[PATCH 1/1] i2c: sh_mobile: eliminate a misreported warning

From: Zhen Lei
Date: Wed Apr 29 2020 - 08:41:02 EST


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 âsh_mobile_i2c_isrâ:
drivers/i2c/busses/i2c-sh_mobile.c:396:26: warning: âdataâ 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: âdataâ 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