Patchwork powerpc: SPI: specify chip select active high

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Submitter Wolfgang Ocker
Date Oct. 15, 2008, 1 p.m.
Message ID <1224075647.4022.33.camel@galileo.recco.de>
Download mbox | patch
Permalink /patch/4598/
State Accepted
Delegated to: Kumar Gala
Headers show

Comments

Wolfgang Ocker - Oct. 15, 2008, 1 p.m.
The patch allows to specify that an SPI device needs an active high chip
select.

Signed-off-by: Wolfgang Ocker <weo@reccoware.de>
---
Grant Likely - Oct. 15, 2008, 2:22 p.m.
On Wed, Oct 15, 2008 at 03:00:47PM +0200, Wolfgang Ocker wrote:
> The patch allows to specify that an SPI device needs an active high chip
> select.

This look reasonable to me.  Anyone else have comments on this binding?

g.

> 
> Signed-off-by: Wolfgang Ocker <weo@reccoware.de>
> ---
> 
> --- linux-2.6.27-rc7/drivers/of/of_spi.c.of_spi_cshigh	2008-09-22 00:29:55.000000000 +0200
> +++ linux-2.6.27-rc7/drivers/of/of_spi.c	2008-09-29 13:43:06.000000000 +0200
> @@ -61,6 +61,8 @@
>  			spi->mode |= SPI_CPHA;
>  		if (of_find_property(nc, "spi-cpol", NULL))
>  			spi->mode |= SPI_CPOL;
> +		if (of_find_property(nc, "spi-cs-high", NULL))
> +			spi->mode |= SPI_CS_HIGH;
>  
>  		/* Device speed */
>  		prop = of_get_property(nc, "spi-max-frequency", &len);
> --- linux-2.6.27-rc7/Documentation/powerpc/booting-without-of.txt.of_spi_cshigh	2008-09-29 14:14:08.000000000 +0200
> +++ linux-2.6.27-rc7/Documentation/powerpc/booting-without-of.txt	2008-09-29 14:24:26.000000000 +0200
> @@ -1917,6 +1917,8 @@
>  			inverse clock polarity (CPOL) mode
>      - spi-cpha        - (optional) Empty property indicating device requires
>  			shifted clock phase (CPHA) mode
> +    - spi-cs-high     - (optional) Empty property indicating device requires
> +			chip select active high
>  
>      SPI example for an MPC5200 SPI bus:
>  		spi@f00 {
> 
> 
> _______________________________________________
> Linuxppc-dev mailing list
> Linuxppc-dev@ozlabs.org
> https://ozlabs.org/mailman/listinfo/linuxppc-dev
Anton Vorontsov - Oct. 15, 2008, 3:51 p.m.
On Wed, Oct 15, 2008 at 08:22:28AM -0600, Grant Likely wrote:
> On Wed, Oct 15, 2008 at 03:00:47PM +0200, Wolfgang Ocker wrote:
> > The patch allows to specify that an SPI device needs an active high chip
> > select.
> 
> This look reasonable to me.  Anyone else have comments on this binding?

Looks good. I'm assuming that a spi controller has its own chip select
machine, since for GPIO chip-select we can pass active-high/low stuff
via gpios = <> property. But well, we can support both ways even for
GPIO chip-selects, I see no problem.

> g.
> 
> > 
> > Signed-off-by: Wolfgang Ocker <weo@reccoware.de>
> > ---
> > 
> > --- linux-2.6.27-rc7/drivers/of/of_spi.c.of_spi_cshigh	2008-09-22 00:29:55.000000000 +0200
> > +++ linux-2.6.27-rc7/drivers/of/of_spi.c	2008-09-29 13:43:06.000000000 +0200
> > @@ -61,6 +61,8 @@
> >  			spi->mode |= SPI_CPHA;
> >  		if (of_find_property(nc, "spi-cpol", NULL))
> >  			spi->mode |= SPI_CPOL;
> > +		if (of_find_property(nc, "spi-cs-high", NULL))
> > +			spi->mode |= SPI_CS_HIGH;
> >  
> >  		/* Device speed */
> >  		prop = of_get_property(nc, "spi-max-frequency", &len);
> > --- linux-2.6.27-rc7/Documentation/powerpc/booting-without-of.txt.of_spi_cshigh	2008-09-29 14:14:08.000000000 +0200
> > +++ linux-2.6.27-rc7/Documentation/powerpc/booting-without-of.txt	2008-09-29 14:24:26.000000000 +0200
> > @@ -1917,6 +1917,8 @@
> >  			inverse clock polarity (CPOL) mode
> >      - spi-cpha        - (optional) Empty property indicating device requires
> >  			shifted clock phase (CPHA) mode
> > +    - spi-cs-high     - (optional) Empty property indicating device requires
> > +			chip select active high
> >  
> >      SPI example for an MPC5200 SPI bus:
> >  		spi@f00 {
> > 
> >
Kumar Gala - Oct. 20, 2008, 2:52 p.m.
On Oct 15, 2008, at 8:00 AM, Wolfgang Ocker wrote:

> The patch allows to specify that an SPI device needs an active high  
> chip
> select.
>
> Signed-off-by: Wolfgang Ocker <weo@reccoware.de>
> ---

applied

- k

Patch

--- linux-2.6.27-rc7/drivers/of/of_spi.c.of_spi_cshigh	2008-09-22 00:29:55.000000000 +0200
+++ linux-2.6.27-rc7/drivers/of/of_spi.c	2008-09-29 13:43:06.000000000 +0200
@@ -61,6 +61,8 @@ 
 			spi->mode |= SPI_CPHA;
 		if (of_find_property(nc, "spi-cpol", NULL))
 			spi->mode |= SPI_CPOL;
+		if (of_find_property(nc, "spi-cs-high", NULL))
+			spi->mode |= SPI_CS_HIGH;
 
 		/* Device speed */
 		prop = of_get_property(nc, "spi-max-frequency", &len);
--- linux-2.6.27-rc7/Documentation/powerpc/booting-without-of.txt.of_spi_cshigh	2008-09-29 14:14:08.000000000 +0200
+++ linux-2.6.27-rc7/Documentation/powerpc/booting-without-of.txt	2008-09-29 14:24:26.000000000 +0200
@@ -1917,6 +1917,8 @@ 
 			inverse clock polarity (CPOL) mode
     - spi-cpha        - (optional) Empty property indicating device requires
 			shifted clock phase (CPHA) mode
+    - spi-cs-high     - (optional) Empty property indicating device requires
+			chip select active high
 
     SPI example for an MPC5200 SPI bus:
 		spi@f00 {