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Based on kernel version 4.3. Page generated on 2015-11-02 12:49 EST.

1	Kernel driver i2c-parport
2	
3	Author: Jean Delvare <jdelvare@suse.de>
4	
5	This is a unified driver for several i2c-over-parallel-port adapters,
6	such as the ones made by Philips, Velleman or ELV. This driver is
7	meant as a replacement for the older, individual drivers:
8	 * i2c-philips-par
9	 * i2c-elv
10	 * i2c-velleman
11	 * video/i2c-parport (NOT the same as this one, dedicated to home brew
12	                      teletext adapters)
13	
14	It currently supports the following devices:
15	 * (type=0) Philips adapter
16	 * (type=1) home brew teletext adapter
17	 * (type=2) Velleman K8000 adapter
18	 * (type=3) ELV adapter
19	 * (type=4) Analog Devices ADM1032 evaluation board
20	 * (type=5) Analog Devices evaluation boards: ADM1025, ADM1030, ADM1031
21	 * (type=6) Barco LPT->DVI (K5800236) adapter
22	 * (type=7) One For All JP1 parallel port adapter
23	 * (type=8) VCT-jig
24	
25	These devices use different pinout configurations, so you have to tell
26	the driver what you have, using the type module parameter. There is no
27	way to autodetect the devices. Support for different pinout configurations
28	can be easily added when needed.
29	
30	Earlier kernels defaulted to type=0 (Philips).  But now, if the type
31	parameter is missing, the driver will simply fail to initialize.
32	
33	SMBus alert support is available on adapters which have this line properly
34	connected to the parallel port's interrupt pin.
35	
36	
37	Building your own adapter
38	-------------------------
39	
40	If you want to build you own i2c-over-parallel-port adapter, here is
41	a sample electronics schema (credits go to Sylvain Munaut):
42	
43	Device                                                      PC
44	Side          ___________________Vdd (+)                    Side
45	               |    |         |
46	              ---  ---       ---
47	              | |  | |       | |
48	              |R|  |R|       |R|
49	              | |  | |       | |
50	              ---  ---       ---
51	               |    |         |
52	               |    |    /|   |
53	SCL  ----------x--------o |-----------x-------------------  pin 2
54	                    |    \|   |       |
55	                    |         |       |
56	                    |   |\    |       |
57	SDA  ----------x----x---| o---x---------------------------  pin 13
58	               |        |/            |
59	               |                      |
60	               |         /|           |
61	               ---------o |----------------x--------------  pin 3
62	                         \|           |    |
63	                                      |    |
64	                                     ---  ---
65	                                     | |  | |
66	                                     |R|  |R|
67	                                     | |  | |
68	                                     ---  ---
69	                                      |    | 
70	                                     ###  ###
71	                                     GND  GND
72	        
73	Remarks:
74	 - This is the exact pinout and electronics used on the Analog Devices
75	   evaluation boards.
76	                   /|
77	 - All inverters -o |- must be 74HC05, they must be open collector output.
78	                   \|
79	 - All resitors are 10k.
80	 - Pins 18-25 of the parallel port connected to GND.
81	 - Pins 4-9 (D2-D7) could be used as VDD is the driver drives them high.
82	   The ADM1032 evaluation board uses D4-D7. Beware that the amount of
83	   current you can draw from the parallel port is limited. Also note that
84	   all connected lines MUST BE driven at the same state, else you'll short
85	   circuit the output buffers! So plugging the I2C adapter after loading
86	   the i2c-parport module might be a good safety since data line state
87	   prior to init may be unknown. 
88	 - This is 5V!
89	 - Obviously you cannot read SCL (so it's not really standard-compliant).
90	   Pretty easy to add, just copy the SDA part and use another input pin.
91	   That would give (ELV compatible pinout):
92	
93	
94	Device                                                      PC
95	Side          ______________________________Vdd (+)         Side
96	               |    |            |    |
97	              ---  ---          ---  ---
98	              | |  | |          | |  | |
99	              |R|  |R|          |R|  |R|
100	              | |  | |          | |  | |
101	              ---  ---          ---  ---
102	               |    |            |    |
103	               |    |      |\    |    |
104	SCL  ----------x--------x--| o---x------------------------  pin 15
105	                    |   |  |/         | 
106	                    |   |             |
107	                    |   |   /|        |
108	                    |   ---o |-------------x--------------  pin 2
109	                    |       \|        |    |
110	                    |                 |    |
111	                    |                 |    |
112	                    |      |\         |    |
113	SDA  ---------------x---x--| o--------x-------------------  pin 10
114	                        |  |/              |
115	                        |                  |
116	                        |   /|             |
117	                        ---o |------------------x---------  pin 3
118	                            \|             |    |
119	                                           |    |
120	                                          ---  ---
121	                                          | |  | |
122	                                          |R|  |R|
123	                                          | |  | |
124	                                          ---  ---
125	                                           |    | 
126	                                          ###  ###
127	                                          GND  GND
128	
129	
130	If possible, you should use the same pinout configuration as existing
131	adapters do, so you won't even have to change the code.
132	
133	
134	Similar (but different) drivers
135	-------------------------------
136	
137	This driver is NOT the same as the i2c-pport driver found in the i2c
138	package. The i2c-pport driver makes use of modern parallel port features so
139	that you don't need additional electronics. It has other restrictions
140	however, and was not ported to Linux 2.6 (yet).
141	
142	This driver is also NOT the same as the i2c-pcf-epp driver found in the
143	lm_sensors package. The i2c-pcf-epp driver doesn't use the parallel port as
144	an I2C bus directly. Instead, it uses it to control an external I2C bus
145	master. That driver was not ported to Linux 2.6 (yet) either.
146	
147	
148	Legacy documentation for Velleman adapter
149	-----------------------------------------
150	
151	Useful links:
152	Velleman                http://www.velleman.be/
153	Velleman K8000 Howto    http://howto.htlw16.ac.at/k8000-howto.html
154	
155	The project has lead to new libs for the Velleman K8000 and K8005:
156	  LIBK8000 v1.99.1 and LIBK8005 v0.21
157	With these libs, you can control the K8000 interface card and the K8005
158	stepper motor card with the simple commands which are in the original
159	Velleman software, like SetIOchannel, ReadADchannel, SendStepCCWFull and
160	many more, using /dev/velleman.
161	  http://home.wanadoo.nl/hihihi/libk8000.htm
162	  http://home.wanadoo.nl/hihihi/libk8005.htm
163	  http://struyve.mine.nu:8080/index.php?block=k8000
164	  http://sourceforge.net/projects/libk8005/
165	
166	
167	One For All JP1 parallel port adapter
168	-------------------------------------
169	
170	The JP1 project revolves around a set of remote controls which expose
171	the I2C bus their internal configuration EEPROM lives on via a 6 pin
172	jumper in the battery compartment. More details can be found at:
173	
174	http://www.hifi-remote.com/jp1/
175	
176	Details of the simple parallel port hardware can be found at:
177	
178	http://www.hifi-remote.com/jp1/hardware.shtml
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