code so I followed the example of the rest of the
>>> codebase where the result of this function is never checked - even in
>>> functions that do return values. I didn't know the reason for this and
>>> so didn't want to break anything as I have no means of testing it.
>>
>> The return value of mcp251x_spi_write() is used in mcp251x_hw_reset(). In other
>> locations, mcp251x_spi_write() is only used in functions which return void, so
>> obviously, the return value is not checked.
>>
>
> Wait, after a second look GPIO callbacks (including those that return
> a value like request()) use mcp251x_write_bits() which has no return
> value.
Yes. Read again my first message:
mcp251x_gpio_set() calls mcp251x_write_bits() which calls mcp251x_spi_write()
which can fail.
My point is that the grand father can fail.
> It probably should propagate what mcp251x_spi_write() returns
Exactly what I asked for :)
> but that's material for a different series.
Why? Are you going to do this other series?
If the answer is no, then please just do it here. Propagating the error in
mcp251x_write_bits() is a three line change. Am I asking for too much?
> The goal of this one is to
> use the new setters treewide and drop the old ones from struct
> gpio_chip.
Yours sincerely,
Vincent Mailhol
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