> -----Original Message----- > From: Aleksei Mamlin [mailto:mamlinav@xxxxxxxxx] > Sent: 15 September, 2015 12:48 > To: Tirdea, Irina > Cc: Dmitry Torokhov; Bastien Nocera; linux-input@xxxxxxxxxxxxxxx; Mark Rutland; Purdila, Octavian; linux-kernel@xxxxxxxxxxxxxxx; > devicetree@xxxxxxxxxxxxxxx > Subject: Re: [PATCH v5 3/9] Input: goodix - reset device at init > > On Mon, 7 Sep 2015 17:36:17 +0300 > Irina Tirdea <irina.tirdea@xxxxxxxxx> wrote: > > > After power on, it is recommended that the driver resets the device. > > The reset procedure timing is described in the datasheet and is used > > at device init (before writing device configuration) and > > for power management. It is a sequence of setting the interrupt > > and reset pins high/low at specific timing intervals. This procedure > > also includes setting the slave address to the one specified in the > > ACPI/device tree. > > > > This is based on Goodix datasheets for GT911 and GT9271 and on Goodix > > driver gt9xx.c for Android (publicly available in Android kernel > > trees for various devices). > > > > For reset the driver needs to control the interrupt and > > reset gpio pins (configured through ACPI/device tree). For devices > > that do not have the gpio pins declared, the functionality depending > > on these pins will not be available, but the device can still be used > > with basic functionality. > > > > Signed-off-by: Octavian Purdila <octavian.purdila@xxxxxxxxx> > > Signed-off-by: Irina Tirdea <irina.tirdea@xxxxxxxxx> > > --- > > .../bindings/input/touchscreen/goodix.txt | 5 + > > drivers/input/touchscreen/goodix.c | 136 +++++++++++++++++++++ > > 2 files changed, 141 insertions(+) > > <snip> > > +/** > > + * goodix_reset - Reset device during power on > > + * > > + * @ts: goodix_ts_data pointer > > + */ > > +static int goodix_reset(struct goodix_ts_data *ts) > > +{ > > + int error; > > + > > + /* begin select I2C slave addr */ > > + error = gpiod_direction_output(ts->gpiod_rst, 0); > > + if (error) > > + return error; > > + msleep(20); /* T2: > 10ms */ > > + /* HIGH: 0x28/0x29, LOW: 0xBA/0xBB */ > > + error = gpiod_direction_output(ts->gpiod_int, ts->client->addr == 0x14); > > + if (error) > > + return error; > > + usleep_range(100, 2000); /* T3: > 100us */ > > + error = gpiod_direction_output(ts->gpiod_rst, 1); > > + if (error) > > + return error; > > + usleep_range(6000, 10000); /* T4: > 5ms */ > > + /* end select I2C slave addr */ > > + error = gpiod_direction_input(ts->gpiod_rst); > > + if (error) > > + return error; > > + return goodix_int_sync(ts); > > +} > > + <snip> > > /** > > * goodix_read_config - Read the embedded configuration of the panel > > * > > @@ -419,6 +542,19 @@ static int goodix_ts_probe(struct i2c_client *client, > > > > ts->cfg_len = goodix_get_cfg_len(id_info); > > > > + error = goodix_get_gpio_config(ts, id); > > + if (error) > > + return error; > > + > > + if (ts->gpiod_int && ts->gpiod_rst) { > > + /* reset the controller */ > > + error = goodix_reset(ts); > > + if (error) { > > + dev_err(&client->dev, "Controller reset failed.\n"); > > + return error; > > + } > > + } > > + > > On devices with devicetree, such as ARM tablets, we can set I2C address via DT, so driver should reset controller and set right address. > If we don't do this we get "I2C communication failure: -6". > This is exactly what this patch tries to do. The address set in ACPI or DT will be available in ts->client->addr. The reset code checks for the address set by ACPI/DT and configures the device to use that address. > Also, most of touchscreen drivers tries to reset controllers before start communicating, so we need do the same. Good catch! goodix_reset should be called before goodix_i2c_test. I'll send a new version with this fix. Thanks, Irina > > > goodix_read_config(ts); > > > > error = goodix_request_input_dev(ts, version_info, id_info); > > -- > > 1.9.1 > > > > > -- > Thanks and regards, > Aleksei Mamlin -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
