Sometimes (as the case with fixed regulator) we only want to look up,
but not necessarily reserve right away, GPIO. gpiod_lookup() and
gpiod_lookup_by_index() allow us doing just that.
Signed-off-by: Dmitry Torokhov <d...@chromium.org>
Signed-off-by: Furquan Shaikh <furq...@chromium.org>
---
drivers/gpio/gpiolib.c | 75 ++++++++++++++++++++++++++++++++++---------
include/linux/gpio/consumer.h | 21 ++++++++++++
2 files changed, 80 insertions(+), 16 deletions(-)
diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index a07ae9e37930..7f8ac6c229e8 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -3165,6 +3165,22 @@ int gpiod_count(struct device *dev, const char *con_id)
EXPORT_SYMBOL_GPL(gpiod_count);
/**
+ * gpiod_lookup - look up a GPIO for a given GPIO function
+ * @dev: GPIO consumer, can be NULL for system-global GPIOs
+ * @con_id: function within the GPIO consumer
+ *
+ * Return the GPIO descriptor corresponding to the function con_id of device
+ * dev, -ENOENT if no GPIO has been assigned to the requested function, or
+ * another IS_ERR() code.
+ */
+struct gpio_desc *__must_check gpiod_lookup(struct device *dev,
+ const char *con_id)
+{
+ return gpiod_lookup_index(dev, con_id, 0);
+}
+EXPORT_SYMBOL_GPL(gpiod_lookup);
+
+/**
* gpiod_get - obtain a GPIO for a given GPIO function
* @dev: GPIO consumer, can be NULL for system-global GPIOs
* @con_id: function within the GPIO consumer
@@ -3241,26 +3257,19 @@ static int gpiod_configure_flags(struct gpio_desc
*desc, const char *con_id,
}
/**
- * gpiod_get_index - obtain a GPIO from a multi-index GPIO function
+ * gpiod_lookup_index - look up a GPIO from a multi-index GPIO function
* @dev: GPIO consumer, can be NULL for system-global GPIOs
* @con_id: function within the GPIO consumer
* @idx: index of the GPIO to obtain in the consumer
- * @flags: optional GPIO initialization flags
- *
- * This variant of gpiod_get() allows to access GPIOs other than the first
- * defined one for functions that define several GPIOs.
*
- * Return a valid GPIO descriptor, -ENOENT if no GPIO has been assigned to the
- * requested function and/or index, or another IS_ERR() code if an error
- * occurred while trying to acquire the GPIO.
+ * Return a valid GPIO descriptor, or -ENOENT if no GPIO has been assigned to
+ * the requested function and/or index, or another IS_ERR() code.
*/
-struct gpio_desc *__must_check gpiod_get_index(struct device *dev,
- const char *con_id,
- unsigned int idx,
- enum gpiod_flags flags)
+struct gpio_desc *__must_check gpiod_lookup_index(struct device *dev,
+ const char *con_id,
+ unsigned int idx)
{
struct gpio_desc *desc = NULL;
- int status;
enum gpio_lookup_flags lookupflags = 0;
dev_dbg(dev, "GPIO lookup for consumer %s\n", con_id);
@@ -3285,16 +3294,50 @@ struct gpio_desc *__must_check gpiod_get_index(struct
device *dev,
desc = gpiod_find(dev, con_id, idx, &lookupflags);
}
- if (IS_ERR(desc)) {
+ if (IS_ERR(desc))
dev_dbg(dev, "lookup for GPIO %s failed\n", con_id);
+
+ /*
+ * Configure static flags based on lookup data (such as
+ * "active low", "open drain", etc.)
+ */
+ gpiod_configure_flags(desc, con_id, lookupflags, 0);
+
+ return desc;
+}
+EXPORT_SYMBOL_GPL(gpiod_lookup_index);
+
+/**
+ * gpiod_get_index - obtain a GPIO from a multi-index GPIO function
+ * @dev: GPIO consumer, can be NULL for system-global GPIOs
+ * @con_id: function within the GPIO consumer
+ * @idx: index of the GPIO to obtain in the consumer
+ * @flags: optional GPIO initialization flags
+ *
+ * This variant of gpiod_get() allows to access GPIOs other than the first
+ * defined one for functions that define several GPIOs.
+ *
+ * Return a valid GPIO descriptor, -ENOENT if no GPIO has been assigned to the
+ * requested function and/or index, or another IS_ERR() code if an error
+ * occurred while trying to acquire the GPIO.
+ */
+struct gpio_desc *__must_check gpiod_get_index(struct device *dev,
+ const char *con_id,
+ unsigned int idx,
+ enum gpiod_flags flags)
+{
+ struct gpio_desc *desc;
+ int status;
+
+ desc = gpiod_lookup_index(dev, con_id, idx);
+ if (IS_ERR(desc))
return desc;
- }
status = gpiod_request(desc, con_id);
if (status < 0)
return ERR_PTR(status);
- status = gpiod_configure_flags(desc, con_id, lookupflags, flags);
+ status = gpiod_configure_flags(desc, con_id, 0, flags);
if (status < 0) {
dev_dbg(dev, "setup of GPIO %s failed\n", con_id);
gpiod_put(desc);
diff --git a/include/linux/gpio/consumer.h b/include/linux/gpio/consumer.h
index fb0fde686cb1..8fcb638f5568 100644
--- a/include/linux/gpio/consumer.h
+++ b/include/linux/gpio/consumer.h
@@ -46,6 +46,13 @@ enum gpiod_flags {
/* Return the number of GPIOs associated with a device / function */
int gpiod_count(struct device *dev, const char *con_id);
+/* Look up GPIOs */
+struct gpio_desc *__must_check gpiod_lookup(struct device *dev,
+ const char *con_id);
+struct gpio_desc *__must_check gpiod_lookup_index(struct device *dev,
+ const char *con_id,
+ unsigned int idx);
+
/* Acquire and dispose GPIOs */
struct gpio_desc *__must_check gpiod_get(struct device *dev,
const char *con_id,
@@ -146,6 +153,20 @@ static inline int gpiod_count(struct device *dev, const
char *con_id)
return 0;
}
+static inline struct gpio_desc *__must_check gpiod_lookup(struct device *dev,
+ const char *con_id)
+{
+ return ERR_PTR(-ENOSYS);
+}
+
+static inline struct gpio_desc *__must_check
+gpiod_lookup_index(struct device *dev,
+ const char *con_id,
+ unsigned int idx)
+{
+ return ERR_PTR(-ENOSYS);
+}
+
static inline struct gpio_desc *__must_check gpiod_get(struct device *dev,
const char *con_id,
enum gpiod_flags flags)
--
2.11.0.483.g087da7b7c-goog
