--- /dev/null
+From 2a6c045640c38a407a39cd40c3c4d8dd2fd89aa8 Mon Sep 17 00:00:00 2001
+From: Geert Uytterhoeven <geert+renesas@glider.be>
+Date: Thu, 6 Nov 2025 14:34:00 +0100
+Subject: [PATCH 1/2] bitfield: Add less-checking __FIELD_{GET,PREP}()
+
+The BUILD_BUG_ON_MSG() check against "~0ull" works only with "unsigned
+(long) long" _mask types. For constant masks, that condition is usually
+met, as GENMASK() yields an UL value. The few places where the
+constant mask is stored in an intermediate variable were fixed by
+changing the variable type to u64 (see e.g. [1] and [2]).
+
+However, for non-constant masks, smaller unsigned types should be valid,
+too, but currently lead to "result of comparison of constant
+18446744073709551615 with expression of type ... is always
+false"-warnings with clang and W=1.
+
+Hence refactor the __BF_FIELD_CHECK() helper, and factor out
+__FIELD_{GET,PREP}(). The later lack the single problematic check, but
+are otherwise identical to FIELD_{GET,PREP}(), and are intended to be
+used in the fully non-const variants later.
+
+[1] commit 5c667d5a5a3ec166 ("clk: sp7021: Adjust width of _m in
+ HWM_FIELD_PREP()")
+[2] commit cfd6fb45cfaf46fa ("crypto: ccree - avoid out-of-range
+ warnings from clang")
+
+Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
+Link: https://git.kernel.org/torvalds/c/5c667d5a5a3ec166 [1]
+Signed-off-by: Yury Norov (NVIDIA) <yury.norov@gmail.com>
+---
+ include/linux/bitfield.h | 36 ++++++++++++++++++++++++++++--------
+ 1 file changed, 28 insertions(+), 8 deletions(-)
+
+--- a/include/linux/bitfield.h
++++ b/include/linux/bitfield.h
+@@ -60,7 +60,7 @@
+
+ #define __bf_cast_unsigned(type, x) ((__unsigned_scalar_typeof(type))(x))
+
+-#define __BF_FIELD_CHECK(_mask, _reg, _val, _pfx) \
++#define __BF_FIELD_CHECK_MASK(_mask, _val, _pfx) \
+ ({ \
+ BUILD_BUG_ON_MSG(!__builtin_constant_p(_mask), \
+ _pfx "mask is not constant"); \
+@@ -69,13 +69,33 @@
+ ~((_mask) >> __bf_shf(_mask)) & \
+ (0 + (_val)) : 0, \
+ _pfx "value too large for the field"); \
+- BUILD_BUG_ON_MSG(__bf_cast_unsigned(_mask, _mask) > \
+- __bf_cast_unsigned(_reg, ~0ull), \
+- _pfx "type of reg too small for mask"); \
+ __BUILD_BUG_ON_NOT_POWER_OF_2((_mask) + \
+ (1ULL << __bf_shf(_mask))); \
+ })
+
++#define __BF_FIELD_CHECK_REG(mask, reg, pfx) \
++ BUILD_BUG_ON_MSG(__bf_cast_unsigned(mask, mask) > \
++ __bf_cast_unsigned(reg, ~0ull), \
++ pfx "type of reg too small for mask")
++
++#define __BF_FIELD_CHECK(mask, reg, val, pfx) \
++ ({ \
++ __BF_FIELD_CHECK_MASK(mask, val, pfx); \
++ __BF_FIELD_CHECK_REG(mask, reg, pfx); \
++ })
++
++#define __FIELD_PREP(mask, val, pfx) \
++ ({ \
++ __BF_FIELD_CHECK_MASK(mask, val, pfx); \
++ ((typeof(mask))(val) << __bf_shf(mask)) & (mask); \
++ })
++
++#define __FIELD_GET(mask, reg, pfx) \
++ ({ \
++ __BF_FIELD_CHECK_MASK(mask, 0U, pfx); \
++ (typeof(mask))(((reg) & (mask)) >> __bf_shf(mask)); \
++ })
++
+ /**
+ * FIELD_MAX() - produce the maximum value representable by a field
+ * @_mask: shifted mask defining the field's length and position
+@@ -112,8 +132,8 @@
+ */
+ #define FIELD_PREP(_mask, _val) \
+ ({ \
+- __BF_FIELD_CHECK(_mask, 0ULL, _val, "FIELD_PREP: "); \
+- ((typeof(_mask))(_val) << __bf_shf(_mask)) & (_mask); \
++ __BF_FIELD_CHECK_REG(_mask, 0ULL, "FIELD_PREP: "); \
++ __FIELD_PREP(_mask, _val, "FIELD_PREP: "); \
+ })
+
