[PATCH V2] Input: synaptics-rmi4 - Supports to query DPM value.

[Marge Yang <marge.yang@xxxxxxxxxxxxxxxx>]

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.

RMI4 F12 will support to query DPM value on Touchpad.
When TP firmware doesn't support to report logical and
physical value within the Touchpad's HID report.
We can directly query the DPM value through RMI.

Signed-off-by: Marge Yang <marge.yang@xxxxxxxxxxxxxxxx>
Signed-off-by: Vincent Huang <Vincent.Huang@xxxxxxxxxxxxxxxx>
---
 drivers/input/rmi4/rmi_f12.c | 41 +++++++++++++++++++++++++++---------
 1 file changed, 31 insertions(+), 10 deletions(-)

diff --git a/drivers/input/rmi4/rmi_f12.c b/drivers/input/rmi4/rmi_f12.c
index 7e97944f7616..b8dfb9ffdbf5 100644
--- a/drivers/input/rmi4/rmi_f12.c
+++ b/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) {
@@ -122,18 +125,36 @@ static int rmi_f12_read_sensor_tuning(struct f12_data *f12)
 		offset += 4;
 	}
 
-	if (rmi_register_desc_has_subpacket(item, 3)) {
-		rx_receivers = buf[offset];
-		tx_receivers = buf[offset + 1];
-		offset += 2;
-	}
+	/* Use the Query DPM feature when the query register exists for resolution. */
+	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];
+			offset += 2;
+		}
 
-	/* Skip over sensor flags */
-	if (rmi_register_desc_has_subpacket(item, 4))
-		offset += 1;
+		/* Skip over sensor flags */
+		if (rmi_register_desc_has_subpacket(item, 4))
+			offset += 1;
+
+		sensor->x_mm = (pitch_x * rx_receivers) >> 12;
+		sensor->y_mm = (pitch_y * tx_receivers) >> 12;
+	}
 
-	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);
-- 
2.25.1