Merge series from Andy Shevchenko <andriy.shevchenko@linux.intel.com>:
As Arnd suggested we may drop linux/spi/pxa2xx_spi.h as most of
its content is being used solely internally to SPI subsystem
(PXA2xx drivers). Hence this refactoring series with the additional
win of getting rid of legacy documentation.
Note, that we have the only user of a single plain integer field
in the entire kernel for that. Switching to software nodes does not
diminish any of type checking as we only pass an integer.
Merge series from Serge Semin <fancer.lancer@gmail.com>:
The main goal of the short series is to provide a procedure implementing
the auto-detection of the number of native Chip-Select signals supported
by the controller. The suggested algorithm is straightforward. It relies
on the fact that the SER register writable flags reflects the actual
number of available native chip-select signals. So the DW APB/AHB SSI
driver now tests the SER register for having the writable bits,
calculates the number of CS signals based on the number of set flags and
then initializes the num_cs private data field based on that, which then
will be passed to the SPI-core subsystem indicating the number of
supported hardware chip-selects. The implemented procedure will be useful
for the DW SSI device nodes not having the explicitly set "num-cs"
property. In case if the property is specified it will be utilized instead
of the auto-detection procedure.
Besides of that a small cleanup patch is introduced in the head of the
series. It converts the driver to using the BITS_TO_BYTES() macro instead
of the hard-coded DIV_ROUND_UP()-based calculation of the number of
bytes-per-transfer-word.
Now the struct chip_data is local to spi-pxa2xx.c, move
its definition to the C file. This will slightly speed up
a build and also hide badly named data type (too generic).
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/20240417110334.2671228-10-andriy.shevchenko@linux.intel.com
Signed-off-by: Mark Brown <broonie@kernel.org>
The timeout field is used only once and assigned to a predefined
constant. Replace all that by using the constant directly.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/20240417110334.2671228-9-andriy.shevchenko@linux.intel.com
Signed-off-by: Mark Brown <broonie@kernel.org>
The DMA related fields are set once and never modified. It effectively
repeats the content of the same fields in struct pxa2xx_spi_controller.
With that, remove DMA parameters from struct chip_data.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/20240417110334.2671228-8-andriy.shevchenko@linux.intel.com
Signed-off-by: Mark Brown <broonie@kernel.org>
The documentation is referring to the legacy enumeration of the SPI
host controllers and target devices. It has nothing to do with the
modern way, which is the only supported in kernel right now. Hence,
remove outdated documentation file.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/20240417110334.2671228-5-andriy.shevchenko@linux.intel.com
Signed-off-by: Mark Brown <broonie@kernel.org>
There is no user of the linux/spi/pxa2xx_spi.h. Move its contents
to the drivers/spi/spi-pxa2xx.h.
Suggested-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/20240417110334.2671228-4-andriy.shevchenko@linux.intel.com
Signed-off-by: Mark Brown <broonie@kernel.org>
Since driver can parse num-cs device property, replace platform data
with this new approach. This pursues the following objectives:
- getting rid of the public header that barely used outside of
the SPI subsystem (more specifically the SPI PXA2xx drivers)
- making a trampoline for the driver to support non-default number
of the chip select pins in case the original code is going to be
converted to Device Tree model
It's not expected to have more users in board files except this one.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/20240417110334.2671228-3-andriy.shevchenko@linux.intel.com
Signed-off-by: Mark Brown <broonie@kernel.org>
In some cases the number of the chip select pins might come from
the device property. Allow driver to use it.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/20240417110334.2671228-2-andriy.shevchenko@linux.intel.com
Signed-off-by: Mark Brown <broonie@kernel.org>
Convert txt binding of TI's qspi controller (found on their omap SoCs) to
dtschema to allow for validation.
The changes, w.r.t. the original txt binding, are:
- Introduce "clocks" and "clock-names" which was never mentioned.
- Reflect that "ti,hwmods" is deprecated and is not a "required"
property anymore.
- Introduce "num-cs" which allows for setting the number of chip
selects.
- Drop "qspi_ctrlmod".
Signed-off-by: Kousik Sanagavarapu <five231003@gmail.com>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://lore.kernel.org/r/20240501165203.13763-1-five231003@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>
The modpost script is not happy
WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/spi/spi-bitbang.o
because there is a missing module description.
Add it to the module.
