diff options
Diffstat (limited to 'Documentation/driver-api')
| -rw-r--r-- | Documentation/driver-api/dpll.rst | 43 | ||||
| -rw-r--r-- | Documentation/driver-api/gpio/driver.rst | 2 | ||||
| -rw-r--r-- | Documentation/driver-api/media/v4l2-controls.rst | 9 |
3 files changed, 47 insertions, 7 deletions
diff --git a/Documentation/driver-api/dpll.rst b/Documentation/driver-api/dpll.rst index e6855cd37e85..eca72d9b9ed8 100644 --- a/Documentation/driver-api/dpll.rst +++ b/Documentation/driver-api/dpll.rst @@ -214,6 +214,24 @@ offset values are fractional with 3-digit decimal places and shell be divided with ``DPLL_PIN_PHASE_OFFSET_DIVIDER`` to get integer part and modulo divided to get fractional part. +Phase offset monitor +==================== + +Phase offset measurement is typically performed against the current active +source. However, some DPLL (Digital Phase-Locked Loop) devices may offer +the capability to monitor phase offsets across all available inputs. +The attribute and current feature state shall be included in the response +message of the ``DPLL_CMD_DEVICE_GET`` command for supported DPLL devices. +In such cases, users can also control the feature using the +``DPLL_CMD_DEVICE_SET`` command by setting the ``enum dpll_feature_state`` +values for the attribute. +Once enabled the phase offset measurements for the input shall be returned +in the ``DPLL_A_PIN_PHASE_OFFSET`` attribute. + + =============================== ======================== + ``DPLL_A_PHASE_OFFSET_MONITOR`` attr state of a feature + =============================== ======================== + Embedded SYNC ============= @@ -235,6 +253,31 @@ the pin. ``DPLL_A_PIN_ESYNC_PULSE`` pulse type of Embedded SYNC ========================================= ================================= +Reference SYNC +============== + +The device may support the Reference SYNC feature, which allows the combination +of two inputs into a input pair. In this configuration, clock signals +from both inputs are used to synchronize the DPLL device. The higher frequency +signal is utilized for the loop bandwidth of the DPLL, while the lower frequency +signal is used to syntonize the output signal of the DPLL device. This feature +enables the provision of a high-quality loop bandwidth signal from an external +source. + +A capable input provides a list of inputs that can be bound with to create +Reference SYNC. To control this feature, the user must request a desired +state for a target pin: use ``DPLL_PIN_STATE_CONNECTED`` to enable or +``DPLL_PIN_STATE_DISCONNECTED`` to disable the feature. An input pin can be +bound to only one other pin at any given time. + + ============================== ========================================== + ``DPLL_A_PIN_REFERENCE_SYNC`` nested attribute for providing info or + requesting configuration of the Reference + SYNC feature + ``DPLL_A_PIN_ID`` target pin id for Reference SYNC feature + ``DPLL_A_PIN_STATE`` state of Reference SYNC connection + ============================== ========================================== + Configuration commands group ============================ diff --git a/Documentation/driver-api/gpio/driver.rst b/Documentation/driver-api/gpio/driver.rst index ae433261e11a..85d86f92c41b 100644 --- a/Documentation/driver-api/gpio/driver.rst +++ b/Documentation/driver-api/gpio/driver.rst @@ -750,7 +750,7 @@ compliance: - Test your driver with the appropriate in-kernel real-time test cases for both level and edge IRQs -* [1] http://www.spinics.net/lists/linux-omap/msg120425.html +* [1] https://lore.kernel.org/r/1437496011-11486-1-git-send-email-bigeasy@linutronix.de/ * [2] https://lore.kernel.org/r/1443209283-20781-2-git-send-email-grygorii.strashko@ti.com * [3] https://lore.kernel.org/r/1443209283-20781-3-git-send-email-grygorii.strashko@ti.com diff --git a/Documentation/driver-api/media/v4l2-controls.rst b/Documentation/driver-api/media/v4l2-controls.rst index b2e91804829b..fc04907589ab 100644 --- a/Documentation/driver-api/media/v4l2-controls.rst +++ b/Documentation/driver-api/media/v4l2-controls.rst @@ -110,6 +110,7 @@ For sub-device drivers: v4l2_ctrl_handler_free(&foo->ctrl_handler); +:c:func:`v4l2_ctrl_handler_free` does not touch the handler's ``error`` field. 2) Add controls: @@ -191,12 +192,8 @@ These functions are typically called right after the V4L2_CID_TEST_PATTERN, ARRAY_SIZE(test_pattern) - 1, 0, 0, test_pattern); ... - if (foo->ctrl_handler.error) { - int err = foo->ctrl_handler.error; - - v4l2_ctrl_handler_free(&foo->ctrl_handler); - return err; - } + if (foo->ctrl_handler.error) + return v4l2_ctrl_handler_free(&foo->ctrl_handler); The :c:func:`v4l2_ctrl_new_std` function returns the v4l2_ctrl pointer to the new control, but if you do not need to access the pointer outside the |