[U-Boot] [PATCH v3 11/11] spi: cadence_qspi: Support specifying the sample edge used

[Phil Edworthy]

Hi Jagan,

On 05 December 2016 10:42, Jagan Teki wrote:
> On Mon, Dec 5, 2016 at 11:31 AM, Phil Edworthy
> <phil.edworthy at renesas.com> wrote:
> > HI Jagan,
> >
> > On 05 December 2016 10:26, Jagan Teki wrote:
> >> On Mon, Dec 5, 2016 at 11:09 AM, Phil Edworthy
> >> <phil.edworthy at renesas.com> wrote:
> >> > Hi Jagan,
> >> >
> >> > On 02 December 2016 14:23, Jagan Teki wrote:
> >> >> On Tue, Nov 29, 2016 at 6:28 PM, Phil Edworthy
> >> >> <phil.edworthy at renesas.com> wrote:
> >> >> > Introduce a new DT property to specify whether the QSPI Controller
> >> >> > samples the data on a rising edge. The default is falling edge.
> >> >> > Some versions of the QSPI Controller do not implement this bit, in
> >> >> > which case the property should be omitted.
> >> >> >
> >> >> > Signed-off-by: Phil Edworthy <phil.edworthy at renesas.com>
> >> >> > ---
> >> >> >  v3:
> >> >> >   - Patch split so this one only has code related to the subject.
> >> >> >   - Commit message updated.
> >> >> >  v2:
> >> >> >   - Change name of DT prop and provide details of what it does.
> >> >> >     Whilst at it, move the code to read the "sram-size" property
> >> >> >     into the other code that reads properties from the node, rather
> >> >> >     than the SF subnode.
> >> >> >
> >> >> >     Also change the code to use a bool for the bypass arg.
> >> >> > ---
> >> >> >  doc/device-tree-bindings/spi/spi-cadence.txt |  2 ++
> >> >> >  drivers/spi/cadence_qspi.c                   | 10 +++++++---
> >> >> >  drivers/spi/cadence_qspi.h                   |  3 ++-
> >> >> >  drivers/spi/cadence_qspi_apb.c               |  8 +++++++-
> >> >> >  4 files changed, 18 insertions(+), 5 deletions(-)
> >> >> >
> >> >> > diff --git a/doc/device-tree-bindings/spi/spi-cadence.txt b/doc/device-
> tree-
> >> >> bindings/spi/spi-cadence.txt
> >> >> > index c1e2233..94c800b 100644
> >> >> > --- a/doc/device-tree-bindings/spi/spi-cadence.txt
> >> >> > +++ b/doc/device-tree-bindings/spi/spi-cadence.txt
> >> >> > @@ -26,3 +26,5 @@ connected flash properties
> >> >> >                           select (n_ss_out).
> >> >> >  - tslch-ns             : Delay in master reference clocks between setting
> >> >> >                           n_ss_out low and first bit transfer
> >> >> > +- sample-edge-rising   : Data outputs from flash memory will be sampled
> on
> >> >> the
> >> >> > +                         rising edge. Default is falling edge.
> >> >>
> >> >> Code look reasonable, but how Linux handling this with the same dt
> >> >> property, any idea? I couldn't find it either.
> >> > The Linux driver does not yet have this property. Is there a policy to add new
> >> > props to Linux first?
> >>
> >> If the same/equal code used in Linux better to have the same property
> >> instead of another name used in U-boot?
> > Of course, but I cannot see this in Linux:
> > https://git.kernel.org/cgit/linux/kernel/git/next/linux-
> next.git/tree/Documentation/devicetree/bindings/spi/spi-cadence.txt
> 
> Yeah, I saw this. Do you have any idea how Linux handling this sample edge?
The same way U-Boot currently handles it, i.e. it does nothing with this. Intel/Altera
(Chin Liang) said that they do not have this bit in their version of the Cadence QSPI
Controller.

We are using a later version that has had this bit added.

BR
Phil

> thanks!
> --
> Jagan Teki
> Free Software Engineer | www.openedev.com
> U-Boot, Linux | Upstream Maintainer
> Hyderabad, India.