+ #define __BF_CHECK_POW2(n) BUILD_BUG_ON_ZERO(((n) & ((n) - 1)) != 0)
+@@ -152,8 +172,8 @@
+ */
+ #define FIELD_GET(_mask, _reg) \
+ ({ \
+- __BF_FIELD_CHECK(_mask, _reg, 0U, "FIELD_GET: "); \
+- (typeof(_mask))(((_reg) & (_mask)) >> __bf_shf(_mask)); \
++ __BF_FIELD_CHECK_REG(_mask, _reg, "FIELD_GET: "); \
++ __FIELD_GET(_mask, _reg, "FIELD_GET: "); \
+ })
+
+ extern void __compiletime_error("value doesn't fit into mask")
--- /dev/null
+From c1c6ab80b25c8db1e2ef5ae3ac8075d2c242ae13 Mon Sep 17 00:00:00 2001
+From: Geert Uytterhoeven <geert+renesas@glider.be>
+Date: Thu, 6 Nov 2025 14:34:01 +0100
+Subject: [PATCH 2/2] bitfield: Add non-constant field_{prep,get}() helpers
+MIME-Version: 1.0
+Content-Type: text/plain; charset=UTF-8
+Content-Transfer-Encoding: 8bit
+
+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 and several other
+drivers already have their own non-const field_{prep,get}() macros.
+Make them available for general use by adding them to
+<linux/bitfield.h>, and improve them slightly:
+ 1. Avoid evaluating macro parameters more than once,
+ 2. Replace "ffs() - 1" by "__ffs()",
+ 3. Support 64-bit use on 32-bit architectures,
+ 4. Wire field_{get,prep}() to FIELD_{GET,PREP}() when mask is
+ actually constant.
+
+This is deliberately not merged into the existing FIELD_{GET,PREP}()
+macros, as people expressed the desire to keep stricter variants for
+increased safety, or for performance critical paths.
+
+Yury: use __mask withing new macros.
+
+Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
+Acked-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
+Acked-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
+Acked-by: Crt Mori <cmo@melexis.com>
+Acked-by: Nuno Sá <nuno.sa@analog.com>
+Acked-by: Richard Genoud <richard.genoud@bootlin.com>
+Reviewed-by: Andy Shevchenko <andriy.shevchenko@intel.com>
+Reviewed-by: Yury Norov (NVIDIA) <yury.norov@gmail.com>
+Signed-off-by: Yury Norov (NVIDIA) <yury.norov@gmail.com>
+---
+ include/linux/bitfield.h | 59 ++++++++++++++++++++++++++++++++++++++++
+ 1 file changed, 59 insertions(+)
+
+--- a/include/linux/bitfield.h
++++ b/include/linux/bitfield.h
+@@ -16,6 +16,7 @@
+ * FIELD_{GET,PREP} macros take as first parameter shifted mask
+ * from which they extract the base mask and shift amount.
+ * Mask must be a compilation time constant.
++ * field_{get,prep} are variants that take a non-const mask.
+ *
+ * Example:
+ *
+@@ -223,4 +224,62 @@ __MAKE_OP(64)
+ #undef __MAKE_OP
+ #undef ____MAKE_OP
+
++#define __field_prep(mask, val) \
++ ({ \
++ __auto_type __mask = (mask); \
++ typeof(__mask) __val = (val); \
++ unsigned int __shift = BITS_PER_TYPE(__mask) <= 32 ? \
++ __ffs(__mask) : __ffs64(__mask); \
++ (__val << __shift) & __mask; \
++ })
++
++#define __field_get(mask, reg) \
++ ({ \
++ __auto_type __mask = (mask); \
++ typeof(__mask) __reg = (reg); \
++ unsigned int __shift = BITS_PER_TYPE(__mask) <= 32 ? \
++ __ffs(__mask) : __ffs64(__mask); \
++ (__reg & __mask) >> __shift; \
++ })
++
++/**
++ * field_prep() - prepare a bitfield element
++ * @mask: shifted mask defining the field's length and position, must be
++ * non-zero
++ * @val: value to put in the field
++ *
++ * Return: field value masked and shifted to its final destination
++ *
++ * field_prep() masks and shifts up the value. The result should be
++ * combined with other fields of the bitfield using logical OR.
