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Input: mms114 - fix endianness portability in I2C packet layout

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The driver defines the I2C packet layout using C bitfields in struct
mms114_touch. This is not portable as the layout of bitfields within a
byte is compiler-dependent and varies with endianness. On Big Endian
systems, the fields will be parsed incorrectly.

Fix this by redefining struct mms114_touch with plain u8 fields and
introducing bitwise macros to extract the values portably.

Reported-by: sashiko-bot@kernel.org
Assisted-by: Antigravity:gemini-3.5-flash
Link: https://patch.msgid.link/20260704060115.353049-2-dmitry.torokhov@gmail.com
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
This commit is contained in:
Dmitry Torokhov
2026-07-03 23:01:13 -07:00
parent 76904fccf8
commit 72fe16c61b
1 changed files with 33 additions and 19 deletions
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52
drivers/input/touchscreen/mms114.c
View File

@@ -4,6 +4,8 @@
// Copyright (c) 2012 Samsung Electronics Co., Ltd.
// Author: Joonyoung Shim <jy0922.shim@samsung.com>
#include <linux/bitfield.h>
#include <linux/bits.h>
#include <linux/module.h>
#include <linux/delay.h>
#include <linux/of.h>
@@ -76,9 +78,16 @@ struct mms_chip {
int (*get_version)(struct mms114_data *data);
};
#define MMS114_FLAGS_ID_MASK GENMASK(3, 0)
#define MMS114_FLAGS_TYPE_MASK GENMASK(6, 5)
#define MMS114_FLAGS_PRESSED_MASK BIT(7)
#define MMS114_XY_HI_X_MASK GENMASK(3, 0)
#define MMS114_XY_HI_Y_MASK GENMASK(7, 4)
struct mms114_touch {
u8 id:4, reserved_bit4:1, type:2, pressed:1;
u8 x_hi:4, y_hi:4;
u8 flags;
u8 xy_hi;
u8 x_lo;
u8 y_lo;
u8 width;
@@ -244,28 +253,30 @@ static void mms114_process_mt(struct mms114_data *data, struct mms114_touch *tou
{
struct i2c_client *client = data->client;
struct input_dev *input_dev = data->input_dev;
unsigned int id;
unsigned int id = FIELD_GET(MMS114_FLAGS_ID_MASK, touch->flags);
unsigned int type = FIELD_GET(MMS114_FLAGS_TYPE_MASK, touch->flags);
bool pressed = FIELD_GET(MMS114_FLAGS_PRESSED_MASK, touch->flags);
unsigned int x;
unsigned int y;
if (touch->id == 0 || touch->id > MMS114_MAX_TOUCH) {
dev_err(&client->dev, "Wrong touch id (%d)\n", touch->id);
if (id == 0 || id > MMS114_MAX_TOUCH) {
dev_err(&client->dev, "Wrong touch id (%d)\n", id);
return;
}
id = touch->id - 1;
x = touch->x_lo | touch->x_hi << 8;
y = touch->y_lo | touch->y_hi << 8;
id--;
x = touch->x_lo | FIELD_GET(MMS114_XY_HI_X_MASK, touch->xy_hi) << 8;
y = touch->y_lo | FIELD_GET(MMS114_XY_HI_Y_MASK, touch->xy_hi) << 8;
dev_dbg(&client->dev,
"id: %d, type: %d, pressed: %d, x: %d, y: %d, width: %d, strength: %d\n",
id, touch->type, touch->pressed,
id, type, pressed,
x, y, touch->width, touch->strength);
input_mt_slot(input_dev, id);
input_mt_report_slot_state(input_dev, MT_TOOL_FINGER, touch->pressed);
input_mt_report_slot_state(input_dev, MT_TOOL_FINGER, pressed);
if (touch->pressed) {
if (pressed) {
touchscreen_report_pos(input_dev, &data->props, x, y, true);
input_report_abs(input_dev, ABS_MT_TOUCH_MAJOR, touch->width);
input_report_abs(input_dev, ABS_MT_PRESSURE, touch->strength);
@@ -278,21 +289,23 @@ static void mms114_process_touchkey(struct mms114_data *data,
struct i2c_client *client = data->client;
struct input_dev *input_dev = data->input_dev;
unsigned int keycode_id;
unsigned int id = FIELD_GET(MMS114_FLAGS_ID_MASK, touch->flags);
bool pressed = FIELD_GET(MMS114_FLAGS_PRESSED_MASK, touch->flags);
if (touch->id == 0)
if (id == 0)
return;
if (touch->id > data->num_keycodes) {
if (id > data->num_keycodes) {
dev_err(&client->dev, "Wrong touch id for touchkey (%d)\n",
touch->id);
id);
return;
}
keycode_id = touch->id - 1;
keycode_id = id - 1;
dev_dbg(&client->dev, "keycode id: %d, pressed: %d\n", keycode_id,
touch->pressed);
pressed);
input_report_key(input_dev, data->keycodes[keycode_id], touch->pressed);
input_report_key(input_dev, data->keycodes[keycode_id], pressed);
}
static irqreturn_t mms114_interrupt(int irq, void *dev_id)
@@ -325,8 +338,9 @@ static irqreturn_t mms114_interrupt(int irq, void *dev_id)
for (index = 0; index < touch_size; index++) {
t = (struct mms114_touch *)((u8 *)touch + index * event_size);
unsigned int type = FIELD_GET(MMS114_FLAGS_TYPE_MASK, t->flags);
switch (t->type) {
switch (type) {
case MMS114_TYPE_TOUCHSCREEN:
mms114_process_mt(data, t);
break;
@@ -337,7 +351,7 @@ static irqreturn_t mms114_interrupt(int irq, void *dev_id)
default:
dev_err(&client->dev, "Wrong touch type (%d)\n",
t->type);
type);
break;
}
}