Input: zinitix - varying icon status registers

The different revisions of the Zinitix BTXXX touchscreens place
the icon status register (to read out touchkey status) in
different places. Use the chip revision bits to discern
between the different versions at runtime.

This makes touchkeys work on the BT404 on the Samsung Codina
GT-I8160 mobile phone.
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/20240830-zinitix-tk-versions-v2-2-90eae6817eda@linaro.orgSigned-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

drivers/input/touchscreen/zinitix.c

@@ -35,7 +35,13 @@
 #define ZINITIX_DEBUG_REG			0x0115 /* 0~7 */
 
 #define ZINITIX_TOUCH_MODE			0x0010
+
 #define ZINITIX_CHIP_REVISION			0x0011
+#define ZINITIX_CHIP_BTX0X_MASK			0xF0F0
+#define ZINITIX_CHIP_BT4X2			0x4020
+#define ZINITIX_CHIP_BT4X3			0x4030
+#define ZINITIX_CHIP_BT4X4			0x4040
+
 #define ZINITIX_FIRMWARE_VERSION		0x0012
 
 #define ZINITIX_USB_DETECT			0x116
@@ -63,7 +69,11 @@
 #define ZINITIX_Y_RESOLUTION			0x00C1
 
 #define ZINITIX_POINT_STATUS_REG		0x0080
-#define ZINITIX_ICON_STATUS_REG			0x00AA
+
+#define ZINITIX_BT4X2_ICON_STATUS_REG		0x009A
+#define ZINITIX_BT4X3_ICON_STATUS_REG		0x00A0
+#define ZINITIX_BT4X4_ICON_STATUS_REG		0x00A0
+#define ZINITIX_BT5XX_ICON_STATUS_REG		0x00AA
 
 #define ZINITIX_POINT_COORD_REG			(ZINITIX_POINT_STATUS_REG + 2)
 
@@ -154,6 +164,7 @@ struct bt541_ts_data {
 	u16 chip_revision;
 	u16 firmware_version;
 	u16 regdata_version;
+	u16 icon_status_reg;
 };
 
 static int zinitix_read_data(struct i2c_client *client,
@@ -241,6 +252,28 @@ static int zinitix_init_touch(struct bt541_ts_data *bt541)
 			"chip revision %04x firmware version %04x regdata version %04x\n",
 			bt541->chip_revision, bt541->firmware_version,
 			bt541->regdata_version);
+
+		/*
+		 * Determine the "icon" status register which varies by the
+		 * chip.
+		 */
+		switch (bt541->chip_revision & ZINITIX_CHIP_BTX0X_MASK) {
+		case ZINITIX_CHIP_BT4X2:
+			bt541->icon_status_reg = ZINITIX_BT4X2_ICON_STATUS_REG;
+			break;
+
+		case ZINITIX_CHIP_BT4X3:
+			bt541->icon_status_reg = ZINITIX_BT4X3_ICON_STATUS_REG;
+			break;
+
+		case ZINITIX_CHIP_BT4X4:
+			bt541->icon_status_reg = ZINITIX_BT4X4_ICON_STATUS_REG;
+			break;
+
+		default:
+			bt541->icon_status_reg = ZINITIX_BT5XX_ICON_STATUS_REG;
+			break;
+		}
 	}
 
 	error = zinitix_write_u16(client, ZINITIX_INT_ENABLE_FLAG, 0x0);
@@ -427,7 +460,7 @@ static irqreturn_t zinitix_ts_irq_handler(int irq, void *bt541_handler)
 	}
 
 	if (le16_to_cpu(touch_event.status) & BIT_ICON_EVENT) {
-		error = zinitix_read_data(bt541->client, ZINITIX_ICON_STATUS_REG,
+		error = zinitix_read_data(bt541->client, bt541->icon_status_reg,
 					  &icon_events, sizeof(icon_events));
 		if (error) {
 			dev_err(&client->dev, "Failed to read icon events\n");