drivers: touchscreen: tsc2007 and ads7846/tsc2046 improvements (use common touchscreen bindings, pre-calibration, spi fix and provide iio raw values)

commit b98abe52fa8e ("Input: add common DT binding for touchscreens") introduced common DT bindings for touchscreens [1] and a helper function to parse the DT.

This has been integrated and interpretation of the inversion (flipping) properties for the x and y axis has been added to accommodate any orientation of the touch in relation to the LCD.

By scaling the min/max ADC values to the screen size it is now possible to pre-calibrate the touch so that is (almost) exactly matches the LCD it is glued onto. This allows to well enough operate the touch before a user space calibration can improve the precision.

calculate_pressure has been renamed to calculate_resistance because that is what it is doing.

[1]: Documentation/devicetree/bindings/input/touchscreen/touchscreen.txt

Signed-off-by H. Nikolaus Schaller <[email protected]>

---
 .../bindings/input/touchscreen/tsc2007.txt         |  20 +--
 drivers/input/touchscreen/tsc2007.c                | 135 +++++++++++++++++----
 include/linux/i2c/tsc2007.h                        |   8 ++
 3 files changed, 135 insertions(+), 28 deletions(-)

Documentation/devicetree/bindings/input/touchscreen/tsc2007.txt +13 -7

index ec365e1..6e9fd55 100644
@@ -6,6 +6,7 @@ Required properties:
 - ti,x-plate-ohms: X-plate resistance in ohms.
 
 Optional properties:
+- generic touch screen properties: see touchscreen binding [2].
 - gpios: the interrupt gpio the chip is connected to (trough the penirq pin).
   The penirq pin goes to low when the panel is touched.
   (see GPIO binding[1] for more details).

@@ -13,17 +14,20 @@ Optional properties:
   (see interrupt binding[0]).
 - interrupts: (gpio) interrupt to which the chip is connected
   (see interrupt binding[0]).
-- ti,max-rt: maximum pressure.
-- ti,fuzzx: specifies the absolute input fuzz x value.
-  If set, it will permit noise in the data up to +- the value given to the fuzz
-  parameter, that is used to filter noise from the event stream.
-- ti,fuzzy: specifies the absolute input fuzz y value.
-- ti,fuzzz: specifies the absolute input fuzz z value.
+- ti,max-rt: maximum pressure resistance above which samples are ignored
+  (default: 4095).
+- ti,report-resistance: report resistance (no pressure = max_rt) instead
+  of pressure (no pressure = 0).
+- ti,min-x: minimum value reported by X axis ADC (default 0).
+- ti,max-x: maximum value reported by X axis ADC (default 4095).
+- ti,min-y: minimum value reported by Y axis ADC (default 0).
+- ti,max-y: maximum value reported by Y axis ADC (default 4095).
 - ti,poll-period: how much time to wait (in milliseconds) before reading again the
-  values from the tsc2007.
+  values from the tsc2007 (default 1).
 
 [0]: Documentation/devicetree/bindings/interrupt-controller/interrupts.txt
 [1]: Documentation/devicetree/bindings/gpio/gpio.txt
+[2]: Documentation/devicetree/bindings/input/touchscreen/touchscreen.txt
 
 Example:
 	&i2c1 {

@@ -35,6 +39,8 @@ Example:
 			interrupts = <0x0 0x8>;
 			gpios = <&gpio4 0 0>;
 			ti,x-plate-ohms = <180>;
+			touchscreen-size-x = <640>;
+			touchscreen-size-y = <480>;
 		};
 
 		/* ... */

drivers/input/touchscreen/tsc2007.c +114 -21

index 5d0cd51..e0c7173 100644
@@ -29,6 +29,7 @@
 #include <linux/of_device.h>
 #include <linux/of.h>
 #include <linux/of_gpio.h>
+#include <linux/input/touchscreen.h>
 
 #define TSC2007_MEASURE_TEMP0		(0x0 << 4)
 #define TSC2007_MEASURE_AUX		(0x2 << 4)

@@ -74,6 +75,14 @@ struct tsc2007 {
 
 	u16			model;
 	u16			x_plate_ohms;
+	bool			swap_xy;
+	bool			invert_x;
+	bool			invert_y;
+	bool			report_resistance;
+	u16			min_x;
+	u16			min_y;
+	u16			max_x;
+	u16			max_y;
 	u16			max_rt;
 	unsigned long		poll_period; /* in jiffies */
 	int			fuzzx;

