gpio: mxc: implement get_direction callback

gpiolib's gpiod_get_direction() function returns an erro if
.get_direction callback is not defined.

The patch implements the callback for IMX platform which is useful
for debugging and also the kernel docs about struct gpio_chip
recommends it.

Inspired by drivers/gpio/gpio-mxs.c

Signed-off-by: Stefan Wahren <wahrenst@gmx.net>
---
 drivers/gpio/gpio-mxc.c | 13 +++++++++++++
 1 file changed, 13 insertions(+)

--
2.34.1

Hi Stefan,

On Sun, Nov 12, 2023 at 08:24:28PM +0100, Stefan Wahren wrote:
> gpiolib's gpiod_get_direction() function returns an erro if
> .get_direction callback is not defined.
> 
> The patch implements the callback for IMX platform which is useful
> for debugging and also the kernel docs about struct gpio_chip
> recommends it.
> 
> Inspired by drivers/gpio/gpio-mxs.c
> 
> Signed-off-by: Stefan Wahren <wahrenst@gmx.net>
> ---
>  drivers/gpio/gpio-mxc.c | 13 +++++++++++++
>  1 file changed, 13 insertions(+)
> 
> diff --git a/drivers/gpio/gpio-mxc.c b/drivers/gpio/gpio-mxc.c
> index 4cb455b2bdee..ad8a4c73d47b 100644
> --- a/drivers/gpio/gpio-mxc.c
> +++ b/drivers/gpio/gpio-mxc.c
> @@ -418,6 +418,18 @@ static void mxc_update_irq_chained_handler(struct mxc_gpio_port *port, bool enab
>  	}
>  }
> 
> +static int mxc_gpio_get_direction(struct gpio_chip *gc, unsigned int offset)
> +{
> +	struct mxc_gpio_port *port = gpiochip_get_data(gc);
> +	u32 dir;
> +
> +	dir = readl(port->base + GPIO_GDIR);
> +	if (dir & BIT(offset))
> +		return GPIO_LINE_DIRECTION_OUT;
> +
> +	return GPIO_LINE_DIRECTION_IN;
> +}
> +
>  static int mxc_gpio_probe(struct platform_device *pdev)
>  {
>  	struct device_node *np = pdev->dev.of_node;
> @@ -490,6 +502,7 @@ static int mxc_gpio_probe(struct platform_device *pdev)
>  	port->gc.request = mxc_gpio_request;
>  	port->gc.free = mxc_gpio_free;
>  	port->gc.to_irq = mxc_gpio_to_irq;
> +	port->gc.get_direction = mxc_gpio_get_direction;

The driver passes port->base + GPIO_GDIR as *dirout argument to
bgpio_init(). This should result in the .get_direction hook already
being set to bgpio_get_dir() in the bgpio code. Doesn't this work as
expected?

Sascha

Hi Sascha,

Am 13.11.23 um 08:04 schrieb Sascha Hauer:
> Hi Stefan,
>
> On Sun, Nov 12, 2023 at 08:24:28PM +0100, Stefan Wahren wrote:
>> gpiolib's gpiod_get_direction() function returns an erro if
>> .get_direction callback is not defined.
>>
>> The patch implements the callback for IMX platform which is useful
>> for debugging and also the kernel docs about struct gpio_chip
>> recommends it.
>>
>> Inspired by drivers/gpio/gpio-mxs.c
>>
>> Signed-off-by: Stefan Wahren <wahrenst@gmx.net>
>> ---
>>   drivers/gpio/gpio-mxc.c | 13 +++++++++++++
>>   1 file changed, 13 insertions(+)
>>
>> diff --git a/drivers/gpio/gpio-mxc.c b/drivers/gpio/gpio-mxc.c
>> index 4cb455b2bdee..ad8a4c73d47b 100644
>> --- a/drivers/gpio/gpio-mxc.c
>> +++ b/drivers/gpio/gpio-mxc.c
>> @@ -418,6 +418,18 @@ static void mxc_update_irq_chained_handler(struct mxc_gpio_port *port, bool enab
>>   	}
>>   }
>>
>> +static int mxc_gpio_get_direction(struct gpio_chip *gc, unsigned int offset)
>> +{
>> +	struct mxc_gpio_port *port = gpiochip_get_data(gc);
>> +	u32 dir;
>> +
>> +	dir = readl(port->base + GPIO_GDIR);
>> +	if (dir & BIT(offset))
>> +		return GPIO_LINE_DIRECTION_OUT;
>> +
>> +	return GPIO_LINE_DIRECTION_IN;
>> +}
>> +
>>   static int mxc_gpio_probe(struct platform_device *pdev)
>>   {
>>   	struct device_node *np = pdev->dev.of_node;
>> @@ -490,6 +502,7 @@ static int mxc_gpio_probe(struct platform_device *pdev)
>>   	port->gc.request = mxc_gpio_request;
>>   	port->gc.free = mxc_gpio_free;
>>   	port->gc.to_irq = mxc_gpio_to_irq;
>> +	port->gc.get_direction = mxc_gpio_get_direction;
> The driver passes port->base + GPIO_GDIR as *dirout argument to
> bgpio_init(). This should result in the .get_direction hook already
> being set to bgpio_get_dir() in the bgpio code. Doesn't this work as
> expected?
oh dear, i missed that. What a shame. Sorry, for the noise and thanks
for pointing out.

Regards
Stefan
>
> Sascha
>