Commit Graph

27 Commits

Author SHA1 Message Date
Douglas Anderson cc71c42b3d
spi: spi-qcom-qspi: Add mem_ops to avoid PIO for badly sized reads
In the patch ("spi: spi-qcom-qspi: Fallback to PIO for xfers that
aren't multiples of 4 bytes") we detect reads that we can't handle
properly and fallback to PIO mode. While that's correct behavior, we
can do better by adding "spi_controller_mem_ops" for our
controller. Once we do this then the caller will give us a transfer
that's a multiple of 4-bytes so we can DMA.

Fixes: b5762d9560 ("spi: spi-qcom-qspi: Add DMA mode support")
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Vijaya Krishna Nivarthi <quic_vnivarth@quicinc.com>
Link: https://lore.kernel.org/r/20230725110226.2.Id4a39804e01e4a06dae9b73fd2a5194c4c7ea453@changeid
Signed-off-by: Mark Brown <broonie@kernel.org>
2023-07-26 12:47:20 +01:00
Douglas Anderson 138d73b627
spi: spi-qcom-qspi: Fallback to PIO for xfers that aren't multiples of 4 bytes
The Qualcomm QSPI driver appears to require that any reads using DMA
are a mutliple of 4 bytes. If this isn't true then the controller will
clobber any extra bytes in memory following the last word. Let's
detect this and falback to PIO.

This fixes problems reported by slub_debug=FZPUA, which would complain
about "kmalloc Redzone overwritten". One such instance said:

  0xffffff80c29d541a-0xffffff80c29d541b @offset=21530. First byte 0x0 instead of 0xcc
  Allocated in mtd_kmalloc_up_to+0x98/0xac age=36 cpu=3 pid=6658

Tracing through what was happening I saw that, while we often did DMA
tranfers of 0x1000 bytes, sometimes we'd end up doing ones of 0x41a
bytes. Those 0x41a byte transfers were the problem.

NOTE: a future change will enable the SPI "mem ops" to help avoid this
case, but it still seems good to add the extra check in the transfer.

Fixes: b5762d9560 ("spi: spi-qcom-qspi: Add DMA mode support")
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Vijaya Krishna Nivarthi <quic_vnivarth@quicinc.com>
Reviewed-by: Bjorn Andersson <andersson@kernel.org>
Link: https://lore.kernel.org/r/20230725110226.1.Ia2f980fc7cd0b831e633391f0bb1272914d8f381@changeid
Signed-off-by: Mark Brown <broonie@kernel.org>
2023-07-26 12:47:19 +01:00
Vijaya Krishna Nivarthi 916a4edf3d
spi: spi-qcom-qspi: Add DMA_CHAIN_DONE to ALL_IRQS
Add latest added DMA_CHAIN_DONE irq to QSPI_ALL_IRQS that encompasses all
of the qspi IRQs.

Signed-off-by: Vijaya Krishna Nivarthi <quic_vnivarth@quicinc.com>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Link: https://lore.kernel.org/r/1690285689-30233-5-git-send-email-quic_vnivarth@quicinc.com
Signed-off-by: Mark Brown <broonie@kernel.org>
2023-07-25 19:11:56 +01:00
Vijaya Krishna Nivarthi cfb81f2243
spi: spi-qcom-qspi: Call dma_wmb() after setting up descriptors
After setting up dma descriptors and before initiaiting dma transfer, call
dma_wmb() to ensure all writes go through.
This doesn't fix any reported problem but is added for safety.

Signed-off-by: Vijaya Krishna Nivarthi <quic_vnivarth@quicinc.com>
Fixes: b5762d9560 ("spi: spi-qcom-qspi: Add DMA mode support")
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Link: https://lore.kernel.org/r/1690285689-30233-4-git-send-email-quic_vnivarth@quicinc.com
Signed-off-by: Mark Brown <broonie@kernel.org>
2023-07-25 19:11:55 +01:00
Vijaya Krishna Nivarthi f7ba36d399
spi: spi-qcom-qspi: Use GFP_ATOMIC flag while allocating for descriptor
While allocating for DMA descriptor, GFP_KERNEL flag is being used and
this allocation happens within critical section with spinlock acquired.
This generates a static checker warning.

