On Tue, Jul 13, 2021 at 06:35:28PM +0200, Sebastian Reichel wrote:

General Electric Healthcare's PPD has a secondary processor from
NXP's Kinetis K20 series. That device has two SPI chip selects:

The main interface's behaviour depends on the loaded firmware
and is currently unused.

The secondary interface can be used to update the firmware using
EzPort protocol. This is implemented by this driver using the
kernel's firmware API. The firmware is being flashed into
non-volatile flash memory, so it is enough to flash it once
and not on every boot. Flashing will wear the flash memory
(it has a life time of at least 10k programming cycles) and
takes 3 minutes with the microcontroller being unusable. At
the same time only occasional FW updates are expected (like e.g.
a BIOS update). Thus the firmware update is triggered via sysfs
instead of doing it in the driver's probe routine like many
other drivers.

Signed-off-by: Sebastian Reichel <redacted>
---
 .../ABI/testing/sysfs-driver-ge-achc          |  14 +
 drivers/misc/Kconfig                          |  11 +
 drivers/misc/Makefile                         |   1 +
 drivers/misc/gehc-achc.c                      | 542 ++++++++++++++++++
 drivers/spi/spidev.c                          |   1 -
 5 files changed, 568 insertions(+), 1 deletion(-)
 create mode 100644 Documentation/ABI/testing/sysfs-driver-ge-achc
 create mode 100644 drivers/misc/gehc-achc.c

This patch gives me build warnings:

drivers/misc/gehc-achc.c: In function ‘ezport_firmware_compare_data’:
./include/linux/minmax.h:20:35: warning: comparison of distinct pointer types lacks a cast
   20 |         (!!(sizeof((typeof(x) *)1 == (typeof(y) *)1)))
      |                                   ^~
./include/linux/minmax.h:26:18: note: in expansion of macro ‘__typecheck’
   26 |                 (__typecheck(x, y) && __no_side_effects(x, y))
      |                  ^~~~~~~~~~~
./include/linux/minmax.h:36:31: note: in expansion of macro ‘__safe_cmp’
   36 |         __builtin_choose_expr(__safe_cmp(x, y), \
      |                               ^~~~~~~~~~
./include/linux/minmax.h:45:25: note: in expansion of macro ‘__careful_cmp’
   45 | #define min(x, y)       __careful_cmp(x, y, <)
      |                         ^~~~~~~~~~~~~
drivers/misc/gehc-achc.c:305:33: note: in expansion of macro ‘min’
  305 |                 transfer_size = min((u32) EZPORT_TRANSFER_SIZE, size - address);
      |                                 ^~~
drivers/misc/gehc-achc.c: In function ‘ezport_firmware_flash_data’:
./include/linux/minmax.h:20:35: warning: comparison of distinct pointer types lacks a cast
   20 |         (!!(sizeof((typeof(x) *)1 == (typeof(y) *)1)))
      |                                   ^~
./include/linux/minmax.h:26:18: note: in expansion of macro ‘__typecheck’
   26 |                 (__typecheck(x, y) && __no_side_effects(x, y))
      |                  ^~~~~~~~~~~
./include/linux/minmax.h:36:31: note: in expansion of macro ‘__safe_cmp’
   36 |         __builtin_choose_expr(__safe_cmp(x, y), \
      |                               ^~~~~~~~~~
./include/linux/minmax.h:45:25: note: in expansion of macro ‘__careful_cmp’
   45 | #define min(x, y)       __careful_cmp(x, y, <)
      |                         ^~~~~~~~~~~~~
drivers/misc/gehc-achc.c:347:33: note: in expansion of macro ‘min’
  347 |                 transfer_size = min((u32) EZPORT_TRANSFER_SIZE, size - address);
      |                                 ^~~


How did you test build this?

thanks,

greg k-h