[PATCH 8/8] Input: st1232 - switch to using MT-B protocol

Dmitry Torokhov
2019-10-22T19:56:43Z

Switch the driver to the slotted variant of multitouch protocol (MT-B)
with in-kernel tracking of the contacts.

Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

---

drivers/input/touchscreen/st1232.c | 110 +++++++++++++++--------------
1 file changed, 56 insertions(+), 54 deletions(-)

diff --git a/drivers/input/touchscreen/st1232.c b/drivers/input/touchscreen/st1232.c
index a4a3b82ee69d..63b29c7279e2 100644
--- a/drivers/input/touchscreen/st1232.c
+++ b/drivers/input/touchscreen/st1232.c
@@ -14,23 +14,19 @@
#include <linux/gpio/consumer.h>
#include <linux/i2c.h>
#include <linux/input.h>
+#include <linux/input/mt.h>
+#include <linux/input/touchscreen.h>
#include <linux/interrupt.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/pm_qos.h>
#include <linux/slab.h>
#include <linux/types.h>
-#include <linux/input/touchscreen.h>

#define ST1232_TS_NAME "st1232-ts"
#define ST1633_TS_NAME "st1633-ts"

-struct st1232_ts_finger {
- u16 x;
- u16 y;
- u8 t;
- bool is_valid;
-};
+#define ST_TS_MAX_FINGERS 10

struct st_chip_info {
bool have_z;
@@ -50,12 +46,10 @@ struct st1232_ts_data {
const struct st_chip_info *chip_info;
int read_buf_len;
u8 *read_buf;
- struct st1232_ts_finger fingers[];
};

static int st1232_ts_read_data(struct st1232_ts_data *ts)
{
- struct st1232_ts_finger *finger = ts->fingers;
struct i2c_client *client = ts->client;
u8 start_reg = ts->chip_info->start_reg;
struct i2c_msg msg[] = {
@@ -72,59 +66,69 @@ static int st1232_ts_read_data(struct st1232_ts_data *ts)
}
};
int ret;
- int i;
- u8 *buf;

ret = i2c_transfer(client->adapter, msg, ARRAY_SIZE(msg));
if (ret != ARRAY_SIZE(msg))
return ret < 0 ? ret : -EIO;

+ return 0;
+}
+
+static int st1232_ts_parse_and_report(struct st1232_ts_data *ts)
+{
+ struct input_dev *input = ts->input_dev;
+ struct input_mt_pos pos[ST_TS_MAX_FINGERS];
+ u8 z[ST_TS_MAX_FINGERS];
+ int slots[ST_TS_MAX_FINGERS];
+ int n_contacts = 0;
+ int i;
+
for (i = 0; i < ts->chip_info->max_fingers; i++) {
- buf = &ts->read_buf[i * 4];
- finger[i].is_valid = buf[0] >> 7;
- if (finger[i].is_valid) {
- finger[i].x = ((buf[0] & 0x70) << 4) | buf[1];
- finger[i].y = ((buf[0] & 0x07) << 8) | buf[2];
+ u8 *buf = &ts->read_buf[i * 4];
+
+ if (buf[0] & BIT(7)) {
+ unsigned int x = ((buf[0] & 0x70) << 4) | buf[1];
+ unsigned int y = ((buf[0] & 0x07) << 8) | buf[2];
+
+ touchscreen_set_mt_pos(&pos[n_contacts],
+ &ts->prop, x, y);

/* st1232 includes a z-axis / touch strength */
if (ts->chip_info->have_z)
- finger[i].t = ts->read_buf[i + 6];
+ z[n_contacts] = ts->read_buf[i + 6];
+
+ n_contacts++;
}
}

- return 0;
+ input_mt_assign_slots(input, slots, pos, n_contacts, 0);
+ for (i = 0; i < n_contacts; i++) {
+ input_mt_slot(input, slots[i]);
+ input_mt_report_slot_state(input, MT_TOOL_FINGER, true);
+ input_report_abs(input, ABS_MT_POSITION_X, pos[i].x);
+ input_report_abs(input, ABS_MT_POSITION_Y, pos[i].y);
+ if (ts->chip_info->have_z)
+ input_report_abs(input, ABS_MT_TOUCH_MAJOR, z[i]);
+ }
+
+ input_mt_sync_frame(input);
+ input_sync(input);
+
+ return n_contacts;
}

static irqreturn_t st1232_ts_irq_handler(int irq, void *dev_id)
{
struct st1232_ts_data *ts = dev_id;
- struct st1232_ts_finger *finger = ts->fingers;
- struct input_dev *input_dev = ts->input_dev;
- int count = 0;
- int i, ret;
-
- ret = st1232_ts_read_data(ts);
- if (ret < 0)
- goto end;
-
- /* multi touch protocol */
- for (i = 0; i < ts->chip_info->max_fingers; i++) {
- if (!finger[i].is_valid)
- continue;
+ int count;
+ int error;

- if (ts->chip_info->have_z)
- input_report_abs(input_dev, ABS_MT_TOUCH_MAJOR,
- finger[i].t);
+ error = st1232_ts_read_data(ts);
+ if (error)
+ goto out;

- touchscreen_report_pos(input_dev, &ts->prop,
- finger[i].x, finger[i].y, true);
- input_mt_sync(input_dev);
- count++;
- }
-
- /* SYN_MT_REPORT only if no contact */
+ count = st1232_ts_parse_and_report(ts);
if (!count) {
- input_mt_sync(input_dev);
if (ts->low_latency_req.dev) {
dev_pm_qos_remove_request(&ts->low_latency_req);
ts->low_latency_req.dev = NULL;
@@ -136,10 +140,7 @@ static irqreturn_t st1232_ts_irq_handler(int irq, void *dev_id)
DEV_PM_QOS_RESUME_LATENCY, 100);
}

- /* SYN_REPORT */
- input_sync(input_dev);
-
-end:
+out:
return IRQ_HANDLED;
}

@@ -198,9 +199,7 @@ static int st1232_ts_probe(struct i2c_client *client,
return -EINVAL;
}

- ts = devm_kzalloc(&client->dev,
- struct_size(ts, fingers, match->max_fingers),
- GFP_KERNEL);
+ ts = devm_kzalloc(&client->dev, sizeof(*ts), GFP_KERNEL);
if (!ts)
return -ENOMEM;

@@ -240,11 +239,6 @@ static int st1232_ts_probe(struct i2c_client *client,
input_dev->name = "st1232-touchscreen";
input_dev->id.bustype = BUS_I2C;

- __set_bit(INPUT_PROP_DIRECT, input_dev->propbit);
- __set_bit(EV_SYN, input_dev->evbit);
- __set_bit(EV_KEY, input_dev->evbit);
- __set_bit(EV_ABS, input_dev->evbit);
-
if (ts->chip_info->have_z)
input_set_abs_params(input_dev, ABS_MT_TOUCH_MAJOR, 0,
ts->chip_info->max_area, 0, 0);
@@ -256,6 +250,14 @@ static int st1232_ts_probe(struct i2c_client *client,

touchscreen_parse_properties(input_dev, true, &ts->prop);

+ error = input_mt_init_slots(input_dev, ts->chip_info->max_fingers,
+ INPUT_MT_DIRECT | INPUT_MT_TRACK |
+ INPUT_MT_DROP_UNUSED);
+ if (error) {
+ dev_err(&client->dev, "failed to initialize MT slots\n");
+ return error;
+ }
+
error = devm_request_threaded_irq(&client->dev, client->irq,
NULL, st1232_ts_irq_handler,
IRQF_ONESHOT,
--
2.23.0.866.gb869b98d4c-goog