Hi Stephan, On Sun, Apr 05, 2020 at 07:09:03PM +0200, Stephan Gerhold wrote: > 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. > > Add a separate melfas,mms345l binding, and make use of I2C_M_NOSTART > only for MMS114 and MMS152. > > Reviewed-by: Andi Shyti <andi@xxxxxxxxxxx> > Signed-off-by: Stephan Gerhold <stephan@xxxxxxxxxxx> Sorry for sitting on this for so long. I looked around, and I think that instead of adding separate handling for 345L we shoudl simply drop the "no start" bit for everyone. I am not sure what the original version tried to do here, as far as I can see in various public Android trees the driver for these devices does not use I2C_M_NOSTART. Actually, I wonder if the difference is not in the touch controller that is being used, but rather in the I2C controller the device in connected to. I would like to apply the version of the patch below. Thanks. -- Dmitry Input: mms114 - fix handling of mms345l From: Stephan Gerhold <stephan@xxxxxxxxxxx> 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@xxxxxxxxxxx> Signed-off-by: Stephan Gerhold <stephan@xxxxxxxxxxx> Link: https://lore.kernel.org/r/20200405170904.61512-1-stephan@xxxxxxxxxxx Patchwork-Id: 11474771 [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@xxxxxxxxx> --- 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 69c6d559eeb0..2ef1adaed9af 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; }
