This adds a simple driver for reading the efuse block of the RK3399. It should be easy enough to add drivers for other devices (e.g. the RK3328, RK3368, etc.) by passing the device details via driver_data.
Unlike the kernel driver (using the nvmem subsystem), we don't expose the efuse as multiple named cells, but rather as a linear memory that can be read using misc_read(...).
The primary use case (as of today) is the generation of a 'serial#' (and a 'cpuid#') environment variable for the RK3399-Q7 (Puma) system-on-module.
Note that this adds a debug-only (i.e. only if DEBUG is defined) command 'rk3399_dump_efuses' that dumps the efuse block's content. N.B.: The name 'rk3399_dump_efuses' was intentionally chosen to include a SoC-name (together with a comment in the function) to remind whoever adds support for additional SoCs that this function currently makes assumptions regarding the size of the fuse-box based on the RK3399. The hope is that the function is adjusted to reflect any changes resulting from generalising the driver for multiple SoCs and is then renamed.
Signed-off-by: Philipp Tomsich philipp.tomsich@theobroma-systems.com
Reviewed-by: Simon Glass sjg@chromium.org
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Changes in v3: - uses uclass_get_device_by_driver() to ensure we don't pick up the wrong misc-device
Changes in v2: None
drivers/misc/Kconfig | 14 ++++ drivers/misc/Makefile | 1 + drivers/misc/rockchip-efuse.c | 162 ++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 177 insertions(+) create mode 100644 drivers/misc/rockchip-efuse.c
Applied to u-boot-rockchip, thanks!