Input: ili210x - define and use chip operations structure

Instead of doing if/else if/else on the chip's model number let's define
chip operations structure and use it to perform indirect calls. With number
of protocols supported by the driver growing, this makes it better
maintainable.

This change includes fixes to checks whether the driver should continue
polling the controller by Sven Van Asbroeck <thesven73@gmail.com>.

Tested-by: Adam Ford <aford173@gmail.com> #imx6q-logicpd
Tested-by: Sven Van Asbroeck <TheSven73@gmail.com> # ILI2118A variant
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

drivers/input/touchscreen/ili210x.c

@@ -11,12 +11,13 @@
 #include <linux/slab.h>
 #include <asm/unaligned.h>
 
-#define ILI210X_TOUCHES		2
-#define ILI211X_TOUCHES		10
-#define ILI251X_TOUCHES		10
-
 #define ILI2XXX_POLL_PERIOD	20
 
+#define ILI210X_DATA_SIZE	64
+#define ILI211X_DATA_SIZE	43
+#define ILI251X_DATA_SIZE1	31
+#define ILI251X_DATA_SIZE2	20
+
 /* Touchscreen commands */
 #define REG_TOUCHDATA		0x10
 #define REG_PANEL_INFO		0x20
@@ -29,10 +30,14 @@ struct firmware_version {
 	u8 minor;
 } __packed;
 
-enum ili2xxx_model {
-	MODEL_ILI210X,
-	MODEL_ILI211X,
-	MODEL_ILI251X,
+struct ili2xxx_chip {
+	int (*read_reg)(struct i2c_client *client, u8 reg,
+			void *buf, size_t len);
+	int (*get_touch_data)(struct i2c_client *client, u8 *data);
+	bool (*parse_touch_data)(const u8 *data, unsigned int finger,
+				 unsigned int *x, unsigned int *y);
+	bool (*continue_polling)(const u8 *data, bool touch);
+	unsigned int max_touches;
 };
 
 struct ili210x {
@@ -40,16 +45,14 @@ struct ili210x {
 	struct input_dev *input;
 	struct gpio_desc *reset_gpio;
 	struct touchscreen_properties prop;
-	enum ili2xxx_model model;
-	unsigned int max_touches;
+	const struct ili2xxx_chip *chip;
 	bool stop;
 };
 
-static int ili210x_read_reg(struct i2c_client *client, u8 reg, void *buf,
-			    size_t len)
+static int ili210x_read_reg(struct i2c_client *client,
+			    u8 reg, void *buf, size_t len)
 {
-	struct ili210x *priv = i2c_get_clientdata(client);
-	struct i2c_msg msg[2] = {
+	struct i2c_msg msg[] = {
 		{
 			.addr	= client->addr,
 			.flags	= 0,
@@ -63,53 +66,28 @@ static int ili210x_read_reg(struct i2c_client *client, u8 reg, void *buf,
 			.buf	= buf,
 		}
 	};
+	int error, ret;
 
-	if (priv->model == MODEL_ILI251X) {
-		if (i2c_transfer(client->adapter, msg, 1) != 1) {
-			dev_err(&client->dev, "i2c transfer failed\n");
-			return -EIO;
-		}
-
-		usleep_range(5000, 5500);
-
-		if (i2c_transfer(client->adapter, msg + 1, 1) != 1) {
-			dev_err(&client->dev, "i2c transfer failed\n");
-			return -EIO;
-		}
-	} else {
-		if (i2c_transfer(client->adapter, msg, 2) != 2) {
-			dev_err(&client->dev, "i2c transfer failed\n");
-			return -EIO;
-		}
+	ret = i2c_transfer(client->adapter, msg, ARRAY_SIZE(msg));
+	if (ret != ARRAY_SIZE(msg)) {
+		error = ret < 0 ? ret : -EIO;
+		dev_err(&client->dev, "%s failed: %d\n", __func__, error);
+		return error;
 	}
 
 	return 0;
 }
 
-static int ili210x_read(struct i2c_client *client, void *buf, size_t len)
+static int ili210x_read_touch_data(struct i2c_client *client, u8 *data)
 {
-	struct i2c_msg msg = {
-		.addr	= client->addr,
-		.flags	= I2C_M_RD,
-		.len	= len,
-		.buf	= buf,
-	};
-
-	if (i2c_transfer(client->adapter, &msg, 1) != 1) {
-		dev_err(&client->dev, "i2c transfer failed\n");
-		return -EIO;
-	}
-
-	return 0;
+	return ili210x_read_reg(client, REG_TOUCHDATA,
+				data, ILI210X_DATA_SIZE);
 }
 
