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i2c: busses with dynamic ids should start after fixed ids for DT

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Make sure dynamic ids do not interfere with fixed ones and let them
start after the highest fixed id. This patch might cause different
bus-numbers than before for dynamic ids, however it fixes a bug. Assume:

- fixed id0 defers probe
- fixed id1 succeeds and registers a muxed bus with dynamic id
- muxed bus gets id0
- fixed id0 wants to probe again, but its fixed id is gone now
- fixed id0 probe fails

With this patch, the fixed ids are always reserved in the DT case.
For legacy board init, we already have a mechanism like this in
i2c_register_board_info().

Reported-by: Bob Feretich <bob.feretich@rafresearch.com>
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
This commit is contained in:
Wolfram Sang 2015-03-12 17:17:59 +01:00 committed by Wolfram Sang
parent 351d224f64
commit 03bde7c31a
1 changed files with 7 additions and 0 deletions
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7
drivers/i2c/i2c-core.c
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@ -1878,6 +1878,13 @@ static int __init i2c_init(void)
{
int retval;
retval = of_alias_get_highest_id("i2c");
down_write(&__i2c_board_lock);
if (retval >= __i2c_first_dynamic_bus_num)
__i2c_first_dynamic_bus_num = retval + 1;
up_write(&__i2c_board_lock);
retval = bus_register(&i2c_bus_type);
if (retval)
return retval;