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. The temperature sensor returns valid values only when the GPADC is in touchscreen mode. This patch series is based on the patch series named "add support for Allwinner SoCs ADC": https://lkml.org/lkml/2016/6/28/226 This adds the TP_UP_PENDING VIRQ in the MFD which occurs when the thing (stylus or finger) touching the screen releases the touch. This VIRQ is then handled in the touchscreen driver to notify the input framework of an up event. The MFD probes the touchscreen driver if the property "allwinner,ts-attached" is set in rtp node of the DT. The touchscreen driver needs data from the IIO ADC driver to retrieve touch coordinates. The ADC driver exposes its four ADC channels to the touchscreen driver. The touchscreen driver retrieves the four ADC channels, associates a buffer with these channels and registers a callback to handle buffer data. When the touchscreen driver is open, it starts the buffering in the ADC driver and activates the callback. The ADC driver will be notified a buffer is started and will then activate the FIFO_DATA_PENDING interrupt which occurs when there is data to read in the FIFO. It also selects the right mode (touchscreen or ADC). Then the FIFO_DATA_PENDING VIRQ handler will continuously fill in a buffer with all data from the hardware FIFO and send it to the touchscreen driver via the callback the touchscreen driver registered previously when the VIRQ has been handled. When in touchscreen mode, the hardware FIFO is filled in following this pattern: X then Y coordinates of the first event, X and Y coordinates of the second event, etc. This VIRQ is disabled only when the ADC driver is notified a buffer is stopped. The touchscreen driver gets this buffer in its defined callback and notifies the input framework of all events' coordinates. When the touchscreen driver is closed, it stops the buffering which deactivates the callback. The hardware FIFO contains a maximum of 32 u32 values. Locations of the first buffer retrieved after an up event are unreliable and are thus dropped. This patch replaces drivers/input/touchscreen/sun4i-ts.c by drivers/input/touchscreen/sunxi-gpadc-ts.c, adding the ADC feature to Allwinner SoCs' GPADC. Quentin Schulz (5): mfd: sunxi-gpadc-mfd: add TP_UP_PENDING irq mfd: sunxi-gpadc-mfd: add buffer structure iio: adc: sunxi-gpadc-iio: enable iio_buffers input: touchscreen: support Allwinner SoCs' touchscreen mfd: sunxi-gpadc-mfd: probe sunxi-gpadc-ts driver drivers/iio/adc/Kconfig | 1 + drivers/iio/adc/sunxi-gpadc-iio.c | 153 +++++++++-- drivers/input/touchscreen/Kconfig | 11 +- drivers/input/touchscreen/Makefile | 2 +- drivers/input/touchscreen/sun4i-ts.c | 419 ----------------------------- drivers/input/touchscreen/sunxi-gpadc-ts.c | 195 ++++++++++++++ drivers/mfd/sunxi-gpadc-mfd.c | 127 ++++++--- include/linux/mfd/sunxi-gpadc-mfd.h | 5 + 8 files changed, 433 insertions(+), 480 deletions(-) delete mode 100644 drivers/input/touchscreen/sun4i-ts.c create mode 100644 drivers/input/touchscreen/sunxi-gpadc-ts.c -- 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
