[PATCH v2 3/7] iio: core: Match iio_device_claim_*() semantics and implementation
From: Kurt Borja
Date: Thu Dec 11 2025 - 21:45:40 EST
Implement iio_device_claim_buffer_mode() fully inline with the use of
__iio_dev_mode_lock(), which takes care of sparse annotations.
To completely match iio_device_claim_direct() semantics, we need to
also change iio_device_claim_buffer_mode() return semantics to usual
true/false conditional lock semantics.
Signed-off-by: Kurt Borja <kuurtb@xxxxxxxxx>
---
drivers/iio/adc/ade9000.c | 2 +-
.../common/cros_ec_sensors/cros_ec_sensors_core.c | 5 +--
drivers/iio/health/max30100.c | 2 +-
drivers/iio/health/max30102.c | 2 +-
drivers/iio/industrialio-core.c | 40 ----------------------
drivers/iio/light/opt4060.c | 2 +-
include/linux/iio/iio.h | 38 ++++++++++++++++++--
7 files changed, 41 insertions(+), 50 deletions(-)
diff --git a/drivers/iio/adc/ade9000.c b/drivers/iio/adc/ade9000.c
index 2de8a718d62a..b345c4d1ef24 100644
--- a/drivers/iio/adc/ade9000.c
+++ b/drivers/iio/adc/ade9000.c
@@ -964,7 +964,7 @@ static irqreturn_t ade9000_dready_thread(int irq, void *data)
struct iio_dev *indio_dev = data;
/* Handle data ready interrupt from C4/EVENT/DREADY pin */
- if (!iio_device_claim_buffer_mode(indio_dev)) {
+ if (iio_device_claim_buffer_mode(indio_dev)) {
ade9000_iio_push_buffer(indio_dev);
iio_device_release_buffer_mode(indio_dev);
}
diff --git a/drivers/iio/common/cros_ec_sensors/cros_ec_sensors_core.c b/drivers/iio/common/cros_ec_sensors/cros_ec_sensors_core.c
index 9ac80e4b7d75..8ed4b2e410c8 100644
--- a/drivers/iio/common/cros_ec_sensors/cros_ec_sensors_core.c
+++ b/drivers/iio/common/cros_ec_sensors/cros_ec_sensors_core.c
@@ -188,11 +188,8 @@ int cros_ec_sensors_push_data(struct iio_dev *indio_dev,
/*
* Ignore samples if the buffer is not set: it is needed if the ODR is
* set but the buffer is not enabled yet.
- *
- * Note: iio_device_claim_buffer_mode() returns -EBUSY if the buffer
- * is not enabled.
*/
- if (iio_device_claim_buffer_mode(indio_dev) < 0)
+ if (!iio_device_claim_buffer_mode(indio_dev))
return 0;
out = (s16 *)st->samples;
diff --git a/drivers/iio/health/max30100.c b/drivers/iio/health/max30100.c
index 3d441013893c..3f3680c4b42f 100644
--- a/drivers/iio/health/max30100.c
+++ b/drivers/iio/health/max30100.c
@@ -417,7 +417,7 @@ static int max30100_read_raw(struct iio_dev *indio_dev,
* Temperature reading can only be acquired while engine
* is running
*/
- if (iio_device_claim_buffer_mode(indio_dev)) {
+ if (!iio_device_claim_buffer_mode(indio_dev)) {
/*
* Replacing -EBUSY or other error code
* returned by iio_device_claim_buffer_mode()
diff --git a/drivers/iio/health/max30102.c b/drivers/iio/health/max30102.c
index a48c0881a4c7..288c2f37a4a2 100644
--- a/drivers/iio/health/max30102.c
+++ b/drivers/iio/health/max30102.c
@@ -476,7 +476,7 @@ static int max30102_read_raw(struct iio_dev *indio_dev,
* shutdown; leave shutdown briefly when buffer not running
*/
any_mode_retry:
- if (iio_device_claim_buffer_mode(indio_dev)) {
+ if (!iio_device_claim_buffer_mode(indio_dev)) {
/*
* This one is a *bit* hacky. If we cannot claim buffer
* mode, then try direct mode so that we make sure
diff --git a/drivers/iio/industrialio-core.c b/drivers/iio/industrialio-core.c
index cffc6efb6617..46e336bff64c 100644
--- a/drivers/iio/industrialio-core.c
+++ b/drivers/iio/industrialio-core.c
@@ -2201,46 +2201,6 @@ void __iio_dev_mode_unlock(struct iio_dev *indio_dev)
}
EXPORT_SYMBOL_GPL(__iio_dev_mode_unlock);
-/**
- * iio_device_claim_buffer_mode - Keep device in buffer mode
- * @indio_dev: the iio_dev associated with the device
- *
- * If the device is in buffer mode it is guaranteed to stay
- * that way until iio_device_release_buffer_mode() is called.