@@ -128,7 +137,8 @@ static void tsc2007_read_values(struct tsc2007 *tsc, struct ts_event *tc)
 	tsc2007_xfer(tsc, PWRDOWN);
 }
 
-static u32 tsc2007_calculate_pressure(struct tsc2007 *tsc, struct ts_event *tc)
+static u32 tsc2007_calculate_resistance(struct tsc2007 *tsc,
+					struct ts_event *tc)
 {
 	u32 rt = 0;
 

@@ -177,12 +187,13 @@ static irqreturn_t tsc2007_soft_irq(int irq, void *handle)
 	struct ts_event tc;
 	u32 rt;
 
+	dev_dbg(&ts->client->dev, "soft irq %d\n", irq);
 	while (!ts->stopped && tsc2007_is_pen_down(ts)) {
 
 		/* pen is down, continue with the measurement */
 		tsc2007_read_values(ts, &tc);
 
-		rt = tsc2007_calculate_pressure(ts, &tc);
+		rt = tsc2007_calculate_resistance(ts, &tc);
 
 		if (!rt && !ts->get_pendown_state) {
 			/*

@@ -198,6 +209,48 @@ static irqreturn_t tsc2007_soft_irq(int irq, void *handle)
 				"DOWN point(%4d,%4d), pressure (%4u)\n",
 				tc.x, tc.y, rt);
 
+			/* clamp to expected ADC range */
+			if (tc.x < ts->min_x)
+				tc.x = ts->min_x;
+			if (tc.x > ts->max_x)
+				tc.x = ts->max_x;
+			if (tc.y < ts->min_y)
+				tc.y = ts->min_y;
+			if (tc.y > ts->max_y)
+				tc.y = ts->max_y;
+
+			dev_dbg(&ts->client->dev,
+					"Clamped point(%4d,%4d), pressure (%4u)\n",
+					tc.x, tc.y, rt);
+
+			/* flip */
+			if (ts->invert_x)
+				tc.x = (ts->max_x - tc.x) + ts->min_x;
+			if (ts->invert_y)
+				tc.y = (ts->max_y - tc.y) + ts->min_y;
+			if (!ts->report_resistance)
+				rt = ts->max_rt - rt;
+
+			dev_dbg(&ts->client->dev,
+					"Flipped point(%4d,%4d), pressure (%4u)\n",
+					tc.x, tc.y, rt);
+
+			/* scale to desired output range */
+			tc.x = (input->absinfo[ABS_X].maximum *
+				(tc.x - ts->min_x)) / (ts->max_x - ts->min_x);
+			tc.y = (input->absinfo[ABS_Y].maximum *
+				(tc.y - ts->min_y)) / (ts->max_y - ts->min_y);
+			rt = (input->absinfo[ABS_PRESSURE].maximum * rt)
+				/ ts->max_rt;
+
+			/* swap x and y */
+			if (ts->swap_xy)
+				swap(tc.x, tc.y);
+
+			/* report event */
+			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);

@@ -207,8 +260,8 @@ static irqreturn_t tsc2007_soft_irq(int irq, void *handle)
 
 		} else {
 			/*
-			 * Sample found inconsistent by debouncing or pressure is
-			 * beyond the maximum. Don't report it to user space,
+			 * Sample found inconsistent by debouncing or resistance
+			 * is beyond the maximum. Don't report it to user space,
 			 * repeat at least once more the measurement.
 			 */
 			dev_dbg(&ts->client->dev, "ignored pressure %d\n", rt);

@@ -233,6 +286,7 @@ static irqreturn_t tsc2007_hard_irq(int irq, void *handle)
 {
 	struct tsc2007 *ts = handle;
 
+	dev_dbg(&ts->client->dev, "hard irq %d\n", irq);
 	if (tsc2007_is_pen_down(ts))
 		return IRQ_WAKE_THREAD;
 

@@ -303,14 +357,25 @@ static int tsc2007_probe_dt(struct i2c_client *client, struct tsc2007 *ts)
 	else
 		ts->max_rt = MAX_12BIT;
 
