Re: [PATCH 2/2] spi: qcom-geni: Add property to force GSI mode

[Mukesh Savaliya]

On 6/30/2026 3:36 PM, Pengyu Luo wrote:
> On Tue, Jun 30, 2026 at 5:52 PM Mukesh Savaliya
> <mukesh.savaliya@xxxxxxxxxxxxxxxx> wrote:
> > On 6/29/2026 1:33 PM, Pengyu Luo wrote:
> > > On Mon, Jun 29, 2026 at 1:36 PM Mukesh Savaliya
> > > <mukesh.savaliya@xxxxxxxxxxxxxxxx> wrote:
> > > > Hi Pengyu,
> > > >
> > > > On 6/15/2026 2:48 AM, Dmitry Baryshkov wrote:
> > > > > On Sun, Jun 14, 2026 at 04:34:24PM +0800, Pengyu Luo wrote:
> > > > > > Some devices (such as gaokun3) do not disable FIFO mode, causing the
> > > > > > driver to fallback to FIFO mode by default. However, these platforms
> > > > > > also support GSI mode, which is highly preferred for certain
> > > > > > peripherals like SPI touchscreens to improve performance.
> > > > > >
> > > > > > Introduce the "qcom,force-gsi-mode" device property to hint and force
> > > > > > the controller into GSI mode during initialization.
> > > > Why to force ? You can directly configure in GSI mode. Note there are
> > > > some configuration done prior to Linux bootup too.
> > >
> > > Sorry, I don't get it. how? I know there may be a qupfw, but it is
> > > impossible for a normal user like me to generate one with GSI
> > > preferred.
> > If firmware doesn't program in GSI, you can't have this working in GSI
> > mode, its going to fail (and work with fallback). if it's programmed in
> > GSI, anyway this will run in GSI mode. So why to add extra things
> > without any usage ?
>
> What I can confirm is that fifo is not disabled on my device, and gsi
> is definitely enabled (under windows, check the register
> SE_GENI_DMA_MODE_EN), forcing the device to enable GSI mode on linux
> works well.
Thanks  ! if GSI is already enabled, then why do you need forced gsi ?
My point here - SW should only decide mode based on register read, not 
enforce by DT flag. As such it's not a SOC exposed, can't be overridden 
by user.
> > > > > Ideally, this should be decided by the SPI controller based on the
> > > > > requirements. Another option would be to prefer GSI for all transfers if
> > > > > it is available, ignoring the FIFO even if it is not disabled.
> > > > Yes, it should be decided in advance and configured accordingly for GSI
> > > > vs non GSI mode. Because there would be limited set of GSI pipes, which
> > > > will actually make must have GSI mode device run with FIFO mode.
> > > >
> > > > Why don't you decide prior and configure for GSI mode ? We don't need to
> > > > change the current logic of deciding FIFO vs GSI.
> > > > > > Signed-off-by: Pengyu Luo <mitltlatltl@xxxxxxxxx>
> > > > > > ---
> > > > > >     drivers/spi/spi-geni-qcom.c | 7 +++++++
> > > > > >     1 file changed, 7 insertions(+)