Hi, The PPD has a secondary processor (NXP Kinetis K20), which can be programmed from the main system. It is connected to the main processor by having it's EzPort interface connected to the SPI bus. Currently both (normal and EzPort) interfaces are simply exposed to userspace. This does not work for the EzPort, since EzPort usage requires a device reset. The proper solution is to do the flashing from kernel space with properly timed toggling of EzPort chip-select and reset line. In PATCHv2 it was suggested, that this should happen via an SPI ancillary device, so this is how it has been implemented now. Changes since PATCHv3: * https://lore.kernel.org/lkml/20210528113346.37137-1-sebastian.reichel@xxxxxxxxxxxxx/ * Add Rob's Acked-by to 2nd patch * use GPL-2-only instead of GPL-2+ * use %zu for printing a size_t * use driver's .dev_groups to register sysfs group * Add sysfs property documentation * split EzPort and ACHC drivers into separate patches * drop minItems/maxItems from achc binding, which seems to fix the problems reported by dt_binding_check. The information of two items being required is implied by the explicit item list. * drop spidev functionality for the main SPI interface. The current firmware communicates via UART and adding spidev support is complex. If future firmware releases start using it, spidev support for the main interface can be added later. Changes since PATCHv2: * https://lore.kernel.org/lkml/20180327135259.30890-1-sebastian.reichel@xxxxxxxxxxxxxxx/ * add SPI core support for ancillary devices * modify ACHC binding to make use of ancillary device * rewrite driver to use ancillary device * rebased to 5.13-rc1 Changes since PATCHv1: * https://lore.kernel.org/lkml/20180320172201.2065-1-sebastian.reichel@xxxxxxxxxxxxxxx/ * split DT binding update into its own patch * add sysfs attribute documentation * fix problem reported by kbuild test robot -- Sebastian Sebastian Reichel (6): spi: add ancillary device support spi: dt-bindings: support devices with multiple chipselects dt-bindings: misc: ge-achc: Convert to DT schema format ARM: dts: imx53-ppd: Fix ACHC entry misc: nxp-ezport: introduce EzPort support misc: gehc-achc: new driver .../ABI/testing/sysfs-driver-ge-achc | 9 + .../devicetree/bindings/misc/ge-achc.txt | 26 - .../devicetree/bindings/misc/ge-achc.yaml | 65 +++ .../bindings/spi/spi-controller.yaml | 7 +- arch/arm/boot/dts/imx53-ppd.dts | 23 +- drivers/misc/Kconfig | 15 + drivers/misc/Makefile | 2 + drivers/misc/gehc-achc.c | 136 +++++ drivers/misc/nxp-ezport.c | 476 ++++++++++++++++++ drivers/spi/spi.c | 139 +++-- drivers/spi/spidev.c | 1 - include/linux/platform_data/nxp-ezport.h | 9 + include/linux/spi/spi.h | 2 + 13 files changed, 839 insertions(+), 71 deletions(-) create mode 100644 Documentation/ABI/testing/sysfs-driver-ge-achc delete mode 100644 Documentation/devicetree/bindings/misc/ge-achc.txt create mode 100644 Documentation/devicetree/bindings/misc/ge-achc.yaml create mode 100644 drivers/misc/gehc-achc.c create mode 100644 drivers/misc/nxp-ezport.c create mode 100644 include/linux/platform_data/nxp-ezport.h -- 2.30.2