-	if (!of_property_read_u32(np, "ti,fuzzx", &val32))
-		ts->fuzzx = val32;
+	ts->swap_xy = of_property_read_bool(np, "touchscreen-swapped-x-y");
+	ts->invert_x = of_property_read_bool(np, "touchscreen-inverted-x");
+	ts->invert_y = of_property_read_bool(np, "touchscreen-inverted-y");
+	ts->report_resistance =
+		       of_property_read_bool(np, "ti,report-resistance");
 
-	if (!of_property_read_u32(np, "ti,fuzzy", &val32))
-		ts->fuzzy = val32;
+	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,fuzzz", &val32))
-		ts->fuzzz = val32;
+	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_u64(np, "ti,poll-period", &val64))
 		ts->poll_period = msecs_to_jiffies(val64);

@@ -324,6 +389,16 @@ 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,
+			"max_rt (%4d)\n",
+			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;

@@ -332,6 +407,10 @@ static int tsc2007_probe_dt(struct i2c_client *client, struct tsc2007 *ts)
 			 "GPIO not specified in DT (of_get_gpio returned %d)\n",
 			 ts->gpio);
 
+	dev_dbg(&client->dev,
+			"ts-gpio: %d\n",
+			ts->gpio);
+
 	return 0;
 }
 #else

@@ -349,6 +428,14 @@ 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->max_rt            = pdata->max_rt ? : MAX_12BIT;
+	ts->swap_xy           = pdata->swap_xy;
+	ts->invert_x          = pdata->invert_x;
+	ts->invert_y          = pdata->invert_y;
+	ts->report_resistance = pdata->report_resistance;
+	ts->min_x             = pdata->min_x ? : 0;
+	ts->min_y             = pdata->min_y ? : 0;
+	ts->max_x             = pdata->max_x ? : MAX_12BIT;
+	ts->max_y             = pdata->max_y ? : MAX_12BIT;
 	ts->poll_period       = msecs_to_jiffies(pdata->poll_period ? : 1);
 	ts->get_pendown_state = pdata->get_pendown_state;
 	ts->clear_penirq      = pdata->clear_penirq;

@@ -388,13 +475,6 @@ static int tsc2007_probe(struct i2c_client *client,
 	if (!ts)
 		return -ENOMEM;
 
-	if (pdata)
-		err = tsc2007_probe_pdev(client, ts, pdata, id);
-	else
-		err = tsc2007_probe_dt(client, ts);
-	if (err)
-		return err;
-
 	input_dev = devm_input_allocate_device(&client->dev);
 	if (!input_dev)
 		return -ENOMEM;

@@ -421,10 +501,21 @@ 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,
-			     ts->fuzzz, 0);
+	if (pdata)
+		err = tsc2007_probe_pdev(client, ts, pdata, id);
+	else
+		err = tsc2007_probe_dt(client, ts);
+	if (err)
+		return err;
+
+	input_set_abs_params(input_dev, ABS_X, 0, ts->max_x-ts->min_x,
+						  ts->fuzzx, 0);
+	input_set_abs_params(input_dev, ABS_Y, 0, ts->max_y-ts->min_y,
+						  ts->fuzzy, 0);
+	input_set_abs_params(input_dev, ABS_PRESSURE, 0, ts->max_rt,
+						  ts->fuzzz, 0);
+
+	touchscreen_parse_properties(input_dev, false);
 
 	if (pdata) {
 		if (pdata->exit_platform_hw) {

@@ -443,6 +534,8 @@ static int tsc2007_probe(struct i2c_client *client,
 			pdata->init_platform_hw();
 	}
 
+	dev_dbg(&client->dev, "request irq %d\n",
+			ts->irq);
 	err = devm_request_threaded_irq(&client->dev, ts->irq,
 					tsc2007_hard_irq, tsc2007_soft_irq,
 					IRQF_ONESHOT,

include/linux/i2c/tsc2007.h +8 -0

index 4f35b6a..632db20 100644
@@ -6,6 +6,14 @@
 struct tsc2007_platform_data {
 	u16	model;				/* 2007. */
 	u16	x_plate_ohms;	/* must be non-zero value */
+	bool	swap_xy;	/* swap x and y axis */
+	bool	invert_x;
+	bool	invert_y;
+	bool	report_resistance;
+	u16	min_x;	/* min and max values reported by ADC */
+	u16	min_y;
+	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 */

Signature · 1 line

2.5.1

Quoted 13 lines

commit b98abe52fa8e ("Input: add common DT binding for touchscreens") introduced common DT bindings for touchscreens [1] and a helper function to parse the DT.

