On Wed, 18 Dec 2013, Sebastian Andrzej Siewior wrote:

The purpose of reg_se_cache has been defeated. It should avoid the
read-back of the register to avoid the latency and the fact that the
bits are reset to 0 after the individual conversation took place.

The reason why this is required like this to work, is that read-back of
the register removes the bits of the ADC so they do not start another
conversation after the register is re-written from the TSC side for the
update.
To avoid the unrequired read-back I introduce a "set adc" variant which
does not update the cache mask. After the conversation completes, the
register bit is removed from the SE reister anyway and we don't plan a
new conversation "any time soon".
This is a small preparation for a larger sync-rework.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
---
 drivers/iio/adc/ti_am335x_adc.c      |  2 +-
 drivers/mfd/ti_am335x_tscadc.c       | 12 ++++++++++--
 include/linux/mfd/ti_am335x_tscadc.h |  1 +
 3 files changed, 12 insertions(+), 3 deletions(-)

Looks about right: Acked-by: Lee Jones [off-list ref]

-- 
Lee Jones
Linaro STMicroelectronics Landing Team Lead
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