Re: [PATCH v6 0/4] fpga: xilinx-selectmap: add new driver

[Charles Perry]

On Mar 31, 2024, at 10:50 AM, Xu Yilun yilun.xu@xxxxxxxxxxxxxxx wrote:
> On Thu, Mar 21, 2024 at 06:04:32PM -0400, Charles Perry wrote:
>> Hello,
>> 
>> This patchset adds a new driver for the 7 series FPGA's SelectMAP
>> interface.
>> 
>> The SelectMAP interface shares a common GPIO protocol with the SPI
>> interface which is already in the kernel (drivers/fpga/xilinx-spi.c).
>> The approach proposed in this patchset is to refactor xilinx-spi.c into
>> xilinx-core.c which would handle the common GPIO protocol. This is then
>> used to build two drivers, the already existing xilinx-spi.c driver and
>> a newly added xilinx-selectmap.c driver.
>> 
>> The SelectMAP driver proposed only supports 8 bit mode. This is because
>> the 16 and 32 bits mode have limitations with regards to compressed
>> bitstream support as well as introducing endianness considerations.
>> 
>> I'm testing xilinx-selectmap.c on a custom i.MX6 board connected to an
>> Artix 7 FPGA. Flashing a 913K bitstream takes 0.44 seconds.
>> 
>> Changes since v5: (from Yilun review)
>>  * xilinx-core.h: remove private fields kernel-doc
>>  * xilinx-spi.c: rename conf into core in xilinx_spi_probe
>>  * xilinx-core.c: introduce the new gpio names in patch 4/4
>>  * xilinx-core.c: remove kernel-doc on xilinx_core_devm_gpiod_get()
>>  * xilinx-selectmap.c:
>>    * reorder includes in alphabetical order
>>    * xilinx_selectmap_probe(): remove unused resource *r variable
>>    * xilinx_selectmap_probe(): use a single gpio_desc* temporary
>>    * xilinx_selectmap_probe(): declare variables in reverse xmas tree
>> 
>> Changes since v4: (from Yilun and Krzysztof review)
>>  * xilinx-core: use sizeof() instead of hardcoded immediate
>>  * xilinx-core: fix module compilation (EXPORT_SYMBOL_GPL, MODULE_LICENSE,
>>    MODULE_AUTHOR, MODULE_DESCRIPTION)
>>  * xilinx-core: add private/public qualifiers for struct xilinx_fpga_core
>>  * xilinx-spi: remove struct xilinx_spi_conf. This struct isn't needed as
>>    the struct spi_device* can be retrieved from the struct device*.
>>  * dt-bindings: remove usage of "_b" and "-b" for the new driver. We
>>    agreed that the spi and selectmap driver will use different bindings
>>    which will be handled by the driver core and that the legacy names will
>>    be used only for the spi compatible.
>>  * xilinx-core: select between prog/init and prog_b/init-b
>> 
>> Changes since v3: (from Rob Herring review)
>>  * Fix an error in the DT binding example compatible.
>>  * Drop the renaming of "prog_b" to "prog" and "init-b" to "init".
>>    Patches 2 and 3 are removed.
>> 
>> Changes since v2:
>>  * Inserted patch 2 and 3 which rename "prog_b" and "init-b" into "prog"
>>    and "init" for the SPI driver.
>>  * From Krzysztof Kozlowski review's:
>>    * Use more specific compatible names
>>    * Remove other missing occurences of the slave word missed in v2.
>>  * From Xu Yilun review's:
>>    * Fix vertical whitespace in get_done_gpio().
>>    * Combine write() and write_one_dummy_byte() together.
>>    * Eliminate most of the xilinx_core_probe() arguments, the driver
>>      needs to populate those directly into the xilinx_fpga_core struct.
>>      Added some documentation to struct xilinx_fpga_core to clarify
>>      this.
>>    * Removed typedefs from xilinx-core.h.
>>    * Moved null checks in xilinx_core_probe() to first patch.
>>    * Move csi_b and rdwr_b out of xilinx_selectmap_conf as they are not
>>      used out of the probe function.
>> 
>> Changes since v1: (from Krzysztof Kozlowski review's)
>>   * Use more conventional names for gpio DT bindings
>>   * fix example in DT bindings
>>   * add mc-peripheral-props.yaml to DT bindings
>>   * fix various formatting mistakes
>>   * Remove all occurences of the "slave" word.
>> 
>> Charles Perry (4):
>>   fpga: xilinx-spi: extract a common driver core
>>   dt-bindings: fpga: xlnx,fpga-selectmap: add DT schema
>>   fpga: xilinx-selectmap: add new driver
>>   xilinx-core: add new gpio names for prog and init
>> 
>>  .../bindings/fpga/xlnx,fpga-selectmap.yaml    |  86 +++++++
>>  drivers/fpga/Kconfig                          |  12 +
>>  drivers/fpga/Makefile                         |   2 +
>>  drivers/fpga/xilinx-core.c                    | 229 ++++++++++++++++++
>>  drivers/fpga/xilinx-core.h                    |  27 +++
>>  drivers/fpga/xilinx-selectmap.c               |  95 ++++++++
>>  drivers/fpga/xilinx-spi.c                     | 224 ++---------------
>>  7 files changed, 466 insertions(+), 209 deletions(-)
>>  create mode 100644
>>  Documentation/devicetree/bindings/fpga/xlnx,fpga-selectmap.yaml
>>  create mode 100644 drivers/fpga/xilinx-core.c
>>  create mode 100644 drivers/fpga/xilinx-core.h
>>  create mode 100644 drivers/fpga/xilinx-selectmap.c
> 
> Applied this series to for-next with a nit.
> 
> Thanks,
> Yilun
> 

Thanks again for all the good reviews Yilun.

Regards,
Charles

>> 
>> --
>> 2.43.0