-static bool ili210x_touchdata_to_coords(struct ili210x *priv, u8 *touchdata,
+static bool ili210x_touchdata_to_coords(const u8 *touchdata,
 					unsigned int finger,
 					unsigned int *x, unsigned int *y)
 {
-	if (finger >= ILI210X_TOUCHES)
-		return false;
-
 	if (touchdata[0] & BIT(finger))
 		return false;
 
@@ -119,15 +97,53 @@ static bool ili210x_touchdata_to_coords(struct ili210x *priv, u8 *touchdata,
 	return true;
 }
 
-static bool ili211x_touchdata_to_coords(struct ili210x *priv, u8 *touchdata,
+static bool ili210x_check_continue_polling(const u8 *data, bool touch)
+{
+	return data[0] & 0xf3;
+}
+
+static const struct ili2xxx_chip ili210x_chip = {
+	.read_reg		= ili210x_read_reg,
+	.get_touch_data		= ili210x_read_touch_data,
+	.parse_touch_data	= ili210x_touchdata_to_coords,
+	.continue_polling	= ili210x_check_continue_polling,
+	.max_touches		= 2,
+};
+
+static int ili211x_read_touch_data(struct i2c_client *client, u8 *data)
+{
+	s16 sum = 0;
+	int error;
+	int ret;
+	int i;
+
+	ret = i2c_master_recv(client, data, ILI211X_DATA_SIZE);
+	if (ret != ILI211X_DATA_SIZE) {
+		error = ret < 0 ? ret : -EIO;
+		dev_err(&client->dev, "%s failed: %d\n", __func__, error);
+		return error;
+	}
+
+	/* This chip uses custom checksum at the end of data */
+	for (i = 0; i < ILI211X_DATA_SIZE - 1; i++)
+		sum = (sum + data[i]) & 0xff;
+
+	if ((-sum & 0xff) != data[ILI211X_DATA_SIZE - 1]) {
+		dev_err(&client->dev,
+			"CRC error (crc=0x%02x expected=0x%02x)\n",
+			sum, data[ILI211X_DATA_SIZE - 1]);
+		return -EIO;
+	}
+
+	return 0;
+}
+
+static bool ili211x_touchdata_to_coords(const u8 *touchdata,
 					unsigned int finger,
 					unsigned int *x, unsigned int *y)
 {
 	u32 data;
 
-	if (finger >= ILI211X_TOUCHES)
-		return false;
-
 	data = get_unaligned_be32(touchdata + 1 + (finger * 4) + 0);
 	if (data == 0xffffffff)	/* Finger up */
 		return false;
@@ -140,58 +156,104 @@ static bool ili211x_touchdata_to_coords(struct ili210x *priv, u8 *touchdata,
 	return true;
 }
 
-static bool ili251x_touchdata_to_coords(struct ili210x *priv, u8 *touchdata,
+static bool ili211x_decline_polling(const u8 *data, bool touch)
+{
+	return false;
+}
+
+static const struct ili2xxx_chip ili211x_chip = {
+	.read_reg		= ili210x_read_reg,
+	.get_touch_data		= ili211x_read_touch_data,
+	.parse_touch_data	= ili211x_touchdata_to_coords,
+	.continue_polling	= ili211x_decline_polling,
+	.max_touches		= 10,
+};
+
+static int ili251x_read_reg(struct i2c_client *client,
+			    u8 reg, void *buf, size_t len)
+{
+	int error;
+	int ret;
+
+	ret = i2c_master_send(client, &reg, 1);
+	if (ret == 1) {
+		usleep_range(5000, 5500);
+
+		ret = i2c_master_recv(client, buf, len);
+		if (ret == len)
+			return 0;
+	}
+
+	error = ret < 0 ? ret : -EIO;
+	dev_err(&client->dev, "%s failed: %d\n", __func__, error);
+	return ret;
+}
+
+static int ili251x_read_touch_data(struct i2c_client *client, u8 *data)
+{
+	int error;
+
+	error = ili251x_read_reg(client, REG_TOUCHDATA,
+				 data, ILI251X_DATA_SIZE1);
+	if (!error && data[0] == 2) {
+		error = i2c_master_recv(client, data + ILI251X_DATA_SIZE1,
+					ILI251X_DATA_SIZE2);
+		if (error >= 0 && error != ILI251X_DATA_SIZE2)
+			error = -EIO;
+	}
+
+	return error;
+}
+
+static bool ili251x_touchdata_to_coords(const u8 *touchdata,
 					unsigned int finger,
 					unsigned int *x, unsigned int *y)
 {
-	if (finger >= ILI251X_TOUCHES)
-		return false;
+	u16 val;
 
