On Wed, Nov 27, 2019 at 01:09:44PM +0100, Marco Felsch wrote:
> From: Philipp Zabel <p.zabel@xxxxxxxxxxxxxx>
>
> The EP0700MLP1 returns bogus data on the first register read access
> (reading the threshold parameter from register 0x00):
>
> edt_ft5x06 2-0038: crc error: 0xfc expected, got 0x40
>
> It ignores writes until then. This patch adds a dummy read after which
> the number of sensors and parameter read/writes work correctly.
>
> Signed-off-by: Philipp Zabel <p.zabel@xxxxxxxxxxxxxx>
Need your signed-off-by as well.
> ---
> drivers/input/touchscreen/edt-ft5x06.c | 7 +++++++
> 1 file changed, 7 insertions(+)
>
> diff --git a/drivers/input/touchscreen/edt-ft5x06.c b/drivers/input/touchscreen/edt-ft5x06.c
> index d61731c0037d..b87b1e074f62 100644
> --- a/drivers/input/touchscreen/edt-ft5x06.c
> +++ b/drivers/input/touchscreen/edt-ft5x06.c
> @@ -1050,6 +1050,7 @@ static int edt_ft5x06_ts_probe(struct i2c_client *client,
> {
> const struct edt_i2c_chip_data *chip_data;
> struct edt_ft5x06_ts_data *tsdata;
> + u8 buf[2] = { 0xfc, 0x00 };
> struct input_dev *input;
> unsigned long irq_flags;
> int error;
> @@ -1140,6 +1141,12 @@ static int edt_ft5x06_ts_probe(struct i2c_client *client,
> return error;
> }
>
> + /*
> + * Dummy read access. EP0700MLP1 returns bogus data on the first
> + * register read access and ignores writes.
> + */
> + edt_ft5x06_ts_readwrite(tsdata->client, 2, buf, 2, buf);
> +
> edt_ft5x06_ts_set_regs(tsdata);
> edt_ft5x06_ts_get_defaults(&client->dev, tsdata);
> edt_ft5x06_ts_get_parameters(tsdata);
> --
> 2.20.1
>
--
Dmitry