++ * Unlike FIELD_PREP(), @mask is not limited to a compile-time constant.
++ * Typical usage patterns are a value stored in a table, or calculated by
++ * shifting a constant by a variable number of bits.
++ * If you want to ensure that @mask is a compile-time constant, please use
++ * FIELD_PREP() directly instead.
++ */
++#define field_prep(mask, val) \
++ (__builtin_constant_p(mask) ? __FIELD_PREP(mask, val, "field_prep: ") \
++ : __field_prep(mask, val))
++
++/**
++ * field_get() - extract a bitfield element
++ * @mask: shifted mask defining the field's length and position, must be
++ * non-zero
++ * @reg: value of entire bitfield
++ *
++ * Return: extracted field value
++ *
++ * field_get() extracts the field specified by @mask from the
++ * bitfield passed in as @reg by masking and shifting it down.
++ * Unlike FIELD_GET(), @mask is not limited to a compile-time constant.
++ * Typical usage patterns are a value stored in a table, or calculated by
++ * shifting a constant by a variable number of bits.
++ * If you want to ensure that @mask is a compile-time constant, please use
++ * FIELD_GET() directly instead.
++ */
++#define field_get(mask, reg) \
++ (__builtin_constant_p(mask) ? __FIELD_GET(mask, reg, "field_get: ") \
++ : __field_get(mask, reg))
++
+ #endif
--- /dev/null
+From b1cff2f4b2391a13bd3e9263502072df1ee5d035 Mon Sep 17 00:00:00 2001
+From: Geert Uytterhoeven <geert+renesas@glider.be>
+Date: Thu, 6 Nov 2025 14:34:10 +0100
+Subject: [PATCH] ALSA: usb-audio: Convert to common field_{get,prep}() helpers
+
+Drop the driver-specific field_get() and field_prep() macros, in favor
+of the globally available variants from <linux/bitfield.h>.
+
+Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
+Acked-by: Takashi Iwai <tiwai@suse.de>
+Signed-off-by: Yury Norov (NVIDIA) <yury.norov@gmail.com>
+---
+ sound/usb/mixer_quirks.c | 6 ------
+ 1 file changed, 6 deletions(-)
+
+--- a/sound/usb/mixer_quirks.c
++++ b/sound/usb/mixer_quirks.c
+@@ -3367,10 +3367,6 @@ static int snd_bbfpro_controls_create(st
+ #define RME_DIGIFACE_REGISTER(reg, mask) (((reg) << 16) | (mask))
+ #define RME_DIGIFACE_INVERT BIT(31)
+
+-/* Nonconst helpers */
+-#define field_get(_mask, _reg) (((_reg) & (_mask)) >> (ffs(_mask) - 1))
+-#define field_prep(_mask, _val) (((_val) << (ffs(_mask) - 1)) & (_mask))
+-
+ static int snd_rme_digiface_write_reg(struct snd_kcontrol *kcontrol, int item, u16 mask, u16 val)
+ {
+ struct usb_mixer_elem_list *list = snd_kcontrol_chip(kcontrol);
--- /dev/null
+From 0f8407a1f1c795c417e4c7750654a6024a3ec68b Mon Sep 17 00:00:00 2001
+From: Geert Uytterhoeven <geert+renesas@glider.be>
+Date: Thu, 6 Nov 2025 14:34:02 +0100
+Subject: [PATCH] clk: at91: Convert to common field_{get,prep}() helpers
+
+Drop the driver-specific field_get() and field_prep() macros, in favor
+of the globally available variants from <linux/bitfield.h>.