While at it, update the terminology in Kconfig section to be in align
with added description along with the code comments.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20240502171518.2792895-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Mark Brown <broonie@kernel.org>
DW APB/AHB SSI core now supports the procedure automatically detecting the
number of native chip-select lines. Thus there is no longer point in
defaulting to four CS if the platform doesn't specify the real number
especially seeing the default number didn't correspond to any original DW
APB/AHB databook.
Signed-off-by: Serge Semin <fancer.lancer@gmail.com>
Reviewed-by: Andy Shevchenko <andy@kernel.org>
Link: https://lore.kernel.org/r/20240424150657.9678-5-fancer.lancer@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>
Number of native chip-select lines is either retrieved from the "num-cs"
DT-property or auto-detected in the generic DW APB/AHB SSI probe method.
In the former case the property is supposed to be of the "u32" size.
Convert the field type to being u32 then to be able to drop the temporary
variable afterwards.
Signed-off-by: Serge Semin <fancer.lancer@gmail.com>
Reviewed-by: Andy Shevchenko <andy@kernel.org>
Link: https://lore.kernel.org/r/20240424150657.9678-4-fancer.lancer@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>
Aside with the FIFO depth and DFS field size it's possible to auto-detect
a number of native chip-select synthesized in the DW APB/AHB SSI IP-core.
It can be done just by writing ones to the SER register. The number of
writable flags in the register is limited by the SSI_NUM_SLAVES IP-core
synthesize parameter. All the upper flags are read-only and wired to zero.
Based on that let's add the number of native CS auto-detection procedure
so the low-level platform drivers wouldn't need to manually set it up
unless it's required to set a constraint due to platform-specific reasons
(for instance, due to a hardware bug).
Signed-off-by: Serge Semin <fancer.lancer@gmail.com>
Reviewed-by: Andy Shevchenko <andy@kernel.org>
Link: https://lore.kernel.org/r/20240424150657.9678-3-fancer.lancer@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>
Since commit dd3e7cba16 ("ocfs2/dlm: move BITS_TO_BYTES() to bitops.h
for wider use") there is a generic helper available to calculate a number
of bytes needed to accommodate the specified number of bits. Let's use it
instead of the hard-coded DIV_ROUND_UP() macro function.
Signed-off-by: Serge Semin <fancer.lancer@gmail.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Link: https://lore.kernel.org/r/20240424150657.9678-2-fancer.lancer@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>
Merge series from Wolfram Sang <wsa+renesas@sang-engineering.com>:
There is a confusing pattern in the kernel to use a variable named 'timeout' to
store the result of wait_for_*() functions causing patterns like:
timeout = wait_for_completion_timeout(...)
if (!timeout) return -ETIMEDOUT;
with all kinds of permutations. Use 'time_left' as a variable to make the code
obvious and self explaining.
This is part of a tree-wide series. The rest of the patches can be found here
(some parts may still be WIP):
git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux.git i2c/time_left
Because these patches are generated, I audit them before sending. This is why I
will send series step by step. Build bot is happy with these patches, though.
No functional changes intended.
Merge series from Lorenzo Bianconi <lorenzo@kernel.org>:
Introduce support for SPI-NAND driver of the Airoha NAND Flash Interface
found on Airoha ARM EN7581 SoCs.
There are macros spi_valid_txbuf() and spi_valid_rxbuf() for determining
if an xfer actually intended to send or receive data.
These checks were hard-coded in spi_statistics_add_transfer_stats(). We
can make use of the macros instead to make the code more readable and
more robust against potential future changes in case the definition of
what valid means changes.
The macro takes the spi_message as an argument, so we need to change
spi_statistics_add_transfer_stats() to take the spi_message as an
argument instead of the controller.
Signed-off-by: David Lechner <dlechner@baylibre.com>
Link: https://lore.kernel.org/r/20240430201530.2138095-3-dlechner@baylibre.com
Signed-off-by: Mark Brown <broonie@kernel.org>
There is a confusing pattern in the kernel to use a variable named 'timeout' to
store the result of wait_for_completion_timeout() causing patterns like:
timeout = wait_for_completion_timeout(...)
if (!timeout) return -ETIMEDOUT;
with all kinds of permutations. Use 'time_left' as a variable to make the code
self explaining.
Fix to the proper variable type 'unsigned long' while here.
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Link: https://lore.kernel.org/r/20240430114142.28551-9-wsa+renesas@sang-engineering.com
Signed-off-by: Mark Brown <broonie@kernel.org>
There is a confusing pattern in the kernel to use a variable named 'timeout' to
store the result of wait_for_completion_timeout() causing patterns like:
timeout = wait_for_completion_timeout(...)
if (!timeout) return -ETIMEDOUT;
with all kinds of permutations. Use 'time_left' as a variable to make the code
self explaining.
