Hi, Jerry Huang <jerry.huang@xxxxxxx> writes: <snip> >> >> So, I think we still need two vaue to specify INCRBrstEna and INCRx >> >> burst type. >> > Hi, Balbi, >> > It seems there is no feedback for my comment, so these patches can be >> accepted? >> >> probably not, we need to really understand what information we need so it >> can be described properly. The last thing we want is unnecessary DT >> properties. >> >> It seems to me that we can extrapolate INCRBrstEna based on which burst >> modes are enabled. If only 0 is passed, then that bit should be 1, if 0 and any >> other size is passed, then that bit should be 0, no? > Hi, Balbi, > Below is the definition for this property, > snps,incr-burst-type-adjustment = <x>, <y> > x: Undefined Length INCR Burst Type Enable (INCRBrstEna) > 0 - INCRX burst mode (not enable INCRBrstEna) > 1 - INCR (undefined length) burst mode (enable INCRBrstEna) > y: the burst length > > 1> if x = 0: means INCRBrstEna not enabled, set bit0 to zero (or clear > it) , we select one of > INCR1/INCR4/INCR8/INCR16/INCR32/INCR64/INCR128/INCR256 (pass this > value through "y")to set the fix burst length controller supported. > > For example: > > snps,incr-burst-type-adjustment = <0>, <16> > > driver will set bit0 to zero and set bit3 to 1 (INCR16 Burst Type > Enabled), controller will use INCR16 (with 16 bytes) to transfer data. > > 2> if x = 1: means INCRBrstEna enabled, we select one of > INCR4/INCR8/INCR16/INCR32/INCR64/INCR128/INCR256 (pass this value > through "y") to set the burst length, and controller will use any > length less than or equal to that we selected. > > For example: > > snps,incr-burst-type-adjustment = <1>, <32> > > driver will set bit0 to 1 and set bit4 to 1 (INCR32 Burst Type > Enabled), controller will use any burst length less than (such as 4, > 8, 16 byte) or equal to 32 byte to transfer data. > > Therefore, I think this two fileds are needed. Do you think about it? no, I don't think two values are needed, because first value can be extrapolated from the second. Something like this: snps,incr-burst-type-adjustment = <4>, <8>, <16>, <32>; This is basically telling us that we can support anything in this list. So INCRBrstEna should be set to 1. If DT, on the other hand, says: snps,incr-burst-type-adjustment = <32>; this means that we can only support INCR32, so INCRBrstEna should be cleared to 0. -- balbi
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