forked from luck/tmp_suning_uos_patched
i2c: testunit: improve documentation
Mention that new CMDs will be NACKed while the old one is still on-going, that the I2C address parameter of READ_BYTES is 7 bit only, and reword one paragraph to be more precise. Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com> Signed-off-by: Wolfram Sang <wsa@kernel.org>
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@ -20,10 +20,10 @@ Instantiating the device is regular. Example for bus 0, address 0x30:
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# echo "slave-testunit 0x1030" > /sys/bus/i2c/devices/i2c-0/new_device
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After that, you will have a write-only device listening. Reads will return an
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8-bit version number. The device consists of 4 8-bit registers and all must be
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written to start a testcase, i.e. you must always write 4 bytes to the device.
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The registers are:
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After that, you will have a write-only device listening. Reads will just return
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an 8-bit version number of the testunit. When writing, the device consists of 4
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8-bit registers and all must be written to start a testcase, i.e. you must
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always write 4 bytes to the device. The registers are:
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0x00 CMD - which test to trigger
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0x01 DATAL - configuration byte 1 for the test
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@ -35,6 +35,9 @@ Using 'i2cset' from the i2c-tools package, the generic command looks like:
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# i2cset -y <bus_num> <testunit_address> <CMD> <DATAL> <DATAH> <DELAY> i
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DELAY is a generic parameter which will delay the execution of the test in CMD.
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While a command is running (including the delay), new commands will not be
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acknowledged. You need to wait until the old one is completed.
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The commands are described in the following section. An invalid command will
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result in the transfer not being acknowledged.
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@ -44,7 +47,7 @@ Commands
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0x00 NOOP (reserved for future use)
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0x01 READ_BYTES (also needs master mode)
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DATAL - address to read data from
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DATAL - address to read data from (lower 7 bits, highest bit currently unused)
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DATAH - number of bytes to read
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This is useful to test if your bus master driver is handling multi-master
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