Hi all,
This is an updated subset of a patch series I sent more than 3 years
ago[1].
<linux/bitfield.h> contains various helpers for accessing bitfields, as
typically used in hardware registers for memory-mapped I/O blocks.
These helpers ensure type safety, and deduce automatically shift values
from mask values, avoiding mistakes due to inconsistent shifts and
masks, and leading to a reduction in source code size.
The existing FIELD_{GET,PREP}() macros are limited to compile-time
constants. However, it is very common to prepare or extract bitfield
elements where the bitfield mask is not a compile-time constant.
To avoid this limitation, the AT91 clock driver introduced its own
field_{prep,get}() macros. Hence my v1 series aimed to make them
available for general use, and convert several drivers to the existing
FIELD_{GET,PREP}() and the new field_{get,prep}() helpers.
Due to some pushback (mostly centered around using the typed
{u*,be*,le*,...}_get_bits() macros instead, which of course would
require making them work with non-constant masks first, too), this
series was never applied, and became buried deep in my TODO haystack...
However, several people still liked the idea: since v1, multiple copies
of the field_{prep,get}() macros appeared upstream, and one more is
queued for v6.15.
Hence I think it's time to revive and consolidate...
Changes compared to v1:
- Cast val resp. reg to the mask type,
- Fix 64-bit use on 32-bit architectures,
- Convert new upstream users:
- drivers/crypto/intel/qat/qat_common/adf_gen4_pm_debugfs.c
- drivers/gpio/gpio-aspeed.c
- drivers/iio/temperature/mlx90614.c
- drivers/pinctrl/nuvoton/pinctrl-ma35.c
- sound/usb/mixer_quirks.c
- Convert new user queued in renesas-devel for v6.15:
- drivers/soc/renesas/rz-sysc.c
- Drop the last 14 RFC patches.
They can be updated/resubmitted/applied later.
I can take all three patches through the Renesas tree, and provide an
immutable branch with the first patch for ther interested parties.
Thanks for your comments!
[1] "[PATCH 00/17] Non-const bitfield helper conversions"
https://lore.kernel.org/all/cover.1637592133.git.geert+renesas@xxxxxxxxx
Geert Uytterhoeven (3):
bitfield: Add non-constant field_{prep,get}() helpers
clk: renesas: Use bitfield helpers
soc: renesas: Use bitfield helpers
drivers/clk/at91/clk-peripheral.c | 1 +
drivers/clk/at91/pmc.h | 3 --
drivers/clk/renesas/clk-div6.c | 6 ++--
drivers/clk/renesas/rcar-gen3-cpg.c | 15 +++-----
drivers/clk/renesas/rcar-gen4-cpg.c | 9 ++---
.../qat/qat_common/adf_gen4_pm_debugfs.c | 8 +----
drivers/gpio/gpio-aspeed.c | 5 +--
drivers/iio/temperature/mlx90614.c | 5 +--
drivers/pinctrl/nuvoton/pinctrl-ma35.c | 4 ---
drivers/soc/renesas/renesas-soc.c | 4 +--
drivers/soc/renesas/rz-sysc.c | 3 +-
include/linux/bitfield.h | 34 +++++++++++++++++++
sound/usb/mixer_quirks.c | 4 ---
13 files changed, 52 insertions(+), 49 deletions(-)
--
2.43.0
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
