linux/include
Ville Syrjälä 9df8043a54 iopoll: Generalize read_poll_timeout() into poll_timeout_us()
While read_poll_timeout() & co. were originally introduced just
for simple I/O usage scenarios they have since been generalized to
be useful in more cases.

However the interface is very cumbersome to use in the general case.
Attempt to make it more flexible by combining the 'op', 'var' and
'args' parameter into just a single 'op' that the caller can fully
specify.

For example i915 has one case where one might currently
have to write something like:
	ret = read_poll_timeout(drm_dp_dpcd_read_byte, err,
				err || (status & mask),
				0 * 1000, 200 * 1000, false,
				aux, DP_FEC_STATUS, &status);
which is practically illegible, but with the adjusted macro
we do:
	ret = poll_timeout_us(err = drm_dp_dpcd_read_byte(aux, DP_FEC_STATUS, &status),
			      err || (status & mask),
			      0 * 1000, 200 * 1000, false);
which much easier to understand.

One could even combine the 'op' and 'cond'  parameters into
one, but that might make the caller a bit too unwieldly with
assignments and checks being done on the same statement.

This makes poll_timeout_us() closer to the i915 __wait_for()
macro, with the main difference being that __wait_for() uses
expenential backoff as opposed to the fixed polling interval
used by poll_timeout_us(). Eventually we might be able to switch
(at least most of) i915 to use poll_timeout_us().

v2: Fix typos (Jani)
    Fix delay_us docs for poll_timeout_us_atomic() (Jani)

Cc: Lucas De Marchi <lucas.demarchi@intel.com>
Cc: Dibin Moolakadan Subrahmanian <dibin.moolakadan.subrahmanian@intel.com>
Cc: Imre Deak <imre.deak@intel.com>
Cc: David Laight <david.laight.linux@gmail.com>
Cc: Geert Uytterhoeven <geert+renesas@glider.be>
Cc: Matt Wagantall <mattw@codeaurora.org>
Cc: Dejin Zheng <zhengdejin5@gmail.com>
Cc: intel-gfx@lists.freedesktop.org
Cc: intel-xe@lists.freedesktop.org
Cc: linux-kernel@vger.kernel.org
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Acked-by: Simona Vetter <simona.vetter@ffwll.ch>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://lore.kernel.org/r/20250826121859.15497-1-ville.syrjala@linux.intel.com
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
2025-08-28 12:16:36 +03:00
..
acpi Merge branches 'acpi-processor' and 'acpi-cppc' 2025-05-26 18:37:38 +02:00
asm-generic hyperv-next for v6.16 2025-06-03 08:39:20 -07:00
clocksource
crypto Networking changes for 6.16. 2025-05-28 15:24:36 -07:00
cxl cxl/features: Remove the inline specifier from to_cxlfs() 2025-05-22 07:39:01 -07:00
drm drm/ttm: Add ttm_bo_kmap_try_from_panic() 2025-06-27 11:48:22 +02:00
dt-bindings USB/Thunderbolt changes for 6.16-rc1 2025-06-06 12:45:35 -07:00
hyperv hyperv-next for v6.16 2025-06-03 08:39:20 -07:00
keys rxrpc: Add YFS RxGK (GSSAPI) security class 2025-04-14 17:36:41 -07:00
kunit I've recently moved computers (among other things) so I'm sending this from a 2025-05-30 09:15:40 -07:00
kvm KVM: arm64: Resolve vLPI by host IRQ in vgic_v4_unset_forwarding() 2025-05-30 09:11:29 +01:00
linux iopoll: Generalize read_poll_timeout() into poll_timeout_us() 2025-08-28 12:16:36 +03:00
math-emu
media media: common: Add v4l2_find_nearest_size_conditional() 2025-05-06 13:06:30 +02:00
memory memory: renesas-rpc-if: Add RZ/G3E xSPI support 2025-05-01 12:22:25 +02:00
misc
net bluetooth pull request for net: 2025-06-12 08:13:48 -07:00
pcmcia
ras
rdma Linux 6.15 2025-05-26 15:33:52 -03:00
rv
scsi SCSI misc on 20250529 2025-05-29 22:17:52 -07:00
soc - The 3 patch series "hung_task: extend blocking task stacktrace dump to 2025-05-31 19:12:53 -07:00
sound USB/Thunderbolt changes for 6.16-rc1 2025-06-06 12:45:35 -07:00
target scsi: target: core: Constify enabled() in struct target_opcode_descriptor 2025-05-20 22:11:03 -04:00
trace dma-fence: Add safe access helpers and document the rules 2025-06-13 08:26:49 +01:00
uapi drm-misc-next for 6.17: 2025-06-20 11:34:09 +10:00
ufs Merge branch '6.15/scsi-fixes' into 6.16/scsi-staging 2025-04-28 20:56:57 -04:00
vdso
video video: Make global edid_info depend on CONFIG_FIRMWARE_EDID 2025-06-16 11:00:29 +02:00
xen
Kbuild