Use GFP_ATOMIC to prevent sleeping; and since this increases chances of
allocation failure, add handling accordingly.

Reported-by: Dan Carpenter <dan.carpenter@linaro.org>
Closes: https://lore.kernel.org/all/abc223e8-44af-40bb-a0bd-9865b393f435@moroto.mountain/
Signed-off-by: Vijaya Krishna Nivarthi <quic_vnivarth@quicinc.com>
Fixes: b5762d9560 ("spi: spi-qcom-qspi: Add DMA mode support")
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Link: https://lore.kernel.org/r/1690285689-30233-3-git-send-email-quic_vnivarth@quicinc.com
Signed-off-by: Mark Brown <broonie@kernel.org>
2023-07-25 19:11:54 +01:00
Vijaya Krishna Nivarthi 17aaf9ea07
spi: spi-qcom-qspi: Ignore disabled interrupts' status in isr
During FIFO/DMA modes dynamic switching, only corresponding interrupts are
enabled. However its possible that FIFO related interrupt status registers
get set during DMA mode. For example WR_FIFO_EMPTY bit is set during DMA
TX.

Ignore such status bits so that they don't trip unwanted operations.

Suggested-by: Douglas Anderson <dianders@chromium.org>
Signed-off-by: Vijaya Krishna Nivarthi <quic_vnivarth@quicinc.com>
Fixes: b5762d9560 ("spi: spi-qcom-qspi: Add DMA mode support")
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Tested-by: Douglas Anderson <dianders@chromium.org>
Link: https://lore.kernel.org/r/1690285689-30233-2-git-send-email-quic_vnivarth@quicinc.com
Signed-off-by: Mark Brown <broonie@kernel.org>
2023-07-25 19:11:53 +01:00
Douglas Anderson 55c33e5ee6
spi: spi-qcom-qspi: Add newline to PIO fallback warning
A warning added in commit b5762d9560 ("spi: spi-qcom-qspi: Add DMA
mode support") was missing a newline. Add it.

Reported-by: Stephen Boyd <swboyd@chromium.org>
Closes: https://chromium-review.googlesource.com/c/chromiumos/third_party/kernel/+/4573857/comment/44331d65_79128099/
Fixes: b5762d9560 ("spi: spi-qcom-qspi: Add DMA mode support")
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Link: https://lore.kernel.org/r/20230530111348.1.Ibd1f4827e18a26dc802cd6e5ac300d83dc1bc41c@changeid
Signed-off-by: Mark Brown <broonie@kernel.org>
2023-05-30 19:28:48 +01:00
Vijaya Krishna Nivarthi b5762d9560
spi: spi-qcom-qspi: Add DMA mode support
Current driver supports only PIO mode.

HW supports DMA, so add DMA mode support to the driver
for better performance for larger xfers.

Signed-off-by: Vijaya Krishna Nivarthi <quic_vnivarth@quicinc.com
Reviewed-by: Douglas Anderson <dianders@chromium.org
Link: https://lore.kernel.org/r/1682328761-17517-6-git-send-email-quic_vnivarth@quicinc.com
Signed-off-by: Mark Brown <broonie@kernel.org
2023-05-08 08:50:40 +09:00
Douglas Anderson 0098c52745
spi: spi-qcom-qspi: Support pinctrl sleep states
It's fairly common practice for drivers to switch to a "sleep" pinctrl
state at the end of its runtime_suspend function and then back to
"default" at the beginning of runtime_resume. Let's do that for
spi-qcom-qspi.

