From: Dmitry Torokhov <dmitry.torokhov@gmail.com>
To: Jiri Kosina <jikos@kernel.org>,
Benjamin Tissoires <bentiss@kernel.org>,
Gideon Heinz <gideonheinz02@gmail.com>
Cc: "Filipe Laíns" <lains@riseup.net>,
"Bastien Nocera" <hadess@hadess.net>,
"Hans de Goede" <hansg@kernel.org>,
"Edwin Velds" <e.velds@gmail.com>,
"Stuart Hayhurst" <stuart.a.hayhurst@gmail.com>,
"Andrey Smirnov" <andrew.smirnov@gmail.com>,
linux-input@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH 12/18] HID: logitech-hidpp: use unaligned accessors for multi-byte values
Date: Sun, 8 Nov 2026 22:10:56 -0800 [thread overview]
Message-ID: <20261109061103.2887636-13-dmitry.torokhov@gmail.com> (raw)
In-Reply-To: <20261109061103.2887636-1-dmitry.torokhov@gmail.com>
Several paths in the Logitech HID++ driver manually split and reassemble
16-bit protocol values using shifts and masks instead of using standard
kernel helpers, which obscures endianness intent and adds unnecessary
noise.
Replace open-coded 16-bit big-endian packing and unpacking with
get_unaligned_be16() and put_unaligned_be16().
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
---
drivers/hid/hid-logitech-hidpp.c | 87 ++++++++++++--------------------
1 file changed, 33 insertions(+), 54 deletions(-)
diff --git a/drivers/hid/hid-logitech-hidpp.c b/drivers/hid/hid-logitech-hidpp.c
index 5169f3873257..c4ebfc4d66fe 100644
--- a/drivers/hid/hid-logitech-hidpp.c
+++ b/drivers/hid/hid-logitech-hidpp.c
@@ -951,7 +951,9 @@ static int hidpp_root_get_feature(struct hidpp_device *hidpp, u16 feature,
{
struct hidpp_report response;
int ret;
- u8 params[2] = { feature >> 8, feature & 0x00FF };
+ u8 params[2];
+
+ put_unaligned_be16(feature, params);
ret = hidpp_send_fap_command_sync(hidpp,
HIDPP_PAGE_ROOT_IDX,
@@ -2156,7 +2158,7 @@ static int hidpp_solar_battery_event(struct hidpp_device *hidpp,
switch (function) {
case EVENT_SOLAR_BATTERY_LIGHT_MEASURE:
- lux = (report->fap.params[1] << 8) | report->fap.params[2];
+ lux = get_unaligned_be16(&report->fap.params[1]);
if (lux > 200)
status = POWER_SUPPLY_STATUS_CHARGING;
else
@@ -2531,10 +2533,10 @@ static void hidpp_ff_work_handler(struct work_struct *w)
}
break;
case HIDPP_FF_SET_GLOBAL_GAINS:
- g920->gain = (wd->params[0] << 8) + wd->params[1];
+ g920->gain = get_unaligned_be16(&wd->params[0]);
break;
case HIDPP_FF_SET_APERTURE:
- g920->range = (wd->params[0] << 8) + wd->params[1];
+ g920->range = get_unaligned_be16(&wd->params[0]);
break;
default:
/* no action needed */
@@ -2581,23 +2583,18 @@ static int hidpp_ff_upload_effect(struct input_dev *dev, struct ff_effect *effec
int force;
/* set common parameters */
- params[2] = effect->replay.length >> 8;
- params[3] = effect->replay.length & 255;
- params[4] = effect->replay.delay >> 8;
- params[5] = effect->replay.delay & 255;
+ put_unaligned_be16(effect->replay.length, ¶ms[2]);
+ put_unaligned_be16(effect->replay.delay, ¶ms[4]);
switch (effect->type) {
case FF_CONSTANT:
force = (effect->u.constant.level * fixp_sin16((effect->direction * 360) >> 16)) >> 15;
params[1] = HIDPP_FF_EFFECT_CONSTANT;
- params[6] = force >> 8;
- params[7] = force & 255;
+ put_unaligned_be16(force, ¶ms[6]);
params[8] = effect->u.constant.envelope.attack_level >> 7;
- params[9] = effect->u.constant.envelope.attack_length >> 8;
- params[10] = effect->u.constant.envelope.attack_length & 255;
+ put_unaligned_be16(effect->u.constant.envelope.attack_length, ¶ms[9]);
params[11] = effect->u.constant.envelope.fade_level >> 7;
- params[12] = effect->u.constant.envelope.fade_length >> 8;
- params[13] = effect->u.constant.envelope.fade_length & 255;
+ put_unaligned_be16(effect->u.constant.envelope.fade_length, ¶ms[12]);
size = 14;
dbg_hid("Uploading constant force level=%d in dir %d = %d\n",
effect->u.constant.level,
