input: elants: read touchscreen size for EKTF3624

EKTF3624 as present in Asus TF300T tablet has touchscreen size encoded
in different registers.

Signed-off-by: Michał Mirosław <mirq-linux@rere.qmqm.pl>
Reviewed-by: Dmitry Osipenko <digetx@gmail.com>
Tested-by: Dmitry Osipenko <digetx@gmail.com>

drivers/input/touchscreen/elants_i2c.c

@@ -35,14 +35,18 @@
 #include <linux/input/mt.h>
 #include <linux/input/touchscreen.h>
 #include <linux/acpi.h>
-#include <linux/of.h>
+#include <linux/of_device.h>
 #include <linux/gpio/consumer.h>
 #include <linux/regulator/consumer.h>
 #include <asm/unaligned.h>
 
 /* Device, Driver information */
 #define DEVICE_NAME	"elants_i2c"
 
+/* Device IDs */
+#define EKTH3500	0
+#define EKTF3624	1
+
 /* Convert from rows or columns into resolution */
 #define ELAN_TS_RESOLUTION(n, m)   (((n) - 1) * (m))
 
@@ -94,6 +98,8 @@
 #define E_ELAN_INFO_REK		0xD0
 #define E_ELAN_INFO_TEST_VER	0xE0
 #define E_ELAN_INFO_FW_ID	0xF0
+#define E_INFO_X_RES		0x60
+#define E_INFO_Y_RES		0x63
 #define E_INFO_OSR		0xD6
 #define E_INFO_PHY_SCAN		0xD7
 #define E_INFO_PHY_DRIVER	0xD8
@@ -157,6 +163,7 @@ struct elants_data {
 
 	bool wake_irq_enabled;
 	bool keep_power_in_suspend;
+	u8 chip_id;
 
 	/* Must be last to be used for DMA operations */
 	u8 buf[MAX_PACKET_SIZE] ____cacheline_aligned;
@@ -434,7 +441,58 @@ static int elants_i2c_query_bc_version(struct elants_data *ts)
 	return 0;
 }
 
-static int elants_i2c_query_ts_info(struct elants_data *ts)
+static int elants_i2c_query_ts_info_ektf(struct elants_data *ts)
+{
+	struct i2c_client *client = ts->client;
+	int error;
+	u8 resp[4];
+	u16 phy_x, phy_y;
+	const u8 get_xres_cmd[] = {
+		CMD_HEADER_READ, E_INFO_X_RES, 0x00, 0x00
+	};
+	const u8 get_yres_cmd[] = {
+		CMD_HEADER_READ, E_INFO_Y_RES, 0x00, 0x00
+	};
+
+	/* Get X/Y size in mm */
+	error = elants_i2c_execute_command(client, get_xres_cmd,
+					   sizeof(get_xres_cmd),
+					   resp, sizeof(resp), 1,
+					   "get X size");
+	if (error)
+		return error;
+
+	phy_x = resp[2] | ((resp[3] & 0xF0) << 4);
+
+	error = elants_i2c_execute_command(client, get_yres_cmd,
+					   sizeof(get_yres_cmd),
+					   resp, sizeof(resp), 1,
+					   "get Y size");
+	if (error)
+		return error;
+
+	phy_y = resp[2] | ((resp[3] & 0xF0) << 4);
+
+	if (!phy_x || !phy_y) {
+		dev_warn(&client->dev,
+			 "invalid size data: %d x %d mm\n",
+			 phy_x, phy_y);
+		return 0;
+	}
+
+	dev_dbg(&client->dev, "phy_x=%d, phy_y=%d\n", phy_x, phy_y);
+
+	/* calculate resolution from size */
+	ts->x_max = 2240-1;
+	ts->x_res = DIV_ROUND_CLOSEST(ts->prop.max_x, phy_x);
+
+	ts->y_max = 1408-1;
+	ts->y_res = DIV_ROUND_CLOSEST(ts->prop.max_y, phy_y);
+
+	return 0;
+}
+
+static int elants_i2c_query_ts_info_ekth(struct elants_data *ts)
 {
 	struct i2c_client *client = ts->client;
 	int error;
@@ -588,8 +646,20 @@ static int elants_i2c_initialize(struct elants_data *ts)
 		error = elants_i2c_query_fw_version(ts);
 	if (!error)
 		error = elants_i2c_query_test_version(ts);
-	if (!error)
-		error = elants_i2c_query_ts_info(ts);
+
+	switch (ts->chip_id) {
+	case EKTH3500:
+		if (!error)
+			error = elants_i2c_query_ts_info_ekth(ts);
+		break;
+	case EKTF3624:
+		if (!error)
+			error = elants_i2c_query_ts_info_ektf(ts);
+		break;
+	default:
+		unreachable();
+		break;
+	}
 
 	if (error)
 		ts->iap_mode = ELAN_IAP_RECOVERY;
@@ -1266,6 +1336,9 @@ static int elants_i2c_probe(struct i2c_client *client,
 	ts->client = client;
 	i2c_set_clientdata(client, ts);
 
+	if (client->dev.of_node)
+		ts->chip_id = (uintptr_t)of_device_get_match_data(&client->dev);
+
 	ts->vcc33 = devm_regulator_get(&client->dev, "vcc33");
 	if (IS_ERR(ts->vcc33)) {
 		error = PTR_ERR(ts->vcc33);
@@ -1495,7 +1568,8 @@ MODULE_DEVICE_TABLE(acpi, elants_acpi_id);
 
 #ifdef CONFIG_OF
 static const struct of_device_id elants_of_match[] = {
-	{ .compatible = "elan,ekth3500" },
+	{ .compatible = "elan,ekth3500", .data = (void *)EKTH3500 },
+	{ .compatible = "elan,ektf3624", .data = (void *)EKTF3624 },
 	{ /* sentinel */ }
 };
 MODULE_DEVICE_TABLE(of, elants_of_match);