Value comes from DT, so it could be 0. Unlikely, but could be.

Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
---
 drivers/i2c/busses/i2c-riic.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/i2c/busses/i2c-riic.c b/drivers/i2c/busses/i2c-riic.c
index f0ee8871d5ae..e43ff483c56e 100644
--- a/drivers/i2c/busses/i2c-riic.c
+++ b/drivers/i2c/busses/i2c-riic.c
@@ -313,7 +313,7 @@ static int riic_init_hw(struct riic_dev *riic, struct i2c_timings *t)
 	 * frequency with only 62 clock ticks max (31 high, 31 low).
 	 * Aim for a duty of 60% LOW, 40% HIGH.
 	 */
-	total_ticks = DIV_ROUND_UP(rate, t->bus_freq_hz);
+	total_ticks = DIV_ROUND_UP(rate, t->bus_freq_hz ?: 1);
 
 	for (cks = 0; cks < 7; cks++) {
 		/*
-- 
2.35.1

On Wed, 6 Sep 2023, Wolfram Sang wrote:
> Value comes from DT, so it could be 0. Unlikely, but could be.
>
> Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>

Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>

Gr{oetje,eeting}s,

 						Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
 							    -- Linus Torvalds

Hi Wolfram Sang,

> Subject: [PATCH 5/5] i2c: riic: avoid potential division by zero
> 
> Value comes from DT, so it could be 0. Unlikely, but could be.
> 
> Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
> ---
>  drivers/i2c/busses/i2c-riic.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/i2c/busses/i2c-riic.c b/drivers/i2c/busses/i2c-riic.c
> index f0ee8871d5ae..e43ff483c56e 100644
> --- a/drivers/i2c/busses/i2c-riic.c
> +++ b/drivers/i2c/busses/i2c-riic.c
> @@ -313,7 +313,7 @@ static int riic_init_hw(struct riic_dev *riic, struct
> i2c_timings *t)
>  	 * frequency with only 62 clock ticks max (31 high, 31 low).
>  	 * Aim for a duty of 60% LOW, 40% HIGH.
>  	 */
> -	total_ticks = DIV_ROUND_UP(rate, t->bus_freq_hz);
> +	total_ticks = DIV_ROUND_UP(rate, t->bus_freq_hz ?: 1);

Not sure clamping function min_t/min(t->bus_freq_hz, 1)
Or ternary condition is good in this case for avoiding potential division by 0?

Cheers,
Biju

> 
>  	for (cks = 0; cks < 7; cks++) {
>  		/*
> --
> 2.35.1

> > -	total_ticks = DIV_ROUND_UP(rate, t->bus_freq_hz);
> > +	total_ticks = DIV_ROUND_UP(rate, t->bus_freq_hz ?: 1);
> 
> Not sure clamping function min_t/min(t->bus_freq_hz, 1)
> Or ternary condition is good in this case for avoiding potential division by 0?

Both work. I chose the ternary because I believe it involves less
computation and a tad tighter syntax.

> Subject: RE: [PATCH 5/5] i2c: riic: avoid potential division by zero
> 
> Hi Wolfram Sang,
> 
> > Subject: [PATCH 5/5] i2c: riic: avoid potential division by zero
> >
> > Value comes from DT, so it could be 0. Unlikely, but could be.
> >
> > Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
> > ---
> >  drivers/i2c/busses/i2c-riic.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/drivers/i2c/busses/i2c-riic.c
> > b/drivers/i2c/busses/i2c-riic.c index f0ee8871d5ae..e43ff483c56e
> > 100644
> > --- a/drivers/i2c/busses/i2c-riic.c
> > +++ b/drivers/i2c/busses/i2c-riic.c
> > @@ -313,7 +313,7 @@ static int riic_init_hw(struct riic_dev *riic,
> > struct i2c_timings *t)
> >  	 * frequency with only 62 clock ticks max (31 high, 31 low).
> >  	 * Aim for a duty of 60% LOW, 40% HIGH.
> >  	 */
> > -	total_ticks = DIV_ROUND_UP(rate, t->bus_freq_hz);
> > +	total_ticks = DIV_ROUND_UP(rate, t->bus_freq_hz ?: 1);
> 
> Not sure clamping function min_t/min(t->bus_freq_hz, 1) 

Typo min->max.