On Thursday 18 April 2013, Lee Jones wrote:
> +Clients
> +Required properties:
> +- dmas: Comma separated list of dma channel requests
> +- dma-names: Names of the aforementioned requested channels
> +
> +Each dmas request consists of 4 cells:
> + 1. A phandle pointing to the DMA controller
> + 2. Device Type
> + 3. The DMA request line number (only when 'use fixed channel' is set)
> + 4. A 32bit mask specifying; mode, direction and endianess [NB: This list
> will grow]
> + bit 1: Mode:
> + 0: Logical
> + 1: Physical
> + bit 2: Direction:
> + 0: Mem to Mem
> + 1: Mem to Dev
You probably mean
0: Dev to mem
Related to this, I would recommend not listing bit numbers like this, since
there
is some amount of confusion regarding how they are counted: zero-based on
one-based
and LSB-to-MSB or MSB-to-LSB
You can completely avoid this problem by listing them as bit masks:
0x00000002:
Logical channel when unset
Physical channel when set
0x00000004:
Direction from device when unset
Direction to device when unset
...
> + dmas = <&dma 13 0 0x8>, /* Logical - DevToMem */
> + <&dma 13 0 0x4>; /* Logical - MemToDev */
The bit in the example no longer matches the description.
> +
> + switch (D40_DT_FLAGS_DIR(flags)) {
> + case 0: cfg.dir = STEDMA40_MEM_TO_MEM; break;
> + case 1: cfg.dir = STEDMA40_MEM_TO_PERIPH; break;
> + }
Same typo above.
> + if (cfg.dir == STEDMA40_PERIPH_TO_MEM)
> + cfg.src_info.big_endian = D40_DT_FLAGS_BIG_ENDIAN(flags);
> + if (cfg.dir == STEDMA40_MEM_TO_PERIPH)
> + cfg.dst_info.big_endian = D40_DT_FLAGS_BIG_ENDIAN(flags);
You can fold these two into the switch statement above.
Arnd
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