On Mon, Jun 29, 2020 at 10:01 PM Lee Jones <[email protected]> wrote: > > On Mon, 29 Jun 2020, Johan Hovold wrote: > > > On Mon, Jun 29, 2020 at 01:32:14PM +0100, Lee Jones wrote: > > > Since ddata->irqs[] is already zeroed when allocated by devm_kcalloc() and > > > dividing 0 by anything is still 0, there is no need to re-assign > > > ddata->irqs[i].* values. Instead, it should be safe to begin at 1. > > > > > > This fixes the following W=1 warning: > > > > > > drivers/mfd/sprd-sc27xx-spi.c:255 sprd_pmic_probe() debug: > > > sval_binop_unsigned: divide by zero > > > > > > Cc: Orson Zhai <[email protected]> > > > Cc: Baolin Wang <[email protected]> > > > Cc: Chunyan Zhang <[email protected]> > > > Signed-off-by: Lee Jones <[email protected]> > > > --- > > > drivers/mfd/sprd-sc27xx-spi.c | 2 +- > > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > > > diff --git a/drivers/mfd/sprd-sc27xx-spi.c b/drivers/mfd/sprd-sc27xx-spi.c > > > index c305e941e435c..694a7d429ccff 100644 > > > --- a/drivers/mfd/sprd-sc27xx-spi.c > > > +++ b/drivers/mfd/sprd-sc27xx-spi.c > > > @@ -251,7 +251,7 @@ static int sprd_pmic_probe(struct spi_device *spi) > > > return -ENOMEM; > > > > > > ddata->irq_chip.irqs = ddata->irqs; > > > - for (i = 0; i < pdata->num_irqs; i++) { > > > + for (i = 1; i < pdata->num_irqs; i++) { > > > ddata->irqs[i].reg_offset = i / pdata->num_irqs; > > > ddata->irqs[i].mask = BIT(i % pdata->num_irqs); > > > } > > > > This doesn't look right either. > > > > First, the loop is never executed if num_irqs is zero. > > The point of the patch is that 0 entries are never processed. > > However, what I appear to have overlooked is that BIT(0 % x) is not 0, > it's 1.
Yes. > > > Second, the current code looks bogus too as reg_offset is always set to > > zero and mask to BIT(i)... Now the result is correct, since all PMIC irq mask bits are in one register now, which means the reg_offset is always 0 can work well. But I think the logics still can be improved if our PMIC irq numbers are larger than 32 in future. > > Heh. I wonder if/how this was tested. > > I'm going to wait to hear from the authors before attempting to fix > this again. > > Baolin, Could you please clarify this for us please? Yes, see above comments. -- Baolin Wang
