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authorTakashi Iwai <tiwai@suse.de>2009-11-01 05:11:07 -0500
committerTakashi Iwai <tiwai@suse.de>2009-11-01 05:11:07 -0500
commite87a3dd33eab30b4db539500064a9584867e4f2c (patch)
tree2f7ad16e46ae30518ff63bb5391b63f7f7cc74dd /Documentation/i2c
parentb14f5de731ae657d498d18d713c6431bfbeefb4b (diff)
parent3d00941371a765779c4e3509214c7e5793cce1fe (diff)
Merge branch 'fix/misc' into topic/misc
Diffstat (limited to 'Documentation/i2c')
-rw-r--r--Documentation/i2c/busses/i2c-piix42
-rw-r--r--Documentation/i2c/chips/eeprom96
-rw-r--r--Documentation/i2c/chips/max6875108
-rw-r--r--Documentation/i2c/chips/pca953958
-rw-r--r--Documentation/i2c/chips/pcf857465
-rw-r--r--Documentation/i2c/chips/pcf857569
-rw-r--r--Documentation/i2c/instantiating-devices2
7 files changed, 3 insertions, 397 deletions
diff --git a/Documentation/i2c/busses/i2c-piix4 b/Documentation/i2c/busses/i2c-piix4
index f889481762b5..c5b37c570554 100644
--- a/Documentation/i2c/busses/i2c-piix4
+++ b/Documentation/i2c/busses/i2c-piix4
@@ -8,6 +8,8 @@ Supported adapters:
8 Datasheet: Only available via NDA from ServerWorks 8 Datasheet: Only available via NDA from ServerWorks
9 * ATI IXP200, IXP300, IXP400, SB600, SB700 and SB800 southbridges 9 * ATI IXP200, IXP300, IXP400, SB600, SB700 and SB800 southbridges
10 Datasheet: Not publicly available 10 Datasheet: Not publicly available
11 * AMD SB900
12 Datasheet: Not publicly available
11 * Standard Microsystems (SMSC) SLC90E66 (Victory66) southbridge 13 * Standard Microsystems (SMSC) SLC90E66 (Victory66) southbridge
12 Datasheet: Publicly available at the SMSC website http://www.smsc.com 14 Datasheet: Publicly available at the SMSC website http://www.smsc.com
13 15
diff --git a/Documentation/i2c/chips/eeprom b/Documentation/i2c/chips/eeprom
deleted file mode 100644
index f7e8104b5764..000000000000
--- a/Documentation/i2c/chips/eeprom
+++ /dev/null
@@ -1,96 +0,0 @@
1Kernel driver eeprom
2====================
3
4Supported chips:
5 * Any EEPROM chip in the designated address range
6 Prefix: 'eeprom'
7 Addresses scanned: I2C 0x50 - 0x57
8 Datasheets: Publicly available from:
9 Atmel (www.atmel.com),
10 Catalyst (www.catsemi.com),
11 Fairchild (www.fairchildsemi.com),
12 Microchip (www.microchip.com),
13 Philips (www.semiconductor.philips.com),
14 Rohm (www.rohm.com),
15 ST (www.st.com),
16 Xicor (www.xicor.com),
17 and others.