This has been integrated and interpretation of the inversion (flipping) properties for the x and y axis has been added to accommodate any orientation of the touch in relation to the LCD.

By scaling the min/max ADC values to the screen size it is now possible to pre-calibrate the touch so that is (almost) exactly matches the LCD it is glued onto. This allows to well enough operate the touch before a user space calibration can improve the precision.

Quoted 4 lines

calculate_pressure has been renamed to calculate_resistance because that is what it is doing.

[1]: Documentation/devicetree/bindings/input/touchscreen/touchscreen.txt

This still looks like it will break with old dtbs. It doesn't matter if you update the in tree dts files, you should not force users to update their dtb.

Rob

Quoted 323 lines

Signed-off-by H. Nikolaus Schaller <[email protected]>

---

.../bindings/input/touchscreen/tsc2007.txt         |  20 +--
drivers/input/touchscreen/tsc2007.c                | 135 +++++++++++++++++----
include/linux/i2c/tsc2007.h                        |   8 ++
3 files changed, 135 insertions(+), 28 deletions(-)

Documentation/devicetree/bindings/input/touchscreen/tsc2007.txt +0 -1

index ec365e1..6e9fd55 100644
@@ -6,6 +6,7 @@ Required properties:
- ti,x-plate-ohms: X-plate resistance in ohms.
 

Optional properties:
+- generic touch screen properties: see touchscreen binding [2].
- gpios: the interrupt gpio the chip is connected to (trough the penirq pin). The penirq pin goes to low when the panel is touched.
(see GPIO binding[1] for more details).

Documentation/devicetree/bindings/input/touchscreen/tsc2007.txt +9 -9

@@ -13,17 +14,20 @@ Optional properties:
  (see interrupt binding[0]).
- interrupts: (gpio) interrupt to which the chip is connected
  (see interrupt binding[0]).
-- ti,max-rt: maximum pressure.
-- ti,fuzzx: specifies the absolute input fuzz x value.
-  If set, it will permit noise in the data up to +- the value given to the fuzz
-  parameter, that is used to filter noise from the event stream.
-- ti,fuzzy: specifies the absolute input fuzz y value.
-- ti,fuzzz: specifies the absolute input fuzz z value.
+- ti,max-rt: maximum pressure resistance above which samples are ignored
+  (default: 4095).
+- ti,report-resistance: report resistance (no pressure = max_rt) instead
+  of pressure (no pressure = 0).
+- ti,min-x: minimum value reported by X axis ADC (default 0).
+- ti,max-x: maximum value reported by X axis ADC (default 4095).
+- ti,min-y: minimum value reported by Y axis ADC (default 0).
+- ti,max-y: maximum value reported by Y axis ADC (default 4095).
- ti,poll-period: how much time to wait (in milliseconds) before reading again the
-  values from the tsc2007.
+  values from the tsc2007 (default 1).
 

[0]: Documentation/devicetree/bindings/interrupt-controller/interrupts.txt [1]: Documentation/devicetree/bindings/gpio/gpio.txt
+[2]: Documentation/devicetree/bindings/input/touchscreen/touchscreen.txt

Example:

	&i2c1 {

Documentation/devicetree/bindings/input/touchscreen/tsc2007.txt +2 -0

@@ -35,6 +39,8 @@ Example:
 			interrupts = <0x0 0x8>;
 			gpios = <&gpio4 0 0>;
 			ti,x-plate-ohms = <180>;
+			touchscreen-size-x = <640>;
+			touchscreen-size-y = <480>;
 		};
 
 		/* ... */

drivers/input/touchscreen/tsc2007.c +114 -21

index 5d0cd51..e0c7173 100644
@@ -29,6 +29,7 @@
 #include <linux/of_device.h>
 #include <linux/of.h>
 #include <linux/of_gpio.h>
+#include <linux/input/touchscreen.h>
 
 #define TSC2007_MEASURE_TEMP0		(0x0 << 4)
 #define TSC2007_MEASURE_AUX		(0x2 << 4)

@@ -74,6 +75,14 @@ struct tsc2007 {
 
 	u16			model;
 	u16			x_plate_ohms;
+	bool			swap_xy;
+	bool			invert_x;
+	bool			invert_y;
+	bool			report_resistance;
+	u16			min_x;
+	u16			min_y;
+	u16			max_x;
+	u16			max_y;
 	u16			max_rt;
 	unsigned long		poll_period; /* in jiffies */
 	int			fuzzx;

