From aacd152ecd7b18af5d2d96dea9e7284c1c93abea Mon Sep 17 00:00:00 2001 From: Mariusz Bialonczyk Date: Thu, 30 May 2019 09:51:25 +0200 Subject: w1: ds2413: fix state byte comparision This commit is fixing a smatch warning: drivers/w1/slaves/w1_ds2413.c:61 state_read() warn: impossible condition '(*buf == 255) => ((-128)-127 == 255)' by creating additional u8 variable for the bus reading and comparision Reported-by: kbuild test robot Reported-by: Dan Carpenter Cc: Dan Carpenter Fixes: 3856032a0628 ("w1: ds2413: when the slave is not responding during read, select it again") Signed-off-by: Mariusz Bialonczyk Signed-off-by: Greg Kroah-Hartman --- drivers/w1/slaves/w1_ds2413.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) (limited to 'drivers/w1') diff --git a/drivers/w1/slaves/w1_ds2413.c b/drivers/w1/slaves/w1_ds2413.c index 21f08ac8a4e0..3364ad276b15 100644 --- a/drivers/w1/slaves/w1_ds2413.c +++ b/drivers/w1/slaves/w1_ds2413.c @@ -33,6 +33,7 @@ static ssize_t state_read(struct file *filp, struct kobject *kobj, struct w1_slave *sl = kobj_to_w1_slave(kobj); unsigned int retries = W1_F3A_RETRIES; ssize_t bytes_read = -EIO; + u8 state; dev_dbg(&sl->dev, "Reading %s kobj: %p, off: %0#10x, count: %zu, buff addr: %p", @@ -53,12 +54,13 @@ next: while (retries--) { w1_write_8(sl->master, W1_F3A_FUNC_PIO_ACCESS_READ); - *buf = w1_read_8(sl->master); - if ((*buf & 0x0F) == ((~*buf >> 4) & 0x0F)) { + state = w1_read_8(sl->master); + if ((state & 0x0F) == ((~state >> 4) & 0x0F)) { /* complement is correct */ + *buf = state; bytes_read = 1; goto out; - } else if (*buf == W1_F3A_INVALID_PIO_STATE) { + } else if (state == W1_F3A_INVALID_PIO_STATE) { /* slave didn't respond, try to select it again */ dev_warn(&sl->dev, "slave device did not respond to PIO_ACCESS_READ, " \ "reselecting, retries left: %d\n", retries); -- cgit v1.2.3-55-g7522