18
19 Chip Size (bits) Address
20 24C01 1K 0x50 (shadows at 0x51 - 0x57)
21 24C01A 1K 0x50 - 0x57 (Typical device on DIMMs)
22 24C02 2K 0x50 - 0x57
23 24C04 4K 0x50, 0x52, 0x54, 0x56
24 (additional data at 0x51, 0x53, 0x55, 0x57)
25 24C08 8K 0x50, 0x54 (additional data at 0x51, 0x52,
26 0x53, 0x55, 0x56, 0x57)
27 24C16 16K 0x50 (additional data at 0x51 - 0x57)
28 Sony 2K 0x57
29
30 Atmel 34C02B 2K 0x50 - 0x57, SW write protect at 0x30-37
31 Catalyst 34FC02 2K 0x50 - 0x57, SW write protect at 0x30-37
32 Catalyst 34RC02 2K 0x50 - 0x57, SW write protect at 0x30-37
33 Fairchild 34W02 2K 0x50 - 0x57, SW write protect at 0x30-37
34 Microchip 24AA52 2K 0x50 - 0x57, SW write protect at 0x30-37
35 ST M34C02 2K 0x50 - 0x57, SW write protect at 0x30-37
36
37
38Authors:
39 Frodo Looijaard <frodol@dds.nl>,
40 Philip Edelbrock <phil@netroedge.com>,
41 Jean Delvare <khali@linux-fr.org>,
42 Greg Kroah-Hartman <greg@kroah.com>,
43 IBM Corp.
44
45Description
46-----------
47
48This is a simple EEPROM module meant to enable reading the first 256 bytes
49of an EEPROM (on a SDRAM DIMM for example). However, it will access serial
50EEPROMs on any I2C adapter. The supported devices are generically called
5124Cxx, and are listed above; however the numbering for these
52industry-standard devices may vary by manufacturer.
53
54This module was a programming exercise to get used to the new project
55organization laid out by Frodo, but it should be at least completely
56effective for decoding the contents of EEPROMs on DIMMs.
57
58DIMMS will typically contain a 24C01A or 24C02, or the 34C02 variants.
59The other devices will not be found on a DIMM because they respond to more
60than one address.
61
62DDC Monitors may contain any device. Often a 24C01, which responds to all 8
63addresses, is found.
64
65Recent Sony Vaio laptops have an EEPROM at 0x57. We couldn't get the
66specification, so it is guess work and far from being complete.
67
68The Microchip 24AA52/24LCS52, ST M34C02, and others support an additional
69software write protect register at 0x30 - 0x37 (0x20 less than the memory
70location). The chip responds to "write quick" detection at this address but
71does not respond to byte reads. If this register is present, the lower 128
72bytes of the memory array are not write protected. Any byte data write to
73this address will write protect the memory array permanently, and the
74device will no longer respond at the 0x30-37 address. The eeprom driver
75does not support this register.
76
77Lacking functionality:
78
79* Full support for larger devices (24C04, 24C08, 24C16). These are not
80typically found on a PC. These devices will appear as separate devices at
81multiple addresses.
82
83* Support for really large devices (24C32, 24C64, 24C128, 24C256, 24C512).
84These devices require two-byte address fields and are not supported.
85
86* Enable Writing. Again, no technical reason why not, but making it easy
87to change the contents of the EEPROMs (on DIMMs anyway) also makes it easy
88to disable the DIMMs (potentially preventing the computer from booting)
89until the values are restored somehow.
90
91Use:
92
93After inserting the module (and any other required SMBus/i2c modules), you
94should have some EEPROM directories in /sys/bus/i2c/devices/* of names such
95as "0-0050". Inside each of these is a series of files, the eeprom file
96contains the binary data from EEPROM.
diff --git a/Documentation/i2c/chips/max6875 b/Documentation/i2c/chips/max6875
deleted file mode 100644
index 10ca43cd1a72..000000000000
--- a/Documentation/i2c/chips/max6875
+++ /dev/null
@@ -1,108 +0,0 @@
1Kernel driver max6875
2=====================
3
4Supported chips:
5 * Maxim MAX6874, MAX6875
6 Prefix: 'max6875'
7 Addresses scanned: None (see below)
8 Datasheet:
9 http://pdfserv.maxim-ic.com/en/ds/MAX6874-MAX6875.pdf
10
11Author: Ben Gardner <bgardner@wabtec.com>
12
13
14Description
15-----------
16
17The Maxim MAX6875 is an EEPROM-programmable power-supply sequencer/supervisor.
18It provides timed outputs that can be used as a watchdog, if properly wired.
