[deliverable/linux.git] / Documentation / i2c / busses / i2c-parport

Kernel driver i2c-parport

Author: Jean Delvare <jdelvare@suse.de>

This is a unified driver for several i2c-over-parallel-port adapters,
such as the ones made by Philips, Velleman or ELV. This driver is
meant as a replacement for the older, individual drivers:
 * i2c-philips-par
 * i2c-elv
 * i2c-velleman
 * video/i2c-parport (NOT the same as this one, dedicated to home brew
                      teletext adapters)

It currently supports the following devices:
 * (type=0) Philips adapter
 * (type=1) home brew teletext adapter
 * (type=2) Velleman K8000 adapter
 * (type=3) ELV adapter
 * (type=4) Analog Devices ADM1032 evaluation board
 * (type=5) Analog Devices evaluation boards: ADM1025, ADM1030, ADM1031
 * (type=6) Barco LPT->DVI (K5800236) adapter
 * (type=7) One For All JP1 parallel port adapter

These devices use different pinout configurations, so you have to tell
the driver what you have, using the type module parameter. There is no
way to autodetect the devices. Support for different pinout configurations
can be easily added when needed.

Earlier kernels defaulted to type=0 (Philips).  But now, if the type
parameter is missing, the driver will simply fail to initialize.

SMBus alert support is available on adapters which have this line properly
connected to the parallel port's interrupt pin.


Building your own adapter
-------------------------

If you want to build you own i2c-over-parallel-port adapter, here is
a sample electronics schema (credits go to Sylvain Munaut):

Device                                                      PC
Side          ___________________Vdd (+)                    Side
               |    |         |
              ---  ---       ---
              | |  | |       | |
              |R|  |R|       |R|
              | |  | |       | |
              ---  ---       ---
               |    |         |
               |    |    /|   |
SCL  ----------x--------o |-----------x-------------------  pin 2
                    |    \|   |       |
                    |         |       |
                    |   |\    |       |
SDA  ----------x----x---| o---x---------------------------  pin 13
               |        |/            |
               |                      |
               |         /|           |
               ---------o |----------------x--------------  pin 3
                         \|           |    |
                                      |    |
                                     ---  ---
                                     | |  | |
                                     |R|  |R|
                                     | |  | |
                                     ---  ---
                                      |    | 
                                     ###  ###
                                     GND  GND
        
Remarks:
 - This is the exact pinout and electronics used on the Analog Devices
   evaluation boards.
                   /|
 - All inverters -o |- must be 74HC05, they must be open collector output.
                   \|
 - All resitors are 10k.
 - Pins 18-25 of the parallel port connected to GND.
 - Pins 4-9 (D2-D7) could be used as VDD is the driver drives them high.
   The ADM1032 evaluation board uses D4-D7. Beware that the amount of
   current you can draw from the parallel port is limited. Also note that
   all connected lines MUST BE driven at the same state, else you'll short
   circuit the output buffers! So plugging the I2C adapter after loading
   the i2c-parport module might be a good safety since data line state
   prior to init may be unknown. 
 - This is 5V!
 - Obviously you cannot read SCL (so it's not really standard-compliant).
   Pretty easy to add, just copy the SDA part and use another input pin.
   That would give (ELV compatible pinout):


Device                                                      PC
Side          ______________________________Vdd (+)         Side
               |    |            |    |
              ---  ---          ---  ---
              | |  | |          | |  | |
              |R|  |R|          |R|  |R|
              | |  | |          | |  | |
              ---  ---          ---  ---
               |    |            |    |
               |    |      |\    |    |
SCL  ----------x--------x--| o---x------------------------  pin 15
                    |   |  |/         | 
                    |   |             |
                    |   |   /|        |
                    |   ---o |-------------x--------------  pin 2
                    |       \|        |    |
                    |                 |    |
                    |                 |    |
                    |      |\         |    |
SDA  ---------------x---x--| o--------x-------------------  pin 10
                        |  |/              |
                        |                  |
                        |   /|             |
                        ---o |------------------x---------  pin 3
                            \|             |    |
                                           |    |
                                          ---  ---
                                          | |  | |
                                          |R|  |R|
                                          | |  | |
                                          ---  ---
                                           |    | 
                                          ###  ###
                                          GND  GND


If possible, you should use the same pinout configuration as existing
adapters do, so you won't even have to change the code.


