On Wed, 16 May 2018, Fabrice Gasnier wrote:

STM32 Timers can support up to 7 DMA requests:
- 4 channels, update, compare and trigger.
Optionally request part, or all DMAs from stm32-timers MFD core.

Also add routine to implement burst reads using DMA from timer registers.
This is exported. So, it can be used by child drivers, PWM capture
for instance (but not limited to).

Signed-off-by: Fabrice Gasnier <redacted>
Reviewed-by: Benjamin Gaignard <redacted>
---
Changes in v5:
- fix warning on dma_mapping_error() that doesn't return an error code.
- move stm32_timers_dma struct to header file as discussed with Lee.
  This allows to remove alloc for this struct in stm32_timers_dma_probe.

Changes in v4:
- Lee's comments: Add kerneldoc header, better format comments.

Changes in v3:
- Basically Lee's comments:
- rather create a struct stm32_timers_dma, and place a reference to it
  in existing ddata (instead of adding priv struct).
- rather use a struct device in exported routine prototype, and use
  standard helpers instead of ddata. Get rid of to_stm32_timers_priv().
- simplify error handling in probe (remove a goto)
- comment on devm_of_platform_*populate() usage.

Changes in v2:
- Abstract DMA handling from child driver: move it to MFD core
- Add comments on optional dma support
---
 drivers/mfd/stm32-timers.c       | 201 ++++++++++++++++++++++++++++++++++++++-
 include/linux/mfd/stm32-timers.h |  46 +++++++++
 2 files changed, 245 insertions(+), 2 deletions(-)

For my own reference:
  Acked-for-MFD-by: Lee Jones [off-list ref]

-- 
Lee Jones [???]
Linaro Services Technical Lead
Linaro.org ? Open source software for ARM SoCs
Follow Linaro: Facebook | Twitter | Blog