Input: ti_am335x_tsc - interchange touchscreen and ADC steps

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 v3.19rc1]
Signed-off-by: Vignesh R <vigneshr@ti.com>
Acked-by: Jonathan Cameron <jic23@kernel.org>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

1 files changed, 24 insertions, 18 deletions

diff --git a/drivers/input/touchscreen/ti_am335x_tsc.c b/drivers/input/touchscreen/ti_am335x_tsc.c
index 004f1346a957..dfbb9fe6a270 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;
                 }
         }
 }