The Allwinner SoCs all have an ADC that can also act as a touchscreen controller and a thermal sensor. The first four channels can be used either for the ADC or the touchscreen and the fifth channel is used for the 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. This adds initial support for Allwinner SoCs ADC with all features. Yet, the touchscreen is not implemented but will be added later. To switch between touchscreen and ADC modes, you need to poke few bits in registers and (de)activate an interrupt (pen-up). A MFD is provided to let the input driver activate the pen-up interrupt through virtual interrupt, poke few bits via regmap and read data from the ADC driver while both (and iio_hwmon) are probed by the MFD. There exists slight modifications between the different SoCs ADC like the address of some registers and the scale and offset to apply to thermal sensor raw values. These modifications are done by drivers on different platform_device_id passed by the MFD when probing subdrivers. This also modifies iio-hwmon to allow probe deferring when no iio channel is found. Currently when no iio channel is found, the probing of iio-hwmon fails. This is problematic when iio-hwmon probes before the iio driver could register iio channels to share. Quentin Schulz (3): mfd: add support for Allwinner SoCs ADC iio: adc: add support for Allwinner SoCs ADC hwmon: iio_hwmon: defer probe when no channel is found drivers/hwmon/iio_hwmon.c | 5 +- drivers/iio/adc/Kconfig | 12 ++ drivers/iio/adc/Makefile | 1 + drivers/iio/adc/sunxi-gpadc-iio.c | 371 ++++++++++++++++++++++++++++++++++++ drivers/mfd/Kconfig | 14 ++ drivers/mfd/Makefile | 2 + drivers/mfd/sunxi-gpadc-mfd.c | 188 ++++++++++++++++++ include/linux/mfd/sunxi-gpadc-mfd.h | 14 ++ 8 files changed, 606 insertions(+), 1 deletion(-) create mode 100644 drivers/iio/adc/sunxi-gpadc-iio.c create mode 100644 drivers/mfd/sunxi-gpadc-mfd.c create mode 100644 include/linux/mfd/sunxi-gpadc-mfd.h -- 2.5.0 -- 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
