The warning is caused by the branches "if (pd->pos == -1)" and "if (pd->pos == 0)", because they appear after "real_pos = pd->pos - 2", so the compiler doesn't known the value of real_pos is negative through these two branches. To avoid this warning, eliminate the middleman "data". drivers/i2c/busses/i2c-sh_mobile.c: In function ‘sh_mobile_i2c_isr’: drivers/i2c/busses/i2c-sh_mobile.c:396:26: warning: ‘data’ may be used uninitialized in this function [-Wmaybe-uninitialized] pd->msg->buf[real_pos] = data; ^ drivers/i2c/busses/i2c-sh_mobile.c:369:16: note: ‘data’ was declared here unsigned char data; Signed-off-by: Zhen Lei <thunder.leizhen@xxxxxxxxxx> --- drivers/i2c/busses/i2c-sh_mobile.c | 7 ++----- 1 file changed, 2 insertions(+), 5 deletions(-) diff --git a/drivers/i2c/busses/i2c-sh_mobile.c b/drivers/i2c/busses/i2c-sh_mobile.c index d83ca4028fa0..2cca1b21e26e 100644 --- a/drivers/i2c/busses/i2c-sh_mobile.c +++ b/drivers/i2c/busses/i2c-sh_mobile.c @@ -366,7 +366,6 @@ static int sh_mobile_i2c_isr_tx(struct sh_mobile_i2c_data *pd) static int sh_mobile_i2c_isr_rx(struct sh_mobile_i2c_data *pd) { - unsigned char data; int real_pos; /* switch from TX (address) to RX (data) adds two interrupts */ @@ -387,13 +386,11 @@ static int sh_mobile_i2c_isr_rx(struct sh_mobile_i2c_data *pd) if (real_pos < 0) i2c_op(pd, OP_RX_STOP); else - data = i2c_op(pd, OP_RX_STOP_DATA); + pd->msg->buf[real_pos] = i2c_op(pd, OP_RX_STOP_DATA); } else if (real_pos >= 0) { - data = i2c_op(pd, OP_RX); + pd->msg->buf[real_pos] = i2c_op(pd, OP_RX); } - if (real_pos >= 0) - pd->msg->buf[real_pos] = data; done: pd->pos++; return pd->pos == (pd->msg->len + 2); -- 2.26.0.106.g9fadedd