Fix to the proper variable type 'unsigned long' while here.
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Acked-by: Jernej Skrabec <jernej.skrabec@gmail.com>
Reviewed-by: Andre Przywara <andre.przywara@arm.com>
Link: https://lore.kernel.org/r/20240430114142.28551-8-wsa+renesas@sang-engineering.com
Signed-off-by: Mark Brown <broonie@kernel.org>
There is a confusing pattern in the kernel to use a variable named 'timeout' to
store the result of wait_for_completion_timeout() causing patterns like:
timeout = wait_for_completion_timeout(...)
if (!timeout) return -ETIMEDOUT;
with all kinds of permutations. Use 'time_left' as a variable to make the code
self explaining.
Fix to the proper variable type 'unsigned long' while here.
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Acked-by: Jernej Skrabec <jernej.skrabec@gmail.com>
Reviewed-by: Andre Przywara <andre.przywara@arm.com>
Link: https://lore.kernel.org/r/20240430114142.28551-7-wsa+renesas@sang-engineering.com
Signed-off-by: Mark Brown <broonie@kernel.org>
There is a confusing pattern in the kernel to use a variable named 'timeout' to
store the result of wait_for_completion_timeout() causing patterns like:
timeout = wait_for_completion_timeout(...)
if (!timeout) return -ETIMEDOUT;
with all kinds of permutations. Use 'time_left' as a variable to make the code
self explaining.
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Link: https://lore.kernel.org/r/20240430114142.28551-6-wsa+renesas@sang-engineering.com
Signed-off-by: Mark Brown <broonie@kernel.org>
There is a confusing pattern in the kernel to use a variable named 'timeout' to
store the result of wait_for_completion_timeout() causing patterns like:
timeout = wait_for_completion_timeout(...)
if (!timeout) return -ETIMEDOUT;
with all kinds of permutations. Use 'time_left' as a variable to make the code
self explaining.
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Link: https://lore.kernel.org/r/20240430114142.28551-5-wsa+renesas@sang-engineering.com
Signed-off-by: Mark Brown <broonie@kernel.org>
There is a confusing pattern in the kernel to use a variable named 'timeout' to
store the result of wait_for_completion_timeout() causing patterns like:
timeout = wait_for_completion_timeout(...)
if (!timeout) return -ETIMEDOUT;
with all kinds of permutations. Use 'time_left' as a variable to make the code
self explaining.
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Reviewed-by: Peng Fan <peng.fan@nxp.com>
Link: https://lore.kernel.org/r/20240430114142.28551-4-wsa+renesas@sang-engineering.com
Signed-off-by: Mark Brown <broonie@kernel.org>
There is a confusing pattern in the kernel to use a variable named 'timeout' to
store the result of wait_for_completion_timeout() causing patterns like:
timeout = wait_for_completion_timeout(...)
if (!timeout) return -ETIMEDOUT;
with all kinds of permutations. Use 'time_left' as a variable to make the code
self explaining.
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Link: https://lore.kernel.org/r/20240430114142.28551-3-wsa+renesas@sang-engineering.com
Signed-off-by: Mark Brown <broonie@kernel.org>
There is a confusing pattern in the kernel to use a variable named 'timeout' to
store the result of wait_for_completion_timeout() causing patterns like:
timeout = wait_for_completion_timeout(...)
if (!timeout) return -ETIMEDOUT;
with all kinds of permutations. Use 'time_left' as a variable to make the code
self explaining.
Fix to the proper variable type 'unsigned long' while here.
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Link: https://lore.kernel.org/r/20240430114142.28551-2-wsa+renesas@sang-engineering.com
Signed-off-by: Mark Brown <broonie@kernel.org>
Introduce support for SPI-NAND driver of the Airoha NAND Flash Interface
found on Airoha ARM SoCs.
Tested-by: Rajeev Kumar <Rajeev.Kumar@airoha.com>
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Reviewed-by: Andy Shevchenko <andy@kernel.org>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Link: https://lore.kernel.org/r/6c9db20505b01a66807995374f2af475a23ce5b2.1714377864.git.lorenzo@kernel.org
Signed-off-by: Mark Brown <broonie@kernel.org>
Call readl_relaxed_poll_timeout() with no sleep at the start of
cqspi_wait_for_bit(). If its short timeout expires, a sleeping
readl_relaxed_poll_timeout() call takes the relay.
