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Intel Keem Bay platform supports multi-master operations over same i2c
bus using Synopsys i2c DesignWare IP. When multi-masters initiate i2c
operation simultaneously in a loop, SCL line is stucked low forever
after few i2c operations. Following interrupt sequences are observed
in:
working case: TX_EMPTY, RX_FULL and STOP_DET
non working case: TX_EMPTY, STOP_DET, RX_FULL.
DW_apb_i2c stretches the SCL line when the TX FIFO is empty or when
RX FIFO is full. The DW_apb_i2c master will continue to hold the SCL
line LOW until RX FIFO is read.
Linux kernel i2c DesignWare driver does not handle above non working
sequence. TX_EMPTY, RX_FULL and STOP_DET routine execution are required
in sequence although RX_FULL interrupt is raised after STOP_DET by
hardware. Clear STOP_DET for the following conditions:
(STOP_DET ,RX_FULL, rx_outstanding)
Write Operation: (1, 0, 0)
Read Operation:
RX_FULL followed by STOP_DET: (0, 1, 1) -> (1, 0, 0)
STOP_DET followed by RX_FULL: (1, 0, 1) -> (1, 1, 0)
RX_FULL and STOP_DET together: (1, 1, 1)
Signed-off-by: Tamal Saha <tamal.saha@intel.com>
Signed-off-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
Signed-off-by: Wolfram Sang <wsa@kernel.org>
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| .. | ||
| algos | ||
| busses | ||
| muxes | ||
| i2c-boardinfo.c | ||
| i2c-core-acpi.c | ||
| i2c-core-base.c | ||
| i2c-core-of.c | ||
| i2c-core-slave.c | ||
| i2c-core-smbus.c | ||
| i2c-core.h | ||
| i2c-dev.c | ||
| i2c-mux.c | ||
| i2c-slave-eeprom.c | ||
| i2c-slave-testunit.c | ||
| i2c-smbus.c | ||
| i2c-stub.c | ||
| Kconfig | ||
| Makefile | ||