Input: st1232 - add support for st1633

Add support for the Sitronix ST1633 touchscreen controller to the st1232
driver. A protocol spec can be found here:
www.ampdisplay.com/documents/pdf/AM-320480B6TZQW-TC0H.pdf

Signed-off-by: Martin Kepplinger <martin.kepplinger@ginzinger.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

2 files changed, 89 insertions, 37 deletions

diff --git a/drivers/input/touchscreen/Kconfig b/drivers/input/touchscreen/Kconfig
index af6027cc7bbf..6c16aaeb4191 100644
--- a/drivers/input/touchscreen/Kconfig
+++ b/drivers/input/touchscreen/Kconfig
@@ -1168,11 +1168,11 @@ config TOUCHSCREEN_SIS_I2C
           module will be called sis_i2c.
 
 config TOUCHSCREEN_ST1232
-        tristate "Sitronix ST1232 touchscreen controllers"
+        tristate "Sitronix ST1232 or ST1633 touchscreen controllers"
         depends on I2C
         help
-          Say Y here if you want to support Sitronix ST1232
-          touchscreen controller.
+          Say Y here if you want to support the Sitronix ST1232
+          or ST1633 touchscreen controller.
 
           If unsure, say N.
 
diff --git a/drivers/input/touchscreen/st1232.c b/drivers/input/touchscreen/st1232.c
index 11ff32c68025..777df903605d 100644
--- a/drivers/input/touchscreen/st1232.c
+++ b/drivers/input/touchscreen/st1232.c
@@ -23,13 +23,7 @@
 #include <linux/types.h>
 
 #define ST1232_TS_NAME  "st1232-ts"
-
-#define MIN_X           0x00
-#define MIN_Y           0x00
-#define MAX_X           0x31f   /* (800 - 1) */
-#define MAX_Y           0x1df   /* (480 - 1) */
-#define MAX_AREA        0xff
-#define MAX_FINGERS     2
+#define ST1633_TS_NAME  "st1633-ts"
 
 struct st1232_ts_finger {
         u16 x;
@@ -38,12 +32,24 @@ struct st1232_ts_finger {
         bool is_valid;
 };
 
+struct st_chip_info {
+        bool    have_z;
+        u16     max_x;
+        u16     max_y;
+        u16     max_area;
+        u16     max_fingers;
+        u8      start_reg;
+};
+
 struct st1232_ts_data {
         struct i2c_client *client;
         struct input_dev *input_dev;
-        struct st1232_ts_finger finger[MAX_FINGERS];
         struct dev_pm_qos_request low_latency_req;
         int reset_gpio;
+        const struct st_chip_info *chip_info;
+        int read_buf_len;
+        u8 *read_buf;
+        struct st1232_ts_finger *finger;
 };
 
 static int st1232_ts_read_data(struct st1232_ts_data *ts)
@@ -52,40 +58,35 @@ static int st1232_ts_read_data(struct st1232_ts_data *ts)
         struct i2c_client *client = ts->client;
         struct i2c_msg msg[2];
         int error;
-        u8 start_reg;
-        u8 buf[10];
+        int i, y;
+        u8 start_reg = ts->chip_info->start_reg;
+        u8 *buf = ts->read_buf;
 
-        /* read touchscreen data from ST1232 */
+        /* read touchscreen data */
         msg[0].addr = client->addr;
         msg[0].flags = 0;
         msg[0].len = 1;
         msg[0].buf = &start_reg;
-        start_reg = 0x10;
 
         msg[1].addr = ts->client->addr;
         msg[1].flags = I2C_M_RD;
-        msg[1].len = sizeof(buf);
+        msg[1].len = ts->read_buf_len;
         msg[1].buf = buf;
 
         error = i2c_transfer(client->adapter, msg, 2);
         if (error < 0)
                 return error;
 
-        /* get "valid" bits */
-        finger[0].is_valid = buf[2] >> 7;
-        finger[1].is_valid = buf[5] >> 7;
-
-        /* get xy coordinate */
-        if (finger[0].is_valid) {
-                finger[0].x = ((buf[2] & 0x0070) << 4) | buf[3];
-                finger[0].y = ((buf[2] & 0x0007) << 8) | buf[4];
-                finger[0].t = buf[8];
-        }
+        for (i = 0, y = 0; i < ts->chip_info->max_fingers; i++, y += 3) {
+                finger[i].is_valid = buf[i + y] >> 7;
+                if (finger[i].is_valid) {
+                        finger[i].x = ((buf[i + y] & 0x0070) << 4) | buf[i + 1];
+                        finger[i].y = ((buf[i + y] & 0x0007) << 8) | buf[i + 2];
 
-        if (finger[1].is_valid) {
-                finger[1].x = ((buf[5] & 0x0070) << 4) | buf[6];
-                finger[1].y = ((buf[5] & 0x0007) << 8) | buf[7];
-                finger[1].t = buf[9];
+                        /* st1232 includes a z-axis / touch strength */
+                        if (ts->chip_info->have_z)
+                                finger[i].t = buf[i + 6];
+                }
         }
 
         return 0;
@@ -104,11 +105,14 @@ static irqreturn_t st1232_ts_irq_handler(int irq, void *dev_id)
                 goto end;
 