The reason is to avoid hrtimer interrupts on the system. All read
operations are expected to take less than 100µs.
Signed-off-by: Théo Lebrun <theo.lebrun@bootlin.com>
Link: https://lore.kernel.org/r/20240423-cdns-qspi-mbly-v4-3-3d2a7b535ad0@bootlin.com
Signed-off-by: Mark Brown <broonie@kernel.org>
Support reads through polling, without any IRQ. The main reason is
performance; profiling shows that the first IRQ comes quickly on our
specific hardware. Once this IRQ arrives, we poll until all data is
retrieved. Avoid initial sleep to reduce IRQ count.
Hide this behavior behind a quirk flag.
This is confirmed through micro-benchmarks, but also end-to-end
performance tests. Mobileye EyeQ5, octal flash, reading 235M on a UBIFS
filesystem:
- No optimizations, ~10.34s, ~22.7 MB/s, 199230 IRQs
- CQSPI_SLOW_SRAM, ~10.34s, ~22.7 MB/s, 70284 IRQs
- CQSPI_RD_NO_IRQ, ~9.37s, ~25.1 MB/s, 521 IRQs
Signed-off-by: Théo Lebrun <theo.lebrun@bootlin.com>
Link: https://lore.kernel.org/r/20240423-cdns-qspi-mbly-v4-2-3d2a7b535ad0@bootlin.com
Signed-off-by: Mark Brown <broonie@kernel.org>
If FIFO depth DT property is provided, check it matches what hardware
reports and warn otherwise. Else, use hardware provided value.
Hardware exposes FIFO depth indirectly because
CQSPI_REG_SRAMPARTITION is partially read-only.
Move probe cqspi->ddata assignment prior to cqspi_of_get_pdata() call.
Signed-off-by: Théo Lebrun <theo.lebrun@bootlin.com>
Link: https://lore.kernel.org/r/20240423-cdns-qspi-mbly-v4-1-3d2a7b535ad0@bootlin.com
Signed-off-by: Mark Brown <broonie@kernel.org>
Use the scope based of_node_put() cleanup in s3c64xx_spi_csinfo to
automatically release the device node with the __free() cleanup handler
Initialize data_np at the point of declaration for clarity of scope.
This change reduces the risk of memory leaks and simplifies the code by
removing manual node put call.
Suggested-by: Julia Lawall <julia.lawall@inria.fr>
Signed-off-by: Shivani Gupta <shivani07g@gmail.com>
Link: https://lore.kernel.org/r/20240418000505.731724-1-shivani07g@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>
In some cases SPI child devices behind spi-mux require different
settings like: max_speed_hz, mode and bits_per_word.
Typically the slave device driver puts the settings in place and calls
spi_setup() once during probe and assumes they stay in place for all
following spi transfers.
However spi-mux forwarded spi_setup() -call to SPI master driver only
when slave driver calls spi_setup(). If second slave device was
accessed meanwhile and that driver called spi_setup(), the
settings did not change back to the first spi device.
In case of wrong max_speed_hz this caused spi trasfers to fail.
This commit adds spi_setup() call after mux is changed. This way
the right device specific parameters are set to the master driver.
The fix has been tested by using custom hardware and debugging
spi master driver speed settings.
Co-authored-by: Petri Tauriainen <petri.tauriainen@bittium.com>
Signed-off-by: Heikki Keranen <heikki.keranen@bittium.com>
Link: https://lore.kernel.org/r/20240422114150.84426-1-heikki.keranen@bittium.com
Signed-off-by: Mark Brown <broonie@kernel.org>
Convert txt binding of marvell armada 3700 SoC spi controller to dtschema
to allow for validation.
Signed-off-by: Kousik Sanagavarapu <five231003@gmail.com>
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://lore.kernel.org/r/20240417052729.6612-1-five231003@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>
Use devm_add_action_or_reset() rather than manually cleaning up on the
error path.
Suggested-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Charles Keepax <ckeepax@opensource.cirrus.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Link: https://lore.kernel.org/r/20240417093026.79396-1-ckeepax@opensource.cirrus.com
Signed-off-by: Mark Brown <broonie@kernel.org>
Merge series from Charles Keepax <ckeepax@opensource.cirrus.com>:
In some cs42l43 systems a couple of cs35l56 amplifiers are attached
to the cs42l43's SPI and I2S. On Windows the cs42l43 is controlled
by a SDCA class driver and these two amplifiers are controlled by
firmware running on the cs42l43. However, under Linux the decision
was made to interact with the cs42l43 directly, affording the user
greater control over the audio system. However, this has resulted
in an issue where these two bridged cs35l56 amplifiers are not
populated in ACPI and must be added manually. There is at least an
SDCA extension unit DT entry we can key off.
