Hello Michał Mirosław,
The patch 9517b95bdc46: "Input: elants_i2c - add support for
eKTF3624" from Jan 24, 2021, leads to the following static checker
warning:
drivers/input/touchscreen/elants_i2c.c:966 elants_i2c_mt_event()
warn: should this be a bitwise negate mask?
drivers/input/touchscreen/elants_i2c.c
942 /* Note: all fingers have the same tool type */
943 tool_type = buf[FW_POS_TOOL_TYPE] & BIT(0) ?
944 MT_TOOL_FINGER : MT_TOOL_PALM;
945
946 for (i = 0; i < MAX_CONTACT_NUM && n_fingers; i++) {
947 if (finger_state & 1) {
948 unsigned int x, y, p, w;
949 u8 *pos;
950
951 pos = &buf[FW_POS_XY + i * 3];
952 x = (((u16)pos[0] & 0xf0) << 4) | pos[1];
953 y = (((u16)pos[0] & 0x0f) << 8) | pos[2];
954
955 /*
956 * eKTF3624 may have use "old" touch-report format,
957 * depending on a device and TS firmware version.
958 * For example, ASUS Transformer devices use the "old"
959 * format, while ASUS Nexus 7 uses the "new" formant.
960 */
961 if (packet_size == PACKET_SIZE_OLD &&
962 ts->chip_id == EKTF3624) {
963 w = buf[FW_POS_WIDTH + i / 2];
964 w >>= 4 * (~i & 1);
965 w |= w << 4;
966 w |= !w;
^^^^^^^^
This code is just very puzzling. I think it may actually be correct?
The boring and conventional way to write this would be to do it like so:
if (!w)
w = 1;
967 p = w;
968 } else {
969 p = buf[FW_POS_PRESSURE + i];
970 w = buf[FW_POS_WIDTH + i];
971 }
972
973 dev_dbg(&ts->client->dev, "i=%d x=%d y=%d p=%d w=%d\n",
974 i, x, y, p, w);
975
976 input_mt_slot(input, i);
977 input_mt_report_slot_state(input, tool_type, true);
978 touchscreen_report_pos(input, &ts->prop, x, y, true);
regards,
dan carpenter
