[PATCH v3 1/6] input: touchscreen: ti_am335x_tsc Interchange touchscreen and ADC steps

Vignesh R
2014-11-11T08:33:59Z

From: Brad Griffis <bgriffis@ti.com>

This patch makes the initial changes required to workaround TSC-false
pen-up interrupts. It is required to implement these changes in order to
remove udelay in the TSC interrupt handler and false pen-up events.
The charge step is to be executed immediately after sampling X+. Hence
TSC is made to use higher numbered steps (steps 5 to 16 for 5 co-ordinate
readouts, 4 wire TSC configuration) and ADC to use lower ones. Further
X co-ordinate readouts must be the last to be sampled, thus co-ordinates
are sampled in the order Y-Z-X.

Signed-off-by: Brad Griffis <bgriffis@ti.com>
[vigneshr@ti.com: Ported the patch from v3.12 to v3.18rc2]

Signed-off-by: Vignesh R <vigneshr@ti.com>
Acked-by: Jonathan Cameron <jic23@kernel.org>
---
drivers/iio/adc/ti_am335x_adc.c | 5 ++--
drivers/input/touchscreen/ti_am335x_tsc.c | 42 ++++++++++++++++++-------------
2 files changed, 26 insertions(+), 21 deletions(-)

diff --git a/drivers/iio/adc/ti_am335x_adc.c b/drivers/iio/adc/ti_am335x_adc.c
index b730864731e8..adba23246474 100644
--- a/drivers/iio/adc/ti_am335x_adc.c
+++ b/drivers/iio/adc/ti_am335x_adc.c
@@ -86,19 +86,18 @@ static void tiadc_step_config(struct iio_dev *indio_dev)
{
struct tiadc_device *adc_dev = iio_priv(indio_dev);
unsigned int stepconfig;
- int i, steps;
+ int i, steps = 0;

/*
* There are 16 configurable steps and 8 analog input
* lines available which are shared between Touchscreen and ADC.
*
- * Steps backwards i.e. from 16 towards 0 are used by ADC
+ * Steps forwards i.e. from 0 towards 16 are used by ADC
* depending on number of input lines needed.
* Channel would represent which analog input
* needs to be given to ADC to digitalize data.
*/

- steps = TOTAL_STEPS - adc_dev->channels;
if (iio_buffer_enabled(indio_dev))
stepconfig = STEPCONFIG_AVG_16 | STEPCONFIG_FIFO1
| STEPCONFIG_MODE_SWCNT;
diff --git a/drivers/input/touchscreen/ti_am335x_tsc.c b/drivers/input/touchscreen/ti_am335x_tsc.c
index 2ce649520fe0..1aeac9675fe7 100644
--- a/drivers/input/touchscreen/ti_am335x_tsc.c
+++ b/drivers/input/touchscreen/ti_am335x_tsc.c
@@ -121,7 +121,7 @@ static void titsc_step_config(struct titsc *ts_dev)
{
unsigned int config;
int i;
- int end_step;
+ int end_step, first_step, tsc_steps;
u32 stepenable;

config = STEPCONFIG_MODE_HWSYNC |
@@ -140,9 +140,11 @@ static void titsc_step_config(struct titsc *ts_dev)
break;
}

- /* 1 … coordinate_readouts is for X */
- end_step = ts_dev->coordinate_readouts;
- for (i = 0; i < end_step; i++) {
+ tsc_steps = ts_dev->coordinate_readouts * 2 + 2;
+ first_step = TOTAL_STEPS - tsc_steps;
+ /* Steps 16 to 16-coordinate_readouts is for X */
+ end_step = first_step + tsc_steps;
+ for (i = end_step - ts_dev->coordinate_readouts; i < end_step; i++) {
titsc_writel(ts_dev, REG_STEPCONFIG(i), config);
titsc_writel(ts_dev, REG_STEPDELAY(i), STEPCONFIG_OPENDLY);
}
@@ -164,9 +166,9 @@ static void titsc_step_config(struct titsc *ts_dev)
break;
}

- /* coordinate_readouts … coordinate_readouts * 2 is for Y */
- end_step = ts_dev->coordinate_readouts * 2;
- for (i = ts_dev->coordinate_readouts; i < end_step; i++) {
+ /* 1 ... coordinate_readouts is for Y */
+ end_step = first_step + ts_dev->coordinate_readouts;
+ for (i = first_step; i < end_step; i++) {
titsc_writel(ts_dev, REG_STEPCONFIG(i), config);
titsc_writel(ts_dev, REG_STEPDELAY(i), STEPCONFIG_OPENDLY);
}
@@ -179,7 +181,7 @@ static void titsc_step_config(struct titsc *ts_dev)
titsc_writel(ts_dev, REG_CHARGECONFIG, config);
titsc_writel(ts_dev, REG_CHARGEDELAY, CHARGEDLY_OPENDLY);

- /* coordinate_readouts * 2 … coordinate_readouts * 2 + 2 is for Z */
+ /* coordinate_readouts + 1 ... coordinate_readouts + 2 is for Z */
config = STEPCONFIG_MODE_HWSYNC |
STEPCONFIG_AVG_16 | ts_dev->bit_yp |
ts_dev->bit_xn | STEPCONFIG_INM_ADCREFM |
@@ -194,8 +196,11 @@ static void titsc_step_config(struct titsc *ts_dev)
titsc_writel(ts_dev, REG_STEPDELAY(end_step),
STEPCONFIG_OPENDLY);

- /* The steps1 … end and bit 0 for TS_Charge */
- stepenable = (1 << (end_step + 2)) - 1;
+ /* The steps end ... end - readouts * 2 + 2 and bit 0 for TS_Charge */
+ stepenable = 1;
+ for (i = 0; i < tsc_steps; i++)
+ stepenable |= 1 << (first_step + i + 1);
+
ts_dev->step_mask = stepenable;
am335x_tsc_se_set_cache(ts_dev->mfd_tscadc, ts_dev->step_mask);
}
@@ -209,6 +214,7 @@ static void titsc_read_coordinates(struct titsc *ts_dev,
unsigned int read, diff;
unsigned int i, channel;
unsigned int creads = ts_dev->coordinate_readouts;
+ unsigned int first_step = TOTAL_STEPS - (creads * 2 + 2);

*z1 = *z2 = 0;
if (fifocount % (creads * 2 + 2))
@@ -226,7 +232,7 @@ static void titsc_read_coordinates(struct titsc *ts_dev,

channel = (read & 0xf0000) >> 16;
read &= 0xfff;
- if (channel < creads) {
+ if (channel > first_step + creads + 2) {
diff = abs(read - prev_val_x);
if (diff < prev_diff_x) {
prev_diff_x = diff;
@@ -234,19 +240,19 @@ static void titsc_read_coordinates(struct titsc *ts_dev,
}
prev_val_x = read;

- } else if (channel < creads * 2) {
+ } else if (channel == first_step + creads + 1) {
+ *z1 = read;
+
+ } else if (channel == first_step + creads + 2) {
+ *z2 = read;
+
+ } else if (channel > first_step) {
diff = abs(read - prev_val_y);
if (diff < prev_diff_y) {
prev_diff_y = diff;
*y = read;
}
prev_val_y = read;
-
- } else if (channel < creads * 2 + 1) {
- *z1 = read;
-
- } else if (channel < creads * 2 + 2) {
- *z2 = read;
}
}
}
--
1.9.1