-	*x = get_unaligned_be16(touchdata + 1 + (finger * 5) + 0);
-	if (!(*x & BIT(15)))	/* Touch indication */
+	val = get_unaligned_be16(touchdata + 1 + (finger * 5) + 0);
+	if (!(val & BIT(15)))	/* Touch indication */
 		return false;
 
-	*x &= 0x3fff;
+	*x = val & 0x3fff;
 	*y = get_unaligned_be16(touchdata + 1 + (finger * 5) + 2);
 
 	return true;
 }
 
+static bool ili251x_check_continue_polling(const u8 *data, bool touch)
+{
+	return touch;
+}
+
+static const struct ili2xxx_chip ili251x_chip = {
+	.read_reg		= ili251x_read_reg,
+	.get_touch_data		= ili251x_read_touch_data,
+	.parse_touch_data	= ili251x_touchdata_to_coords,
+	.continue_polling	= ili251x_check_continue_polling,
+	.max_touches		= 10,
+};
+
 static bool ili210x_report_events(struct ili210x *priv, u8 *touchdata)
 {
 	struct input_dev *input = priv->input;
 	int i;
-	bool contact = false, touch = false;
+	bool contact = false, touch;
 	unsigned int x = 0, y = 0;
 
-	for (i = 0; i < priv->max_touches; i++) {
-		if (priv->model == MODEL_ILI210X) {
-			touch = ili210x_touchdata_to_coords(priv, touchdata,
-							    i, &x, &y);
-		} else if (priv->model == MODEL_ILI211X) {
-			touch = ili211x_touchdata_to_coords(priv, touchdata,
-							    i, &x, &y);
-		} else if (priv->model == MODEL_ILI251X) {
-			touch = ili251x_touchdata_to_coords(priv, touchdata,
-							    i, &x, &y);
-			if (touch)
-				contact = true;
-		}
+	for (i = 0; i < priv->chip->max_touches; i++) {
+		touch = priv->chip->parse_touch_data(touchdata, i, &x, &y);
 
 		input_mt_slot(input, i);
-		input_mt_report_slot_state(input, MT_TOOL_FINGER, touch);
-		if (!touch)
-			continue;
-		touchscreen_report_pos(input, &priv->prop, x, y,
-				       true);
+		if (input_mt_report_slot_state(input, MT_TOOL_FINGER, touch)) {
+			touchscreen_report_pos(input, &priv->prop, x, y, true);
+			contact = true;
+		}
 	}
 
 	input_mt_report_pointer_emulation(input, false);
 	input_sync(input);
 
-	if (priv->model == MODEL_ILI210X)
-		contact = touchdata[0] & 0xf3;
-
 	return contact;
 }
 
@@ -199,50 +261,25 @@ static irqreturn_t ili210x_irq(int irq, void *irq_data)
 {
 	struct ili210x *priv = irq_data;
 	struct i2c_client *client = priv->client;
-	u8 touchdata[64] = { 0 };
-	s16 sum = 0;
+	const struct ili2xxx_chip *chip = priv->chip;
+	u8 touchdata[ILI210X_DATA_SIZE] = { 0 };
+	bool keep_polling;
 	bool touch;
-	int i;
 	int error;
 
 	do {
-		if (priv->model == MODEL_ILI210X) {
-			error = ili210x_read_reg(client, REG_TOUCHDATA,
-						 touchdata, sizeof(touchdata));
-		} else if (priv->model == MODEL_ILI211X) {
-			error = ili210x_read(client, touchdata, 43);
-			if (!error) {
-				/*
-				 * This chip uses custom checksum at the end
-				 * of data.
-				 */
-				for (i = 0; i <= 41; i++)
-					sum = (sum + touchdata[i]) & 0xff;
-				if ((-sum & 0xff) != touchdata[42]) {
-					dev_err(&client->dev,
-						"CRC error (crc=0x%02x expected=0x%02x)\n",
-						sum, touchdata[42]);
-					break;
-				}
-			}
-		} else if (priv->model == MODEL_ILI251X) {
-			error = ili210x_read_reg(client, REG_TOUCHDATA,
-						 touchdata, 31);
-			if (!error && touchdata[0] == 2)
-				error = ili210x_read(client,
-						     &touchdata[31], 20);
-		}
-
+		error = chip->get_touch_data(client, touchdata);
 		if (error) {
 			dev_err(&client->dev,
-				"Unable to get touchdata, err = %d\n", error);
+				"Unable to get touch data: %d\n", error);
 			break;
 		}
 