@@ -128,7 +137,8 @@ static void tsc2007_read_values(struct tsc2007 *tsc, struct ts_event *tc)
 	tsc2007_xfer(tsc, PWRDOWN);
 }
 
-static u32 tsc2007_calculate_pressure(struct tsc2007 *tsc, struct ts_event *tc)
+static u32 tsc2007_calculate_resistance(struct tsc2007 *tsc,
+					struct ts_event *tc)
 {
 	u32 rt = 0;
 

@@ -177,12 +187,13 @@ static irqreturn_t tsc2007_soft_irq(int irq, void *handle)
 	struct ts_event tc;
 	u32 rt;
 
+	dev_dbg(&ts->client->dev, "soft irq %d\n", irq);
 	while (!ts->stopped && tsc2007_is_pen_down(ts)) {
 
 		/* pen is down, continue with the measurement */
 		tsc2007_read_values(ts, &tc);
 
-		rt = tsc2007_calculate_pressure(ts, &tc);
+		rt = tsc2007_calculate_resistance(ts, &tc);
 
 		if (!rt && !ts->get_pendown_state) {
 			/*

@@ -198,6 +209,48 @@ static irqreturn_t tsc2007_soft_irq(int irq, void *handle)
 				"DOWN point(%4d,%4d), pressure (%4u)\n",
 				tc.x, tc.y, rt);
 
+			/* clamp to expected ADC range */
+			if (tc.x < ts->min_x)
+				tc.x = ts->min_x;
+			if (tc.x > ts->max_x)
+				tc.x = ts->max_x;
+			if (tc.y < ts->min_y)
+				tc.y = ts->min_y;
+			if (tc.y > ts->max_y)
+				tc.y = ts->max_y;
+
+			dev_dbg(&ts->client->dev,
+					"Clamped point(%4d,%4d), pressure (%4u)\n",
+					tc.x, tc.y, rt);
+
+			/* flip */
+			if (ts->invert_x)
+				tc.x = (ts->max_x - tc.x) + ts->min_x;
+			if (ts->invert_y)
+				tc.y = (ts->max_y - tc.y) + ts->min_y;
+			if (!ts->report_resistance)
+				rt = ts->max_rt - rt;
+
+			dev_dbg(&ts->client->dev,
+					"Flipped point(%4d,%4d), pressure (%4u)\n",
+					tc.x, tc.y, rt);
+
+			/* scale to desired output range */
+			tc.x = (input->absinfo[ABS_X].maximum *
+				(tc.x - ts->min_x)) / (ts->max_x - ts->min_x);
+			tc.y = (input->absinfo[ABS_Y].maximum *
+				(tc.y - ts->min_y)) / (ts->max_y - ts->min_y);
+			rt = (input->absinfo[ABS_PRESSURE].maximum * rt)
+				/ ts->max_rt;
+
+			/* swap x and y */
+			if (ts->swap_xy)
+				swap(tc.x, tc.y);
+
+			/* report event */
+			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);

@@ -207,8 +260,8 @@ static irqreturn_t tsc2007_soft_irq(int irq, void *handle)
 
 		} else {
 			/*
-			 * Sample found inconsistent by debouncing or pressure is
-			 * beyond the maximum. Don't report it to user space,
+			 * Sample found inconsistent by debouncing or resistance
+			 * is beyond the maximum. Don't report it to user space,
 			 * repeat at least once more the measurement.
 			 */
 			dev_dbg(&ts->client->dev, "ignored pressure %d\n", rt);

@@ -233,6 +286,7 @@ static irqreturn_t tsc2007_hard_irq(int irq, void *handle)
 {
 	struct tsc2007 *ts = handle;
 
+	dev_dbg(&ts->client->dev, "hard irq %d\n", irq);
 	if (tsc2007_is_pen_down(ts))
 		return IRQ_WAKE_THREAD;
 

@@ -303,14 +357,25 @@ static int tsc2007_probe_dt(struct i2c_client *client, struct tsc2007 *ts)
 	else
 		ts->max_rt = MAX_12BIT;
 