The process of adding this is handled using a software node, firstly the
ability to add native chip selects to software nodes must be added.
Secondly, an additional flag for naming the SPI devices is added this
allows the machine driver to key to the correct amplifier. Then finally,
the cs42l43 SPI driver adds the two amplifiers directly onto its SPI
bus.
An additional series will follow soon to add the audio machine driver
parts (in the sof-sdw driver), however that is fairly orthogonal to
this part of the process, getting the actual amplifiers registered.
Merge series from Andy Shevchenko <andriy.shevchenko@linux.intel.com>:
A couple of additional refactorings on top of the multi-CS support.
One is to make sure that the comment and the code are not disrupted
if additional changes come in the future and second one is f or the
sake of deduplication. In both cases it also makes indentation level
smaller in the affected pieces of the code.
No functional changes intended.
On some cs42l43 systems a couple of cs35l56 amplifiers are attached
to the cs42l43's SPI and I2S. On Windows the cs42l43 is controlled
by a SDCA class driver and these two amplifiers are controlled by
firmware running on the cs42l43. However, under Linux the decision
was made to interact with the cs42l43 directly, affording the user
greater control over the audio system. However, this has resulted
in an issue where these two bridged cs35l56 amplifiers are not
populated in ACPI and must be added manually.
Check for the presence of the "01fa-cirrus-sidecar-instances" property
in the SDCA extension unit's ACPI properties to confirm the presence
of these two amplifiers and if they exist add them manually onto the
SPI bus.
Reviewed-by: Andy Shevchenko <andy@kernel.org>
Signed-off-by: Maciej Strozek <mstrozek@opensource.cirrus.com>
Signed-off-by: Charles Keepax <ckeepax@opensource.cirrus.com>
Link: https://lore.kernel.org/r/20240416100904.3738093-5-ckeepax@opensource.cirrus.com
Signed-off-by: Mark Brown <broonie@kernel.org>
Update the name for software node based SPI devices to use the fwnode
name as the device name. This is helpful since swnode devices are
usually added within the kernel, and the kernel often then requires a
predictable name such that it can refer back to the device.
Reviewed-by: Andy Shevchenko <andy@kernel.org>
Signed-off-by: Charles Keepax <ckeepax@opensource.cirrus.com>
Link: https://lore.kernel.org/r/20240416100904.3738093-4-ckeepax@opensource.cirrus.com
Signed-off-by: Mark Brown <broonie@kernel.org>
Use is_acpi_device_node() rather than checking ACPI_COMPANION(), such
that when checking for other types of firmware node, the code can
consistently do checks against the fwnode.
Suggested-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Charles Keepax <ckeepax@opensource.cirrus.com>
Link: https://lore.kernel.org/r/20240416100904.3738093-3-ckeepax@opensource.cirrus.com
Signed-off-by: Mark Brown <broonie@kernel.org>
SPI devices can specify a cs-gpios property to enumerate their
chip selects. Under device tree, a zero entry in this property can
be used to specify that a particular chip select is using the SPI
controllers native chip select, for example:
cs-gpios = <&gpio1 0 0>, <0>;
Here, the second chip select is native. However, when using swnodes
there is currently no way to specify a native chip select. The
proposal here is to register a swnode_gpio_undefined software node,
that can be specified to allow the indication of a native chip
select. For example:
static const struct software_node_ref_args device_cs_refs[] = {
{
.node = &device_gpiochip_swnode,
.nargs = 2,
.args = { 0, GPIO_ACTIVE_LOW },
},
{
.node = &swnode_gpio_undefined,
.nargs = 0,
},
};
Register the swnode as the gpiolib is initialised and check in
swnode_get_gpio_device() if the returned node matches
swnode_gpio_undefined and return -ENOENT, which matches the
behaviour of the device tree system when it encounters a 0 phandle.
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Reviewed-by: Andy Shevchenko <andy@kernel.org>
Signed-off-by: Charles Keepax <ckeepax@opensource.cirrus.com>
Link: https://lore.kernel.org/r/20240416100904.3738093-2-ckeepax@opensource.cirrus.com
Signed-off-by: Mark Brown <broonie@kernel.org>
