This patch adds new parameters that allow to address typical hardware
design differences: touch screens may be wired or oriented differently
(portrait or landscape). And usually the active area of the touch is a
little larger than the active area of the LCD. This results in the touch
coordinates that have some significant deviation from LCD coordinates.
Usually this is addressed in user space by a calibration tool (e.g. tslib
or xinput-calibrator) but some systems don't have these tools or require
that the screen is already roughly calibrated (e.g. Replicant) to operate
the device until a better calibration can be done. And, some systems
react very strangely if the touch event stream reports coordinates
outside of the active area.

This makes it necessry to be able to configure:
1. swapping x and y wires (coordinate values)
2. flipping of x (left - right) or y (top - bottom) or even both
3. define an active area so that an uncalibrated screen already
roughly matches the LCD to be useful.
4. clip reported coordinates to the active area.

If none of the new parameters is defined (in DT) or set in a board file,
the driver behaves the same as without this patch.

Author (1&2): H. Nikolaus Schaller <[email protected]>
Author (3&4): Paul Kocialkowski <[email protected]>

Signed-off-by: H. Nikolaus Schaller <[email protected]>
---
 drivers/input/touchscreen/tsc2007.c | 89 +++++++++++++++++++++++++++++++++++--
 include/linux/i2c/tsc2007.h         |  6 +++
 2 files changed, 91 insertions(+), 4 deletions(-)

diff --git a/drivers/input/touchscreen/tsc2007.c 
b/drivers/input/touchscreen/tsc2007.c
index 1bf9906..cc0cc3c 100644
--- a/drivers/input/touchscreen/tsc2007.c
+++ b/drivers/input/touchscreen/tsc2007.c
@@ -74,6 +74,12 @@ struct tsc2007 {
 
        u16                     model;
        u16                     x_plate_ohms;
+       bool                    swap_xy;        /* swap x and y axis */
+       u16                     min_x;
+       u16                     min_y;
+       u16                     min_rt;
+       u16                     max_x;
+       u16                     max_y;
        u16                     max_rt;
        unsigned long           poll_period;
        int                     fuzzx;
@@ -193,11 +199,50 @@ static irqreturn_t tsc2007_soft_irq(int irq, void *handle)
                        break;
                }
 
-               if (rt <= ts->max_rt) {
+               if (rt <= max(ts->min_rt, ts->max_rt)) {
                        dev_dbg(&ts->client->dev,
                                "DOWN point(%4d,%4d), pressure (%4u)\n",
                                tc.x, tc.y, rt);
 
+                       if (ts->swap_xy) {
+                               /* swap before applying the range limits */
+                               u16 h = tc.x;
+
+                               tc.x = tc.y;
+                               tc.y = h;
+                       }
+
+                       /* flip and/or clip X */
+                       if (ts->max_x < ts->min_x)
+                               tc.x = (ts->min_x - tc.x) + ts->max_x;
+
+                       if (tc.x > max(ts->min_x, ts->max_x))
+                               tc.x = max(ts->min_x, ts->max_x);
+                       else if (tc.x < min(ts->min_x, ts->max_x))
+                               tc.x = min(ts->min_x, ts->max_x);
+
+                       /* flip and/or clip Y */
+                       if (ts->max_y < ts->min_y)
+                               tc.y = (ts->min_y - tc.y) + ts->max_y;
+
+                       if (tc.y > max(ts->min_y, ts->max_y))
+                               tc.y = max(ts->min_y, ts->max_y);
+                       else if (tc.y < min(ts->min_y, ts->max_y))
+                               tc.y = min(ts->min_y, ts->max_y);
+
+                       /* clip Z */
+                       if (ts->max_rt < ts->min_rt)
+                               rt = (ts->min_rt - rt) + ts->max_rt;
+
+                       if (rt > max(ts->min_rt, ts->max_rt))
+                               rt = max(ts->min_rt, ts->max_rt);
+                       else if (rt < min(ts->min_rt, ts->max_rt))
+                               rt = min(ts->min_rt, ts->max_rt);
+
+                       dev_dbg(&ts->client->dev,
+                                       "shaped point(%4d,%4d), pressure 
(%4u)\n",
+                                       tc.x, tc.y, rt);
+
                        input_report_key(input, BTN_TOUCH, 1);
                        input_report_abs(input, ABS_X, tc.x);
                        input_report_abs(input, ABS_Y, tc.y);
@@ -299,6 +344,24 @@ static int tsc2007_probe_dt(struct i2c_client *client, 
struct tsc2007 *ts)
                return -EINVAL;
        }
 
