Input: st1232 - add support resolution reading

Hard-coding resolution for st1633 device was wrong. Some of LCDs like
YTS700TLBC-02-100C has assembled Sitronix st1633 touchcontroller too. But
the resolution is not 320x480 as was hard-coded.
Add new function which reads correct resolution directly from register.

Signed-off-by: Andrej Valek <andrej.valek@siemens.com>
Link: https://lore.kernel.org/r/20201103073949.12198-1-andrej.valek@siemens.com
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

diff --git a/drivers/input/touchscreen/st1232.c b/drivers/input/touchscreen/st1232.c
index 63b29c7..bda9676 100644 (file)
--- a/drivers/input/touchscreen/st1232.c
+++ b/drivers/input/touchscreen/st1232.c
@@ -26,15 +26,14 @@
 #define ST1232_TS_NAME "st1232-ts"
 #define ST1633_TS_NAME "st1633-ts"
 
+#define REG_XY_RESOLUTION      0x04
+#define REG_XY_COORDINATES     0x12
 #define ST_TS_MAX_FINGERS      10
 
 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 {
@@ -48,15 +47,14 @@ struct st1232_ts_data {
        u8 *read_buf;
 };
 
-static int st1232_ts_read_data(struct st1232_ts_data *ts)
+static int st1232_ts_read_data(struct st1232_ts_data *ts, u8 reg)
 {
        struct i2c_client *client = ts->client;
-       u8 start_reg = ts->chip_info->start_reg;
        struct i2c_msg msg[] = {
                {
                        .addr   = client->addr,
-                       .len    = sizeof(start_reg),
-                       .buf    = &start_reg,
+                       .len    = sizeof(reg),
+                       .buf    = &reg,
                },
                {
                        .addr   = client->addr,
@@ -74,6 +72,25 @@ static int st1232_ts_read_data(struct st1232_ts_data *ts)
        return 0;
 }
 
+static int st1232_ts_read_resolution(struct st1232_ts_data *ts, u16 *max_x,
+                                    u16 *max_y)
+{
+       u8 *buf;
+       int error;
+
+       /* select resolution register */
+       error = st1232_ts_read_data(ts, REG_XY_RESOLUTION);
+       if (error)
+               return error;
+
+       buf = ts->read_buf;
+
+       *max_x = ((buf[0] & 0x0070) << 4) | buf[1];
+       *max_y = ((buf[0] & 0x0007) << 8) | buf[2];
+
+       return 0;
+}
+
 static int st1232_ts_parse_and_report(struct st1232_ts_data *ts)
 {
        struct input_dev *input = ts->input_dev;
@@ -123,7 +140,7 @@ static irqreturn_t st1232_ts_irq_handler(int irq, void *dev_id)
        int count;
        int error;
 
-       error = st1232_ts_read_data(ts);
+       error = st1232_ts_read_data(ts, REG_XY_COORDINATES);
        if (error)
                goto out;
 
@@ -157,20 +174,14 @@ static void st1232_ts_power_off(void *data)
 
 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,
@@ -179,6 +190,7 @@ static int st1232_ts_probe(struct i2c_client *client,
        const struct st_chip_info *match;
        struct st1232_ts_data *ts;
        struct input_dev *input_dev;
+       u16 max_x, max_y;
        int error;
 
        match = device_get_match_data(&client->dev);
@@ -239,14 +251,22 @@ static int st1232_ts_probe(struct i2c_client *client,
        input_dev->name = "st1232-touchscreen";
        input_dev->id.bustype = BUS_I2C;
 
+       /* Read resolution from the chip */
+       error = st1232_ts_read_resolution(ts, &max_x, &max_y);
+       if (error) {
+               dev_err(&client->dev,
+                       "Failed to read resolution: %d\n", error);
+               return error;
+       }
+
        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);
+                            0, max_x, 0, 0);
        input_set_abs_params(input_dev, ABS_MT_POSITION_Y,
-                            0, ts->chip_info->max_y, 0, 0);
+                            0, max_y, 0, 0);
 
        touchscreen_parse_properties(input_dev, true, &ts->prop);