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. The SPI core changes have been applied in PATCHv5 and are part of v5.14-rc1. Changes since PATCHv6: * https://lore.kernel.org/lkml/20210712150242.146545-1-sebastian.reichel@xxxxxxxxxxxxx/ * use kstrtoul() in sysfs store routines * merge nxp-ezport.c into gehc-achc.c * reword commit message Changes since PATCHv5: * https://lore.kernel.org/lkml/20210621175359.126729-1-sebastian.reichel@xxxxxxxxxxxxx/ * Rebased to v5.14-rc1 * Fixed compilation as module * Dropped no longer needed module.h include from ezport code Changes since PATCHv4: * https://lore.kernel.org/lkml/20210609151235.48964-1-sebastian.reichel@xxxxxxxxxxxxx/ * Add Rob's Acked-by to ge-achc binding update * Don't use of_property_read_u32_index() in of_spi_parse_dt() * Don't build separate module for EzPort code * Use GPL2-only for the header * ACHC_MAX_FREQ -> ACHC_MAX_FREQ_HZ * Only accept '1' for the sysfs files, not any data * Update sysfs file documentation * Rebased to spi-next tree (b8f9dce0f4eb) 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 (3): dt-bindings: misc: ge-achc: Convert to DT schema format ARM: dts: imx53-ppd: Fix ACHC entry misc: gehc-achc: new driver .../ABI/testing/sysfs-driver-ge-achc | 14 + .../devicetree/bindings/misc/ge-achc.txt | 26 - .../devicetree/bindings/misc/ge-achc.yaml | 65 +++ arch/arm/boot/dts/imx53-ppd.dts | 23 +- drivers/misc/Kconfig | 11 + drivers/misc/Makefile | 1 + drivers/misc/gehc-achc.c | 542 ++++++++++++++++++ drivers/spi/spidev.c | 1 - 8 files changed, 646 insertions(+), 37 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 -- 2.30.2
