Hello, I ran into the issue with using i2c-mt65xx driver on MT6577 hardware. Device tree documentation for the driver says "reg" property requires 2 addresses: > reg: physical base address of the controller and dma base Physical base address for MT6577 is 0xC1012000, but AFAIK MT6577 does not have a DMA base dedicated especially to I2C. What value has to be used as DMA base on MT6577? For the sake of example, I did my own research and checked other SoC listed as compatible in dt-binding doc. I compared the source code of Linux kernels for devices based on MT6589 and MT6577. See example below. MT6589, Lenovo A820: https://github.com/jawad6233/Lenovo_A820_Kernel There are IRQ IDs defined for I2C DMA: mediatek/platform/mt6589/kernel/core/include/mach/mt_irq.h (line 47) > #define MT_DMA_I2C1_ID (GIC_PRIVATE_SIGNALS + 62) > #define MT_DMA_I2C2_ID (GIC_PRIVATE_SIGNALS + 63) > #define MT_DMA_I2C3_ID (GIC_PRIVATE_SIGNALS + 64) > #define MT_DMA_I2C4_ID (GIC_PRIVATE_SIGNALS + 65) > #define MT_DMA_I2C5_ID (GIC_PRIVATE_SIGNALS + 66) > #define MT_DMA_I2C6_ID (GIC_PRIVATE_SIGNALS + 67) > #define MT_DMA_I2C7_ID (GIC_PRIVATE_SIGNALS + 68) There are DMA address calculations for various I2C busses: mediatek/platform/mt6589/kernel/drivers/i2c/i2c.c (line 1135) > i2c->pdmabase = AP_DMA_BASE + 0x300 + (0x80*(i2c->id)); MT6577, ZTE v970: https://github.com/dragonpt/Kernel_3.4.67_KK_ZTE_v970 There are no IRQ IDs defined for I2C DMA: mediatek/platform/mt6577/kernel/core/include/mach/mt_irq.h >From line 80 down to line 92 there are DMA addresses for various subsystems except I2C. And there are no DMA address calculaltions either: mediatek/platform/mt6577/kernel/drivers/i2c/i2c.c Please point me to DMA base I should use on MT6577. Thanks.
