1577a7ad3SMauro Carvalho Chehab.. SPDX-License-Identifier: GPL-2.0 2577a7ad3SMauro Carvalho Chehab 3577a7ad3SMauro Carvalho ChehabThe bttv driver 4577a7ad3SMauro Carvalho Chehab=============== 5577a7ad3SMauro Carvalho Chehab 6577a7ad3SMauro Carvalho Chehabbttv and sound mini howto 7577a7ad3SMauro Carvalho Chehab------------------------- 8577a7ad3SMauro Carvalho Chehab 9577a7ad3SMauro Carvalho ChehabThere are a lot of different bt848/849/878/879 based boards available. 10577a7ad3SMauro Carvalho ChehabMaking video work often is not a big deal, because this is handled 11577a7ad3SMauro Carvalho Chehabcompletely by the bt8xx chip, which is common on all boards. But 12577a7ad3SMauro Carvalho Chehabsound is handled in slightly different ways on each board. 13577a7ad3SMauro Carvalho Chehab 14577a7ad3SMauro Carvalho ChehabTo handle the grabber boards correctly, there is a array tvcards[] in 15577a7ad3SMauro Carvalho Chehabbttv-cards.c, which holds the information required for each board. 16577a7ad3SMauro Carvalho ChehabSound will work only, if the correct entry is used (for video it often 17577a7ad3SMauro Carvalho Chehabmakes no difference). The bttv driver prints a line to the kernel 184605a610SMauro Carvalho Chehablog, telling which card type is used. Like this one:: 19577a7ad3SMauro Carvalho Chehab 20577a7ad3SMauro Carvalho Chehab bttv0: model: BT848(Hauppauge old) [autodetected] 21577a7ad3SMauro Carvalho Chehab 22577a7ad3SMauro Carvalho ChehabYou should verify this is correct. If it isn't, you have to pass the 234605a610SMauro Carvalho Chehabcorrect board type as insmod argument, ``insmod bttv card=2`` for 24*a169c44eSMauro Carvalho Chehabexample. The file Documentation/admin-guide/media/bttv-cardlist.rst has a list 254605a610SMauro Carvalho Chehabof valid arguments for card. 264605a610SMauro Carvalho Chehab 27577a7ad3SMauro Carvalho ChehabIf your card isn't listed there, you might check the source code for 28577a7ad3SMauro Carvalho Chehabnew entries which are not listed yet. If there isn't one for your 29577a7ad3SMauro Carvalho Chehabcard, you can check if one of the existing entries does work for you 30577a7ad3SMauro Carvalho Chehab(just trial and error...). 31577a7ad3SMauro Carvalho Chehab 32577a7ad3SMauro Carvalho ChehabSome boards have an extra processor for sound to do stereo decoding 33577a7ad3SMauro Carvalho Chehaband other nice features. The msp34xx chips are used by Hauppauge for 34577a7ad3SMauro Carvalho Chehabexample. If your board has one, you might have to load a helper 354605a610SMauro Carvalho Chehabmodule like ``msp3400`` to make sound work. If there isn't one for the 36577a7ad3SMauro Carvalho Chehabchip used on your board: Bad luck. Start writing a new one. Well, 37577a7ad3SMauro Carvalho Chehabyou might want to check the video4linux mailing list archive first... 38577a7ad3SMauro Carvalho Chehab 39577a7ad3SMauro Carvalho ChehabOf course you need a correctly installed soundcard unless you have the 40577a7ad3SMauro Carvalho Chehabspeakers connected directly to the grabber board. Hint: check the 41577a7ad3SMauro Carvalho Chehabmixer settings too. ALSA for example has everything muted by default. 42577a7ad3SMauro Carvalho Chehab 43577a7ad3SMauro Carvalho Chehab 44577a7ad3SMauro Carvalho ChehabHow sound works in detail 45577a7ad3SMauro Carvalho Chehab~~~~~~~~~~~~~~~~~~~~~~~~~ 46577a7ad3SMauro Carvalho Chehab 47577a7ad3SMauro Carvalho ChehabStill doesn't work? Looks like some driver hacking is required. 48577a7ad3SMauro Carvalho ChehabBelow is a do-it-yourself description for you. 49577a7ad3SMauro Carvalho Chehab 50577a7ad3SMauro Carvalho ChehabThe bt8xx chips have 32 general purpose pins, and registers to control 51577a7ad3SMauro Carvalho Chehabthese pins. One register is the output enable register 524605a610SMauro Carvalho Chehab(``BT848_GPIO_OUT_EN``), it says which pins are actively driven by the 534605a610SMauro Carvalho Chehabbt848 chip. Another one is the data register (``BT848_GPIO_DATA``), where 54577a7ad3SMauro Carvalho Chehabyou can get/set the status if these pins. They can be used for input 55577a7ad3SMauro Carvalho Chehaband output. 56577a7ad3SMauro Carvalho Chehab 57577a7ad3SMauro Carvalho ChehabMost grabber board vendors use these pins to control an external chip 58577a7ad3SMauro Carvalho Chehabwhich does the sound routing. But every board is a little different. 