Lines Matching +full:i2c +full:- +full:fast +full:- +full:mode

1 .. SPDX-License-Identifier: GPL-2.0
4 Linux I2C slave testunit backend
7 by Wolfram Sang <wsa@sang-engineering.com> in 2020
9 This backend can be used to trigger test cases for I2C bus masters which
11 easy to obtain). Examples include multi-master testing, and SMBus Host Notify
12 testing. For some tests, the I2C slave controller must be able to switch
13 between master and slave mode because it needs to send data, too.
21   # echo "slave-testunit 0x1030" > /sys/bus/i2c/devices/i2c-0/new_device
30 		compatible = "slave-testunit";
39 When writing, the device consists of 4 8-bit registers and, except for some
43 .. csv-table::
51 Using 'i2cset' from the i2c-tools package, the generic command looks like::
53   # i2cset -y <bus_num> <testunit_address> <CMD> <DATAL> <DATAH> <DELAY> i
63 --------
73 .. list-table::
74   :header-rows: 1
76   * - CMD
77     - DATAL
78     - DATAH
79     - DELAY
81   * - 0x01
82     - address to read data from (lower 7 bits, highest bit currently unused)
83     - number of bytes to read
84     - n * 10ms
86 Also needs master mode. This is useful to test if your bus master driver is
87 handling multi-master correctly. You can trigger the testunit to read bytes
92   # i2cset -y 0 0x30 1 0x50 0x80 5 i
97 .. list-table::
98   :header-rows: 1
100   * - CMD
101     - DATAL
102     - DATAH
103     - DELAY
105   * - 0x02
106     - low byte of the status word to send
107     - high byte of the status word to send
108     - n * 10ms
110 Also needs master mode. This test will send an SMBUS_HOST_NOTIFY message to the
114   # i2cset -y 0 0x30 2 0x42 0x64 1 i
124 .. list-table::
125   :header-rows: 1
127   * - CMD
128     - DATAL
129     - DATAH
130     - DELAY
132   * - 0x03
133     - 0x01 (i.e. one further byte will be written)
134     - number of bytes to be sent back
135     - leave out, partial command!
144 from length-1 to 0. Here is an example which emulates
145 i2c_smbus_block_process_call() using i2ctransfer (you need i2c-tools v4.2 or
148   # i2ctransfer -y 0 w3@0x30 3 1 0x10 r?
154 .. list-table::
155   :header-rows: 1
157   * - CMD
158     - DATAL
159     - DATAH
160     - DELAY
162   * - 0x04
163     - currently unused
164     - currently unused
165     - leave out, partial command!
174   # i2ctransfer -y 0 w3@0x30 4 0 0 r128
177 If you have i2c-tools 4.4 or later, you can print out the data right away::
179   # i2ctransfer -y -b 0 w3@0x30 4 0 0 r128
180   v6.11.0-rc1-00009-gd37a1b4d3fd0
186   # i2cset -y 0 0x30 4 0 0 i; i2cget -y 0 0x30
192 .. list-table::
193   :header-rows: 1
195   * - CMD
196     - DATAL
197     - DATAH
198     - DELAY
200   * - 0x05
201     - response value (7 MSBs interpreted as I2C address)
202     - currently unused
203     - n * 10ms
216   # i2cset -y 0 0x30 5 0xc9 0x00 100 i
221   smbus_alert 0-000c: SMBALERT# from dev 0x64, flag 1
224 hardware and, thus, may not be able to react to the response of the host fast
228    93:          1  gpio-rcar  26 Edge      smbus_alert