Hi, This patch series improves the SPI driver for AT91 USART IP and adds support for DMA transfers, updates the bindings of driver and PM callback functions. I decided to use DMA only for transfers long than 16 bytes. DMA setup introduces a little overhead and is better to use PIO for short transfers. Radu Pirea (3): spi: at91-usart: add power management support dt-bindings: mfd: atmel-usart: add DMA bindings for SPI mode spi: at91-usart: add DMA support .../devicetree/bindings/mfd/atmel-usart.txt | 15 +- drivers/spi/spi-at91-usart.c | 284 +++++++++++++++++- 2 files changed, 292 insertions(+), 7 deletions(-) -- 2.19.1