86c92b9965
This patch adds DMA support for Tegra I2C. Tegra I2C TX and RX FIFO depth is 8 words. PIO mode is used for transfer size of the max FIFO depth and DMA mode is used for transfer size higher than max FIFO depth to save CPU overhead. PIO mode needs full intervention of CPU to fill or empty FIFO's and also need to service multiple data requests interrupt for the same transaction. This adds delay between data bytes of the same transfer when CPU is fully loaded and some slave devices has internal timeout for no bus activity and stops transaction to avoid bus hang. DMA mode is helpful in such cases. DMA mode is also helpful for Large transfers during downloading or uploading FW over I2C to some external devices. Tegra210 and prior Tegra chips use APBDMA driver which is replaced with GPCDMA on Tegra186 and Tegra194. This patch uses has_apb_dma flag in hw_feature to differentiate DMA driver change between Tegra chipset. APBDMA driver is registered from module-init level and this patch also has a change to register I2C driver at module-init level rather than subsys-init to avoid deferring I2C probe till APBDMA driver is registered. Acked-by: Thierry Reding <treding@nvidia.com> Reviewed-by: Dmitry Osipenko <digetx@gmail.com> Tested-by: Dmitry Osipenko <digetx@gmail.com> Signed-off-by: Sowjanya Komatineni <skomatineni@nvidia.com> Signed-off-by: Wolfram Sang <wsa@the-dreams.de> |
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| .. | ||
| algos | ||
| busses | ||
| muxes | ||
| i2c-boardinfo.c | ||
| i2c-core-acpi.c | ||
| i2c-core-base.c | ||
| i2c-core-of.c | ||
| i2c-core-slave.c | ||
| i2c-core-smbus.c | ||
| i2c-core.h | ||
| i2c-dev.c | ||
| i2c-mux.c | ||
| i2c-slave-eeprom.c | ||
| i2c-smbus.c | ||
| i2c-stub.c | ||
| Kconfig | ||
| Makefile | ||