[PATCH 3/3] input/touchscreen: imagis: Add support for Imagis IST3038B

[Markuss Broks <markuss.broks@gmail.com>]

Imagis IST3038B is another variant of Imagis IST3038 IC, which has
a different register interface from IST3038C (possibly firmware defined).
This should also work for IST3044B (though untested), however other
variants using this interface/protocol(IST3026, IST3032, IST3026B,
IST3032B) have a different format for coordinates, and they'd need
additional effort to be supported by this driver.

Signed-off-by: Markuss Broks <markuss.broks@gmail.com>
---
 drivers/input/touchscreen/imagis.c | 58 ++++++++++++++++++++++++------
 1 file changed, 47 insertions(+), 11 deletions(-)

diff --git a/drivers/input/touchscreen/imagis.c b/drivers/input/touchscreen/imagis.c
index b667914a44f1..57bb8f31ac1f 100644
--- a/drivers/input/touchscreen/imagis.c
+++ b/drivers/input/touchscreen/imagis.c
@@ -13,7 +13,7 @@
 
 #define IST3038C_HIB_ACCESS		(0x800B << 16)
 #define IST3038C_DIRECT_ACCESS		BIT(31)
-#define IST3038C_REG_CHIPID		0x40001000
+#define IST3038C_REG_CHIPID		(0x40001000 | IST3038C_DIRECT_ACCESS)
 #define IST3038C_REG_HIB_BASE		0x30000100
 #define IST3038C_REG_TOUCH_STATUS	(IST3038C_REG_HIB_BASE | IST3038C_HIB_ACCESS)
 #define IST3038C_REG_TOUCH_COORD	(IST3038C_REG_HIB_BASE | IST3038C_HIB_ACCESS | 0x8)
@@ -31,8 +31,21 @@
 #define IST3038C_FINGER_COUNT_SHIFT	12
 #define IST3038C_FINGER_STATUS_MASK	GENMASK(9, 0)
 
+#define IST3038B_REG_STATUS		0x20
+#define IST3038B_REG_CHIPID		0x30
+#define IST3038B_WHOAMI			0x30380b
+
+struct imagis_properties {
+	unsigned int interrupt_msg_cmd;
+	unsigned int touch_coord_cmd;
+	unsigned int whoami_cmd;
+	unsigned int whoami_val;
+	bool protocol_b;
+};
+
 struct imagis_ts {
 	struct i2c_client *client;
+	const struct imagis_properties *tdata;
 	struct input_dev *input_dev;
 	struct touchscreen_properties prop;
 	struct regulator_bulk_data supplies[2];
@@ -84,8 +97,7 @@ static irqreturn_t imagis_interrupt(int irq, void *dev_id)
 	int i;
 	int error;
 
-	error = imagis_i2c_read_reg(ts, IST3038C_REG_INTR_MESSAGE,
-				    &intr_message);
+	error = imagis_i2c_read_reg(ts, ts->tdata->interrupt_msg_cmd, &intr_message);
 	if (error) {
 		dev_err(&ts->client->dev,
 			"failed to read the interrupt message: %d\n", error);
@@ -104,9 +116,13 @@ static irqreturn_t imagis_interrupt(int irq, void *dev_id)
 	finger_pressed = intr_message & IST3038C_FINGER_STATUS_MASK;
 
 	for (i = 0; i < finger_count; i++) {
-		error = imagis_i2c_read_reg(ts,
-					    IST3038C_REG_TOUCH_COORD + (i * 4),
-					    &finger_status);
+		if (ts->tdata->protocol_b)
+			error = imagis_i2c_read_reg(ts,
+						    ts->tdata->touch_coord_cmd, &finger_status);
+		else
+			error = imagis_i2c_read_reg(ts,
+						    ts->tdata->touch_coord_cmd + (i * 4),
+						    &finger_status);
 		if (error) {
 			dev_err(&ts->client->dev,
 				"failed to read coordinates for finger %d: %d\n",
@@ -261,6 +277,12 @@ static int imagis_probe(struct i2c_client *i2c)
 
 	ts->client = i2c;
 
+	ts->tdata = device_get_match_data(dev);
+	if (!ts->tdata) {
+		dev_err(dev, "missing chip data\n");
+		return -EINVAL;
+	}
+
 	error = imagis_init_regulators(ts);
 	if (error) {
 		dev_err(dev, "regulator init error: %d\n", error);
@@ -279,15 +301,13 @@ static int imagis_probe(struct i2c_client *i2c)
 		return error;
 	}
 
-	error = imagis_i2c_read_reg(ts,
-			IST3038C_REG_CHIPID | IST3038C_DIRECT_ACCESS,
-			&chip_id);
+	error = imagis_i2c_read_reg(ts, ts->tdata->whoami_cmd, &chip_id);
 	if (error) {
 		dev_err(dev, "chip ID read failure: %d\n", error);
 		return error;
 	}
 
-	if (chip_id != IST3038C_WHOAMI) {
+	if (chip_id != ts->tdata->whoami_val) {
 		dev_err(dev, "unknown chip ID: 0x%x\n", chip_id);
 		return -EINVAL;
 	}
@@ -343,9 +363,25 @@ static int __maybe_unused imagis_resume(struct device *dev)
 
 static SIMPLE_DEV_PM_OPS(imagis_pm_ops, imagis_suspend, imagis_resume);
 
+static const struct imagis_properties imagis_3038b_data = {
+	.interrupt_msg_cmd = IST3038B_REG_STATUS,
+	.touch_coord_cmd = IST3038B_REG_STATUS,
+	.whoami_cmd = IST3038B_REG_CHIPID,
+	.whoami_val = IST3038B_WHOAMI,
+	.protocol_b = true,
+};
+
+static const struct imagis_properties imagis_3038c_data = {
+	.interrupt_msg_cmd = IST3038C_REG_INTR_MESSAGE,
+	.touch_coord_cmd = IST3038C_REG_TOUCH_COORD,
+	.whoami_cmd = IST3038C_REG_CHIPID,
+	.whoami_val = IST3038C_WHOAMI,
+};
+
 #ifdef CONFIG_OF
 static const struct of_device_id imagis_of_match[] = {
-	{ .compatible = "imagis,ist3038c", },
+	{ .compatible = "imagis,ist3038b", .data = &imagis_3038b_data },
+	{ .compatible = "imagis,ist3038c", .data = &imagis_3038c_data },
 	{ },
 };
 MODULE_DEVICE_TABLE(of, imagis_of_match);
-- 
2.35.1