From 7e170c6e4f7501bea900aa66b2b27a6ce5001e25 Mon Sep 17 00:00:00 2001 From: Sebastian Andrzej Siewior Date: Thu, 19 Dec 2013 16:28:29 +0100 Subject: 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 Acked-by: Dmitry Torokhov Acked-by: Jonathan Cameron Signed-off-by: Lee Jones --- drivers/input/touchscreen/ti_am335x_tsc.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'drivers/input') 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; -- cgit v1.2.3