Similar (but different) drivers
-------------------------------

This driver is NOT the same as the i2c-pport driver found in the i2c
package. The i2c-pport driver makes use of modern parallel port features so
that you don't need additional electronics. It has other restrictions
however, and was not ported to Linux 2.6 (yet).

This driver is also NOT the same as the i2c-pcf-epp driver found in the
lm_sensors package. The i2c-pcf-epp driver doesn't use the parallel port as
an I2C bus directly. Instead, it uses it to control an external I2C bus
master. That driver was not ported to Linux 2.6 (yet) either.


Legacy documentation for Velleman adapter
-----------------------------------------

Useful links:
Velleman                http://www.velleman.be/
Velleman K8000 Howto    http://howto.htlw16.ac.at/k8000-howto.html

The project has lead to new libs for the Velleman K8000 and K8005:
  LIBK8000 v1.99.1 and LIBK8005 v0.21
With these libs, you can control the K8000 interface card and the K8005
stepper motor card with the simple commands which are in the original
Velleman software, like SetIOchannel, ReadADchannel, SendStepCCWFull and
many more, using /dev/velleman.
  http://home.wanadoo.nl/hihihi/libk8000.htm
  http://home.wanadoo.nl/hihihi/libk8005.htm
  http://struyve.mine.nu:8080/index.php?block=k8000
  http://sourceforge.net/projects/libk8005/


One For All JP1 parallel port adapter
-------------------------------------

The JP1 project revolves around a set of remote controls which expose
the I2C bus their internal configuration EEPROM lives on via a 6 pin
jumper in the battery compartment. More details can be found at:

http://www.hifi-remote.com/jp1/

Details of the simple parallel port hardware can be found at:

