| From | Sasha Levin <> | Subject | [PATCH AUTOSEL 5.5 324/542] Input: edt-ft5x06 - work around first register access error | Date | Fri, 14 Feb 2020 10:45:16 -0500 |
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From: Philipp Zabel <p.zabel@pengutronix.de>
[ Upstream commit e112324cc0422c046f1cf54c56f333d34fa20885 ]
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@pengutronix.de> Signed-off-by: Marco Felsch <m.felsch@pengutronix.de> Tested-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com> Signed-off-by: Sasha Levin <sashal@kernel.org> --- 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 d61731c0037d1..b87b1e074f624 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
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