On Thu, Nov 05, 2015 at 11:38:38AM -0800, Dmitry Torokhov wrote:
> We should not fall back to the legacy unnamed gpio lookup style if the
> driver requests gpios with different names, because we'll give out the same
> gpio twice. Let's keep track of the names that were used for the device and
> only do the fallback for the first name used.
>
> Also disable fallback to _CRS gpios if ACPI device has DT-like
> properties or driver-supplied gpio mappings.
Thanks for taking care of this!
> Signed-off-by: Dmitry Torokhov <dmitry.torok...@gmail.com>
> ---
>
> This version incorporates changes suggested by Mika Westerberg in
> response to the draft patch I posted in Goodix thread.
>
> drivers/gpio/gpiolib.c | 47 +++++++++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 47 insertions(+)
>
> diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
> index a18f00f..9631ee8 100644
> --- a/drivers/gpio/gpiolib.c
> +++ b/drivers/gpio/gpiolib.c
> @@ -1841,6 +1841,50 @@ static struct gpio_desc *of_find_gpio(struct device
> *dev, const char *con_id,
> return desc;
> }
>
> +struct acpi_gpio_lookup {
> + struct list_head node;
> + struct acpi_device *adev;
> + const char *con_id;
> +};
> +
> +static DEFINE_MUTEX(acpi_gpio_lookup_lock);
> +static LIST_HEAD(acpi_gpio_lookup_list);
> +
> +static bool acpi_can_fallback_to_crs(struct acpi_device *adev,
> + const char *con_id)
> +{
> + struct acpi_gpio_lookup *l, *lookup = NULL;
> +
> + /* Never fallback if the device has properties */
> + if (adev->data.properties || adev->driver_gpios)
> + return false;
I missed the fact that struct acpi_device is declared in
<acpi/acpi_bus.h> so we can't use the two fields directly here when
!CONFIG_ACPI. Sorry about that.
Do you think we can just add
#ifdef CONFIG_ACPI
#endif
around the above check?
Alternatively we could add an inline function to drivers/gpio/gpiolib.h
like:
#ifdef CONFIG_ACPI
static inline bool acpi_gpio_has_properties(struct acpi_device *adev)
{
return adev->data.properties || adev->driver_gpios;
}
#else
static inline bool acpi_gpio_has_properties(struct acpi_device *adev)
{
return false;
}
#endif
> +
> + mutex_lock(&acpi_gpio_lookup_lock);
> +
> + list_for_each_entry(l, &acpi_gpio_lookup_list, node) {
> + if (l->adev == adev) {
> + lookup = l;
> + break;
> + }
> + }
> +
> + if (!lookup) {
> + lookup = kmalloc(sizeof(*lookup), GFP_KERNEL);
> + if (lookup) {
> + lookup->adev = adev;
> + lookup->con_id = con_id;
> + list_add_tail(&lookup->node, &acpi_gpio_lookup_list);
> + }
> + }
> +
> + mutex_unlock(&acpi_gpio_lookup_lock);
> +
> + return lookup &&
> + ((!lookup->con_id && !con_id) ||
> + (lookup->con_id && con_id &&
> + strcmp(lookup->con_id, con_id) == 0));
> +}
> +
> static struct gpio_desc *acpi_find_gpio(struct device *dev, const char
> *con_id,
> unsigned int idx,
> enum gpio_lookup_flags *flags)
> @@ -1868,6 +1912,9 @@ static struct gpio_desc *acpi_find_gpio(struct device
> *dev, const char *con_id,
>
> /* Then from plain _CRS GPIOs */
> if (IS_ERR(desc)) {
> + if (!acpi_can_fallback_to_crs(adev, con_id))
> + return ERR_PTR(-ENOENT);
> +
> desc = acpi_get_gpiod_by_index(adev, NULL, idx, &info);
> if (IS_ERR(desc))
> return desc;
> --
> 2.6.0.rc2.230.g3dd15c0
>
>
> --
> Dmitry
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
