Commit 45c03c65 authored by Wolfram Sang's avatar Wolfram Sang
Browse files

i2c: testunit: return current command on read messages 



Because the testunit can start tests in the future via the DELAY
register, it may happen that a command is still pending. Support
detecting that by returning the number of a command in progress (if
there is one).

Signed-off-by: default avatarWolfram Sang <wsa+renesas@sang-engineering.com>
parent 6b21470a

Documentation/i2c/slave-testunit-backend.rst

+8 −6
Original line number Diff line number Diff line
@@ -20,11 +20,13 @@ Instantiating the device is regular. Example for bus 0, address 0x30:: 


  # echo "slave-testunit 0x1030" > /sys/bus/i2c/devices/i2c-0/new_device



After that, you will have a write-only device listening. Reads will just return

an 8-bit version number of the testunit. When writing, the device consists of 4

8-bit registers and, except for some "partial" commands, all registers must be

written to start a testcase, i.e. you usually write 4 bytes to the device. The

registers are:

After that, you will have the device listening. Reading will return a single

byte. Its value is 0 if the testunit is idle, otherwise the command number of

the currently running command.



When writing, the device consists of 4 8-bit registers and, except for some

"partial" commands, all registers must be written to start a testcase, i.e. you

usually write 4 bytes to the device. The registers are:



.. csv-table::

  :header: "Offset", "Name", "Description"
@@ -170,4 +172,4 @@ are not equivalent to a REPEATED START. As an example, this returns just the 
default response::



  # i2cset -y 0 0x30 4 0 0 i; i2cget -y 0 0x30

  0x01
 
  0x00

drivers/i2c/i2c-slave-testunit.c

+2 −2
Original line number Diff line number Diff line
@@ -15,7 +15,6 @@ 
#include <linux/slab.h>

#include <linux/workqueue.h> /* FIXME: is system_long_wq the best choice? */



#define TU_CUR_VERSION 0x01

#define TU_VERSION_MAX_LENGTH 128



enum testunit_cmds {
@@ -159,7 +158,8 @@ static int i2c_slave_testunit_slave_cb(struct i2c_client *client, 
		else if (is_proc_call)

			*val = tu->regs[TU_REG_DATAH];

		else

			*val = TU_CUR_VERSION;

			*val = test_bit(TU_FLAG_IN_PROCESS, &tu->flags) ?

					tu->regs[TU_REG_CMD] : 0;

		break;

	}