-	if (!of_property_read_u32(np, "ti,fuzzx", &val32))
-		ts->fuzzx = val32;
+	ts->swap_xy = of_property_read_bool(np, "touchscreen-swapped-x-y");
+	ts->invert_x = of_property_read_bool(np, "touchscreen-inverted-x");
+	ts->invert_y = of_property_read_bool(np, "touchscreen-inverted-y");
+	ts->report_resistance =
+		       of_property_read_bool(np, "ti,report-resistance");
 
-	if (!of_property_read_u32(np, "ti,fuzzy", &val32))
-		ts->fuzzy = val32;
+	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,fuzzz", &val32))
-		ts->fuzzz = val32;
+	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_u64(np, "ti,poll-period", &val64))
 		ts->poll_period = msecs_to_jiffies(val64);

@@ -324,6 +389,16 @@ 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,
+			"max_rt (%4d)\n",
+			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;

@@ -332,6 +407,10 @@ static int tsc2007_probe_dt(struct i2c_client *client, struct tsc2007 *ts)
 			 "GPIO not specified in DT (of_get_gpio returned %d)\n",
 			 ts->gpio);
 
+	dev_dbg(&client->dev,
+			"ts-gpio: %d\n",
+			ts->gpio);
+
 	return 0;
 }
 #else

@@ -349,6 +428,14 @@ 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->max_rt            = pdata->max_rt ? : MAX_12BIT;
+	ts->swap_xy           = pdata->swap_xy;
+	ts->invert_x          = pdata->invert_x;
+	ts->invert_y          = pdata->invert_y;
+	ts->report_resistance = pdata->report_resistance;
+	ts->min_x             = pdata->min_x ? : 0;
+	ts->min_y             = pdata->min_y ? : 0;
+	ts->max_x             = pdata->max_x ? : MAX_12BIT;
+	ts->max_y             = pdata->max_y ? : MAX_12BIT;
 	ts->poll_period       = msecs_to_jiffies(pdata->poll_period ? : 1);
 	ts->get_pendown_state = pdata->get_pendown_state;
 	ts->clear_penirq      = pdata->clear_penirq;

@@ -388,13 +475,6 @@ static int tsc2007_probe(struct i2c_client *client,
 	if (!ts)
 		return -ENOMEM;
 
-	if (pdata)
-		err = tsc2007_probe_pdev(client, ts, pdata, id);
-	else
-		err = tsc2007_probe_dt(client, ts);
-	if (err)
-		return err;
-
 	input_dev = devm_input_allocate_device(&client->dev);
 	if (!input_dev)
 		return -ENOMEM;

@@ -421,10 +501,21 @@ 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,
-			     ts->fuzzz, 0);
+	if (pdata)
+		err = tsc2007_probe_pdev(client, ts, pdata, id);
+	else
+		err = tsc2007_probe_dt(client, ts);
+	if (err)
+		return err;
+
+	input_set_abs_params(input_dev, ABS_X, 0, ts->max_x-ts->min_x,
+						  ts->fuzzx, 0);
+	input_set_abs_params(input_dev, ABS_Y, 0, ts->max_y-ts->min_y,
+						  ts->fuzzy, 0);
+	input_set_abs_params(input_dev, ABS_PRESSURE, 0, ts->max_rt,
+						  ts->fuzzz, 0);
+
+	touchscreen_parse_properties(input_dev, false);
 
 	if (pdata) {
 		if (pdata->exit_platform_hw) {

@@ -443,6 +534,8 @@ static int tsc2007_probe(struct i2c_client *client,
 			pdata->init_platform_hw();
 	}
 
+	dev_dbg(&client->dev, "request irq %d\n",
+			ts->irq);
 	err = devm_request_threaded_irq(&client->dev, ts->irq,
 					tsc2007_hard_irq, tsc2007_soft_irq,
 					IRQF_ONESHOT,

include/linux/i2c/tsc2007.h +8 -0

index 4f35b6a..632db20 100644
@@ -6,6 +6,14 @@
 struct tsc2007_platform_data {
 	u16	model;				/* 2007. */
 	u16	x_plate_ohms;	/* must be non-zero value */
+	bool	swap_xy;	/* swap x and y axis */
+	bool	invert_x;
+	bool	invert_y;
+	bool	report_resistance;
+	u16	min_x;	/* min and max values reported by ADC */
+	u16	min_y;
+	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 */

Signature · 1 line

2.5.1

commit b98abe52fa8e ("Input: add common DT binding for touchscreens") introduced common DT bindings for touchscreens [1] and a helper function to parse the DT.

