| Message ID | 20231102193722.3042245-4-ben.wolsieffer@hefring.com (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | 09388379b6d7143ed12fc06900ec9db3bb82ca8f |
| Headers | show |
| Series | Add STM32F7 SPI support | expand |
On Thu, Nov 02, 2023 at 03:37:20PM -0400, Ben Wolsieffer wrote: > The STM32F7 SPI peripheral is nearly identical to the STM32F4, with the > only significant differences being support for a wider range of word > sizes and the addition of 32-bit transmit and receive FIFOs. A wider range of supported word sizes and some additional buffers, implies that the F4 could be used as a fallback compatible. Does the register map change incompatibly in the process of widening the FIFOs or something like that? Cheers, Conor. > > Signed-off-by: Ben Wolsieffer <ben.wolsieffer@hefring.com> > --- > Documentation/devicetree/bindings/spi/st,stm32-spi.yaml | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/Documentation/devicetree/bindings/spi/st,stm32-spi.yaml b/Documentation/devicetree/bindings/spi/st,stm32-spi.yaml > index ae0f082bd377..5754d603f34f 100644 > --- a/Documentation/devicetree/bindings/spi/st,stm32-spi.yaml > +++ b/Documentation/devicetree/bindings/spi/st,stm32-spi.yaml > @@ -23,6 +23,7 @@ properties: > compatible: > enum: > - st,stm32f4-spi > + - st,stm32f7-spi > - st,stm32h7-spi > > reg: > -- > 2.42.0 >
Hi Conor, On Fri, Nov 03, 2023 at 12:50:53PM +0000, Conor Dooley wrote: > On Thu, Nov 02, 2023 at 03:37:20PM -0400, Ben Wolsieffer wrote: > A wider range of supported word sizes and some additional buffers, > implies that the F4 could be used as a fallback compatible. Does the > register map change incompatibly in the process of widening the FIFOs or > something like that? Yes, the F4 has a single bit to select 8 or 16 bit word size, while the F7 uses four bits to select an arbitrary word size from 4 to 16 bits. This series supports the packing mode, to allow sending two <=8 bit words with a single write to the FIFO, but even if we didn't want to support this feature, the F7 would require setting the FRXTH bit (not present in the F4) when using <=8 bit word sizes. > > Cheers, > Conor.
On Fri, Nov 03, 2023 at 09:29:12AM -0400, Ben Wolsieffer wrote: > Hi Conor, > > On Fri, Nov 03, 2023 at 12:50:53PM +0000, Conor Dooley wrote: > > On Thu, Nov 02, 2023 at 03:37:20PM -0400, Ben Wolsieffer wrote: > > A wider range of supported word sizes and some additional buffers, > > implies that the F4 could be used as a fallback compatible. Does the > > register map change incompatibly in the process of widening the FIFOs or > > something like that? > > Yes, the F4 has a single bit to select 8 or 16 bit word size, while the > F7 uses four bits to select an arbitrary word size from 4 to 16 bits. > This series supports the packing mode, to allow sending two <=8 bit > words with a single write to the FIFO, but even if we didn't want to > support this feature, the F7 would require setting the FRXTH bit (not > present in the F4) when using <=8 bit word sizes. Oke. Acked-by: Conor Dooley <conor.dooley@microchip.com> Cheers, Conor.
diff --git a/Documentation/devicetree/bindings/spi/st,stm32-spi.yaml b/Documentation/devicetree/bindings/spi/st,stm32-spi.yaml index ae0f082bd377..5754d603f34f 100644 --- a/Documentation/devicetree/bindings/spi/st,stm32-spi.yaml +++ b/Documentation/devicetree/bindings/spi/st,stm32-spi.yaml @@ -23,6 +23,7 @@ properties: compatible: enum: - st,stm32f4-spi + - st,stm32f7-spi - st,stm32h7-spi reg:
The STM32F7 SPI peripheral is nearly identical to the STM32F4, with the only significant differences being support for a wider range of word sizes and the addition of 32-bit transmit and receive FIFOs. Signed-off-by: Ben Wolsieffer <ben.wolsieffer@hefring.com> --- Documentation/devicetree/bindings/spi/st,stm32-spi.yaml | 1 + 1 file changed, 1 insertion(+)