 		touch = ili210x_report_events(priv, touchdata);
-		if (touch)
+		keep_polling = chip->continue_polling(touchdata, touch);
+		if (keep_polling)
 			msleep(ILI2XXX_POLL_PERIOD);
-	} while (!priv->stop && touch);
+	} while (!priv->stop && keep_polling);
 
 	return IRQ_HANDLED;
 }
@@ -298,20 +335,26 @@ static void ili210x_stop(void *data)
 }
 
 static int ili210x_i2c_probe(struct i2c_client *client,
-				       const struct i2c_device_id *id)
+			     const struct i2c_device_id *id)
 {
 	struct device *dev = &client->dev;
+	const struct ili2xxx_chip *chip;
 	struct ili210x *priv;
 	struct gpio_desc *reset_gpio;
 	struct input_dev *input;
 	struct firmware_version firmware;
-	enum ili2xxx_model model;
 	int error;
 
-	model = (enum ili2xxx_model)id->driver_data;
-
 	dev_dbg(dev, "Probing for ILI210X I2C Touschreen driver");
 
+	chip = device_get_match_data(dev);
+	if (!chip && id)
+		chip = (const struct ili2xxx_chip *)id->driver_data;
+	if (!chip) {
+		dev_err(&client->dev, "unknown device model\n");
+		return -ENODEV;
+	}
+
 	if (client->irq <= 0) {
 		dev_err(dev, "No IRQ!\n");
 		return -EINVAL;
@@ -343,19 +386,12 @@ static int ili210x_i2c_probe(struct i2c_client *client,
 	priv->client = client;
 	priv->input = input;
 	priv->reset_gpio = reset_gpio;
-	priv->model = model;
-	if (model == MODEL_ILI210X)
-		priv->max_touches = ILI210X_TOUCHES;
-	if (model == MODEL_ILI211X)
-		priv->max_touches = ILI211X_TOUCHES;
-	if (model == MODEL_ILI251X)
-		priv->max_touches = ILI251X_TOUCHES;
-
+	priv->chip = chip;
 	i2c_set_clientdata(client, priv);
 
 	/* Get firmware version */
-	error = ili210x_read_reg(client, REG_FIRMWARE_VERSION,
-				 &firmware, sizeof(firmware));
+	error = chip->read_reg(client, REG_FIRMWARE_VERSION,
+			       &firmware, sizeof(firmware));
 	if (error) {
 		dev_err(dev, "Failed to get firmware version, err: %d\n",
 			error);
@@ -371,7 +407,8 @@ static int ili210x_i2c_probe(struct i2c_client *client,
 	input_set_abs_params(input, ABS_MT_POSITION_Y, 0, 0xffff, 0, 0);
 	touchscreen_parse_properties(input, true, &priv->prop);
 
-	error = input_mt_init_slots(input, priv->max_touches, INPUT_MT_DIRECT);
+	error = input_mt_init_slots(input, priv->chip->max_touches,
+				    INPUT_MT_DIRECT);
 	if (error) {
 		dev_err(dev, "Unable to set up slots, err: %d\n", error);
 		return error;
@@ -435,18 +472,18 @@ static SIMPLE_DEV_PM_OPS(ili210x_i2c_pm,
 			 ili210x_i2c_suspend, ili210x_i2c_resume);
 
 static const struct i2c_device_id ili210x_i2c_id[] = {
-	{ "ili210x", MODEL_ILI210X },
-	{ "ili2117", MODEL_ILI211X },
-	{ "ili251x", MODEL_ILI251X },
+	{ "ili210x", (long)&ili210x_chip },
+	{ "ili2117", (long)&ili211x_chip },
+	{ "ili251x", (long)&ili251x_chip },
 	{ }
 };
 MODULE_DEVICE_TABLE(i2c, ili210x_i2c_id);
 
 static const struct of_device_id ili210x_dt_ids[] = {
-	{ .compatible = "ilitek,ili210x", .data = (void *)MODEL_ILI210X },
-	{ .compatible = "ilitek,ili2117", .data = (void *)MODEL_ILI211X },
-	{ .compatible = "ilitek,ili251x", .data = (void *)MODEL_ILI251X },
-	{ },
+	{ .compatible = "ilitek,ili210x", .data = &ili210x_chip },
+	{ .compatible = "ilitek,ili2117", .data = &ili211x_chip },
+	{ .compatible = "ilitek,ili251x", .data = &ili251x_chip },
+	{ }
 };
 MODULE_DEVICE_TABLE(of, ili210x_dt_ids);