Re: [PATCH] gpio: pl061: hook request if gpio-ranges avaiable

[Alexandre Courbot <gnurou@xxxxxxxxx>]

On Fri, Nov 21, 2014 at 3:43 PM, Yunlei He <heyunlei@xxxxxxxxxx> wrote:
> Gpio-ranges property is useful to represent which GPIOs correspond
> to which pins on which pin controllers. But there may be some gpios
> without pinctrl operation. So check whether gpio-ranges property
> exists in device node first.
>
> Signed-off-by: Yunlei He <heyunlei@xxxxxxxxxx>
> Signed-off-by: Xinwei Kong <kong.kongxinwei@xxxxxxxxxxxxx>
> Signed-off-by: Haojian Zhuang <haojian.zhuang@xxxxxxxxxx>
> ---
>  Documentation/devicetree/bindings/gpio/pl061-gpio.txt | 2 +-
>  drivers/gpio/gpio-pl061.c                             | 7 +++++--
>  2 files changed, 6 insertions(+), 3 deletions(-)
>
> diff --git a/Documentation/devicetree/bindings/gpio/pl061-gpio.txt b/Documentation/devicetree/bindings/gpio/pl061-gpio.txt
> index a2c416b..577bcf7 100644
> --- a/Documentation/devicetree/bindings/gpio/pl061-gpio.txt
> +++ b/Documentation/devicetree/bindings/gpio/pl061-gpio.txt
> @@ -7,4 +7,4 @@ Required properties:
>    - bit 0 specifies polarity (0 for normal, 1 for inverted)
>  - gpio-controller : Marks the device node as a GPIO controller.
>  - interrupts : Interrupt mapping for GPIO IRQ.
> -
> +- gpio-ranges : Interaction with the PINCTRL subsystem
> diff --git a/drivers/gpio/gpio-pl061.c b/drivers/gpio/gpio-pl061.c
> index 84b49cf..01875d1 100644
> --- a/drivers/gpio/gpio-pl061.c
> +++ b/drivers/gpio/gpio-pl061.c
> @@ -24,6 +24,7 @@
>  #include <linux/slab.h>
>  #include <linux/pinctrl/consumer.h>
>  #include <linux/pm.h>
> +#include <linux/of_address.h>
>
>  #define GPIODIR 0x400
>  #define GPIOIS  0x404
> @@ -263,9 +264,11 @@ static int pl061_probe(struct amba_device *adev, const struct amba_id *id)
>                 return PTR_ERR(chip->base);
>
>         spin_lock_init(&chip->lock);
> +       if (of_get_property(dev->of_node, "gpio-ranges", NULL)) {
> +               chip->gc.request = pl061_gpio_request;
> +               chip->gc.free = pl061_gpio_free;
> +       }

With this property required to set gc.request and gc.free, aren't we
going to break old DTs that do know of this property but still expect
pl061_gpio_request() and pl061_gpio_free() to be called?

It seems that to preserve backward-compatibility, your property should
be used to negate the legacy behavior, not enable it.
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