If, in a previous transfer, the controller sends more data than expected
by the DSPI target, SR.RFDF (RX FIFO is not empty) will remain asserted.
When flushing the FIFOs at the beginning of a new transfer (writing 1
into MCR.CLR_TXF and MCR.CLR_RXF), SR.RFDF should also be cleared.
Otherwise, when running in target mode with DMA, if SR.RFDF remains
asserted, the DMA callback will be fired before the controller sends any
data.

Take this opportunity to reset all Status Register fields.

Fixes: 5ce3cc567471 ("spi: spi-fsl-dspi: Provide support for DSPI slave mode operation (Vybryd vf610)")
Signed-off-by: Larisa Grigore <larisa.grigore@nxp.com>
Signed-off-by: James Clark <james.clark@linaro.org>
Link: https://patch.msgid.link/20250522-james-nxp-spi-v2-3-bea884630cfb@linaro.org
Signed-off-by: Mark Brown <broonie@kernel.org>

The XSPI mode implementation in this driver still uses the EOQ flag to
signal the last word in a transmission and deassert the PCS signal.
However, at speeds lower than ~200kHZ, the PCS signal seems to remain
asserted even when SR[EOQF] = 1 indicates the end of a transmission.
This is a problem for target devices which require the deassertation of
the PCS signal between transfers.

Hence, this commit 'forces' the deassertation of the PCS by stopping the
module through MCR[HALT] after completing a new transfer. According to
the reference manual, the module stops or transitions from the Running
state to the Stopped state after the current frame, when any one of the
following conditions exist:
- The value of SR[EOQF] = 1.
- The chip is in Debug mode and the value of MCR[FRZ] = 1.
- The value of MCR[HALT] = 1.

This shouldn't be done if the last transfer in the message has cs_change
set.

Fixes: ea93ed4c181b ("spi: spi-fsl-dspi: Use EOQ for last word in buffer even for XSPI mode")
Signed-off-by: Bogdan-Gabriel Roman <bogdan-gabriel.roman@nxp.com>
Signed-off-by: Larisa Grigore <larisa.grigore@nxp.com>
Signed-off-by: James Clark <james.clark@linaro.org>
Link: https://patch.msgid.link/20250522-james-nxp-spi-v2-2-bea884630cfb@linaro.org
Signed-off-by: Mark Brown <broonie@kernel.org>

DSPI registers are NOT continuous, some registers are reserved and
accessing them from userspace will trigger external abort, add regmap
register access table to avoid below abort.

  For example on S32G:

  # cat /sys/kernel/debug/regmap/401d8000.spi/registers

  Internal error: synchronous external abort: 96000210 1 PREEMPT SMP
  ...
  Call trace:
  regmap_mmio_read32le+0x24/0x48
  regmap_mmio_read+0x48/0x70
  _regmap_bus_reg_read+0x38/0x48
  _regmap_read+0x68/0x1b0
  regmap_read+0x50/0x78
  regmap_read_debugfs+0x120/0x338

Fixes: 1acbdeb92c87 ("spi/fsl-dspi: Convert to use regmap and add big-endian support")
Co-developed-by: Xulin Sun <xulin.sun@windriver.com>
Signed-off-by: Xulin Sun <xulin.sun@windriver.com>
Signed-off-by: Larisa Grigore <larisa.grigore@nxp.com>
Signed-off-by: James Clark <james.clark@linaro.org>
Link: https://patch.msgid.link/20250522-james-nxp-spi-v2-1-bea884630cfb@linaro.org
Signed-off-by: Mark Brown <broonie@kernel.org>

The SPI interface is activated before the CPOL setting is applied. In
that moment, the clock idles high and CS goes low. After a short delay,
CPOL and other settings are applied, which may cause the clock to change
state and idle low. This transition is not part of a clock cycle, and it
can confuse the receiving device.

To prevent this unexpected transition, activate the interface while CPOL
and the other settings are being applied.

Signed-off-by: Alessandro Grassi <alessandro.grassi@mailbox.org>
Link: https://patch.msgid.link/20250502095520.13825-1-alessandro.grassi@mailbox.org
Signed-off-by: Mark Brown <broonie@kernel.org>

A delay unit of 0 is a valid entry, thus it is not valid to check for
unused delays. Instead, check the value field; if that is zero, the
given delay is unset.

Fixes: 4426e6b4ecf6 ("spi: tegra114: Don't fail set_cs_timing when delays are zero")
Cc: stable@vger.kernel.org
Signed-off-by: Aaron Kling <webgeek1234@gmail.com>
Reviewed-by: Jon Hunter <jonathanh@nvidia.com>
Link: https://patch.msgid.link/20250506-spi-tegra114-fixup-v1-1-136dc2f732f3@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi_test_print_hex_dump() prints buffers holding less than 1024 bytes in
full.  Larger buffers are truncated: only the first 512 and the last 512
bytes are printed, separated by a truncation message.  The latter is
confusing in case the buffer holds exactly 1024 bytes, as all data is
printed anyway.

