Hi Rob,

On 1/14/2021 11:34 AM, Rob Herring wrote:

quoted

-- reg			: address offset and range of bus
+- reg			: Address offset and range of bus registers.
+
+			  An additional SRAM buffer address offset and range is
+			  optional in case of enabling I2C dedicated SRAM for
+			  buffer mode transfer support. If the optional range
+			  is defined, buffer mode will be enabled.
+			  - AST2400
+			    &i2c0 { reg = <0x40 0x40>, <0x800 0x80>; };
+			    &i2c1 { reg = <0x80 0x40>, <0x880 0x80>; };
+			    &i2c2 { reg = <0xc0 0x40>, <0x900 0x80>; };
+			    &i2c3 { reg = <0x100 0x40>, <0x980 0x80>; };
+			    &i2c4 { reg = <0x140 0x40>, <0xa00 0x80>; };
+			    &i2c5 { reg = <0x180 0x40>, <0xa80 0x80>; };
+			    &i2c6 { reg = <0x1c0 0x40>, <0xb00 0x80>; };
+			    &i2c7 { reg = <0x300 0x40>, <0xb80 0x80>; };
+			    &i2c8 { reg = <0x340 0x40>, <0xc00 0x80>; };
+			    &i2c9 { reg = <0x380 0x40>, <0xc80 0x80>; };
+			    &i2c10 { reg = <0x3c0 0x40>, <0xd00 0x80>; };
+			    &i2c11 { reg = <0x400 0x40>, <0xd80 0x80>; };
+			    &i2c12 { reg = <0x440 0x40>, <0xe00 0x80>; };
+			    &i2c13 { reg = <0x480 0x40>, <0xe80 0x80>; };

All this information doesn't need to be in the binding.

It's also an oddly structured dts file if this is what you are doing...

I removed the default buffer mode settings that I added into
'aspeed-g4.dtsi' and 'aspeed-g5.dtsi' in v1 to avoid touching of the
default transfer mode setting, but each bus should use its dedicated
SRAM buffer range for enabling buffer mode so I added this information
at here as overriding examples instead. I thought that binding document
is a right place for providing this information but looks like it's not.
Any recommended place for it? Is it good enough if I add it just into
the commit message?

quoted

@@ -17,6 +72,25 @@ Optional Properties:
  - bus-frequency	: frequency of the bus clock in Hz defaults to 100 kHz when not
  		  specified
  - multi-master	: states that there is another master active on this bus.
+- aspeed,dma-buf-size	: size of DMA buffer.
+			    AST2400: N/A
+			    AST2500: 2 ~ 4095
+			    AST2600: 2 ~ 4096

If based on the SoC, then all this can be implied from the compatible
string.

Please help me to clarify your comment. Should I remove it from here
with keeping the driver handling code for each SoC compatible string?
Or should I change it like below?
aspeed,ast2400-i2c-bus: N/A
aspeed,ast2500-i2c-bus: 2 ~ 4095
aspeed,ast2600-i2c-bus: 2 ~ 4096

Thanks,
Jae