+
+Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
+Acked-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
+Acked-by: Stephen Boyd <sboyd@kernel.org>
+Acked-by: Claudiu Beznea <claudiu.beznea@tuxon.dev>
+Signed-off-by: Yury Norov (NVIDIA) <yury.norov@gmail.com>
+---
+ drivers/clk/at91/clk-peripheral.c | 1 +
+ drivers/clk/at91/pmc.h | 5 -----
+ 2 files changed, 1 insertion(+), 5 deletions(-)
+
+--- a/drivers/clk/at91/clk-peripheral.c
++++ b/drivers/clk/at91/clk-peripheral.c
+@@ -3,6 +3,7 @@
+ * Copyright (C) 2013 Boris BREZILLON <b.brezillon@overkiz.com>
+ */
+
++#include <linux/bitfield.h>
+ #include <linux/bitops.h>
+ #include <linux/clk-provider.h>
+ #include <linux/clkdev.h>
+--- a/drivers/clk/at91/pmc.h
++++ b/drivers/clk/at91/pmc.h
+@@ -116,9 +116,6 @@ struct at91_clk_pms {
+ unsigned int parent;
+ };
+
+-#define field_get(_mask, _reg) (((_reg) & (_mask)) >> (ffs(_mask) - 1))
+-#define field_prep(_mask, _val) (((_val) << (ffs(_mask) - 1)) & (_mask))
+-
+ #define ndck(a, s) (a[s - 1].id + 1)
+ #define nck(a) (a[ARRAY_SIZE(a) - 1].id + 1)
+
--- /dev/null
+From 1fe1c28a108e4953f083c0106575ee0eccc296ae Mon Sep 17 00:00:00 2001
+From: Geert Uytterhoeven <geert+renesas@glider.be>
+Date: Thu, 6 Nov 2025 14:34:07 +0100
+Subject: [PATCH] iio: mlx90614: Convert to common field_{get,prep}() helpers
+
+Drop the driver-specific field_get() and field_prep() macros, in favor
+of the globally available variants from <linux/bitfield.h>.
+
+Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
+Acked-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
+Acked-by: Crt Mori <cmo@melexis.com>
+Signed-off-by: Yury Norov (NVIDIA) <yury.norov@gmail.com>
+---
+ drivers/iio/temperature/mlx90614.c | 7 +------
+ 1 file changed, 1 insertion(+), 6 deletions(-)
+
+--- a/drivers/iio/temperature/mlx90614.c
++++ b/drivers/iio/temperature/mlx90614.c
+@@ -22,6 +22,7 @@
+ * the "wakeup" GPIO is not given, power management will be disabled.
+ */
+
++#include <linux/bitfield.h>
+ #include <linux/delay.h>
+ #include <linux/err.h>
+ #include <linux/gpio/consumer.h>
+@@ -68,10 +69,6 @@
+ #define MLX90614_CONST_SCALE 20 /* Scale in milliKelvin (0.02 * 1000) */
+ #define MLX90614_CONST_FIR 0x7 /* Fixed value for FIR part of low pass filter */
+
+-/* Non-constant mask variant of FIELD_GET() and FIELD_PREP() */
+-#define field_get(_mask, _reg) (((_reg) & (_mask)) >> (ffs(_mask) - 1))
+-#define field_prep(_mask, _val) (((_val) << (ffs(_mask) - 1)) & (_mask))
+-
+ struct mlx_chip_info {
+ /* EEPROM offsets with 16-bit data, MSB first */
+ /* emissivity correction coefficient */
--- /dev/null
+From bb0e7fda87753a973cb4a86c22905b1177f00d4e Mon Sep 17 00:00:00 2001
+From: Geert Uytterhoeven <geert+renesas@glider.be>
+Date: Thu, 6 Nov 2025 14:34:08 +0100
+Subject: [PATCH] pinctrl: ma35: Convert to common field_{get,prep}() helpers
+
+Drop the driver-specific field_get() and field_prep() macros, in favor
+of the globally available variants from <linux/bitfield.h>.
+
+Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
+Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
+Signed-off-by: Yury Norov (NVIDIA) <yury.norov@gmail.com>
+---
+ drivers/pinctrl/nuvoton/pinctrl-ma35.c | 6 ------
+ 1 file changed, 6 deletions(-)
+
+--- a/drivers/pinctrl/nuvoton/pinctrl-ma35.c
++++ b/drivers/pinctrl/nuvoton/pinctrl-ma35.c
+@@ -81,10 +81,6 @@
+ #define MVOLT_1800 0
+ #define MVOLT_3300 1
+
+-/* Non-constant mask variant of FIELD_GET() and FIELD_PREP() */
+-#define field_get(_mask, _reg) (((_reg) & (_mask)) >> (ffs(_mask) - 1))
+-#define field_prep(_mask, _val) (((_val) << (ffs(_mask) - 1)) & (_mask))
+-
+ static const char * const gpio_group_name[] = {
+ "gpioa", "gpiob", "gpioc", "gpiod", "gpioe", "gpiof", "gpiog",
+ "gpioh", "gpioi", "gpioj", "gpiok", "gpiol", "gpiom", "gpion",
projects / thirdparty / openwrt.git / commitdiff
