On Thu, Aug 01, 2019 at 06:45:21PM +0000, Schrempf Frieder wrote:
> From: Frieder Schrempf <[email protected]>
>
> If CONFIG_GPIOLIB is not enabled, mctrl_gpio_init() and
> mctrl_gpio_init_noauto() will currently return an error pointer with
> -ENOSYS. As the mctrl GPIOs are usually optional, drivers need to
> check for this condition to allow continue probing.
>
> To avoid the need for this check in each driver, we return NULL
> instead, as all the mctrl_gpio_*() functions are skipped anyway.
> We also adapt mctrl_gpio_to_gpiod() to be in line with this change.
>
> Signed-off-by: Frieder Schrempf <[email protected]>
> Reviewed-by: Fabio Estevam <[email protected]>
nitpick: put your S-o-b last.
> ---
> Changes in v2
> =============
> * Move the sh_sci changes to a separate patch
> * Add a patch for the 8250 driver
> * Add Fabio's R-b tag
> ---
> drivers/tty/serial/serial_mctrl_gpio.c | 3 +++
> drivers/tty/serial/serial_mctrl_gpio.h | 6 +++---
> 2 files changed, 6 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/tty/serial/serial_mctrl_gpio.c b/drivers/tty/serial/serial_mctrl_gpio.c
> index 2b400189be91..54c43e02e375 100644
> --- a/drivers/tty/serial/serial_mctrl_gpio.c
> +++ b/drivers/tty/serial/serial_mctrl_gpio.c
> @@ -61,6 +61,9 @@ EXPORT_SYMBOL_GPL(mctrl_gpio_set);
> struct gpio_desc *mctrl_gpio_to_gpiod(struct mctrl_gpios *gpios,
> enum mctrl_gpio_idx gidx)
> {
> + if (gpios == NULL)
> + return NULL;
> +
I wonder why you need this. If GPIOLIB is off this code isn't active and
with GPIOLIB calling mctrl_gpio_to_gpiod with a gpios == NULL is a bug
that IMHO should not be silently ignored.
Am I missing something (again)?
> return gpios->gpio[gidx];
> }
Best regards
Uwe
--
Pengutronix e.K. | Uwe Kleine-K?nig |
Industrial Linux Solutions | http://www.pengutronix.de/ |
On 01.08.19 22:33, Uwe Kleine-König wrote:
> On Thu, Aug 01, 2019 at 06:45:21PM +0000, Schrempf Frieder wrote:
>> From: Frieder Schrempf <[email protected]>
>>
>> If CONFIG_GPIOLIB is not enabled, mctrl_gpio_init() and
>> mctrl_gpio_init_noauto() will currently return an error pointer with
>> -ENOSYS. As the mctrl GPIOs are usually optional, drivers need to
>> check for this condition to allow continue probing.
>>
>> To avoid the need for this check in each driver, we return NULL
>> instead, as all the mctrl_gpio_*() functions are skipped anyway.
>> We also adapt mctrl_gpio_to_gpiod() to be in line with this change.
>>
>> Signed-off-by: Frieder Schrempf <[email protected]>
>> Reviewed-by: Fabio Estevam <[email protected]>
>
> nitpick: put your S-o-b last.
Ok.
>> ---
>> Changes in v2
>> =============
>> * Move the sh_sci changes to a separate patch
>> * Add a patch for the 8250 driver
>> * Add Fabio's R-b tag
>> ---
>> drivers/tty/serial/serial_mctrl_gpio.c | 3 +++
>> drivers/tty/serial/serial_mctrl_gpio.h | 6 +++---
>> 2 files changed, 6 insertions(+), 3 deletions(-)
>>
>> diff --git a/drivers/tty/serial/serial_mctrl_gpio.c b/drivers/tty/serial/serial_mctrl_gpio.c
>> index 2b400189be91..54c43e02e375 100644
>> --- a/drivers/tty/serial/serial_mctrl_gpio.c
>> +++ b/drivers/tty/serial/serial_mctrl_gpio.c
>> @@ -61,6 +61,9 @@ EXPORT_SYMBOL_GPL(mctrl_gpio_set);
>> struct gpio_desc *mctrl_gpio_to_gpiod(struct mctrl_gpios *gpios,
>> enum mctrl_gpio_idx gidx)
>> {
>> + if (gpios == NULL)
>> + return NULL;
>> +
>
> I wonder why you need this. If GPIOLIB is off this code isn't active and
> with GPIOLIB calling mctrl_gpio_to_gpiod with a gpios == NULL is a bug
> that IMHO should not be silently ignored.
>
> Am I missing something (again)?
No, you're right. My thoughts were, that if the mctrl_gpio functions are
allowed to be passed a NULL pointer in general, they all should have a
NULL check, even if in the current context (GPIOLIB disabled) this code
is not active. Apparently there are other cases when a NULL pointer is
passed, see [1]. So you can't really consider gpios == NULL to be a bug
as this seems to be allowed in general.
[1]
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit?id=434be0ae7aa746f481c3a22139e472dbc3f4f817
>
>> return gpios->gpio[gidx];
>> }
>
> Best regards
> Uwe
>
Hello,
On Fri, Aug 02, 2019 at 07:56:54AM +0000, Schrempf Frieder wrote:
> On 01.08.19 22:33, Uwe Kleine-K?nig wrote:
> > On Thu, Aug 01, 2019 at 06:45:21PM +0000, Schrempf Frieder wrote:
> >> diff --git a/drivers/tty/serial/serial_mctrl_gpio.c b/drivers/tty/serial/serial_mctrl_gpio.c
> >> index 2b400189be91..54c43e02e375 100644
> >> --- a/drivers/tty/serial/serial_mctrl_gpio.c
> >> +++ b/drivers/tty/serial/serial_mctrl_gpio.c
> >> @@ -61,6 +61,9 @@ EXPORT_SYMBOL_GPL(mctrl_gpio_set);
> >> struct gpio_desc *mctrl_gpio_to_gpiod(struct mctrl_gpios *gpios,
> >> enum mctrl_gpio_idx gidx)
> >> {
> >> + if (gpios == NULL)
> >> + return NULL;
> >> +
> >
> > I wonder why you need this. If GPIOLIB is off this code isn't active and
> > with GPIOLIB calling mctrl_gpio_to_gpiod with a gpios == NULL is a bug
> > that IMHO should not be silently ignored.
> >
> > Am I missing something (again)?
>
> No, you're right. My thoughts were, that if the mctrl_gpio functions are
> allowed to be passed a NULL pointer in general, they all should have a
> NULL check, even if in the current context (GPIOLIB disabled) this code
> is not active. Apparently there are other cases when a NULL pointer is
> passed, see [1]. So you can't really consider gpios == NULL to be a bug
> as this seems to be allowed in general.
OK, then this is another separate commit, right? Preferably with a
comment pointing to drivers that use mctrl_gpio before being
initialized.
Best regards
Uwe
--
Pengutronix e.K. | Uwe Kleine-K?nig |
Industrial Linux Solutions | http://www.pengutronix.de/ |