Re: [PATCH RFC 2/5] pinctrl: renesas: rzg2l: Fix configuring the GPIO pins as interrupts

From: "Lad, Prabhakar" <prabhakar.csengg@gmail.com>
To: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Thomas Gleixner <tglx@linutronix.de>,
	Marc Zyngier <maz@kernel.org>, Rob Herring <robh+dt@kernel.org>,
	Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
	Geert Uytterhoeven <geert+renesas@glider.be>,
	Magnus Damm <magnus.damm@gmail.com>,
	Linus Walleij <linus.walleij@linaro.org>,
	linux-gpio@vger.kernel.org, linux-renesas-soc@vger.kernel.org,
	devicetree@vger.kernel.org, linux-kernel@vger.kernel.org,
	Biju Das <biju.das.jz@bp.renesas.com>,
	Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Subject: Re: [PATCH RFC 2/5] pinctrl: renesas: rzg2l: Fix configuring the GPIO pins as interrupts
Date: Thu, 17 Nov 2022 12:14:26 +0000	[thread overview]
Message-ID: <CA+V-a8ugHB2NqH4qa01LQm6yXaeSk2WweUX3ZP+fT3F_bU99Pg@mail.gmail.com> (raw)
In-Reply-To: <CAMuHMdW9K=gd7F-G-7v0J5Mz8jyZa_Vu3UZWsNZin76tff7f3g@mail.gmail.com>

Hi Geert,

Thank you for the review.

On Thu, Nov 17, 2022 at 11:09 AM Geert Uytterhoeven
<geert@linux-m68k.org> wrote:
>
> Hi Prabhakar,
>
> On Mon, Nov 7, 2022 at 6:53 PM Prabhakar <prabhakar.csengg@gmail.com> wrote:
> > From: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
> >
> > On the RZ/G2UL SoC we have less number of pins compared to RZ/G2L and also
> > the pin configs are completely different. This patch makes sure we use the
> > appropriate pin configs for each SoC (which is passed as part of the OF
> > data) while configuring the GPIO pin as interrupts instead of using
> > rzg2l_gpio_configs[] for all the SoCs.
> >
> > Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
>
> Thanks for your patch!
>
> Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
> But I do think there is room for improvement...
>
> > --- a/drivers/pinctrl/renesas/pinctrl-rzg2l.c
> > +++ b/drivers/pinctrl/renesas/pinctrl-rzg2l.c
> > @@ -127,6 +127,7 @@ struct rzg2l_dedicated_configs {
> >  struct rzg2l_pinctrl_data {
> >         const char * const *port_pins;
> >         const u32 *port_pin_configs;
> > +       unsigned int n_port_pin_configs;
>
> n_ports?
>
Ok I will rename it to n_ports.

> >         struct rzg2l_dedicated_configs *dedicated_pins;
> >         unsigned int n_port_pins;
>
> n_port_pins is now always n_port_pin_configs * RZG2L_PINS_PER_PORT,
> right?
>
Yes, that's right. So are you suggesting to drop it and use it runtime instead?

> >         unsigned int n_dedicated_pins;
>
> > @@ -1517,6 +1518,7 @@ static int rzg2l_pinctrl_probe(struct platform_device *pdev)
> >  static struct rzg2l_pinctrl_data r9a07g043_data = {
> >         .port_pins = rzg2l_gpio_names,
> >         .port_pin_configs = r9a07g043_gpio_configs,
> > +       .n_port_pin_configs = ARRAY_SIZE(r9a07g043_gpio_configs),
> >         .dedicated_pins = rzg2l_dedicated_pins.common,
> >         .n_port_pins = ARRAY_SIZE(r9a07g043_gpio_configs) * RZG2L_PINS_PER_PORT,
> >         .n_dedicated_pins = ARRAY_SIZE(rzg2l_dedicated_pins.common),
> > @@ -1525,6 +1527,7 @@ static struct rzg2l_pinctrl_data r9a07g043_data = {
> >  static struct rzg2l_pinctrl_data r9a07g044_data = {
> >         .port_pins = rzg2l_gpio_names,
>
> .port_pins is always rzg2l_gpio_names
>
Yes to avoid the huge array to be duplicated for other SoCs but bound
checking is done by  n_port_pins.

> >         .port_pin_configs = rzg2l_gpio_configs,
> > +       .n_port_pin_configs = ARRAY_SIZE(rzg2l_gpio_configs),
> >         .dedicated_pins = rzg2l_dedicated_pins.common,
> >         .n_port_pins = ARRAY_SIZE(rzg2l_gpio_names),
>
> I think this should have become
> ARRAY_SIZE(rzg2l_gpio_configs) * RZG2L_PINS_PER_PORT)
> when support for r9a07g043 was introduced.
>
Agreed, I will update it as part of v2.

> To avoid overflows when adding support for more SoCs, you can add a
> bunch of checks like
>
>     BUILD_BUG_ON(ARRAY_SIZE(r9a07g043_gpio_configs) *
> RZG2L_PINS_PER_PORT > ARRAY_SIZE(rzg2l_gpio_names))
>     BUILD_BUG_ON(ARRAY_SIZE(rzg2l_gpio_configs) * RZG2L_PINS_PER_PORT
> > ARRAY_SIZE(rzg2l_gpio_names))
>
OK, I'll add those checks in the probe as a separate patch.

Cheers,
Prabhakar