Here is v1 of the patch series to support DMA with the i2c-sh_mobile core. DMA works nicely with my tests so far and we save 1 interrupt per transferred byte, yay! DMA is opt-in, so if setting it up fails, we will fall back to PIO. The threshold for selecting DMA is still under test, but probably good enough already. Since the RFC, I learned about dma_request_slave_channel_reason() and deferred probing with DMA channels, so the major show stopper is gone now and this should be ready for inclusion IMO. The other open issues (best threshold value, ensure DMA capable buffers) can later be done incrementally. Please test, review, comment. The series is based on renesas-devel-20141030-v3.18-rc2 with Laurent's series "[PATCH v4 0/5] R-Car Gen2 DMA Controller driver" on top of it. A git tree can be found here: git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux.git renesas/i2c-shmobile-dma-experimental Thanks to Geert and Laurent for reviewing the RFC! Wolfram Wolfram Sang (5): i2c: sh_mobile: sort includes alphabetically i2c: sh_mobile: add DMA support i2c: sh_mobile: improve success message ARM: shmobile: r8a7790: add DMA nodes for IIC ARM: shmobile: r8a7791: add DMA nodes for IIC .../devicetree/bindings/i2c/i2c-sh_mobile.txt | 5 + arch/arm/boot/dts/r8a7790.dtsi | 8 + arch/arm/boot/dts/r8a7791.dtsi | 6 + drivers/i2c/busses/i2c-sh_mobile.c | 219 ++++++++++++++++++--- 4 files changed, 216 insertions(+), 22 deletions(-) -- 2.1.1 -- To unsubscribe from this list: send the line "unsubscribe linux-i2c" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