19It also provides 512 bytes of user EEPROM.
20
21At reset, the MAX6875 reads the configuration EEPROM into its configuration
22registers. The chip then begins to operate according to the values in the
23registers.
24
25The Maxim MAX6874 is a similar, mostly compatible device, with more intputs
26and outputs:
27 vin gpi vout
28MAX6874 6 4 8
29MAX6875 4 3 5
30
31See the datasheet for more information.
32
33
34Sysfs entries
35-------------
36
37eeprom - 512 bytes of user-defined EEPROM space.
38
39
40General Remarks
41---------------
42
43Valid addresses for the MAX6875 are 0x50 and 0x52.
44Valid addresses for the MAX6874 are 0x50, 0x52, 0x54 and 0x56.
45The driver does not probe any address, so you must force the address.
46
47Example:
48$ modprobe max6875 force=0,0x50
49
50The MAX6874/MAX6875 ignores address bit 0, so this driver attaches to multiple
51addresses. For example, for address 0x50, it also reserves 0x51.
52The even-address instance is called 'max6875', the odd one is 'dummy'.
53
54
55Programming the chip using i2c-dev
56----------------------------------
57
58Use the i2c-dev interface to access and program the chips.
59Reads and writes are performed differently depending on the address range.
60
61The configuration registers are at addresses 0x00 - 0x45.
62Use i2c_smbus_write_byte_data() to write a register and
63i2c_smbus_read_byte_data() to read a register.
64The command is the register number.
65
66Examples:
67To write a 1 to register 0x45:
68 i2c_smbus_write_byte_data(fd, 0x45, 1);
69
70To read register 0x45:
71 value = i2c_smbus_read_byte_data(fd, 0x45);
72
73
74The configuration EEPROM is at addresses 0x8000 - 0x8045.
75The user EEPROM is at addresses 0x8100 - 0x82ff.
76
77Use i2c_smbus_write_word_data() to write a byte to EEPROM.
78
79The command is the upper byte of the address: 0x80, 0x81, or 0x82.
80The data word is the lower part of the address or'd with data << 8.
81 cmd = address >> 8;
82 val = (address & 0xff) | (data << 8);
83
84Example:
85To write 0x5a to address 0x8003:
86 i2c_smbus_write_word_data(fd, 0x80, 0x5a03);
87
88
89Reading data from the EEPROM is a little more complicated.
90Use i2c_smbus_write_byte_data() to set the read address and then
91i2c_smbus_read_byte() or i2c_smbus_read_i2c_block_data() to read the data.
92
93Example:
94To read data starting at offset 0x8100, first set the address:
95 i2c_smbus_write_byte_data(fd, 0x81, 0x00);
96
97And then read the data
98 value = i2c_smbus_read_byte(fd);
99
100 or
101
102 count = i2c_smbus_read_i2c_block_data(fd, 0x84, 16, buffer);
103
104The block read should read 16 bytes.
1050x84 is the block read command.
106
107See the datasheet for more details.
108
diff --git a/Documentation/i2c/chips/pca9539 b/Documentation/i2c/chips/pca9539
deleted file mode 100644
index 6aff890088b1..000000000000
--- a/Documentation/i2c/chips/pca9539
+++ /dev/null
@@ -1,58 +0,0 @@
1Kernel driver pca9539
2=====================
3
4NOTE: this driver is deprecated and will be dropped soon, use
5drivers/gpio/pca9539.c instead.
6
7Supported chips:
8 * Philips PCA9539
9 Prefix: 'pca9539'
10 Addresses scanned: none
11 Datasheet:
12 http://www.semiconductors.philips.com/acrobat/datasheets/PCA9539_2.pdf
13
14Author: Ben Gardner <bgardner@wabtec.com>
15
16
17Description
18-----------
19
20The Philips PCA9539 is a 16 bit low power I/O device.
21All 16 lines can be individually configured as an input or output.
