summaryrefslogtreecommitdiffstats
path: root/Documentation/media/kapi/cec-core.rst
diff options
context:
space:
mode:
authorLinus Torvalds <torvalds@linux-foundation.org>2018-04-03 17:16:59 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2018-04-03 17:16:59 -0700
commitef1c4a6fa91bbbe9b09f770d28eba31a9edf770c (patch)
tree52f5d175031c553160d14890e876ffc5432d2467 /Documentation/media/kapi/cec-core.rst
parent147a89bc71e7db40f011454a40add7ff2d10f8d8 (diff)
parentf8a695c4b43d02c89b8bba9ba6058fd5db1bc71d (diff)
downloadlinux-ef1c4a6fa91bbbe9b09f770d28eba31a9edf770c.tar.bz2
Merge tag 'media/v4.17-1' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-media
Pull media updates from Mauro Carvalho Chehab: - new CEC pin injection code for testing purposes - DVB frontend cxd2099 promoted from staging - new platform driver for Sony cxd2880 DVB devices - new sensor drivers: mt9t112, ov2685, ov5695, ov772x, tda1997x, tw9910.c - removal of unused cx18 and ivtv alsa mixers - the reneseas-ceu driver doesn't depend on soc_camera anymore and moved from staging - removed the mantis_vp3028 driver, unused since 2009 - s5p-mfc: add support for version 10 of the MSP - added a decoder for imon protocol - atomisp: lots of cleanups - imx074 and mt9t031: don't depend on soc_camera anymore, being promoted from staging - added helper functions to better support DVB I2C binding - lots of driver improvements and cleanups * tag 'media/v4.17-1' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-media: (438 commits) media: v4l2-ioctl: rename a temp var that stores _IOC_SIZE(cmd) media: fimc-capture: get rid of two warnings media: dvb-usb-v2: fix a missing dependency of I2C_MUX media: uvc: to the right check at uvc_ioctl_enum_framesizes() media: cec-core: fix a bug at cec_error_inj_write() media: tda9840: cleanup a warning media: tm6000: avoid casting just to print pointer address media: em28xx-input: improve error handling code media: zr364xx: avoid casting just to print pointer address media: vivid-radio-rx: add a cast to avoid a warning media: saa7134-alsa: don't use casts to print a buffer address media: solo6x10: get rid of an address space warning media: zoran: don't cast pointers to print them media: ir-kbd-i2c: change the if logic to avoid a warning media: ir-kbd-i2c: improve error handling code media: saa7134-input: improve error handling media: s2255drv: fix a casting warning media: ivtvfb: Cleanup some warnings media: videobuf-dma-sg: Fix a weird cast soc_camera: fix a weird cast on printk ...
Diffstat (limited to 'Documentation/media/kapi/cec-core.rst')
-rw-r--r--Documentation/media/kapi/cec-core.rst72
1 files changed, 71 insertions, 1 deletions
diff --git a/Documentation/media/kapi/cec-core.rst b/Documentation/media/kapi/cec-core.rst
index 62b9a1448177..a9f53f069a2d 100644
--- a/Documentation/media/kapi/cec-core.rst
+++ b/Documentation/media/kapi/cec-core.rst
@@ -110,11 +110,14 @@ your driver:
void (*adap_status)(struct cec_adapter *adap, struct seq_file *file);
void (*adap_free)(struct cec_adapter *adap);
+ /* Error injection callbacks */
+ ...
+
/* High-level callbacks */
...
};
-The five low-level ops deal with various aspects of controlling the CEC adapter
+The seven low-level ops deal with various aspects of controlling the CEC adapter
hardware:
@@ -286,6 +289,70 @@ handling the receive interrupt. The framework expects to see the cec_transmit_do
call before the cec_received_msg call, otherwise it can get confused if the
received message was in reply to the transmitted message.
+Optional: Implementing Error Injection Support
+----------------------------------------------
+
+If the CEC adapter supports Error Injection functionality, then that can
+be exposed through the Error Injection callbacks:
+
+.. code-block:: none
+
+ struct cec_adap_ops {
+ /* Low-level callbacks */
+ ...
+
+ /* Error injection callbacks */
+ int (*error_inj_show)(struct cec_adapter *adap, struct seq_file *sf);
+ bool (*error_inj_parse_line)(struct cec_adapter *adap, char *line);
+
+ /* High-level CEC message callback */
+ ...
+ };
+
+If both callbacks are set, then an ``error-inj`` file will appear in debugfs.
+The basic syntax is as follows:
+
+Leading spaces/tabs are ignored. If the next character is a ``#`` or the end of the
+line was reached, then the whole line is ignored. Otherwise a command is expected.
+
+This basic parsing is done in the CEC Framework. It is up to the driver to decide
+what commands to implement. The only requirement is that the command ``clear`` without
+any arguments must be implemented and that it will remove all current error injection
+commands.
+
+This ensures that you can always do ``echo clear >error-inj`` to clear any error
+injections without having to know the details of the driver-specific commands.
+
+Note that the output of ``error-inj`` shall be valid as input to ``error-inj``.
+So this must work:
+
+.. code-block:: none
+
+ $ cat error-inj >einj.txt
+ $ cat einj.txt >error-inj
+
+The first callback is called when this file is read and it should show the
+the current error injection state:
+
+.. c:function::
+ int (*error_inj_show)(struct cec_adapter *adap, struct seq_file *sf);
+
+It is recommended that it starts with a comment block with basic usage
+information. It returns 0 for success and an error otherwise.
+
+The second callback will parse commands written to the ``error-inj`` file:
+
+.. c:function::
+ bool (*error_inj_parse_line)(struct cec_adapter *adap, char *line);
+
+The ``line`` argument points to the start of the command. Any leading
+spaces or tabs have already been skipped. It is a single line only (so there
+are no embedded newlines) and it is 0-terminated. The callback is free to
+modify the contents of the buffer. It is only called for lines containing a
+command, so this callback is never called for empty lines or comment lines.
+
+Return true if the command was valid or false if there were syntax errors.
+
Implementing the High-Level CEC Adapter
---------------------------------------
@@ -298,6 +365,9 @@ CEC protocol driven. The following high-level callbacks are available:
/* Low-level callbacks */
...
+ /* Error injection callbacks */
+ ...
+
/* High-level CEC message callback */
int (*received)(struct cec_adapter *adap, struct cec_msg *msg);
};