Commit e112324c authored Jan 09, 2020 by Philipp Zabel Committed by Dmitry Torokhov Jan 10, 2020

Input: edt-ft5x06 - work around first register access error



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>

parent fd7bba68

drivers/input/touchscreen/edt-ft5x06.c

+7 −0

Original line number	Diff line number	Diff line
		@@ -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);