Hi all, The Allwinner SoCs all have an ADC that can also act as a touchscreen controller and a thermal sensor. We currently have a driver for the two latter functions in drivers/input/touchscreen/sun4i-ts.c, but we don't have access to the ADC feature at all. Hence, I've been working on an IIO driver for that IP, with the hope that we could use iio-hwmon for the thermal sensor, and a yet-to-be-developped driver for the touchscreen part. The thermal sensor using iio_hwmon to communicate with the IIO driver is working fine. However, the touchscreen needs all the channels of the ADC to be able to get the coordinates. Moreover, you need to poke a few bits in some registers to switch the ADC mode and activate a few interrupts (pen-up and pen-down) to be able to operate as a touchscreen controller. Therefore, I need a way to ask the IIO driver to poke these bits from the input driver. For now, I am calling a function defined in my IIO driver from my input driver to ask to switch between modes. Is it how it is supposed to be done? Now that I switched to touchscreen mode, I need to get data from the IIO driver. I already get hardware interrupts in the IIO driver when something occurs with the touchscreen but now I need to notify the input driver that I received an interrupt for the touchscreen and make the associated data available to the input driver. For now, I am using a callback I set when probing the input driver and call this callback when the correct interrupt is detected in the IIO driver's interrupt handler. I pass the data through a parameter of this callback. However, I don't think it is a good idea since the IIO driver has no idea on what the callback is doing and it might just take too long to execute or even freeze, which is definitely not what we want in an interrupt handler. I've seen iio_channel_get_all_cb (http://lxr.free-electrons.com/source/include/linux/iio/consumer.h#L79) but I don't understand what it is doing or how to use it since there is not a single driver using this function. Can someone explain what it is supposed to do? If that callback mechanism isn't really supposed to address my use-case, do you have a suggestion on how to implement such a thing? Thanks, Quentin -- To unsubscribe from this list: send the line "unsubscribe linux-iio" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
