> -----Original Message-----
> From: Frank Li <frank.li@xxxxxxx>
> Sent: Tuesday, November 26, 2024 1:18 AM
> To: Carlos Song <carlos.song@xxxxxxx>
> Cc: o.rempel@xxxxxxxxxxxxxx; kernel@xxxxxxxxxxxxxx; andi.shyti@xxxxxxxxxx;
> shawnguo@xxxxxxxxxx; s.hauer@xxxxxxxxxxxxxx; festevam@xxxxxxxxx;
> linux-i2c@xxxxxxxxxxxxxxx; imx@xxxxxxxxxxxxxxx;
> linux-arm-kernel@xxxxxxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx
> Subject: Re: [PATCH] i2c: imx: fix divide by zero warning
>
> On Mon, Nov 25, 2024 at 10:15:21PM +0800, carlos.song@xxxxxxx wrote:
> > From: Carlos Song <carlos.song@xxxxxxx>
> >
> > Add "i2c_clk_rate / 2" check to avoid "divide by zero warning".
> > i2c_clk_rate may be zero if i2c clock is disabled.
> >
> > Signed-off-by: Carlos Song <carlos.song@xxxxxxx>
> > Signed-off-by: Clark Wang <xiaoning.wang@xxxxxxx>
> > Signed-off-by: Haibo Chen <haibo.chen@xxxxxxx>
> > ---
>
> You sent this patch twice?
>
Yes, because I meet a net error, I send the patch out and wait for a half of hour, but I don't see the mail in the mail list, so I send it again, but another one come in
after 1 hour.. You can dismiss the same one.
> Reviewed-by: Frank Li <Frank.Li@xxxxxxx>
>
> > drivers/i2c/busses/i2c-imx.c | 23 +++++++++++++++++------
> > 1 file changed, 17 insertions(+), 6 deletions(-)
> >
> > diff --git a/drivers/i2c/busses/i2c-imx.c
> > b/drivers/i2c/busses/i2c-imx.c index 2c782cdc26bd..5ed4cb61e262 100644
> > --- a/drivers/i2c/busses/i2c-imx.c
> > +++ b/drivers/i2c/busses/i2c-imx.c
> > @@ -623,8 +623,8 @@ static int i2c_imx_acked(struct imx_i2c_struct
> *i2c_imx)
> > return 0;
> > }
> >
> > -static void i2c_imx_set_clk(struct imx_i2c_struct *i2c_imx,
> > - unsigned int i2c_clk_rate)
> > +static int i2c_imx_set_clk(struct imx_i2c_struct *i2c_imx,
> > + unsigned int i2c_clk_rate)
> > {
> > struct imx_i2c_clk_pair *i2c_clk_div = i2c_imx->hwdata->clk_div;
> > unsigned int div;
> > @@ -639,7 +639,11 @@ static void i2c_imx_set_clk(struct imx_i2c_struct
> > *i2c_imx,
> >
> > /* Divider value calculation */
> > if (i2c_imx->cur_clk == i2c_clk_rate)
> > - return;
> > + return 0;
> > +
> > + /* Keep the denominator of the following program always NOT equal to 0.
> */
> > + if (!(i2c_clk_rate / 2))
> > + return -EINVAL;
> >
> > i2c_imx->cur_clk = i2c_clk_rate;
> >
> > @@ -670,6 +674,8 @@ static void i2c_imx_set_clk(struct imx_i2c_struct
> *i2c_imx,
> > dev_dbg(&i2c_imx->adapter.dev, "IFDR[IC]=0x%x, REAL DIV=%d\n",
> > i2c_clk_div[i].val, i2c_clk_div[i].div); #endif
> > +
> > + return 0;
> > }
> >
> > static int i2c_imx_clk_notifier_call(struct notifier_block *nb, @@
> > -679,11 +685,12 @@ static int i2c_imx_clk_notifier_call(struct notifier_block
> *nb,
> > struct imx_i2c_struct *i2c_imx = container_of(nb,
> > struct imx_i2c_struct,
> > clk_change_nb);
> > + int ret = 0;
> >
> > if (action & POST_RATE_CHANGE)
> > - i2c_imx_set_clk(i2c_imx, ndata->new_rate);
> > + ret = i2c_imx_set_clk(i2c_imx, ndata->new_rate);
> >
> > - return NOTIFY_OK;
> > + return notifier_from_errno(ret);
> > }
> >
> > static int i2c_imx_start(struct imx_i2c_struct *i2c_imx, bool atomic)
> > @@ -1782,7 +1789,11 @@ static int i2c_imx_probe(struct platform_device
> *pdev)
> > i2c_imx->bitrate = pdata->bitrate;
> > i2c_imx->clk_change_nb.notifier_call = i2c_imx_clk_notifier_call;
> > clk_notifier_register(i2c_imx->clk, &i2c_imx->clk_change_nb);
> > - i2c_imx_set_clk(i2c_imx, clk_get_rate(i2c_imx->clk));
> > + ret = i2c_imx_set_clk(i2c_imx, clk_get_rate(i2c_imx->clk));
> > + if (ret < 0) {
> > + dev_err(&pdev->dev, "can't get I2C clock\n");
> > + goto clk_notifier_unregister;
> > + }
> >
> > i2c_imx_reset_regs(i2c_imx);
> >
> > --
> > 2.34.1
> >