Signed-off-by: Douglas Anderson <dianders@chromium.org>
Link: https://lore.kernel.org/r/20230323102605.5.I79544b9486033bd7b27f2be55adda6d36f62a366@changeid
Signed-off-by: Mark Brown <broonie@kernel.org>
2023-03-28 01:26:10 +01:00
Amit Kumar Mahapatra via Alsa-devel 9e264f3f85
spi: Replace all spi->chip_select and spi->cs_gpiod references with function call
Supporting multi-cs in spi drivers would require the chip_select & cs_gpiod
members of struct spi_device to be an array. But changing the type of these
members to array would break the spi driver functionality. To make the
transition smoother introduced four new APIs to get/set the
spi->chip_select & spi->cs_gpiod and replaced all spi->chip_select and
spi->cs_gpiod references with get or set API calls.
While adding multi-cs support in further patches the chip_select & cs_gpiod
members of the spi_device structure would be converted to arrays & the
"idx" parameter of the APIs would be used as array index i.e.,
spi->chip_select[idx] & spi->cs_gpiod[idx] respectively.

Signed-off-by: Amit Kumar Mahapatra <amit.kumar-mahapatra@amd.com>
Acked-by: Heiko Stuebner <heiko@sntech.de> # Rockchip drivers
Reviewed-by: Michal Simek <michal.simek@amd.com>
Reviewed-by: Cédric Le Goater <clg@kaod.org> # Aspeed driver
Reviewed-by: Dhruva Gole <d-gole@ti.com> # SPI Cadence QSPI
Reviewed-by: Patrice Chotard <patrice.chotard@foss.st.com> # spi-stm32-qspi
Acked-by: William Zhang <william.zhang@broadcom.com> # bcm63xx-hsspi driver
Reviewed-by: Serge Semin <fancer.lancer@gmail.com> # DW SSI part
Link: https://lore.kernel.org/r/167847070432.26.15076794204368669839@mailman-core.alsa-project.org
Signed-off-by: Mark Brown <broonie@kernel.org>
2023-03-11 12:34:01 +00:00
Uwe Kleine-König e0c30566e5
spi: qcom-qspi: Convert to platform remove callback returning void
The .remove() callback for a platform driver returns an int which makes
many driver authors wrongly assume it's possible to do error handling by
returning an error code. However the value returned is (mostly) ignored
and this typically results in resource leaks. To improve here there is a
quest to make the remove callback return void. In the first step of this
quest all drivers are converted to .remove_new() which already returns
void.

Trivially convert this driver from always returning zero in the remove
callback to the void returning variant.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Link: https://lore.kernel.org/r/20230303172041.2103336-57-u.kleine-koenig@pengutronix.de
Signed-off-by: Mark Brown <broonie@kernel.org>
2023-03-06 21:17:59 +00:00
Yangtao Li 6504dcae67 spi: spi-qcom-qspi: Convert to use resource-managed OPP API
Use resource-managed OPP API to simplify code.

Signed-off-by: Yangtao Li <tiny.windzz@gmail.com>
Acked-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
2021-03-16 10:14:11 +05:30
Stephen Boyd eaecba8767
spi: spi-qcom-qspi: Use irq trigger flags from firmware
We don't need to force this to be trigger high here, as the firmware
properly configures the irq flags already. Drop it to save a line.

Cc: Douglas Anderson <dianders@chromium.org>
Cc: Rajendra Nayak <rnayak@codeaurora.org>
Cc: Mukesh Kumar Savaliya <msavaliy@codeaurora.org>
Cc: Akash Asthana <akashast@codeaurora.org>
Signed-off-by: Stephen Boyd <swboyd@chromium.org>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Link: https://lore.kernel.org/r/20210112001301.687628-1-swboyd@chromium.org
Signed-off-by: Mark Brown <broonie@kernel.org>
2021-01-13 12:19:50 +00:00
Lukas Wunner 6cfd39e212
spi: spi-qcom-qspi: Fix use-after-free on unbind
qcom_qspi_remove() accesses the driver's private data after calling
spi_unregister_master() even though that function releases the last
reference on the spi_master and thereby frees the private data.

Fix by switching over to the new devm_spi_alloc_master() helper which
keeps the private data accessible until the driver has unbound.

