The following patches add support for triggered buffer mode. These are based on top of "Add PWM and IIO timer drivers for STM32" series. Reference: https://lkml.org/lkml/2017/1/20/116
STM32 ADC, can use either interrupts or DMA to collect data. Either timer trigger output (TRGO) or PWM can be used as trigger source. This patchset has been tested on STM32F429 eval board. - Example to enable timer1 PWM: cd /sys/devices/platform/soc/40010000.timers/40010000.timers:pwm/pwm/pwmchip4/ echo 0 > export # timer 1 channel 1 echo 1000000 > pwm0/period # 1000Hz echo 500000 > pwm0/duty_cycle echo 1 > pwm0/enable - Example to enable timer3 TRGO: cd /sys/bus/iio/devices/ cat trigger6/name tim1_ch1 cat trigger0/name tim3_trgo echo 1000 > trigger0/sampling_frequency - Example to configure STM32ADC in triggered buffer mode, with timer1 PWM or timer3 TRGO: cd /sys/bus/iio/devices/iio\:device0 echo tim1_ch1 > trigger/current_trigger OR: echo tim3_trgo > trigger/current_trigger echo 1 > scan_elements/in_voltage8_en echo 1 > buffer/enable --- Changes in v2: - Mainly updates following Jonathan's remarks. - make data buffer part of stm32_adc structure - remove defines - add comment on reading DR to clear OEC flag - use bitmap_weight() - fix error handling in stm32_adc_buffer_postenable() - Rename and document custom 'trigger_polarity' attribute - use iio_trigger_poll_chained() to avoid bounce to irq context - rework DMA buffer allocation and use hwfifo_set_watermark() - Fix typo: using stm32f429i-eval Fabrice Gasnier (7): iio: adc: stm32: add support for triggered buffer mode iio: adc: stm32: Enable use of stm32 timer triggers iio: adc: stm32: add trigger polarity extended attribute Documentation: dt: iio: stm32-adc: optional dma support iio: adc: stm32: add optional dma support ARM: dts: stm32: Enable dma by default on stm32f4 adc ARM: dts: stm32: Enable pwm1 and pwm3 on stm32f429i-eval Documentation/ABI/testing/sysfs-bus-iio-adc-stm32 | 18 + .../devicetree/bindings/iio/adc/st,stm32-adc.txt | 7 + arch/arm/boot/dts/stm32429i-eval.dts | 28 + arch/arm/boot/dts/stm32f429.dtsi | 6 + drivers/iio/adc/Kconfig | 5 + drivers/iio/adc/stm32-adc-core.c | 1 + drivers/iio/adc/stm32-adc-core.h | 2 + drivers/iio/adc/stm32-adc.c | 633 ++++++++++++++++++++- 8 files changed, 676 insertions(+), 24 deletions(-) create mode 100644 Documentation/ABI/testing/sysfs-bus-iio-adc-stm32 -- 1.9.1