http://www.hifi-remote.com/jp1/hardware.shtml
Commit	Line	Data
1da177e4 LT	1	Kernel driver i2c-parport
1da177e4 LT	2
7c81c60f	3	Author: Jean Delvare <jdelvare@suse.de>
1da177e4 LT	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:
e97b81dd MH	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
55249cf7	22	* (type=7) One For All JP1 parallel port adapter
1da177e4 LT	23
	24	These devices use different pinout configurations, so you have to tell
	25	the driver what you have, using the type module parameter. There is no
	26	way to autodetect the devices. Support for different pinout configurations
	27	can be easily added when needed.
	28
e97b81dd MH	29	Earlier kernels defaulted to type=0 (Philips). But now, if the type
	30	parameter is missing, the driver will simply fail to initialize.
	31
35859254 JD	32	SMBus alert support is available on adapters which have this line properly
	33	connected to the parallel port's interrupt pin.
	34
1da177e4 LT	35
	36	Building your own adapter
	37	-------------------------
	38
	39	If you want to build you own i2c-over-parallel-port adapter, here is
	40	a sample electronics schema (credits go to Sylvain Munaut):
	41
	42	Device PC
	43	Side ___________________Vdd (+) Side
	44	\| \| \|
	45	--- --- ---
	46	\| \| \| \| \| \|
	47	\|R\| \|R\| \|R\|
	48	\| \| \| \| \| \|
	49	--- --- ---
	50	\| \| \|
	51	\| \| /\| \|
	52	SCL ----------x--------o \|-----------x------------------- pin 2
	53	\| \\| \| \|
	54	\| \| \|
	55	\| \|\ \| \|
	56	SDA ----------x----x---\| o---x--------------------------- pin 13
	57	\| \|/ \|
	58	\| \|
	59	\| /\| \|
	60	---------o \|----------------x-------------- pin 3
	61	\\| \| \|
	62	\| \|
	63	--- ---
	64	\| \| \| \|
	65	\|R\| \|R\|
	66	\| \| \| \|
	67	--- ---
	68	\| \|
	69	### ###
	70	GND GND
	71
	72	Remarks:
	73	- This is the exact pinout and electronics used on the Analog Devices
	74	evaluation boards.
	75	/\|
	76	- All inverters -o \|- must be 74HC05, they must be open collector output.
	77	\\|
	78	- All resitors are 10k.
	79	- Pins 18-25 of the parallel port connected to GND.
	80	- Pins 4-9 (D2-D7) could be used as VDD is the driver drives them high.
	81	The ADM1032 evaluation board uses D4-D7. Beware that the amount of
	82	current you can draw from the parallel port is limited. Also note that
	83	all connected lines MUST BE driven at the same state, else you'll short
	84	circuit the output buffers! So plugging the I2C adapter after loading
	85	the i2c-parport module might be a good safety since data line state
	86	prior to init may be unknown.
	87	- This is 5V!
	88	- Obviously you cannot read SCL (so it's not really standard-compliant).
	89	Pretty easy to add, just copy the SDA part and use another input pin.
	90	That would give (ELV compatible pinout):
	91
	92
	93	Device PC
	94	Side ______________________________Vdd (+) Side
	95	\| \| \| \|
	96	--- --- --- ---
	97	\| \| \| \| \| \| \| \|
	98	\|R\| \|R\| \|R\| \|R\|
99	\| \| \| \| \| \| \| \|
100	--- --- --- ---
101	\| \| \| \|
102	\| \| \|\ \| \|
103	SCL ----------x--------x--\| o---x------------------------ pin 15
104	\| \| \|/ \|
105	\| \| \|
106	\| \| /\| \|
107	\| ---o \|-------------x-------------- pin 2
108	\| \\| \| \|
109	\| \| \|
110	\| \| \|
111	\| \|\ \| \|
112	SDA ---------------x---x--\| o--------x------------------- pin 10
113	\| \|/ \|
114	\| \|
115	\| /\| \|
116	---o \|------------------x--------- pin 3
117	\\| \| \|
118	\| \|
119	--- ---
120	\| \| \| \|
121	\|R\| \|R\|
122	\| \| \| \|
123	--- ---
124	\| \|
125	### ###
126	GND GND
127
128
129	If possible, you should use the same pinout configuration as existing
130	adapters do, so you won't even have to change the code.
131
132
133	Similar (but different) drivers
134	-------------------------------
135
136	This driver is NOT the same as the i2c-pport driver found in the i2c
137	package. The i2c-pport driver makes use of modern parallel port features so
138	that you don't need additional electronics. It has other restrictions
139	however, and was not ported to Linux 2.6 (yet).
140
141	This driver is also NOT the same as the i2c-pcf-epp driver found in the
142	lm_sensors package. The i2c-pcf-epp driver doesn't use the parallel port as
143	an I2C bus directly. Instead, it uses it to control an external I2C bus
144	master. That driver was not ported to Linux 2.6 (yet) either.
145
146
147	Legacy documentation for Velleman adapter
148	-----------------------------------------
149
150	Useful links:
151	Velleman http://www.velleman.be/
152	Velleman K8000 Howto http://howto.htlw16.ac.at/k8000-howto.html
153
154	The project has lead to new libs for the Velleman K8000 and K8005:
155	LIBK8000 v1.99.1 and LIBK8005 v0.21
156	With these libs, you can control the K8000 interface card and the K8005
157	stepper motor card with the simple commands which are in the original
158	Velleman software, like SetIOchannel, ReadADchannel, SendStepCCWFull and
159	many more, using /dev/velleman.
160	http://home.wanadoo.nl/hihihi/libk8000.htm
161	http://home.wanadoo.nl/hihihi/libk8005.htm
162	http://struyve.mine.nu:8080/index.php?block=k8000
163	http://sourceforge.net/projects/libk8005/
55249cf7 JM	164
	165
	166	One For All JP1 parallel port adapter
	167	-------------------------------------
	168
	169	The JP1 project revolves around a set of remote controls which expose
	170	the I2C bus their internal configuration EEPROM lives on via a 6 pin
	171	jumper in the battery compartment. More details can be found at:
	172
	173	http://www.hifi-remote.com/jp1/
	174
	175	Details of the simple parallel port hardware can be found at:
	176
	177	http://www.hifi-remote.com/jp1/hardware.shtml