On 25-04-16, 15:35, Andy Shevchenko wrote: > There are several changes are done here: > > - Convert the property to be in bytes > > Besides this is common practice for such property the use of a value in bytes > much more convenient than handling the encoded value. > > - Rename data_width to data-width in the device tree bindings > > - While here, replace dwc_fast_ffs() by __ffs() > > The change leaves the support for old format as well just in case someone will > use a newer kernel with an old device tree blob. > > Signed-off-by: Andy Shevchenko <andriy.shevche...@linux.intel.com> > --- > Documentation/devicetree/bindings/dma/snps-dma.txt | 6 ++-- > arch/arc/boot/dts/abilis_tb10x.dtsi | 2 +- > arch/arm/boot/dts/spear13xx.dtsi | 4 +-- > drivers/dma/dw/core.c | 42 > ++++++---------------- > drivers/dma/dw/platform.c | 5 ++- > include/linux/platform_data/dma-dw.h | 2 +- > 6 files changed, 21 insertions(+), 40 deletions(-) > > diff --git a/Documentation/devicetree/bindings/dma/snps-dma.txt > b/Documentation/devicetree/bindings/dma/snps-dma.txt > index c99c1ff..544b9b9 100644 > --- a/Documentation/devicetree/bindings/dma/snps-dma.txt > +++ b/Documentation/devicetree/bindings/dma/snps-dma.txt > @@ -13,8 +13,8 @@ Required properties: > - chan_priority: priority of channels. 0 (default): increase from chan 0->n, > 1: > increase from chan n->0 > - block_size: Maximum block size supported by the controller > -- data_width: Maximum data width supported by hardware per AHB master > - (0 - 8bits, 1 - 16bits, ..., 5 - 256bits) > +- data-width: Maximum data width supported by hardware per AHB master > + (in bytes, power of 2) > > > Optional properties: > @@ -38,7 +38,7 @@ Example: > chan_allocation_order = <1>; > chan_priority = <1>; > block_size = <0xfff>; > - data_width = <3 3>; > + data-width = <8 8>; > };
You broke backward compatibility with earlier DTs. What's backward compatibility ? Consider that the DT from an earlier version of kernel is part of the bootrom of a SoC. Now that bootrom should work just fine with any new kernel version. i.e. old DT + new kernels should always work. -- viresh