This has been integrated and interpretation of the inversion (flipping) properties for the x and y axis has been added to accommodate any orientation of the touch in relation to the LCD.

By scaling the min/max ADC values to the screen size it is now possible to pre-calibrate the touch so that is (almost) exactly matches the LCD it is glued onto. This allows to well enough operate the touch before a user space calibration can improve the precision.

[1]: Documentation/devicetree/bindings/input/touchscreen/touchscreen.txt

Signed-off-by H. Nikolaus Schaller <[email protected]>

---
 .../devicetree/bindings/input/ads7846.txt          |  8 ++-
 drivers/input/touchscreen/ads7846.c                | 72 ++++++++++++++++++++--
 2 files changed, 74 insertions(+), 6 deletions(-)

Documentation/devicetree/bindings/input/ads7846.txt +2 -0

index df8b127..ae56355 100644
@@ -26,12 +26,17 @@ Additional required properties:
 
 Optional properties:
 
+You can optionally specify any of the touchscreen parameters described in
+

By this patch we still recognise the old binding ti,swap-xy in parallel to the common binding touchscreen-swapped-x-y. This keeps compatibility to older (out-of-tree) device tree binaries.

We do this in a separate patch so that it can be easily reverted in the future to retire the old API. A notice is printed to remind developers of using old API.

We also fix the bindings name for all in-tree device tree sources in a separate patch.

Signed-off-by H. Nikolaus Schaller <[email protected]>

---
 drivers/input/touchscreen/ads7846.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

drivers/input/touchscreen/ads7846.c +5 -2

index 4525f00..b9896fd 100644
@@ -1259,7 +1259,11 @@ static const struct ads7846_platform_data *ads7846_probe_dt(struct device *dev)
        of_property_read_u16(node, "ti,vref-mv", &pdata->vref_mv);
        pdata->keep_vref_on = of_property_read_bool(node, "ti,keep-vref-on");
 
-       pdata->swap_xy = of_property_read_bool(node, "touchscreen-swapped-x-y");
+       pdata->swap_xy = of_property_read_bool(node, "ti,swap-xy");
+       if (pdata->swap_xy)
+               dev_notice(dev, "please update device tree to use touchscreen-swapped-x-y");
+       pdata->swap_xy |= of_property_read_bool(node,
+                                               "touchscreen-swapped-x-y");
 
        of_property_read_u16(node, "ti,settle-delay-usec",
                             &pdata->settle_delay_usecs);
--

2.5.1

Quoted 4 lines

By this patch we still recognise the old binding ti,swap-xy in parallel to the common binding touchscreen-swapped-x-y. This keeps compatibility to older (out-of-tree) device tree binaries.

Quoted 6 lines

We do this in a separate patch so that it can be easily reverted in the future to retire the old API. A notice is printed to remind developers of using old API.

We also fix the bindings name for all in-tree device tree sources in a separate patch.

This one and patch 5 should be combined, so the series is bisectable.

Rob

Quoted 26 lines

Signed-off-by H. Nikolaus Schaller <[email protected]>

---
drivers/input/touchscreen/ads7846.c | 6 +++++-

1 file changed, 5 insertions(+), 1 deletion(-)

drivers/input/touchscreen/ads7846.c +5 -2

index 4525f00..b9896fd 100644
@@ -1259,7 +1259,11 @@ static const struct ads7846_platform_data *ads7846_probe_dt(struct device *dev)
       of_property_read_u16(node, "ti,vref-mv", &pdata->vref_mv);
       pdata->keep_vref_on = of_property_read_bool(node, "ti,keep-vref-on");
 
-       pdata->swap_xy = of_property_read_bool(node, "touchscreen-swapped-x-y");
+       pdata->swap_xy = of_property_read_bool(node, "ti,swap-xy");
+       if (pdata->swap_xy)
+               dev_notice(dev, "please update device tree to use touchscreen-swapped-x-y");
+       pdata->swap_xy |= of_property_read_bool(node,
+                                               "touchscreen-swapped-x-y");
 
       of_property_read_u16(node, "ti,settle-delay-usec",
                            &pdata->settle_delay_usecs);
--

2.5.1

The standard touch screen bindings [1] replace the private ti,swap-xy with touchscreen-swaped-x-y. And for the Openpandora we use touchscreen-size etc. to match the LCD screen size.