22The input sense can also be inverted.
23The 16 lines are split between two bytes.
24
25
26Detection
27---------
28
29The PCA9539 is difficult to detect and not commonly found in PC machines,
30so you have to pass the I2C bus and address of the installed PCA9539
31devices explicitly to the driver at load time via the force=... parameter.
32
33
34Sysfs entries
35-------------
36
37Each is a byte that maps to the 8 I/O bits.
38A '0' suffix is for bits 0-7, while '1' is for bits 8-15.
39
40input[01] - read the current value
41output[01] - sets the output value
42direction[01] - direction of each bit: 1=input, 0=output
43invert[01] - toggle the input bit sense
44
45input reads the actual state of the line and is always available.
46The direction defaults to input for all channels.
47
48
49General Remarks
50---------------
51
52Note that each output, direction, and invert entry controls 8 lines.
53You should use the read, modify, write sequence.
54For example. to set output bit 0 of 1.
55 val=$(cat output0)
56 val=$(( $val | 1 ))
57 echo $val > output0
58
diff --git a/Documentation/i2c/chips/pcf8574 b/Documentation/i2c/chips/pcf8574
deleted file mode 100644
index 235815c075ff..000000000000
--- a/Documentation/i2c/chips/pcf8574
+++ /dev/null
@@ -1,65 +0,0 @@
1Kernel driver pcf8574
2=====================
3
4Supported chips:
5 * Philips PCF8574
6 Prefix: 'pcf8574'
7 Addresses scanned: none
8 Datasheet: Publicly available at the Philips Semiconductors website
9 http://www.semiconductors.philips.com/pip/PCF8574P.html
10
11 * Philips PCF8574A
12 Prefix: 'pcf8574a'
13 Addresses scanned: none
14 Datasheet: Publicly available at the Philips Semiconductors website
15 http://www.semiconductors.philips.com/pip/PCF8574P.html
16
17Authors:
18 Frodo Looijaard <frodol@dds.nl>,
19 Philip Edelbrock <phil@netroedge.com>,
20 Dan Eaton <dan.eaton@rocketlogix.com>,
21 Aurelien Jarno <aurelien@aurel32.net>,
22 Jean Delvare <khali@linux-fr.org>,
23
24
25Description
26-----------
27The PCF8574(A) is an 8-bit I/O expander for the I2C bus produced by Philips
28Semiconductors. It is designed to provide a byte I2C interface to up to 16
29separate devices (8 x PCF8574 and 8 x PCF8574A).
30
31This device consists of a quasi-bidirectional port. Each of the eight I/Os
32can be independently used as an input or output. To setup an I/O as an
33input, you have to write a 1 to the corresponding output.
34
35For more informations see the datasheet.
36
37
38Accessing PCF8574(A) via /sys interface
39-------------------------------------
40
41The PCF8574(A) is plainly impossible to detect ! Stupid chip.
42So, you have to pass the I2C bus and address of the installed PCF857A
43and PCF8574A devices explicitly to the driver at load time via the
44force=... parameter.
45
46On detection (i.e. insmod, modprobe et al.), directories are being
47created for each detected PCF8574(A):
48
49/sys/bus/i2c/devices/<0>-<1>/
50where <0> is the bus the chip was detected on (e. g. i2c-0)
51and <1> the chip address ([20..27] or [38..3f]):
52
53(example: /sys/bus/i2c/devices/1-0020/)
54
55Inside these directories, there are two files each:
56read and write (and one file with chip name).
57
58The read file is read-only. Reading gives you the current I/O input
59if the corresponding output is set as 1, otherwise the current output
60value, that is to say 0.
