Input: ili210x - implement pressure reporting for ILI251x

The ILI251x seems to report pressure information in the 5th byte of
each per-finger touch data element. On the available hardware, this
information has the values ranging from 0x0 to 0xa, which is also
matching the downstream example code. Report pressure information
on the ILI251x.

Signed-off-by: Marek Vasut <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Dmitry Torokhov <[e-mail]>

drivers/input/touchscreen/ili210x.c

···
 			void *buf, size_t len);
 	int (*get_touch_data)(struct i2c_client *client, u8 *data);
 	bool (*parse_touch_data)(const u8 *data, unsigned int finger,
-				 unsigned int *x, unsigned int *y);
+				 unsigned int *x, unsigned int *y,
+				 unsigned int *z);
 	bool (*continue_polling)(const u8 *data, bool touch);
 	unsigned int max_touches;
 	unsigned int resolution;
 	bool has_calibrate_reg;
+	bool has_pressure_reg;
 };
 
 struct ili210x {
···
 
 static bool ili210x_touchdata_to_coords(const u8 *touchdata,
 					unsigned int finger,
-					unsigned int *x, unsigned int *y)
+					unsigned int *x, unsigned int *y,
+					unsigned int *z)
 {
 	if (touchdata[0] & BIT(finger))
 		return false;
···
 
 static bool ili211x_touchdata_to_coords(const u8 *touchdata,
 					unsigned int finger,
-					unsigned int *x, unsigned int *y)
+					unsigned int *x, unsigned int *y,
+					unsigned int *z)
 {
 	u32 data;
 
···
 
 static bool ili212x_touchdata_to_coords(const u8 *touchdata,
 					unsigned int finger,
-					unsigned int *x, unsigned int *y)
+					unsigned int *x, unsigned int *y,
+					unsigned int *z)
 {
 	u16 val;
 
···
 
 static bool ili251x_touchdata_to_coords(const u8 *touchdata,
 					unsigned int finger,
-					unsigned int *x, unsigned int *y)
+					unsigned int *x, unsigned int *y,
+					unsigned int *z)
 {
 	u16 val;
 
···
 
 	*x = val & 0x3fff;
 	*y = get_unaligned_be16(touchdata + 1 + (finger * 5) + 2);
+	*z = touchdata[1 + (finger * 5) + 4];
 
 	return true;
 }
···
 	.continue_polling	= ili251x_check_continue_polling,
 	.max_touches		= 10,
 	.has_calibrate_reg	= true,
+	.has_pressure_reg	= true,
 };
 
 static bool ili210x_report_events(struct ili210x *priv, u8 *touchdata)
···
 	struct input_dev *input = priv->input;
 	int i;
 	bool contact = false, touch;
-	unsigned int x = 0, y = 0;
+	unsigned int x = 0, y = 0, z = 0;
 
 	for (i = 0; i < priv->chip->max_touches; i++) {
-		touch = priv->chip->parse_touch_data(touchdata, i, &x, &y);
+		touch = priv->chip->parse_touch_data(touchdata, i, &x, &y, &z);
 
 		input_mt_slot(input, i);
 		if (input_mt_report_slot_state(input, MT_TOOL_FINGER, touch)) {
 			touchscreen_report_pos(input, &priv->prop, x, y, true);
+			if (priv->chip->has_pressure_reg)
+				input_report_abs(input, ABS_MT_PRESSURE, z);
 			contact = true;
 		}
 	}
···
 	max_xy = (chip->resolution ?: SZ_64K) - 1;
 	input_set_abs_params(input, ABS_MT_POSITION_X, 0, max_xy, 0, 0);
 	input_set_abs_params(input, ABS_MT_POSITION_Y, 0, max_xy, 0, 0);
+	if (priv->chip->has_pressure_reg)
+		input_set_abs_params(input, ABS_MT_PRESSURE, 0, 0xa, 0, 0);
 	touchscreen_parse_properties(input, true, &priv->prop);
 
 	error = input_mt_init_slots(input, priv->chip->max_touches,