Fixes: f79a158d37 ("spi: spi-qcom-qspi: Use OPP API to set clk/perf state")
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Cc: <stable@vger.kernel.org> # v5.9+: 5e844cc37a5c: spi: Introduce device-managed SPI controller allocation
Cc: <stable@vger.kernel.org> # v5.9+
Cc: Rajendra Nayak <rnayak@codeaurora.org>
Link: https://lore.kernel.org/r/b6d3c4dce571d78a532fd74f27def0d5dc8d8a24.1607286887.git.lukas@wunner.de
Signed-off-by: Mark Brown <broonie@kernel.org>
2020-12-07 14:18:49 +00:00
Barry Song bfc430cab8
spi: spi-qcom-qspi: replace spin_lock_irqsave by spin_lock in hard IRQ
It is redundant to do irqsave and irqrestore in hardIRQ context.

Cc: Andy Gross <agross@kernel.org>
Cc: Bjorn Andersson <bjorn.andersson@linaro.org>
Signed-off-by: Barry Song <song.bao.hua@hisilicon.com>
Link: https://lore.kernel.org/r/20200910100246.32696-1-song.bao.hua@hisilicon.com
Signed-off-by: Mark Brown <broonie@kernel.org>
2020-09-14 15:50:10 +01:00
Mark Brown 6c557d24fa
Merge series "opp: Unconditionally call dev_pm_opp_of_remove_table()" from Viresh Kumar <viresh.kumar@linaro.org>:
Hello,

This cleans up some of the user code around calls to
dev_pm_opp_of_remove_table().

All the patches can be picked by respective maintainers directly except
for the last patch, which needs the previous two to get merged first.

These are based for 5.9-rc1.

Rajendra, Since most of these changes are related to qcom stuff, it
would be great if you can give them a try. I wasn't able to test them
due to lack of hardware.

Ulf, I had to revise the sdhci patch, sorry about that. Please pick this
one.

Diff between V1 and V2 is mentioned in each of the patches separately.

Viresh Kumar (8):
  cpufreq: imx6q: Unconditionally call dev_pm_opp_of_remove_table()
  drm/lima: Unconditionally call dev_pm_opp_of_remove_table()
  drm/msm: Unconditionally call dev_pm_opp_of_remove_table()
  mmc: sdhci-msm: Unconditionally call dev_pm_opp_of_remove_table()
  spi: spi-geni-qcom: Unconditionally call dev_pm_opp_of_remove_table()
  spi: spi-qcom-qspi: Unconditionally call dev_pm_opp_of_remove_table()
  tty: serial: qcom_geni_serial: Unconditionally call
    dev_pm_opp_of_remove_table()
  qcom-geni-se: remove has_opp_table

 drivers/cpufreq/imx6q-cpufreq.c         | 10 ++--------
 drivers/gpu/drm/lima/lima_devfreq.c     |  6 +-----
 drivers/gpu/drm/lima/lima_devfreq.h     |  1 -
 drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c | 14 +++++---------
 drivers/gpu/drm/msm/disp/dpu1/dpu_kms.h |  1 -
 drivers/gpu/drm/msm/dsi/dsi_host.c      |  8 ++------
 drivers/mmc/host/sdhci-msm.c            | 14 +++++---------
 drivers/spi/spi-geni-qcom.c             | 13 +++++--------
 drivers/spi/spi-qcom-qspi.c             | 15 ++++++---------
 drivers/tty/serial/qcom_geni_serial.c   | 13 +++++--------
 include/linux/qcom-geni-se.h            |  2 --
 11 files changed, 31 insertions(+), 66 deletions(-)

base-commit: f4d51dffc6
--
2.25.0.rc1.19.g042ed3e048af
2020-09-09 16:27:47 +01:00
Viresh Kumar 062cf7fc92
spi: spi-qcom-qspi: Unconditionally call dev_pm_opp_of_remove_table()
dev_pm_opp_of_remove_table() doesn't report any errors when it fails to
find the OPP table with error -ENODEV (i.e. OPP table not present for
the device). And we can call dev_pm_opp_of_remove_table()
unconditionally here.

