> > Add spi-tmax-nbits and spi-rmax-nbits for spi slave node. > Modify the related dt document(spi-bus.txt) > spi-tmax-nbits:Max number of bits slave will use for MOSI(writting) > spi-rmax-nbits:Max number of bits slave will use for MISO(reading) > Support for spi-tx/rmax-nbits in SPI framework has been picked[1]. > [1]: http://comments.gmane.org/gmane.linux.kernel.spi.devel/14420 > Commit Id:f477b7fb13df2b843997559ff34e87d054ba6538 > > Signed-off-by: wangyuhang <wangyuhang2014@xxxxxxxxx> > --- > Documentation/devicetree/bindings/spi/spi-bus.txt | 16 > ++++++++++++++++ > 1 file changed, 16 insertions(+) > > diff --git a/Documentation/devicetree/bindings/spi/spi-bus.txt > b/Documentation/devicetree/bindings/spi/spi-bus.txt > index 296015e..211336c 100644 > --- a/Documentation/devicetree/bindings/spi/spi-bus.txt > +++ b/Documentation/devicetree/bindings/spi/spi-bus.txt > @@ -55,6 +55,22 @@ contain the following properties. > chip select active high > - spi-3wire - (optional) Empty property indicating device requires > 3-wire mode. > +- spi-tmax-nbits - (optional) Max number of bits slave will use for > + MOSI(writting) > +- spi-rmax-nbits - (optional) Max number of bits slave will use for > + MISO(reading) > + > +So if for example the slave has 4 wires for writting and 2 wires for reading, > +and the spi-tx/rx-nbits property should be set as follows: > + > +spi-tmax-nbits = <4>; > +spi-rmax-nbits = <2>; > + > +Now the value that spi-tmax-nbits and spi-rmax-nbits can receive is only > +1(single), 2(dual) and 4(quad). If you don't set spi-tmax-nbits or spi-rmax- > nbits, > +spi_device mode will be set in single(1 wire) as default. Another point, if > +property:spi-3wire is set, spi-t/rmax-nbits is forbidden to set to <2 or 4>, > +otherwise, an errro will return. > > If a gpio chipselect is used for the SPI slave the gpio number will be passed > via the cs_gpio > -- > 1.7.9.5 Acked-by: Pekon Gupta <pekon@xxxxxx> with regards, pekon ��.n��������+%������w��{.n����z�{��ܨ}���Ơz�j:+v�����w����ޙ��&�)ߡ�a����z�ޗ���ݢj��w�f