+       ts->swap_xy = of_property_read_bool(np, "ti,swap-xy");
+
+       if (!of_property_read_u32(np, "ti,min-x", &val32))
+               ts->min_x = val32;
+       if (!of_property_read_u32(np, "ti,max-x", &val32))
+               ts->max_x = val32;
+       else
+               ts->max_x = MAX_12BIT;
+
+       if (!of_property_read_u32(np, "ti,min-y", &val32))
+               ts->min_y = val32;
+       if (!of_property_read_u32(np, "ti,max-y", &val32))
+               ts->max_y = val32;
+       else
+               ts->max_y = MAX_12BIT;
+
+       if (!of_property_read_u32(np, "ti,min-rt", &val32))
+               ts->min_rt = val32;
        if (!of_property_read_u32(np, "ti,max-rt", &val32))
                ts->max_rt = val32;
        else
@@ -325,6 +388,16 @@ static int tsc2007_probe_dt(struct i2c_client *client, 
struct tsc2007 *ts)
                return -EINVAL;
        }
 
+       dev_dbg(&client->dev,
+                       "min/max_x (%4d,%4d)\n",
+                       ts->min_x, ts->max_x);
+       dev_dbg(&client->dev,
+                       "min/max_y (%4d,%4d)\n",
+                       ts->min_y, ts->max_y);
+       dev_dbg(&client->dev,
+                       "min/max_rt (%4d,%4d)\n",
+                       ts->min_rt, ts->max_rt);
+
        ts->gpio = of_get_gpio(np, 0);
        if (gpio_is_valid(ts->gpio))
                ts->get_pendown_state = tsc2007_get_pendown_state_gpio;
@@ -349,6 +422,12 @@ static int tsc2007_probe_pdev(struct i2c_client *client, 
struct tsc2007 *ts,
 {
        ts->model             = pdata->model;
        ts->x_plate_ohms      = pdata->x_plate_ohms;
+       ts->swap_xy           = pdata->swap_xy;
+       ts->min_x             = pdata->min_x ? : 0;
+       ts->min_y             = pdata->min_y ? : 0;
+       ts->min_rt            = pdata->min_rt ? : 0;
+       ts->max_x             = pdata->max_x ? : MAX_12BIT;
+       ts->max_y             = pdata->max_y ? : MAX_12BIT;
        ts->max_rt            = pdata->max_rt ? : MAX_12BIT;
        ts->poll_period       = pdata->poll_period ? : 1;
        ts->get_pendown_state = pdata->get_pendown_state;
@@ -422,9 +501,11 @@ static int tsc2007_probe(struct i2c_client *client,
        input_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);
        input_dev->keybit[BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH);
 
-       input_set_abs_params(input_dev, ABS_X, 0, MAX_12BIT, ts->fuzzx, 0);
-       input_set_abs_params(input_dev, ABS_Y, 0, MAX_12BIT, ts->fuzzy, 0);
-       input_set_abs_params(input_dev, ABS_PRESSURE, 0, MAX_12BIT,
+       input_set_abs_params(input_dev, ABS_X, min(ts->min_x, ts->max_x),
+                            max(ts->min_x, ts->max_x), ts->fuzzx, 0);
+       input_set_abs_params(input_dev, ABS_Y, min(ts->min_y, ts->max_y),
+                            max(ts->min_y, ts->max_y), ts->fuzzy, 0);
+       input_set_abs_params(input_dev, ABS_PRESSURE, ts->min_rt, ts->max_rt,
                             ts->fuzzz, 0);
 
        if (pdata) {
diff --git a/include/linux/i2c/tsc2007.h b/include/linux/i2c/tsc2007.h
index 4f35b6a..5ce7b79 100644
--- a/include/linux/i2c/tsc2007.h
+++ b/include/linux/i2c/tsc2007.h
@@ -6,6 +6,12 @@
 struct tsc2007_platform_data {
        u16     model;                          /* 2007. */
        u16     x_plate_ohms;   /* must be non-zero value */
+       bool    swap_xy;        /* swap x and y axis */
+       u16     min_x;  /* min and max values to reported to user space */
+       u16     min_y;
+       u16     min_rt;
+       u16     max_x;
+       u16     max_y;
        u16     max_rt; /* max. resistance above which samples are ignored */
        unsigned long poll_period; /* time (in ms) between samples */
        int     fuzzx; /* fuzz factor for X, Y and pressure axes */
-- 
1.9.3

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