1. s3cx64xx driver was supporting polling mode using quirk for SOC without DMA. However, in order to use PIO mode as an optional rather than a quirk, when DMA is not described, spi operates with pio mode rather than probe fail. 2. Fixed the problem of high CPU usage in PIO mode. 3. If the transfer data size is larger than 32-bit, IRQ base PIO mode used. Jaewon Kim (4): spi: s3c64xx: changed to PIO mode if there is no DMA spi: s3c64xx: add cpu_relax in polling loop spi: s3c64xx: add sleep during transfer spi: s3c64xx: support interrupt based pio mode drivers/spi/spi-s3c64xx.c | 85 ++++++++++++++++++++--- include/linux/platform_data/spi-s3c64xx.h | 1 + 2 files changed, 76 insertions(+), 10 deletions(-) -- 2.17.1
