linux/drivers/i2c
Shinya Kuribayashi 201d6a70b7 i2c-designware: Process all i2c_msg messages in the interrupt handler
Currently we process the first i2c_dw_xfer_msg() in i2c_dw_xfer(),
but in this case there is a possibility to be interrupted by certain
interrupts.  As described before in this patchset, we need to keep
providing new transmit data within a given time period, otherwise Tx
FIFO underrun takes place and STOP condition will be generated on the
bus, even if we have more bytes to be written.

In order to exclude all such possibilities, change TX_EMPTY interrupt
usage as below:

* DW_IC_INTR_DEFAULT_MASK: Define a default interrupt mask set, and
  put TX_EMPTY there.

* i2c_dw_xfer_init: Enable DW_IC_INTR_DEFAULT_MASK prior to initiating
  a new I2C transaction.  The first TX_EMPTY will be triggered shortly.
  With the help of it, we can make the first call to i2c_dw_xfer_msg()
  in the interrupt handler.

* i2c_dw_xfer_msg: Fixup intr_mask operation accordingly.  Make sure
  that TX_EMPTY operations need to be reversed.

* request_irq: Set IRQF_DISABLED so that we could load transmit data
  into Tx FIFO without being distracted by other interrupts.

* Remove i2c_dw_xfer_msg() in i2c_dw_xfer().

Signed-off-by: Shinya Kuribayashi <shinya.kuribayashi@necel.com>
Signed-off-by: Ben Dooks <ben-linux@fluff.org>
2009-12-09 00:19:12 +00:00
..
algos i2c-algo-pca: Let PCA9564 recover from unacked data byte (state 0x30) 2009-05-05 08:39:25 +02:00
busses i2c-designware: Process all i2c_msg messages in the interrupt handler 2009-12-09 00:19:12 +00:00
chips i2c/chips: Move ds1682 to drivers/misc 2009-12-06 17:06:16 +01:00
i2c-boardinfo.c i2c: Use rwsem instead of mutex for board info 2009-06-19 16:58:20 +02:00
i2c-core.c i2c: Refactor for_each callbacks 2009-12-06 17:06:27 +01:00
i2c-core.h i2c: Use rwsem instead of mutex for board info 2009-06-19 16:58:20 +02:00
i2c-dev.c i2c: Remove big kernel lock from i2cdev_open 2009-12-06 17:06:26 +01:00
Kconfig i2c: Prevent priority inversion on top of bus lock 2009-12-06 17:06:22 +01:00
Makefile