[v2,0/3] arm64: exynos: Enable SPI for Exynos850

Message

Sam Protsenko Jan. 25, 2024, 1:38 a.m. UTC

This series enables SPI for Exynos850 SoC. The summary:

  1. Enable PDMA, it's needed for SPI (dts, clk)
  2. Propagate SPI src clock rate change up to DIV clocks, to make it
     possible to change SPI frequency (clk driver)
  3. Add SPI nodes to Exynos850 SoC dtsi

All SPI instances were tested using `spidev_test' tool in all 3 possible
modes:

  - Polling mode: xfer_size <= 32
  - IRQ mode: 64 >= xfer_size >= 32
  - DMA mode: xfer_size > 64

with 200 kHz ... 49.9 MHz SPI frequencies. The next 3 approaches were
used:

  1. Software loopback ('-l' option for `spidev_test' tool)
  2. Hardware loopback (by connecting MISO line to MOSI)
  3. By communicating with ATMega found on Sensors Mezzanine board [1],
     programmed to act as an SPI slave device

and all the transactions were additionally checked on my Logic Analyzer
to make sure the SCK frequencies were actually correct.

This series is supposed to go via Krzysztof's tree. SPI driver additions
and corresponding bindings will be submitted in a separate series and
are independent from this one.

Changes in v2:
  - Fixed indentation in clk patch to make checkpatch strict happy
  - Ordered PDMA node by unit address
  - Sorted pinctrl properties properly

[1] https://www.96boards.org/product/sensors-mezzanine/
[2] https://lore.kernel.org/all/[e-mail]/

Sam Protsenko (3):
  clk: samsung: exynos850: Propagate SPI IPCLK rate change
  arm64: dts: exynos: Add PDMA node for Exynos850
  arm64: dts: exynos: Add SPI nodes for Exynos850

 arch/arm64/boot/dts/exynos/exynos850.dtsi | 64 +++++++++++++++++++++++
 drivers/clk/samsung/clk-exynos850.c       | 33 ++++++------
 2 files changed, 81 insertions(+), 16 deletions(-)