- *
- * Use with iio_device_release_buffer_mode().
- *
- * Returns: 0 on success, -EBUSY on failure.
- */
-int iio_device_claim_buffer_mode(struct iio_dev *indio_dev)
-{
- struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
-
- mutex_lock(&iio_dev_opaque->mlock);
-
- if (iio_buffer_enabled(indio_dev))
- return 0;
-
- mutex_unlock(&iio_dev_opaque->mlock);
- return -EBUSY;
-}
-EXPORT_SYMBOL_GPL(iio_device_claim_buffer_mode);
-
-/**
- * iio_device_release_buffer_mode - releases claim on buffer mode
- * @indio_dev: the iio_dev associated with the device
- *
- * Release the claim. Device is no longer guaranteed to stay
- * in buffer mode.
- *
- * Use with iio_device_claim_buffer_mode().
- */
-void iio_device_release_buffer_mode(struct iio_dev *indio_dev)
-{
- mutex_unlock(&to_iio_dev_opaque(indio_dev)->mlock);
-}
-EXPORT_SYMBOL_GPL(iio_device_release_buffer_mode);
-
/**
* iio_device_get_current_mode() - helper function providing read-only access to
* the opaque @currentmode variable
diff --git a/drivers/iio/light/opt4060.c b/drivers/iio/light/opt4060.c
index 981c704e7df5..8cb3fa38077e 100644
--- a/drivers/iio/light/opt4060.c
+++ b/drivers/iio/light/opt4060.c
@@ -304,7 +304,7 @@ static int opt4060_set_driver_state(struct iio_dev *indio_dev,
struct opt4060_chip *chip = iio_priv(indio_dev);
int ret = 0;
any_mode_retry:
- if (iio_device_claim_buffer_mode(indio_dev)) {
+ if (!iio_device_claim_buffer_mode(indio_dev)) {
/*
* This one is a *bit* hacky. If we cannot claim buffer mode,
* then try direct mode so that we make sure things cannot
diff --git a/include/linux/iio/iio.h b/include/linux/iio/iio.h
index 76398dbfa5ca..f8a7ef709210 100644
--- a/include/linux/iio/iio.h
+++ b/include/linux/iio/iio.h
@@ -702,8 +702,42 @@ static inline void iio_device_release_direct(struct iio_dev *indio_dev)
__iio_dev_mode_unlock(indio_dev);
}
-int iio_device_claim_buffer_mode(struct iio_dev *indio_dev);
-void iio_device_release_buffer_mode(struct iio_dev *indio_dev);
+/**
+ * iio_device_claim_buffer_mode - Keep device in buffer mode
+ * @indio_dev: the iio_dev associated with the device
+ *
+ * If the device is in buffer mode it is guaranteed to stay
+ * that way until iio_device_release_buffer_mode() is called.
+ *
+ * Use with iio_device_release_buffer_mode().
+ *
+ * Returns: true on success, false on failure.
+ */
+static inline bool iio_device_claim_buffer_mode(struct iio_dev *indio_dev)
+{
+ __iio_dev_mode_lock(indio_dev);
+
+ if (!iio_buffer_enabled(indio_dev)) {
+ __iio_dev_mode_unlock(indio_dev);
+ return false;
+ }
+
+ return true;
+}
+
+/**
+ * iio_device_release_buffer_mode - releases claim on buffer mode
+ * @indio_dev: the iio_dev associated with the device
+ *
+ * Release the claim. Device is no longer guaranteed to stay
+ * in buffer mode.
+ *
+ * Use with iio_device_claim_buffer_mode().
+ */
+static inline void iio_device_release_buffer_mode(struct iio_dev *indio_dev)
+{
+ __iio_dev_mode_unlock(indio_dev);
+}
extern const struct bus_type iio_bus_type;
--
2.52.0