Fix this by printing buffers holding up to and including 1024 bytes in
full.

Fixes: 84e0c4e5e2c4ef42 ("spi: add loopback test driver to allow for spi_master regression tests")
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://patch.msgid.link/37ee1bc90c6554c9347040adabf04188c8f704aa.1746184171.git.geert+renesas@glider.be
Signed-off-by: Mark Brown <broonie@kernel.org>

Pull spi fixes from Mark Brown:
 "A fairly small pile of fixes, plus one new compatible string addition
  to the Synopsis driver for a new platform.

  The most notable thing is the fix for divide by zeros in spi-mem if an
  operation has no dummy bytes"

* tag 'spi-fix-v6.15-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/broonie/spi:
  spi: tegra114: Don't fail set_cs_timing when delays are zero
  spi: spi-qpic-snand: fix NAND_READ_LOCATION_2 register handling
  spi: spi-mem: Add fix to avoid divide error
  spi: dt-bindings: snps,dw-apb-ssi: Add compatible for SOPHGO SG2042 SoC
  spi: dt-bindings: snps,dw-apb-ssi: Merge duplicate compatible entry
  spi: spi-qpic-snand: propagate errors from qcom_spi_block_erase()
  spi: stm32-ospi: Fix an error handling path in stm32_ospi_probe()

The original code would skip null delay pointers, but when the pointers
were converted to point within the spi_device struct, the check was not
updated to skip delays of zero. Hence all spi devices that didn't set
delays would fail to probe.

Fixes: 04e6bb0d6bb1 ("spi: modify set_cs_timing parameter")
Cc: stable@vger.kernel.org
Signed-off-by: Aaron Kling <webgeek1234@gmail.com>
Link: https://patch.msgid.link/20250423-spi-tegra114-v1-1-2d608bcc12f9@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>

The precomputed value for the NAND_READ_LOCATION_2 register should be
stored in 'snandc->regs->read_location2'.

Fix the qcom_spi_set_read_loc_first() function accordingly.

Fixes: 7304d1909080 ("spi: spi-qpic: add driver for QCOM SPI NAND flash Interface")
Signed-off-by: Gabor Juhos <j4g8y7@gmail.com>
Reviewed-by: Md Sadre Alam <quic_mdalam@quicinc.com>
Link: https://patch.msgid.link/20250428-qpic-snand-readloc2-fix-v1-1-50ce0877ff72@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>

For some SPI flash memory operations, dummy bytes are not mandatory. For
example, in Winbond SPINAND flash memory devices, the `write_cache` and
`update_cache` operation variants have zero dummy bytes. Calculating the
duration for SPI memory operations with zero dummy bytes causes
a divide error when `ncycles` is calculated in the
spi_mem_calc_op_duration().

Add changes to skip the 'ncylcles' calculation for zero dummy bytes.

Following divide error is fixed by this change:

 Oops: divide error: 0000 [#1] PREEMPT SMP NOPTI
...

  ? do_trap+0xdb/0x100
  ? do_error_trap+0x75/0xb0
  ? spi_mem_calc_op_duration+0x56/0xb0
  ? exc_divide_error+0x3b/0x70
  ? spi_mem_calc_op_duration+0x56/0xb0
  ? asm_exc_divide_error+0x1b/0x20
  ? spi_mem_calc_op_duration+0x56/0xb0
  ? spinand_select_op_variant+0xee/0x190 [spinand]
  spinand_match_and_init+0x13e/0x1a0 [spinand]
  spinand_manufacturer_match+0x6e/0xa0 [spinand]
  spinand_probe+0x357/0x7f0 [spinand]
  ? kernfs_activate+0x87/0xd0
  spi_mem_probe+0x7a/0xb0
  spi_probe+0x7d/0x130

Fixes: 226d6cb3cb79 ("spi: spi-mem: Estimate the time taken by operations")
Suggested-by: Krishnamoorthi M <krishnamoorthi.m@amd.com>
Co-developed-by: Akshata MukundShetty <akshata.mukundshetty@amd.com>
Signed-off-by: Akshata MukundShetty <akshata.mukundshetty@amd.com>
Signed-off-by: Raju Rangoju <Raju.Rangoju@amd.com>
Link: https://patch.msgid.link/20250424121333.417372-1-Raju.Rangoju@amd.com
Reviewed-by: Miquel Raynal <miquel.raynal@bootlin.com>
Signed-off-by: Mark Brown <broonie@kernel.org>