The cardlist section is important for some boards, because they may require extra modprobe parameters. Improve the docs to mention that. Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@xxxxxxxxxx> --- Documentation/admin-guide/media/cardlist.rst | 76 ++++++++++++++++++-- 1 file changed, 71 insertions(+), 5 deletions(-) diff --git a/Documentation/admin-guide/media/cardlist.rst b/Documentation/admin-guide/media/cardlist.rst index 527188ee9697..4beef18fc46d 100644 --- a/Documentation/admin-guide/media/cardlist.rst +++ b/Documentation/admin-guide/media/cardlist.rst @@ -1,22 +1,88 @@ .. SPDX-License-Identifier: GPL-2.0 +========== Cards List ========== +The media subsystem provide support for lots of PCI and USB drivers, plus +platform-specific drivers. It also contains several ancillary I²C drivers. + +This section contains a list of some of those supported drivers. + +USB drivers +=========== + +The USB boards are identified by an identification called USB ID. + +The ``lsusb`` command allows identifying the USB IDs:: + + $ lsusb + ... + Bus 001 Device 015: ID 046d:082d Logitech, Inc. HD Pro Webcam C920 + Bus 001 Device 074: ID 2040:b131 Hauppauge + Bus 001 Device 075: ID 2013:024f PCTV Systems nanoStick T2 290e + ... + +Unfortunately, sometimes the same USB ID is used by different products. +So, several media drivers allow passing a ``card=`` parameter, in order +to setup a card number that would match the correct settings for an +specific board. + .. toctree:: :maxdepth: 1 au0828-cardlist + cx231xx-cardlist + em28xx-cardlist + tm6000-cardlist + usbvision-cardlist + gspca-cardlist + +PCI drivers +=========== + +The PCI boards are identified by an identification called PCI ID. + +The ``lspci`` command allows identifying the PCI IDs:: + + $ lspci -nn + ... + 00:0b.0 Multimedia video controller: Brooktree Corporation Bt878 Video Capture [1822:0026] (rev 11) + ... + +Unfortunately, sometimes the same PCI ID is used by different products. +So, several media drivers allow passing a ``card=`` parameter, in order +to setup a card number that would match the correct settings for an +specific board. + +.. toctree:: + :maxdepth: 1 + bttv-cardlist cx18-cardlist - cx231xx-cardlist cx23885-cardlist cx88-cardlist - em28xx-cardlist ivtv-cardlist saa7134-cardlist saa7164-cardlist - tm6000-cardlist + +I²C drivers +=========== + +The I²C (Inter-Integrated Circuit) bus is a three-wires bus used internally +at the media cards for communication between different chips. While the bus +is not visible to the Linux Kernel, drivers need to send and receive +commands via the bus. The Linux Kernel driver abstraction has support to +implement different drivers for each component inside an I²C bus, as if +the bus were visible to the main system board. + +One of the problems with I²C devices is that sometimes the same device may +work with different I²C hardware. This is common, for example, on devices +that comes with a tuner for North America market, and another one for +Europe. Some drivers have a ``tuner=`` modprobe parameter to allow using a +different tuner number in order to address such issue. + +.. toctree:: + :maxdepth: 1 + tuner-cardlist - usbvision-cardlist - gspca-cardlist -- 2.25.2