[1]: Documentation/devicetree/bindings/input/touchscreen/touchscreen.txt

Signed-off-by H. Nikolaus Schaller <[email protected]>

---
 arch/arm/boot/dts/omap3-lilly-a83x.dtsi              |  2 +-
 arch/arm/boot/dts/omap3-pandora-common.dtsi          | 17 +++++++++++++----
 arch/arm/boot/dts/omap3-panel-sharp-ls037v7dw01.dtsi |  2 +-
 3 files changed, 15 insertions(+), 6 deletions(-)

arch/arm/boot/dts/omap3-lilly-a83x.dtsi +1 -1

index d0dd036..01dae66 100644
@@ -325,7 +325,7 @@
                ti,y-max = /bits/ 16 <3600>;
                ti,x-plate-ohms = /bits/ 16 <80>;
                ti,pressure-max = /bits/ 16 <255>;
-               ti,swap-xy;
+               touchscreen-swapped-x-y;
 
                linux,wakeup;
        };

arch/arm/boot/dts/omap3-pandora-common.dtsi +3 -4

index f672a04..9497cc6 100644
@@ -696,10 +696,19 @@
                pendown-gpio = <&gpio3 30 0>;
                vcc-supply = <&vaux4>;
 
-               ti,x-min = /bits/ 16 <0>;
-               ti,x-max = /bits/ 16 <8000>;
-               ti,y-min = /bits/ 16 <0>;
-               ti,y-max = /bits/ 16 <4800>;
+               touchscreen-size-x = <800>;
+               touchscreen-size-y = <480>;
+               touchscreen-max-pressure = <1000>;

Hi,

Quoted 41 lines · H. Nikolaus Schaller

The standard touch screen bindings [1] replace the private ti,swap-xy with touchscreen-swaped-x-y. And for the Openpandora we use touchscreen-size etc. to match the LCD screen size.

[1]: Documentation/devicetree/bindings/input/touchscreen/touchscreen.txt

Signed-off-by H. Nikolaus Schaller <[email protected]>

---

arch/arm/boot/dts/omap3-lilly-a83x.dtsi              |  2 +-
arch/arm/boot/dts/omap3-pandora-common.dtsi          | 17 +++++++++++++----
arch/arm/boot/dts/omap3-panel-sharp-ls037v7dw01.dtsi |  2 +-
3 files changed, 15 insertions(+), 6 deletions(-)

arch/arm/boot/dts/omap3-lilly-a83x.dtsi +1 -1

index d0dd036..01dae66 100644
@@ -325,7 +325,7 @@
               ti,y-max = /bits/ 16 <3600>;
               ti,x-plate-ohms = /bits/ 16 <80>;
               ti,pressure-max = /bits/ 16 <255>;
-               ti,swap-xy;
+               touchscreen-swapped-x-y;
 
               linux,wakeup;
       };

arch/arm/boot/dts/omap3-pandora-common.dtsi +3 -4

index f672a04..9497cc6 100644
@@ -696,10 +696,19 @@
               pendown-gpio = <&gpio3 30 0>;
               vcc-supply = <&vaux4>;
 
-               ti,x-min = /bits/ 16 <0>;
-               ti,x-max = /bits/ 16 <8000>;
-               ti,y-min = /bits/ 16 <0>;
-               ti,y-max = /bits/ 16 <4800>;
+               touchscreen-size-x = <800>;
+               touchscreen-size-y = <480>;
+               touchscreen-max-pressure = <1000>;

arch/arm/boot/dts/omap3-pandora-common.dtsi line 711

Quoted 10 lines

arch/arm/boot/dts/omap3-pandora-common.dtsi +10 -0

+               touchscreen-fuzz-x = <16>;
+               touchscreen-fuzz-y = <16>;
+               touchscreen-fuzz-pressure = <10>;
+               touchscreen-inverted-x;
+               touchscreen-inverted-y;
+
+               ti,x-min = /bits/ 16 <160>;
+               ti,x-max = /bits/ 16 <3900>;
+               ti,y-min = /bits/ 16 <220>;
+               ti,y-max = /bits/ 16 <3750>;

I'm not sure this is a good idea, there have been at least 3 different batches of LCDs which slightly different touchscreens attached, with such thresholds we might end up with unreachable touchscreen points on some units. If I understand right, calibration won't help if for some screen locations ADC reading goes below/above these min/max thresholds on some specific units? If so there should probably be at least 10% margin in either case to make calibration useful.