@@ -2631,20 +2628,14 @@ static int hidpp_ff_upload_effect(struct input_dev *dev, struct ff_effect *effec
return -EINVAL;
}
force = (effect->u.periodic.magnitude * fixp_sin16((effect->direction * 360) >> 16)) >> 15;
- params[6] = effect->u.periodic.magnitude >> 8;
- params[7] = effect->u.periodic.magnitude & 255;
- params[8] = effect->u.periodic.offset >> 8;
- params[9] = effect->u.periodic.offset & 255;
- params[10] = effect->u.periodic.period >> 8;
- params[11] = effect->u.periodic.period & 255;
- params[12] = effect->u.periodic.phase >> 8;
- params[13] = effect->u.periodic.phase & 255;
+ put_unaligned_be16(effect->u.periodic.magnitude, ¶ms[6]);
+ put_unaligned_be16(effect->u.periodic.offset, ¶ms[8]);
+ put_unaligned_be16(effect->u.periodic.period, ¶ms[10]);
+ put_unaligned_be16(effect->u.periodic.phase, ¶ms[12]);
params[14] = effect->u.periodic.envelope.attack_level >> 7;
- params[15] = effect->u.periodic.envelope.attack_length >> 8;
- params[16] = effect->u.periodic.envelope.attack_length & 255;
+ put_unaligned_be16(effect->u.periodic.envelope.attack_length, ¶ms[15]);
params[17] = effect->u.periodic.envelope.fade_level >> 7;
- params[18] = effect->u.periodic.envelope.fade_length >> 8;
- params[19] = effect->u.periodic.envelope.fade_length & 255;
+ put_unaligned_be16(effect->u.periodic.envelope.fade_length, ¶ms[18]);
size = 20;
dbg_hid("Uploading periodic force mag=%d/dir=%d, offset=%d, period=%d ms, phase=%d\n",
effect->u.periodic.magnitude, effect->direction,
@@ -2661,17 +2652,13 @@ static int hidpp_ff_upload_effect(struct input_dev *dev, struct ff_effect *effec
case FF_RAMP:
params[1] = HIDPP_FF_EFFECT_RAMP;
force = (effect->u.ramp.start_level * fixp_sin16((effect->direction * 360) >> 16)) >> 15;
- params[6] = force >> 8;
- params[7] = force & 255;
+ put_unaligned_be16(force, ¶ms[6]);
force = (effect->u.ramp.end_level * fixp_sin16((effect->direction * 360) >> 16)) >> 15;
- params[8] = force >> 8;
- params[9] = force & 255;
+ put_unaligned_be16(force, ¶ms[8]);
params[10] = effect->u.ramp.envelope.attack_level >> 7;
- params[11] = effect->u.ramp.envelope.attack_length >> 8;
- params[12] = effect->u.ramp.envelope.attack_length & 255;
+ put_unaligned_be16(effect->u.ramp.envelope.attack_length, ¶ms[11]);
params[13] = effect->u.ramp.envelope.fade_level >> 7;
- params[14] = effect->u.ramp.envelope.fade_length >> 8;
- params[15] = effect->u.ramp.envelope.fade_length & 255;
+ put_unaligned_be16(effect->u.ramp.envelope.fade_length, ¶ms[14]);
size = 16;
dbg_hid("Uploading ramp force level=%d -> %d in dir %d = %d\n",
effect->u.ramp.start_level,
@@ -2688,18 +2675,12 @@ static int hidpp_ff_upload_effect(struct input_dev *dev, struct ff_effect *effec
case FF_SPRING:
case FF_DAMPER:
params[1] = HIDPP_FF_CONDITION_CMDS[effect->type - FF_SPRING];
- params[6] = effect->u.condition[0].left_saturation >> 9;
- params[7] = (effect->u.condition[0].left_saturation >> 1) & 255;
- params[8] = effect->u.condition[0].left_coeff >> 8;
- params[9] = effect->u.condition[0].left_coeff & 255;
- params[10] = effect->u.condition[0].deadband >> 9;
- params[11] = (effect->u.condition[0].deadband >> 1) & 255;
- params[12] = effect->u.condition[0].center >> 8;
- params[13] = effect->u.condition[0].center & 255;
- params[14] = effect->u.condition[0].right_coeff >> 8;
- params[15] = effect->u.condition[0].right_coeff & 255;
- params[16] = effect->u.condition[0].right_saturation >> 9;
- params[17] = (effect->u.condition[0].right_saturation >> 1) & 255;
+ put_unaligned_be16(effect->u.condition[0].left_saturation >> 1, ¶ms[6]);
+ put_unaligned_be16(effect->u.condition[0].left_coeff, ¶ms[8]);
+ put_unaligned_be16(effect->u.condition[0].deadband >> 1, ¶ms[10]);
+ put_unaligned_be16(effect->u.condition[0].center, ¶ms[12]);
+ put_unaligned_be16(effect->u.condition[0].right_coeff, ¶ms[14]);
