diff options
| author | Sebastian Andrzej Siewior <bigeasy@linutronix.de> | 2013-12-19 16:28:29 +0100 |
|---|---|---|
| committer | Lee Jones <lee.jones@linaro.org> | 2014-01-07 08:41:15 +0000 |
| commit | 7e170c6e4f7501bea900aa66b2b27a6ce5001e25 (patch) | |
| tree | 76eea8291945b24d8bbbf215243f7239c9728a08 /drivers/input/touchscreen | |
| parent | 3466bd2273b81a0a29d0e134ba1c78b64b84f40b (diff) | |
mfd: ti_am335x_tscadc: Don't read back REG_SE
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 not required read-back I introduce a "set once" variant which
does not update the cache mask. After the conversation completes, the
bit is removed from the SE register anyway and we don't plan a new
conversation "any time soon". The current set function is renamed to
set_cache to distinguish the two operations.
This is a small preparation for a larger sync-rework.
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Acked-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Acked-by: Jonathan Cameron <jic23@kernel.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Diffstat (limited to 'drivers/input/touchscreen')
| -rw-r--r-- | drivers/input/touchscreen/ti_am335x_tsc.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/drivers/input/touchscreen/ti_am335x_tsc.c b/drivers/input/touchscreen/ti_am335x_tsc.c index 68beadaabceb..2ca5a7bee04e 100644 --- a/drivers/input/touchscreen/ti_am335x_tsc.c +++ b/drivers/input/touchscreen/ti_am335x_tsc.c @@ -198,7 +198,7 @@ static void titsc_step_config(struct titsc *ts_dev) /* The steps1 … end and bit 0 for TS_Charge */ stepenable = (1 << (end_step + 2)) - 1; ts_dev->step_mask = stepenable; - am335x_tsc_se_set(ts_dev->mfd_tscadc, ts_dev->step_mask); + am335x_tsc_se_set_cache(ts_dev->mfd_tscadc, ts_dev->step_mask); } static void titsc_read_coordinates(struct titsc *ts_dev, @@ -322,7 +322,7 @@ static irqreturn_t titsc_irq(int irq, void *dev) if (irqclr) { titsc_writel(ts_dev, REG_IRQSTATUS, irqclr); - am335x_tsc_se_set(ts_dev->mfd_tscadc, ts_dev->step_mask); + am335x_tsc_se_set_cache(ts_dev->mfd_tscadc, ts_dev->step_mask); return IRQ_HANDLED; } return IRQ_NONE; |