While at it, create a new label and put clkname on errors.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Link: https://lore.kernel.org/r/b77aa0bbe82a580508e321a34da488b4b27966d0.1598594714.git.viresh.kumar@linaro.org
Signed-off-by: Mark Brown <broonie@kernel.org>
2020-09-09 16:11:42 +01:00
Krzysztof Kozlowski 034532681c
spi: qcom-qspi: Simplify with dev_err_probe()
Common pattern of handling deferred probe can be simplified with
dev_err_probe().  Less code and the error value gets printed.

Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
Link: https://lore.kernel.org/r/20200901152713.18629-7-krzk@kernel.org
Signed-off-by: Mark Brown <broonie@kernel.org>
2020-09-08 18:19:28 +01:00
Douglas Anderson 8592eb959a spi: spi-qcom-qspi: Set an autosuspend delay of 250 ms
In commit cff80645d6 ("spi: spi-qcom-qspi: Add interconnect support")
the spi_geni_runtime_suspend() and spi_geni_runtime_resume()
became a bit slower.  Measuring on my hardware I see numbers in the
hundreds of microseconds now.

Let's use autosuspend to help avoid some of the overhead.  Now if
we're doing a bunch of transfers we won't need to be constantly
chruning.

The number 250 ms for the autosuspend delay was picked a bit
arbitrarily, so if someone has measurements showing a better value we
could easily change this.

Fixes: cff80645d6 ("spi: spi-qcom-qspi: Add interconnect support")
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Acked-by: Mark Brown <broonie@kernel.org>
Reviewed-by: Rajendra Nayak <rnayak@codeaurora.org>
Tested-by: Rajendra Nayak <rnayak@codeaurora.org>
Reviewed-by: Mukesh Kumar Savaliya <msavaliy@codeaurora.org>
Reviewed-by: Akash Asthana <akashast@codeaurora.org>
Link: https://lore.kernel.org/r/20200709075113.v2.2.I3c56d655737c89bd9b766567a04b0854db1a4152@changeid
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
2020-07-13 16:17:15 -07:00
Douglas Anderson 2124331411 spi: spi-qcom-qspi: Avoid clock setting if not needed
As per recent changes to the spi-qcom-qspi, now when we set the clock
we'll call into the interconnect framework and also call the OPP API.
Those are expensive operations.  Let's avoid calling them if possible.
This has a big impact on getting transfer rates back up to where they
were (or maybe slightly better) before those patches landed.

Fixes: cff80645d6 ("spi: spi-qcom-qspi: Add interconnect support")
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Acked-by: Mark Brown <broonie@kernel.org>
Reviewed-by: Rajendra Nayak <rnayak@codeaurora.org>
Tested-by: Rajendra Nayak <rnayak@codeaurora.org>
Reviewed-by: Mukesh Kumar Savaliya <msavaliy@codeaurora.org>
Reviewed-by: Akash Asthana <akashast@codeaurora.org>
Link: https://lore.kernel.org/r/20200709075113.v2.1.Ia7cb4f41ce93d37d0a764b47c8a453ce9e9c70ef@changeid
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
2020-07-13 16:17:13 -07:00
Rajendra Nayak f79a158d37 spi: spi-qcom-qspi: Use OPP API to set clk/perf state
QSPI needs to vote on a performance state of a power domain depending on
the clock rate. Add support for it by specifying the perf state/clock rate
as an OPP table in device tree.

Signed-off-by: Rajendra Nayak <rnayak@codeaurora.org>
Reviewed-by: Matthias Kaehlcke <mka@chromium.org>
Acked-by: Mark Brown <broonie@kernel.org>
Cc: Alok Chauhan <alokc@codeaurora.org>
Cc: Akash Asthana <akashast@codeaurora.org>
Cc: linux-spi@vger.kernel.org
Link: https://lore.kernel.org/r/1593769293-6354-2-git-send-email-rnayak@codeaurora.org
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
2020-07-13 16:15:53 -07:00
Akash Asthana cff80645d6 spi: spi-qcom-qspi: Add interconnect support
Get the interconnect paths for QSPI device and vote according to the
current bus speed of the driver.

