From: Takashi Iwai Date: Thu, 10 Nov 2016 21:26:58 +0000 (+0100) Subject: ASoC: doc: ReSTize jack.txt X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=8155258a7d7600e7b92c6193cf23a11e281a9b0b;p=GitHub%2Fmoto-9609%2Fandroid_kernel_motorola_exynos9610.git ASoC: doc: ReSTize jack.txt A simple conversion from a plain text file. Acked-by: Mark Brown Signed-off-by: Takashi Iwai --- diff --git a/Documentation/sound/alsa/soc/jack.txt b/Documentation/sound/alsa/soc/jack.txt deleted file mode 100644 index fcf82a417293..000000000000 --- a/Documentation/sound/alsa/soc/jack.txt +++ /dev/null @@ -1,71 +0,0 @@ -ASoC jack detection -=================== - -ALSA has a standard API for representing physical jacks to user space, -the kernel side of which can be seen in include/sound/jack.h. ASoC -provides a version of this API adding two additional features: - - - It allows more than one jack detection method to work together on one - user visible jack. In embedded systems it is common for multiple - to be present on a single jack but handled by separate bits of - hardware. - - - Integration with DAPM, allowing DAPM endpoints to be updated - automatically based on the detected jack status (eg, turning off the - headphone outputs if no headphones are present). - -This is done by splitting the jacks up into three things working -together: the jack itself represented by a struct snd_soc_jack, sets of -snd_soc_jack_pins representing DAPM endpoints to update and blocks of -code providing jack reporting mechanisms. - -For example, a system may have a stereo headset jack with two reporting -mechanisms, one for the headphone and one for the microphone. Some -systems won't be able to use their speaker output while a headphone is -connected and so will want to make sure to update both speaker and -headphone when the headphone jack status changes. - -The jack - struct snd_soc_jack -============================== - -This represents a physical jack on the system and is what is visible to -user space. The jack itself is completely passive, it is set up by the -machine driver and updated by jack detection methods. - -Jacks are created by the machine driver calling snd_soc_jack_new(). - -snd_soc_jack_pin -================ - -These represent a DAPM pin to update depending on some of the status -bits supported by the jack. Each snd_soc_jack has zero or more of these -which are updated automatically. They are created by the machine driver -and associated with the jack using snd_soc_jack_add_pins(). The status -of the endpoint may configured to be the opposite of the jack status if -required (eg, enabling a built in microphone if a microphone is not -connected via a jack). - -Jack detection methods -====================== - -Actual jack detection is done by code which is able to monitor some -input to the system and update a jack by calling snd_soc_jack_report(), -specifying a subset of bits to update. The jack detection code should -be set up by the machine driver, taking configuration for the jack to -update and the set of things to report when the jack is connected. - -Often this is done based on the status of a GPIO - a handler for this is -provided by the snd_soc_jack_add_gpio() function. Other methods are -also available, for example integrated into CODECs. One example of -CODEC integrated jack detection can be see in the WM8350 driver. - -Each jack may have multiple reporting mechanisms, though it will need at -least one to be useful. - -Machine drivers -=============== - -These are all hooked together by the machine driver depending on the -system hardware. The machine driver will set up the snd_soc_jack and -the list of pins to update then set up one or more jack detection -mechanisms to update that jack based on their current status. diff --git a/Documentation/sound/soc/index.rst b/Documentation/sound/soc/index.rst index 0055abe16e7e..85ec51764e83 100644 --- a/Documentation/sound/soc/index.rst +++ b/Documentation/sound/soc/index.rst @@ -15,3 +15,4 @@ The documentation is spilt into the following sections:- machine pops-clicks clocking + jack diff --git a/Documentation/sound/soc/jack.rst b/Documentation/sound/soc/jack.rst new file mode 100644 index 000000000000..644b99ecba35 --- /dev/null +++ b/Documentation/sound/soc/jack.rst @@ -0,0 +1,72 @@ +=================== +ASoC jack detection +=================== + +ALSA has a standard API for representing physical jacks to user space, +the kernel side of which can be seen in include/sound/jack.h. ASoC +provides a version of this API adding two additional features: + + - It allows more than one jack detection method to work together on one + user visible jack. In embedded systems it is common for multiple + to be present on a single jack but handled by separate bits of + hardware. + + - Integration with DAPM, allowing DAPM endpoints to be updated + automatically based on the detected jack status (eg, turning off the + headphone outputs if no headphones are present). + +This is done by splitting the jacks up into three things working +together: the jack itself represented by a struct snd_soc_jack, sets of +snd_soc_jack_pins representing DAPM endpoints to update and blocks of +code providing jack reporting mechanisms. + +For example, a system may have a stereo headset jack with two reporting +mechanisms, one for the headphone and one for the microphone. Some +systems won't be able to use their speaker output while a headphone is +connected and so will want to make sure to update both speaker and +headphone when the headphone jack status changes. + +The jack - struct snd_soc_jack +============================== + +This represents a physical jack on the system and is what is visible to +user space. The jack itself is completely passive, it is set up by the +machine driver and updated by jack detection methods. + +Jacks are created by the machine driver calling snd_soc_jack_new(). + +snd_soc_jack_pin +================ + +These represent a DAPM pin to update depending on some of the status +bits supported by the jack. Each snd_soc_jack has zero or more of these +which are updated automatically. They are created by the machine driver +and associated with the jack using snd_soc_jack_add_pins(). The status +of the endpoint may configured to be the opposite of the jack status if +required (eg, enabling a built in microphone if a microphone is not +connected via a jack). + +Jack detection methods +====================== + +Actual jack detection is done by code which is able to monitor some +input to the system and update a jack by calling snd_soc_jack_report(), +specifying a subset of bits to update. The jack detection code should +be set up by the machine driver, taking configuration for the jack to +update and the set of things to report when the jack is connected. + +Often this is done based on the status of a GPIO - a handler for this is +provided by the snd_soc_jack_add_gpio() function. Other methods are +also available, for example integrated into CODECs. One example of +CODEC integrated jack detection can be see in the WM8350 driver. + +Each jack may have multiple reporting mechanisms, though it will need at +least one to be useful. + +Machine drivers +=============== + +These are all hooked together by the machine driver depending on the +system hardware. The machine driver will set up the snd_soc_jack and +the list of pins to update then set up one or more jack detection +mechanisms to update that jack based on their current status.