         /* multi touch protocol */
-        for (i = 0; i < MAX_FINGERS; i++) {
+        for (i = 0; i < ts->chip_info->max_fingers; i++) {
                 if (!finger[i].is_valid)
                         continue;
 
-                input_report_abs(input_dev, ABS_MT_TOUCH_MAJOR, finger[i].t);
+                if (ts->chip_info->have_z)
+                        input_report_abs(input_dev, ABS_MT_TOUCH_MAJOR,
+                                         finger[i].t);
+
                 input_report_abs(input_dev, ABS_MT_POSITION_X, finger[i].x);
                 input_report_abs(input_dev, ABS_MT_POSITION_Y, finger[i].y);
                 input_mt_sync(input_dev);
@@ -142,13 +146,41 @@ static void st1232_ts_power(struct st1232_ts_data *ts, bool poweron)
                 gpio_direction_output(ts->reset_gpio, poweron);
 }
 
+static const struct st_chip_info st1232_chip_info = {
+        .have_z         = true,
+        .max_x          = 0x31f, /* 800 - 1 */
+        .max_y          = 0x1df, /* 480 -1 */
+        .max_area       = 0xff,
+        .max_fingers    = 2,
+        .start_reg      = 0x12,
+};
+
+static const struct st_chip_info st1633_chip_info = {
+        .have_z         = false,
+        .max_x          = 0x13f, /* 320 - 1 */
+        .max_y          = 0x1df, /* 480 -1 */
+        .max_area       = 0x00,
+        .max_fingers    = 5,
+        .start_reg      = 0x12,
+};
+
 static int st1232_ts_probe(struct i2c_client *client,
                            const struct i2c_device_id *id)
 {
+        const struct st_chip_info *match;
         struct st1232_ts_data *ts;
+        struct st1232_ts_finger *finger;
         struct input_dev *input_dev;
         int error;
 
+        match = device_get_match_data(&client->dev);
+        if (!match && id)
+                match = (const void *)id->driver_data;
+        if (!match) {
+                dev_err(&client->dev, "unknown device model\n");
+                return -ENODEV;
+        }
+
         if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
                 dev_err(&client->dev, "need I2C_FUNC_I2C\n");
                 return -EIO;
@@ -163,6 +195,19 @@ static int st1232_ts_probe(struct i2c_client *client,
         if (!ts)
                 return -ENOMEM;
 
+        ts->chip_info = match;
+        ts->finger = devm_kcalloc(&client->dev,
+                                  ts->chip_info->max_fingers, sizeof(*finger),
+                                  GFP_KERNEL);
+        if (!ts->finger)
+                return -ENOMEM;
+
+        /* allocate a buffer according to the number of registers to read */
+        ts->read_buf_len = ts->chip_info->max_fingers * 4;
+        ts->read_buf = devm_kzalloc(&client->dev, ts->read_buf_len, GFP_KERNEL);
+        if (!ts->read_buf)
+                return -ENOMEM;
+
         input_dev = devm_input_allocate_device(&client->dev);
         if (!input_dev)
                 return -ENOMEM;
@@ -192,9 +237,14 @@ static int st1232_ts_probe(struct i2c_client *client,
         __set_bit(EV_KEY, input_dev->evbit);
         __set_bit(EV_ABS, input_dev->evbit);
 
-        input_set_abs_params(input_dev, ABS_MT_TOUCH_MAJOR, 0, MAX_AREA, 0, 0);
-        input_set_abs_params(input_dev, ABS_MT_POSITION_X, MIN_X, MAX_X, 0, 0);
-        input_set_abs_params(input_dev, ABS_MT_POSITION_Y, MIN_Y, MAX_Y, 0, 0);
+        if (ts->chip_info->have_z)
+                input_set_abs_params(input_dev, ABS_MT_TOUCH_MAJOR, 0,
+                                     ts->chip_info->max_area, 0, 0);
+
+        input_set_abs_params(input_dev, ABS_MT_POSITION_X,
+                             0, ts->chip_info->max_x, 0, 0);
+        input_set_abs_params(input_dev, ABS_MT_POSITION_Y,
+                             0, ts->chip_info->max_y, 0, 0);
 
         error = devm_request_threaded_irq(&client->dev, client->irq,
                                           NULL, st1232_ts_irq_handler,
@@ -261,13 +311,15 @@ static SIMPLE_DEV_PM_OPS(st1232_ts_pm_ops,
                          st1232_ts_suspend, st1232_ts_resume);
 
 static const struct i2c_device_id st1232_ts_id[] = {
-        { ST1232_TS_NAME, 0 },
+        { ST1232_TS_NAME, (unsigned long)&st1232_chip_info },
+        { ST1633_TS_NAME, (unsigned long)&st1633_chip_info },
         { }
 };
 MODULE_DEVICE_TABLE(i2c, st1232_ts_id);
 
 static const struct of_device_id st1232_ts_dt_ids[] = {
-        { .compatible = "sitronix,st1232", },
+        { .compatible = "sitronix,st1232", .data = &st1232_chip_info },
+        { .compatible = "sitronix,st1633", .data = &st1633_chip_info },
         { }
 };
 MODULE_DEVICE_TABLE(of, st1232_ts_dt_ids);