From: Sasha Levin <sashal@kernel.org>
To: linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc: Philipp Zabel <p.zabel@pengutronix.de>,
Marco Felsch <m.felsch@pengutronix.de>,
Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
Dmitry Torokhov <dmitry.torokhov@gmail.com>,
Sasha Levin <sashal@kernel.org>,
linux-input@vger.kernel.org
Subject: [PATCH AUTOSEL 4.14 115/186] Input: edt-ft5x06 - work around first register access error
Date: Fri, 14 Feb 2020 11:16:04 -0500 [thread overview]
Message-ID: <20200214161715.18113-115-sashal@kernel.org> (raw)
In-Reply-To: <20200214161715.18113-1-sashal@kernel.org>
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 5bf63f76dddac..4eff5b44640cf 100644
--- a/drivers/input/touchscreen/edt-ft5x06.c
+++ b/drivers/input/touchscreen/edt-ft5x06.c
@@ -888,6 +888,7 @@ 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;
@@ -957,6 +958,12 @@ 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
parent reply other threads:[~2020-02-14 16:51 UTC|newest]
Thread overview: expand[flat|nested] mbox.gz Atom feed
[parent not found: <20200214161715.18113-1-sashal@kernel.org>]
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