Input: synaptics-rmi4 - add support for querying DPM value (F12)

Newer firmware allows to query touchpad resolution information by
reading from resolution register. Presence of resolution register is
signalled via bit 29 of the "register presence" register. On devices
that lack this resolution register we fall back to using pitch and
number of receivers data to calculate size of the sensor.
Signed-off-by: Marge Yang <marge.yang@tw.synaptics.com>
Signed-off-by: Vincent Huang <Vincent.Huang@tw.synaptics.com>
Link: https://lore.kernel.org/r/20240805083636.1381205-1-marge.yang@tw.synaptics.comSigned-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

drivers/input/rmi4/rmi_f12.c

@@ -24,6 +24,7 @@ enum rmi_f12_object_type {
 };
 
 #define F12_DATA1_BYTES_PER_OBJ			8
+#define RMI_F12_QUERY_RESOLUTION		29
 
 struct f12_data {
 	struct rmi_2d_sensor sensor;
@@ -73,6 +74,8 @@ static int rmi_f12_read_sensor_tuning(struct f12_data *f12)
 	int pitch_y = 0;
 	int rx_receivers = 0;
 	int tx_receivers = 0;
+	u16 query_dpm_addr = 0;
+	int dpm_resolution = 0;
 
 	item = rmi_get_register_desc_item(&f12->control_reg_desc, 8);
 	if (!item) {
@@ -122,6 +125,26 @@ static int rmi_f12_read_sensor_tuning(struct f12_data *f12)
 		offset += 4;
 	}
 
+	/*
+	 * Use the Query DPM feature when the resolution query register
+	 * exists.
+	 */
+	item = rmi_get_register_desc_item(&f12->query_reg_desc,
+					  RMI_F12_QUERY_RESOLUTION);
+	if (item) {
+		offset = rmi_register_desc_calc_reg_offset(&f12->query_reg_desc,
+						RMI_F12_QUERY_RESOLUTION);
+		query_dpm_addr = fn->fd.query_base_addr	+ offset;
+		ret = rmi_read(fn->rmi_dev, query_dpm_addr, buf);
+		if (ret < 0) {
+			dev_err(&fn->dev, "Failed to read DPM value: %d\n", ret);
+			return -ENODEV;
+		}
+		dpm_resolution = buf[0];
+
+		sensor->x_mm = sensor->max_x / dpm_resolution;
+		sensor->y_mm = sensor->max_y / dpm_resolution;
+	} else {
 		if (rmi_register_desc_has_subpacket(item, 3)) {
 			rx_receivers = buf[offset];
 			tx_receivers = buf[offset + 1];
@@ -134,6 +157,7 @@ static int rmi_f12_read_sensor_tuning(struct f12_data *f12)
 
 		sensor->x_mm = (pitch_x * rx_receivers) >> 12;
 		sensor->y_mm = (pitch_y * tx_receivers) >> 12;
+	}
 
 	rmi_dbg(RMI_DEBUG_FN, &fn->dev, "%s: x_mm: %d y_mm: %d\n", __func__,
 		sensor->x_mm, sensor->y_mm);