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Diffstat (limited to 'kernel/Documentation/DocBook/device-drivers.tmpl')
| -rw-r--r-- | kernel/Documentation/DocBook/device-drivers.tmpl | 133 |
1 files changed, 133 insertions, 0 deletions
diff --git a/kernel/Documentation/DocBook/device-drivers.tmpl b/kernel/Documentation/DocBook/device-drivers.tmpl index faf09d4a0..42a2d8593 100644 --- a/kernel/Documentation/DocBook/device-drivers.tmpl +++ b/kernel/Documentation/DocBook/device-drivers.tmpl @@ -66,6 +66,7 @@ !Ekernel/time/hrtimer.c </sect1> <sect1><title>Workqueues and Kevents</title> +!Iinclude/linux/workqueue.h !Ekernel/workqueue.c </sect1> <sect1><title>Internal Functions</title> @@ -216,6 +217,111 @@ X!Isound/sound_firmware.c --> </chapter> + <chapter id="mediadev"> + <title>Media Devices</title> + + <sect1><title>Video2Linux devices</title> +!Iinclude/media/tuner.h +!Iinclude/media/tuner-types.h +!Iinclude/media/tveeprom.h +!Iinclude/media/v4l2-async.h +!Iinclude/media/v4l2-ctrls.h +!Iinclude/media/v4l2-dv-timings.h +!Iinclude/media/v4l2-event.h +!Iinclude/media/v4l2-flash-led-class.h +!Iinclude/media/v4l2-mediabus.h +!Iinclude/media/v4l2-mem2mem.h +!Iinclude/media/v4l2-of.h +!Iinclude/media/v4l2-subdev.h +!Iinclude/media/videobuf2-core.h +!Iinclude/media/videobuf2-v4l2.h +!Iinclude/media/videobuf2-memops.h + </sect1> + <sect1><title>Digital TV (DVB) devices</title> +!Idrivers/media/dvb-core/dvb_ca_en50221.h +!Idrivers/media/dvb-core/dvb_frontend.h +!Idrivers/media/dvb-core/dvb_math.h +!Idrivers/media/dvb-core/dvb_ringbuffer.h +!Idrivers/media/dvb-core/dvbdev.h + <sect1><title>Digital TV Demux API</title> + <para>The kernel demux API defines a driver-internal interface for + registering low-level, hardware specific driver to a hardware + independent demux layer. It is only of interest for Digital TV + device driver writers. The header file for this API is named + <constant>demux.h</constant> and located in + <constant>drivers/media/dvb-core</constant>.</para> + + <para>The demux API should be implemented for each demux in the + system. It is used to select the TS source of a demux and to manage + the demux resources. When the demux client allocates a resource via + the demux API, it receives a pointer to the API of that + resource.</para> + <para>Each demux receives its TS input from a DVB front-end or from + memory, as set via this demux API. In a system with more than one + front-end, the API can be used to select one of the DVB front-ends + as a TS source for a demux, unless this is fixed in the HW platform. + The demux API only controls front-ends regarding to their connections + with demuxes; the APIs used to set the other front-end parameters, + such as tuning, are not defined in this document.</para> + <para>The functions that implement the abstract interface demux should + be defined static or module private and registered to the Demux + core for external access. It is not necessary to implement every + function in the struct <constant>dmx_demux</constant>. For example, + a demux interface might support Section filtering, but not PES + filtering. The API client is expected to check the value of any + function pointer before calling the function: the value of NULL means + that the “function is not available”.</para> + <para>Whenever the functions of the demux API modify shared data, + the possibilities of lost update and race condition problems should + be addressed, e.g. by protecting parts of code with mutexes.</para> + <para>Note that functions called from a bottom half context must not + sleep. Even a simple memory allocation without using GFP_ATOMIC can + result in a kernel thread being put to sleep if swapping is needed. + For example, the Linux kernel calls the functions of a network device + interface from a bottom half context. Thus, if a demux API function + is called from network device code, the function must not sleep. + </para> + </sect1> + + <section id="demux_callback_api"> + <title>Demux Callback API</title> + <para>This kernel-space API comprises the callback functions that + deliver filtered data to the demux client. Unlike the other DVB + kABIs, these functions are provided by the client and called from + the demux code.</para> + <para>The function pointers of this abstract interface are not + packed into a structure as in the other demux APIs, because the + callback functions are registered and used independent of each + other. As an example, it is possible for the API client to provide + several callback functions for receiving TS packets and no + callbacks for PES packets or sections.</para> + <para>The functions that implement the callback API need not be + re-entrant: when a demux driver calls one of these functions, + the driver is not allowed to call the function again before + the original call returns. If a callback is triggered by a + hardware interrupt, it is recommended to use the Linux + “bottom half” mechanism or start a tasklet instead of + making the callback function call directly from a hardware + interrupt.</para> + <para>This mechanism is implemented by + <link linkend='API-dmx-ts-cb'>dmx_ts_cb()</link> and + <link linkend='API-dmx-section-cb'>dmx_section_cb()</link>.</para> + </section> + +!Idrivers/media/dvb-core/demux.h + </sect1> + <sect1><title>Remote Controller devices</title> +!Iinclude/media/rc-core.h +!Iinclude/media/lirc_dev.h + </sect1> + <sect1><title>Media Controller devices</title> +!Iinclude/media/media-device.h +!Iinclude/media/media-devnode.h +!Iinclude/media/media-entity.h + </sect1> + + </chapter> + <chapter id="uart16x50"> <title>16x50 UART Driver</title> !Edrivers/tty/serial/serial_core.c @@ -455,4 +561,31 @@ X!Ilib/fonts/fonts.c !Edrivers/hsi/hsi.c </chapter> + <chapter id="pwm"> + <title>Pulse-Width Modulation (PWM)</title> + <para> + Pulse-width modulation is a modulation technique primarily used to + control power supplied to electrical devices. + </para> + <para> + The PWM framework provides an abstraction for providers and consumers + of PWM signals. A controller that provides one or more PWM signals is + registered as <structname>struct pwm_chip</structname>. Providers are + expected to embed this structure in a driver-specific structure. This + structure contains fields that describe a particular chip. + </para> + <para> + A chip exposes one or more PWM signal sources, each of which exposed + as a <structname>struct pwm_device</structname>. Operations can be + performed on PWM devices to control the period, duty cycle, polarity + and active state of the signal. + </para> + <para> + Note that PWM devices are exclusive resources: they can always only be + used by one consumer at a time. + </para> +!Iinclude/linux/pwm.h +!Edrivers/pwm/core.c + </chapter> + </book> |