Acked-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Akash Asthana <akashast@codeaurora.org>
Reviewed-by: Matthias Kaehlcke <mka@chromium.org>
Link: https://lore.kernel.org/r/1592908737-7068-8-git-send-email-akashast@codeaurora.org
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
2020-06-24 21:51:07 -07:00
Matthias Kaehlcke b8d40d7712
spi: spi-qcom-qspi: Use device managed memory for clk_bulk_data
Currrently the memory for the clk_bulk_data of the QSPI controller
is allocated with spi_alloc_master(). The bulk data pointer is passed
to devm_clk_bulk_get() which saves it in clk_bulk_devres->clks. When
the device is removed later devm_clk_bulk_release() is called and
uses the bulk data referenced by the pointer to release the clocks.
For this driver this results in accessing memory that has already
been freed, since the memory allocated with spi_alloc_master() is
released by spi_controller_release(), which is called before the
managed resources are released.

Use device managed memory for the clock bulk data to fix the issue
described above.

Signed-off-by: Matthias Kaehlcke <mka@chromium.org>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Link: https://lore.kernel.org/r/20200108133948.1.I35ceb4db3ad8cfab78f7cd51494aeff4891339f5@changeid
Signed-off-by: Mark Brown <broonie@kernel.org>
2020-01-13 15:04:40 +00:00
YueHaibing e0ea3cc2ba
spi: spi-qcom-qspi: use devm_platform_ioremap_resource() to simplify code
Use devm_platform_ioremap_resource() to simplify the code a bit.
This is detected by coccinelle.

Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Link: https://lore.kernel.org/r/20190904135918.25352-24-yuehaibing@huawei.com
Signed-off-by: Mark Brown <broonie@kernel.org>
2019-09-04 17:21:12 +01:00
Stephen Boyd 6b8ac10e0d
spi: Remove dev_err() usage after platform_get_irq()
We don't need dev_err() messages when platform_get_irq() fails now that
platform_get_irq() prints an error message itself when something goes
wrong. Let's remove these prints with a simple semantic patch.

// <smpl>
@@
expression ret;
struct platform_device *E;
@@

ret =
(
platform_get_irq(E, ...)
|
platform_get_irq_byname(E, ...)
);

if ( \( ret < 0 \| ret <= 0 \) )
{
(
-if (ret != -EPROBE_DEFER)
-{ ...
-dev_err(...);
-... }
|
...
-dev_err(...);
)
...
}
// </smpl>

While we're here, remove braces on if statements that only have one
statement (manually).

Cc: Mark Brown <broonie@kernel.org>
Cc: linux-spi@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Stephen Boyd <swboyd@chromium.org>
Link: https://lore.kernel.org/r/20190730181557.90391-42-swboyd@chromium.org
Signed-off-by: Mark Brown <broonie@kernel.org>
2019-08-02 12:15:43 +01:00
Ryan Case 478652f3d4
spi: spi-qcom-qspi: Fix remaining driver nits
Address remaining comments from original driver patch series

* Move RD_FIFO_CFG to be ordered corretly
* Expand spinlock comment

Signed-off-by: Ryan Case <ryandcase@chromium.org>
Reviewed-by: Stephen Boyd <swboyd@chromium.org>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Signed-off-by: Mark Brown <broonie@kernel.org>
2018-11-22 14:38:13 +00:00
Girish Mahadevan 04000dc6f7
spi: Introduce new driver for Qualcomm QuadSPI controller
New driver for Qualcomm QuadSPI(QSPI) controller that is used to
communicate with slaves such as flash memory devices. The QSPI controller
can operate in 2 or 4 wire mode but only supports SPI Mode 0. The
controller can also operate in Single or Dual data rate modes.

Signed-off-by: Girish Mahadevan <girishm@codeaurora.org>
Signed-off-by: Ryan Case <ryandcase@chromium.org>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Stephen Boyd <swboyd@chromium.org>
Signed-off-by: Mark Brown <broonie@kernel.org>
2018-10-11 15:11:09 +01:00