From dd802fc03b1c71b4297e87068077bfcf9810300a Mon Sep 17 00:00:00 2001 From: Nick Hollinghurst Date: Wed, 11 Oct 2023 15:14:59 +0100 Subject: [PATCH] input: touchscreen: edt-ft5x06: Suppress bogus data on startup When polled without the use of IRQ, FT5x06 registers may return undefined initial data, causing unwanted touches or event spamming. A simple way to filter this out is to suppress touches until the TD_STATUS register changes for the first time. Increase the delay before first polling to 300ms, to avoid transient I2C read flakiness that seems to occur after reset. Signed-off-by: Nick Hollinghurst --- drivers/input/touchscreen/edt-ft5x06.c | 31 +++++++++++++++++++++++--- 1 file changed, 28 insertions(+), 3 deletions(-) --- a/drivers/input/touchscreen/edt-ft5x06.c +++ b/drivers/input/touchscreen/edt-ft5x06.c @@ -75,6 +75,8 @@ #define EDT_DEFAULT_NUM_X 1024 #define EDT_DEFAULT_NUM_Y 1024 +#define RESET_DELAY_MS 300 /* reset deassert to I2C */ +#define FIRST_POLL_DELAY_MS 300 /* in addition to the above */ #define POLL_INTERVAL_MS 17 /* 17ms = 60fps */ enum edt_pmode { @@ -134,6 +136,7 @@ struct edt_ft5x06_ts_data { char name[EDT_NAME_LEN]; char fw_version[EDT_NAME_LEN]; + int init_td_status; struct edt_reg_addr reg_addr; enum edt_ver version; @@ -268,12 +271,33 @@ static irqreturn_t edt_ft5x06_ts_isr(int * points. */ num_points = min(rdbuf[2] & 0xf, tsdata->max_support_points); + + /* When polling FT5x06 without IRQ: initial register contents + * could be stale or undefined; discard all readings until + * TD_STATUS changes for the first time (or num_points is 0). + */ + if (tsdata->init_td_status) { + if (tsdata->init_td_status < 0) + tsdata->init_td_status = rdbuf[2]; + + if (num_points && rdbuf[2] == tsdata->init_td_status) + goto out; + + tsdata->init_td_status = 0; + } + if (num_points) { datalen = tplen * num_points + crclen; cmd = offset; error = edt_ft5x06_ts_readwrite(tsdata->client, sizeof(cmd), &cmd, datalen, &rdbuf[offset]); + if (error) { + dev_err_ratelimited(dev, + "Unable to fetch data, error: %d\n", + error); + goto out; + } } } @@ -1294,7 +1318,7 @@ static int edt_ft5x06_ts_probe(struct i2 if (tsdata->reset_gpio) { usleep_range(5000, 6000); gpiod_set_value_cansleep(tsdata->reset_gpio, 0); - msleep(300); + msleep(RESET_DELAY_MS); } input = devm_input_allocate_device(&client->dev); @@ -1384,11 +1408,12 @@ static int edt_ft5x06_ts_probe(struct i2 return error; } } else { + tsdata->init_td_status = -1; /* filter bogus initial data */ INIT_WORK(&tsdata->work_i2c_poll, edt_ft5x06_ts_work_i2c_poll); timer_setup(&tsdata->timer, edt_ft5x06_ts_irq_poll_timer, 0); - tsdata->timer.expires = jiffies + - msecs_to_jiffies(POLL_INTERVAL_MS); + tsdata->timer.expires = + jiffies + msecs_to_jiffies(FIRST_POLL_DELAY_MS); add_timer(&tsdata->timer); }