59577a7ad3SMauro Carvalho ChehabThese pins are also used by some companies to drive remote control 60577a7ad3SMauro Carvalho Chehabreceiver chips. Some boards use the i2c bus instead of the gpio pins 61577a7ad3SMauro Carvalho Chehabto connect the mux chip. 62577a7ad3SMauro Carvalho Chehab 63577a7ad3SMauro Carvalho ChehabAs mentioned above, there is a array which holds the required 64577a7ad3SMauro Carvalho Chehabinformation for each known board. You basically have to create a new 654605a610SMauro Carvalho Chehabline for your board. The important fields are these two:: 66577a7ad3SMauro Carvalho Chehab 67577a7ad3SMauro Carvalho Chehab struct tvcard 68577a7ad3SMauro Carvalho Chehab { 69577a7ad3SMauro Carvalho Chehab [ ... ] 70577a7ad3SMauro Carvalho Chehab u32 gpiomask; 71577a7ad3SMauro Carvalho Chehab u32 audiomux[6]; /* Tuner, Radio, external, internal, mute, stereo */ 72577a7ad3SMauro Carvalho Chehab }; 73577a7ad3SMauro Carvalho Chehab 74577a7ad3SMauro Carvalho Chehabgpiomask specifies which pins are used to control the audio mux chip. 75577a7ad3SMauro Carvalho ChehabThe corresponding bits in the output enable register 764605a610SMauro Carvalho Chehab(``BT848_GPIO_OUT_EN``) will be set as these pins must be driven by the 77577a7ad3SMauro Carvalho Chehabbt848 chip. 78577a7ad3SMauro Carvalho Chehab 794605a610SMauro Carvalho ChehabThe ``audiomux[]`` array holds the data values for the different inputs 80577a7ad3SMauro Carvalho Chehab(i.e. which pins must be high/low for tuner/mute/...). This will be 814605a610SMauro Carvalho Chehabwritten to the data register (``BT848_GPIO_DATA``) to switch the audio 82577a7ad3SMauro Carvalho Chehabmux. 83577a7ad3SMauro Carvalho Chehab 84577a7ad3SMauro Carvalho Chehab 85577a7ad3SMauro Carvalho ChehabWhat you have to do is figure out the correct values for gpiomask and 86577a7ad3SMauro Carvalho Chehabthe audiomux array. If you have Windows and the drivers four your 87577a7ad3SMauro Carvalho Chehabcard installed, you might to check out if you can read these registers 88577a7ad3SMauro Carvalho Chehabvalues used by the windows driver. A tool to do this is available 894605a610SMauro Carvalho Chehabfrom http://btwincap.sourceforge.net/download.html. 90577a7ad3SMauro Carvalho Chehab 914605a610SMauro Carvalho ChehabYou might also dig around in the ``*.ini`` files of the Windows applications. 92577a7ad3SMauro Carvalho ChehabYou can have a look at the board to see which of the gpio pins are 93577a7ad3SMauro Carvalho Chehabconnected at all and then start trial-and-error ... 94577a7ad3SMauro Carvalho Chehab 95577a7ad3SMauro Carvalho Chehab 96577a7ad3SMauro Carvalho ChehabStarting with release 0.7.41 bttv has a number of insmod options to 97577a7ad3SMauro Carvalho Chehabmake the gpio debugging easier: 98577a7ad3SMauro Carvalho Chehab 994605a610SMauro Carvalho Chehab ================= ============================================== 100577a7ad3SMauro Carvalho Chehab bttv_gpio=0/1 enable/disable gpio debug messages 101577a7ad3SMauro Carvalho Chehab gpiomask=n set the gpiomask value 102577a7ad3SMauro Carvalho Chehab audiomux=i,j,... set the values of the audiomux array 103577a7ad3SMauro Carvalho Chehab audioall=a set the values of the audiomux array (one 104577a7ad3SMauro Carvalho Chehab value for all array elements, useful to check 105577a7ad3SMauro Carvalho Chehab out which effect the particular value has). 1064605a610SMauro Carvalho Chehab ================= ============================================== 107577a7ad3SMauro Carvalho Chehab 1084605a610SMauro Carvalho ChehabThe messages printed with ``bttv_gpio=1`` look like this:: 109577a7ad3SMauro Carvalho Chehab 110577a7ad3SMauro Carvalho Chehab bttv0: gpio: en=00000027, out=00000024 in=00ffffd8 [audio: off] 111577a7ad3SMauro Carvalho Chehab 112577a7ad3SMauro Carvalho Chehab en = output _en_able register (BT848_GPIO_OUT_EN) 113577a7ad3SMauro Carvalho Chehab out = _out_put bits of the data register (BT848_GPIO_DATA), 114577a7ad3SMauro Carvalho Chehab i.e. BT848_GPIO_DATA & BT848_GPIO_OUT_EN 115577a7ad3SMauro Carvalho Chehab in = _in_put bits of the data register, 116577a7ad3SMauro Carvalho Chehab i.e. BT848_GPIO_DATA & ~BT848_GPIO_OUT_EN 117