Re: [PATCH v2] i2c: designware: add support for pinctrl for recovery

[Jarkko Nikula]

On 8/17/23 17:27, Yann Sionneau wrote:
> Hi
>
> Le 17/08/2023 à 10:07, Jarkko Nikula a écrit :
> > Hi
> >
> > On 8/16/23 12:50, Yann Sionneau wrote:
> > > From: Yann Sionneau <ysionneau@xxxxxxxxx>
> > >
> > > Currently if the SoC needs pinctrl to switch the SCL and SDA
> > > from the I2C function to GPIO function, the recovery won't work.
> > >
> > > scl-gpio = <>;
> > > sda-gpio = <>;
> > >
> > > Are not enough for some SoCs to have a working recovery.
> > > Some need:
> > >
> > > scl-gpio = <>;
> > > sda-gpio = <>;
> > > pinctrl-names = "default", "recovery";
> > > pinctrl-0 = <&i2c_pins_hw>;
> > > pinctrl-1 = <&i2c_pins_gpio>;
> > >
> > > The driver was not filling rinfo->pinctrl with the device node
> > > pinctrl data which is needed by generic recovery code.
> > >
> > > Tested-by: Yann Sionneau <ysionneau@xxxxxxxxx>
> > > Signed-off-by: Yann Sionneau <ysionneau@xxxxxxxxx>
> >
> > Tested-by from author is needless. Expectation is that author has 
> > tested the patch while not always true :-)
> Ok, I just wanted to emphasize the fact that I have the device and I 
> tested the change with the device. Ack!
> > > @@ -905,6 +906,15 @@ static int i2c_dw_init_recovery_info(struct 
> > > dw_i2c_dev *dev)
> > >           return PTR_ERR(gpio);
> > >       rinfo->sda_gpiod = gpio;
> > >   +    rinfo->pinctrl = devm_pinctrl_get(dev->dev);
> > > +    if (IS_ERR(rinfo->pinctrl)) {
> > > +        if (PTR_ERR(rinfo->pinctrl) == -EPROBE_DEFER)
> > > +            return PTR_ERR(rinfo->pinctrl);
> > > +
> > > +        rinfo->pinctrl = NULL;
> > > +        dev_info(dev->dev, "can't get pinctrl, bus recovery might 
> > > not work\n");
> >
> > I think dev_dbg() suits better here or is it needed at all? End user 
> > may not be able to do anything when sees this in dmesg. I.e. more like 
> > development time dev_dbg() information.
> I agree dev_dbg() is a better idea.
> > Does i2c-core-base.c: i2c_gpio_init_pinctrl_recovery() already do 
> > dev_info() print when pinctrl & GPIO are set properly making above 
> > also kind of needless?
>
> Thanks for the review. In fact I had to use gdb to understand why the 
> recovery was not working. Because as you said, it only prints something 
> to say "everything looks ok!".
>
> I kind of prefer when it prints when something goes wrong.
>
> But I let you decide what you think is the best.
Fair enough, dev_dbg() is justified when it makes developer's life 
easier :-)