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authorMarek Vasut <marex@denx.de>2013-11-04 14:29:12 +0100
committerHeiko Schocher <hs@denx.de>2013-11-13 06:08:31 +0100
commit124913556c4b99909f40b4bf4ceaefe2b555d6f8 (patch)
treedb5e072f22de6055075a620e21004ced7026e096 /doc/README.commands
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i2c: mxs_i2c: Squash endless loop
The endless waiting for a bit to be set can cause a hang, add a timeout so we prevent such situation. A testcase for such a hang is below. The testcase assumes a device to be present at address 0x50 and a device to NOT be present at address 0x42 . Also note that the "sleep 1" induced delays are imperative for this bug to manifest . i2c read 0x42 0x0.2 0x10 0x42000000 ; sleep 1 ; \ i2c read 0x50 0x0.2 0x10 0x42000000 ; sleep 1 ; \ i2c read 0x42 0x0.2 0x10 0x42000000 The expected result of the above command is: Error reading the chip. Error reading the chip. While without this patch, we observe a hang in the last read from 0x42 precisely when waiting for this bit to be set. Signed-off-by: Marek Vasut <marex@denx.de> Cc: Fabio Estevam <fabio.estevam@freescale.com> Cc: Heiko Schocher <hs@denx.de> Cc: Stefano Babic <sbabic@denx.de>
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