Messages in this thread | | | From | "Jonas Mark (BT-FIR/ENG1)" <> | Subject | Re: [PATCH] Input: add bu21029 touch driver | Date | Tue, 27 Mar 2018 06:57:42 +0000 |
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Hello Dmitry,
> > +++ b/drivers/input/touchscreen/bu21029_ts.c > > @@ -0,0 +1,456 @@ > > Please add SPDX tag for the driver.
We will do.
> Please use GPIOD API (and include linux/gpio/consumer.h instead of > of_gpio.h).
We will do the change.
> > +/* HW_ID1 Register (PAGE=0, ADDR=0x0E, Reset value=0x02, Read only) > > Multi-line comments start with empty comment line: > > /* > * Multi > * line. > */
Will be fixed.
> > + /* calculate Rz (pressure resistance value) by equation: > > + * Rz = Rx * (x/Q) * ((z2/z1) - 1), where > > + * Rx is x-plate resistance, > > + * Q is the touch screen resolution (8bit = 256, 12bit = 4096) > > + * x, z1, z2 are the measured positions. > > + */ > > + rz = z2 - z1; > > + rz *= x; > > + rz *= bu21029->x_plate_ohms; > > + rz /= z1; > > + rz = DIV_ROUND_CLOSEST(rz, SCALE_12BIT); > > + if (rz <= bu21029->max_pressure) { > > + input_report_abs(bu21029->in_dev, ABS_X, x); > > + input_report_abs(bu21029->in_dev, ABS_Y, y); > > + input_report_abs(bu21029->in_dev, ABS_PRESSURE, rz); > > What is the values of pressure reported when finger is touching the > surface? IOW is 'rz' pressure or resistance?
Rz is pressure measured in Ohms. That is, it is a resistance which correlates with finger pressure.
I fear that I do not understand your question. Does ABS_PRESSURE have to be reported in a specific unit, e.g. milli Newton? We thought that it is a device specific scale and that it will be converted into a calibrated value (just like the coordinates) in user space.
> > + if (of_property_read_u32(np, "touchscreen-max-pressure", &val32)) > > + bu21029->max_pressure = MAX_12BIT; > > + else > > + bu21029->max_pressure = val32; > > Please use infrastructure form include/linux/input/touchscreen.h > so that you handle different sizes and orientations.
Thank you for this recommendation. We will check it out and send a new proposal.
> > + in_dev->name = DRIVER_NAME; > > + in_dev->id.bustype = BUS_I2C; > > + in_dev->dev.parent = &client->dev; > > Not needed with devm_input_allocate_device().
We will have a look at the other drivers.
> > +static int bu21029_remove(struct i2c_client *client) > > +{ > > + struct bu21029_ts_data *bu21029 = i2c_get_clientdata(client); > > + > > + del_timer_sync(&bu21029->timer); > > If interrupt comes here kernel will be unhappy. You need to either work > canceling timer into devm unwid stream (devm_add_action_or_reset()) or > somehow make sure that you shut off interrupts before canceling the > timer.
We will work on a solution. Thank you for spotting this.
> > > + > > + return 0; > > +}
> > +static struct i2c_driver bu21029_driver = { > > + .driver = { > > + .name = DRIVER_NAME, > > + .owner = THIS_MODULE, > > Not needed.
OK, we will remove the .owner assignment.
Greetings, Mark Jonas
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