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gpiolib: tighten up ACPI legacy gpio lookups 

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.

Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Acked-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
This commit is contained in:
Dmitry Torokhov 2015-11-11 11:45:30 -08:00 committed by Linus Walleij
parent 615b8a969d
commit 9c3c9bc9cc
3 changed files with 54 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

43
drivers/gpio/gpiolib-acpi.c
View File

@ -925,3 +925,46 @@ int acpi_gpio_count(struct device *dev, const char *con_id)
}
return count;
}
struct acpi_crs_lookup {
struct list_head node;
struct acpi_device *adev;
const char *con_id;
};
static DEFINE_MUTEX(acpi_crs_lookup_lock);
static LIST_HEAD(acpi_crs_lookup_list);
bool acpi_can_fallback_to_crs(struct acpi_device *adev, const char *con_id)
{
struct acpi_crs_lookup *l, *lookup = NULL;
/* Never allow fallback if the device has properties */
if (adev->data.properties || adev->driver_gpios)
return false;
mutex_lock(&acpi_crs_lookup_lock);
list_for_each_entry(l, &acpi_crs_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_crs_lookup_list);
}
}
mutex_unlock(&acpi_crs_lookup_lock);
return lookup &&
((!lookup->con_id && !con_id) ||
(lookup->con_id && con_id &&
strcmp(lookup->con_id, con_id) == 0));
}

3
drivers/gpio/gpiolib.c
View File

@ -1869,6 +1869,9 @@ 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;

8
drivers/gpio/gpiolib.h
View File

@ -47,6 +47,8 @@ struct gpio_desc *acpi_node_get_gpiod(struct fwnode_handle *fwnode,
struct acpi_gpio_info *info);
int acpi_gpio_count(struct device *dev, const char *con_id);
bool acpi_can_fallback_to_crs(struct acpi_device *adev, const char *con_id);
#else
static inline void acpi_gpiochip_add(struct gpio_chip *chip) { }
static inline void acpi_gpiochip_remove(struct gpio_chip *chip) { }
@ -73,6 +75,12 @@ static inline int acpi_gpio_count(struct device *dev, const char *con_id)
{
return -ENODEV;
}
static inline bool acpi_can_fallback_to_crs(struct acpi_device *adev,
const char *con_id)
{
return false;
}
#endif
struct gpio_desc *of_get_named_gpiod_flags(struct device_node *np,