+ put_unaligned_be16(effect->u.condition[0].right_saturation >> 1, ¶ms[16]);
size = 18;
dbg_hid("Uploading %s force left coeff=%d, left sat=%d, right coeff=%d, right sat=%d\n",
HIDPP_FF_CONDITION_NAMES[effect->type - FF_SPRING],
@@ -2753,10 +2734,10 @@ static void hidpp_ff_set_autocenter(struct input_dev *dev, u16 magnitude)
/* zero delay and duration */
params[2] = params[3] = params[4] = params[5] = 0;
/* set coeff to 25% of saturation */
- params[8] = params[14] = magnitude >> 11;
- params[9] = params[15] = (magnitude >> 3) & 255;
- params[6] = params[16] = magnitude >> 9;
- params[7] = params[17] = (magnitude >> 1) & 255;
+ put_unaligned_be16(magnitude >> 3, ¶ms[8]);
+ put_unaligned_be16(magnitude >> 3, ¶ms[14]);
+ put_unaligned_be16(magnitude >> 1, ¶ms[6]);
+ put_unaligned_be16(magnitude >> 1, ¶ms[16]);
/* zero deadband and center */
params[10] = params[11] = params[12] = params[13] = 0;
@@ -2770,8 +2751,7 @@ static void hidpp_ff_set_gain(struct input_dev *dev, u16 gain)
dbg_hid("Setting gain to %d.\n", gain);
- params[0] = gain >> 8;
- params[1] = gain & 255;
+ put_unaligned_be16(gain, params);
params[2] = 0; /* no boost */
params[3] = 0;
@@ -2797,8 +2777,7 @@ static ssize_t hidpp_ff_range_store(struct device *dev, struct device_attribute
range = clamp(range, 180, 900);
- params[0] = range >> 8;
- params[1] = range & 0x00FF;
+ put_unaligned_be16(range, params);
hidpp_ff_queue_work(g920->ff, -1, HIDPP_FF_SET_APERTURE, params, ARRAY_SIZE(params));
--
2.56.0.506.g506a7eabc5-goog
next prev parent reply other threads:[~2026-11-09 6:11 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-11-09 6:10 [PATCH 00/18] HID: logitech-hidpp: G920 force-feedback fixes, rework, and cleanups Dmitry Torokhov
2026-11-09 6:10 ` [PATCH 01/18] HID: logitech-hidpp: fix G920 force-feedback initialization timeout Dmitry Torokhov
2026-11-09 6:10 ` [PATCH 02/18] HID: logitech-hidpp: use GFP_ATOMIC in hidpp_ff_queue_work() Dmitry Torokhov
2026-11-09 6:10 ` [PATCH 03/18] HID: logitech-hidpp: drain G920 FF workqueue before closing transport Dmitry Torokhov
2026-11-09 6:10 ` [PATCH 04/18] HID: logitech-hidpp: disable works before stopping transport Dmitry Torokhov
2026-11-09 6:10 ` [PATCH 05/18] HID: logitech-hidpp: do not store ERR_PTR in battery->ps Dmitry Torokhov
2026-11-09 6:10 ` [PATCH 06/18] HID: logitech-hidpp: avoid NULL subtraction in consumer key report fixup Dmitry Torokhov
2026-11-09 6:10 ` [PATCH 07/18] HID: logitech-hidpp: fix off-by-one in G920 force-feedback slot tracking Dmitry Torokhov
2026-11-09 6:10 ` [PATCH 08/18] HID: logitech-hidpp: rework G920 force-feedback initialization Dmitry Torokhov
2026-11-09 6:10 ` [PATCH 09/18] HID: logitech-hidpp: use sysfs_emit() in hidpp_ff_range_show() Dmitry Torokhov
2026-11-09 6:10 ` [PATCH 10/18] HID: logitech-hidpp: manage G920 range sysfs attribute via dev_groups Dmitry Torokhov
2026-11-09 6:10 ` [PATCH 11/18] HID: logitech-hidpp: shut down G920 force feedback on input unregister Dmitry Torokhov
2026-11-09 6:10 ` Dmitry Torokhov [this message]
2026-11-09 6:10 ` [PATCH 13/18] HID: logitech-hidpp: store device serial as a byte array Dmitry Torokhov
2026-11-09 6:10 ` [PATCH 14/18] HID: logitech-hidpp: use guard() for send_mutex Dmitry Torokhov
2026-11-09 6:10 ` [PATCH 15/18] HID: logitech-hidpp: use __free(kfree) for temporary allocations Dmitry Torokhov
2026-11-09 6:11 ` [PATCH 16/18] HID: logitech-hidpp: use alloc_ordered_workqueue() for FF queue Dmitry Torokhov
2026-11-09 6:11 ` [PATCH 17/18] HID: logitech-hidpp: manage send_mutex with devm_mutex_init() Dmitry Torokhov
2026-11-09 6:11 ` [PATCH 18/18] HID: logitech-hidpp: manage ps_attribute_group with devm_device_add_group() Dmitry Torokhov
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