[PATCH 4.19 015/267] Input: mms114 - fix handling of mms345l

Greg Kroah-Hartman
2020-06-19T14:53:50Z

From: Stephan Gerhold <stephan@gerhold.net>

[ Upstream commit 3f8f770575d911c989043d8f0fb8dec96360c41c ]

MMS345L is another first generation touch screen from Melfas,
which uses the same registers as MMS152.

However, using I2C_M_NOSTART for it causes errors when reading:

i2c i2c-0: sendbytes: NAK bailout.
mms114 0-0048: __mms114_read_reg: i2c transfer failed (-5)

The driver works fine as soon as I2C_M_NOSTART is removed.

Reviewed-by: Andi Shyti <andi@etezian.org>
Signed-off-by: Stephan Gerhold <stephan@gerhold.net>
Link: https://lore.kernel.org/r/20200405170904.61512-1-stephan@gerhold.net
[dtor: removed separate mms345l handling, made everyone use standard
transfer mode, propagated the 10bit addressing flag to the read part of the
transfer as well.]
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/input/touchscreen/mms114.c | 12 +++++-------
1 file changed, 5 insertions(+), 7 deletions(-)

diff --git a/drivers/input/touchscreen/mms114.c b/drivers/input/touchscreen/mms114.c
index a5ab774da4cc..fca908ba4841 100644
--- a/drivers/input/touchscreen/mms114.c
+++ b/drivers/input/touchscreen/mms114.c
@@ -91,15 +91,15 @@ static int __mms114_read_reg(struct mms114_data *data, unsigned int reg,
if (reg <= MMS114_MODE_CONTROL && reg + len > MMS114_MODE_CONTROL)
BUG();

- /* Write register: use repeated start */
+ /* Write register */
xfer[0].addr = client->addr;
- xfer[0].flags = I2C_M_TEN | I2C_M_NOSTART;
+ xfer[0].flags = client->flags & I2C_M_TEN;
xfer[0].len = 1;
xfer[0].buf = &buf;

/* Read data */
xfer[1].addr = client->addr;
- xfer[1].flags = I2C_M_RD;
+ xfer[1].flags = (client->flags & I2C_M_TEN) | I2C_M_RD;
xfer[1].len = len;
xfer[1].buf = val;

@@ -428,10 +428,8 @@ static int mms114_probe(struct i2c_client *client,
const void *match_data;
int error;

- if (!i2c_check_functionality(client->adapter,
- I2C_FUNC_PROTOCOL_MANGLING)) {
- dev_err(&client->dev,
- "Need i2c bus that supports protocol mangling\n");
+ if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
+ dev_err(&client->dev, "Not supported I2C adapter\n");
return -ENODEV;
}

--
2.25.1