[PATCH v4 4/4] Input: st1232 - add support resolution reading

From: Andrej Valek
Date: Tue Nov 10 2020 - 13:16:48 EST


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@xxxxxxxxxxx>
---
drivers/input/touchscreen/st1232.c | 52 +++++++++++++++++++++---------
1 file changed, 36 insertions(+), 16 deletions(-)

diff --git a/drivers/input/touchscreen/st1232.c b/drivers/input/touchscreen/st1232.c
index 63b29c7279e29..1b4b139c85330 100644
--- 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 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);

--
2.20.1