serial: mctrl_gpio: Avoid probe failures in case of missing gpiolib
diff mbox series

Message ID 20190801124446.15703-1-frieder.schrempf@kontron.de
State New
Headers show
Series
  • serial: mctrl_gpio: Avoid probe failures in case of missing gpiolib
Related show

Commit Message

Schrempf Frieder Aug. 1, 2019, 12:46 p.m. UTC
From: Frieder Schrempf <frieder.schrempf@kontron.de>

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 <frieder.schrempf@kontron.de>
---
 drivers/tty/serial/serial_mctrl_gpio.c | 3 +++
 drivers/tty/serial/serial_mctrl_gpio.h | 6 +++---
 drivers/tty/serial/sh-sci.c            | 2 +-
 3 files changed, 7 insertions(+), 4 deletions(-)

Comments

Fabio Estevam Aug. 1, 2019, 1:19 p.m. UTC | #1
Hi Schrempf,

On Thu, Aug 1, 2019 at 9:47 AM Schrempf Frieder
<frieder.schrempf@kontron.de> wrote:
>
> From: Frieder Schrempf <frieder.schrempf@kontron.de>
>
> 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 <frieder.schrempf@kontron.de>

Looks good to me:

Reviewed-by: Fabio Estevam <festevam@gmail.com>

Also adding Geert on Cc as the patch touches sh-sci.

Thanks


> ---
>  drivers/tty/serial/serial_mctrl_gpio.c | 3 +++
>  drivers/tty/serial/serial_mctrl_gpio.h | 6 +++---
>  drivers/tty/serial/sh-sci.c            | 2 +-
>  3 files changed, 7 insertions(+), 4 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;
> +
>         return gpios->gpio[gidx];
>  }
>  EXPORT_SYMBOL_GPL(mctrl_gpio_to_gpiod);
> diff --git a/drivers/tty/serial/serial_mctrl_gpio.h b/drivers/tty/serial/serial_mctrl_gpio.h
> index b7d3cca48ede..1b2ff503b2c2 100644
> --- a/drivers/tty/serial/serial_mctrl_gpio.h
> +++ b/drivers/tty/serial/serial_mctrl_gpio.h
> @@ -114,19 +114,19 @@ static inline
>  struct gpio_desc *mctrl_gpio_to_gpiod(struct mctrl_gpios *gpios,
>                                       enum mctrl_gpio_idx gidx)
>  {
> -       return ERR_PTR(-ENOSYS);
> +       return NULL;
>  }
>
>  static inline
>  struct mctrl_gpios *mctrl_gpio_init(struct uart_port *port, unsigned int idx)
>  {
> -       return ERR_PTR(-ENOSYS);
> +       return NULL;
>  }
>
>  static inline
>  struct mctrl_gpios *mctrl_gpio_init_noauto(struct device *dev, unsigned int idx)
>  {
> -       return ERR_PTR(-ENOSYS);
> +       return NULL;
>  }
>
>  static inline
> diff --git a/drivers/tty/serial/sh-sci.c b/drivers/tty/serial/sh-sci.c
> index d18c680aa64b..249325b65ee0 100644
> --- a/drivers/tty/serial/sh-sci.c
> +++ b/drivers/tty/serial/sh-sci.c
> @@ -3287,7 +3287,7 @@ static int sci_probe_single(struct platform_device *dev,
>                 return ret;
>
>         sciport->gpios = mctrl_gpio_init(&sciport->port, 0);
> -       if (IS_ERR(sciport->gpios) && PTR_ERR(sciport->gpios) != -ENOSYS)
> +       if (IS_ERR(sciport->gpios))
>                 return PTR_ERR(sciport->gpios);
>
>         if (sciport->has_rtscts) {
> --
> 2.17.1
Uwe Kleine-K├Ânig Aug. 1, 2019, 2:47 p.m. UTC | #2
On Thu, Aug 01, 2019 at 12:46:42PM +0000, Schrempf Frieder wrote:
> From: Frieder Schrempf <frieder.schrempf@kontron.de>
> 
> 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 <frieder.schrempf@kontron.de>
> ---
>  drivers/tty/serial/serial_mctrl_gpio.c | 3 +++
>  drivers/tty/serial/serial_mctrl_gpio.h | 6 +++---
>  drivers/tty/serial/sh-sci.c            | 2 +-

I'd split the sh-sci change in a separate patch. And there is another
instance in drivers/tty/serial/8250/8250_core.c that should be dropped.

Other than that looks good.

Best regards
Uwe

Patch
diff mbox series

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;
+
 	return gpios->gpio[gidx];
 }
 EXPORT_SYMBOL_GPL(mctrl_gpio_to_gpiod);
diff --git a/drivers/tty/serial/serial_mctrl_gpio.h b/drivers/tty/serial/serial_mctrl_gpio.h
index b7d3cca48ede..1b2ff503b2c2 100644
--- a/drivers/tty/serial/serial_mctrl_gpio.h
+++ b/drivers/tty/serial/serial_mctrl_gpio.h
@@ -114,19 +114,19 @@  static inline
 struct gpio_desc *mctrl_gpio_to_gpiod(struct mctrl_gpios *gpios,
 				      enum mctrl_gpio_idx gidx)
 {
-	return ERR_PTR(-ENOSYS);
+	return NULL;
 }
 
 static inline
 struct mctrl_gpios *mctrl_gpio_init(struct uart_port *port, unsigned int idx)
 {
-	return ERR_PTR(-ENOSYS);
+	return NULL;
 }
 
 static inline
 struct mctrl_gpios *mctrl_gpio_init_noauto(struct device *dev, unsigned int idx)
 {
-	return ERR_PTR(-ENOSYS);
+	return NULL;
 }
 
 static inline
diff --git a/drivers/tty/serial/sh-sci.c b/drivers/tty/serial/sh-sci.c
index d18c680aa64b..249325b65ee0 100644
--- a/drivers/tty/serial/sh-sci.c
+++ b/drivers/tty/serial/sh-sci.c
@@ -3287,7 +3287,7 @@  static int sci_probe_single(struct platform_device *dev,
 		return ret;
 
 	sciport->gpios = mctrl_gpio_init(&sciport->port, 0);
-	if (IS_ERR(sciport->gpios) && PTR_ERR(sciport->gpios) != -ENOSYS)
+	if (IS_ERR(sciport->gpios))
 		return PTR_ERR(sciport->gpios);
 
 	if (sciport->has_rtscts) {