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authorJonathan Neuschäfer <j.neuschaefer@gmx.net>2019-10-04 19:40:55 +0300
committerLinus Walleij <linus.walleij@linaro.org>2019-10-09 12:12:33 +0300
commit5f07224e0fae2a7d475eb21a79ee5a08251d9c44 (patch)
tree0860bb285fa948ec94eb9f4c39bf530afca1bd69 /Documentation/driver-api/gpio
parent14e8c535ff684876d1be9dae475fe666b97c04a9 (diff)
downloadlinux-5f07224e0fae2a7d475eb21a79ee5a08251d9c44.tar.xz
docs: driver-api: Move bt8xxgpio to the gpio directory
Let's declutter Documentation/driver-api a bit. Signed-off-by: Jonathan Neuschäfer <j.neuschaefer@gmx.net> Link: https://lore.kernel.org/r/20191004164059.10397-1-j.neuschaefer@gmx.net Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Diffstat (limited to 'Documentation/driver-api/gpio')
-rw-r--r--Documentation/driver-api/gpio/bt8xxgpio.rst62
-rw-r--r--Documentation/driver-api/gpio/index.rst1
2 files changed, 63 insertions, 0 deletions
diff --git a/Documentation/driver-api/gpio/bt8xxgpio.rst b/Documentation/driver-api/gpio/bt8xxgpio.rst
new file mode 100644
index 000000000000..a845feb074de
--- /dev/null
+++ b/Documentation/driver-api/gpio/bt8xxgpio.rst
@@ -0,0 +1,62 @@
+===================================================================
+A driver for a selfmade cheap BT8xx based PCI GPIO-card (bt8xxgpio)
+===================================================================
+
+For advanced documentation, see http://www.bu3sch.de/btgpio.php
+
+A generic digital 24-port PCI GPIO card can be built out of an ordinary
+Brooktree bt848, bt849, bt878 or bt879 based analog TV tuner card. The
+Brooktree chip is used in old analog Hauppauge WinTV PCI cards. You can easily
+find them used for low prices on the net.
+
+The bt8xx chip does have 24 digital GPIO ports.
+These ports are accessible via 24 pins on the SMD chip package.
+
+
+How to physically access the GPIO pins
+======================================
+
+The are several ways to access these pins. One might unsolder the whole chip
+and put it on a custom PCI board, or one might only unsolder each individual
+GPIO pin and solder that to some tiny wire. As the chip package really is tiny
+there are some advanced soldering skills needed in any case.
+
+The physical pinouts are drawn in the following ASCII art.
+The GPIO pins are marked with G00-G23::
+
+ G G G G G G G G G G G G G G G G G G
+ 0 0 0 0 0 0 0 0 0 0 1 1 1 1 1 1 1 1
+ 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7
+ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
+ ---------------------------------------------------------------------------
+ --| ^ ^ |--
+ --| pin 86 pin 67 |--
+ --| |--
+ --| pin 61 > |-- G18
+ --| |-- G19
+ --| |-- G20
+ --| |-- G21
+ --| |-- G22
+ --| pin 56 > |-- G23
+ --| |--
+ --| Brooktree 878/879 |--
+ --| |--
+ --| |--
+ --| |--
+ --| |--
+ --| |--
+ --| |--
+ --| |--
+ --| |--
+ --| |--
+ --| |--
+ --| |--
+ --| |--
+ --| |--
+ --| O |--
+ --| |--
+ ---------------------------------------------------------------------------
+ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
+ ^
+ This is pin 1
+
diff --git a/Documentation/driver-api/gpio/index.rst b/Documentation/driver-api/gpio/index.rst
index c5b8467f9104..5b61032aa4ea 100644
--- a/Documentation/driver-api/gpio/index.rst
+++ b/Documentation/driver-api/gpio/index.rst
@@ -13,6 +13,7 @@ Contents:
board
drivers-on-gpio
legacy
+ bt8xxgpio
Core
====