61
62The write file is read/write. Writing a value outputs it on the I/O
63port. Reading returns the last written value. As it is not possible
64to read this value from the chip, you need to write at least once to
65this file before you can read back from it.
diff --git a/Documentation/i2c/chips/pcf8575 b/Documentation/i2c/chips/pcf8575
deleted file mode 100644
index 40b268eb276f..000000000000
--- a/Documentation/i2c/chips/pcf8575
+++ /dev/null
@@ -1,69 +0,0 @@
1About the PCF8575 chip and the pcf8575 kernel driver
2====================================================
3
4The PCF8575 chip is produced by the following manufacturers:
5
6 * Philips NXP
7 http://www.nxp.com/#/pip/cb=[type=product,path=50807/41735/41850,final=PCF8575_3]|pip=[pip=PCF8575_3][0]
8
9 * Texas Instruments
10 http://focus.ti.com/docs/prod/folders/print/pcf8575.html
11
12
13Some vendors sell small PCB's with the PCF8575 mounted on it. You can connect
14such a board to a Linux host via e.g. an USB to I2C interface. Examples of
15PCB boards with a PCF8575:
16
17 * SFE Breakout Board for PCF8575 I2C Expander by RobotShop
18 http://www.robotshop.ca/home/products/robot-parts/electronics/adapters-converters/sfe-pcf8575-i2c-expander-board.html
19
20 * Breakout Board for PCF8575 I2C Expander by Spark Fun Electronics
21 http://www.sparkfun.com/commerce/product_info.php?products_id=8130
22
23
24Description
25-----------
26The PCF8575 chip is a 16-bit I/O expander for the I2C bus. Up to eight of
27these chips can be connected to the same I2C bus. You can find this
28chip on some custom designed hardware, but you won't find it on PC
29motherboards.
30
31The PCF8575 chip consists of a 16-bit quasi-bidirectional port and an I2C-bus
32interface. Each of the sixteen I/O's can be independently used as an input or
33an output. To set up an I/O pin as an input, you have to write a 1 to the
34corresponding output.
35
36For more information please see the datasheet.
37
38
39Detection
40---------
41
42There is no method known to detect whether a chip on a given I2C address is
43a PCF8575 or whether it is any other I2C device, so you have to pass the I2C
44bus and address of the installed PCF8575 devices explicitly to the driver at
45load time via the force=... parameter.
46
47/sys interface
48--------------
49
50For each address on which a PCF8575 chip was found or forced the following
51files will be created under /sys:
52* /sys/bus/i2c/devices/<bus>-<address>/read
53* /sys/bus/i2c/devices/<bus>-<address>/write
54where bus is the I2C bus number (0, 1, ...) and address is the four-digit
55hexadecimal representation of the 7-bit I2C address of the PCF8575
56(0020 .. 0027).
57
58The read file is read-only. Reading it will trigger an I2C read and will hence
59report the current input state for the pins configured as inputs, and the
60current output value for the pins configured as outputs.
61
62The write file is read-write. Writing a value to it will configure all pins
63as output for which the corresponding bit is zero. Reading the write file will
64return the value last written, or -EAGAIN if no value has yet been written to
65the write file.
66
67On module initialization the configuration of the chip is not changed -- the
68chip is left in the state it was already configured in through either power-up
69or through previous I2C write actions.
diff --git a/Documentation/i2c/instantiating-devices b/Documentation/i2c/instantiating-devices
index c740b7b41088..e89490270aba 100644
--- a/Documentation/i2c/instantiating-devices
+++ b/Documentation/i2c/instantiating-devices
@@ -188,7 +188,7 @@ segment, the address is sufficient to uniquely identify the device to be
188deleted. 188deleted.
189 189
190Example: 190Example:
191# echo eeprom 0x50 > /sys/class/i2c-adapter/i2c-3/new_device 191# echo eeprom 0x50 > /sys/bus/i2c/devices/i2c-3/new_device
192 192
193While this interface should only be used when in-kernel device declaration 193While this interface should only be used when in-kernel device declaration
194can't be done, there is a variety of cases where it can be helpful: 194can't be done, there is a variety of cases where it can be helpful: