Re: [PATCH v2 2/5] can: rcar_canfd: Add support for RZ/G2L family

From: "Lad, Prabhakar" <prabhakar.csengg@gmail.com>
To: Philipp Zabel <p.zabel@pengutronix.de>
Cc: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>,
	Geert Uytterhoeven <geert+renesas@glider.be>,
	Rob Herring <robh+dt@kernel.org>,
	Fabrizio Castro <fabrizio.castro.jz@renesas.com>,
	Wolfgang Grandegger <wg@grandegger.com>,
	Marc Kleine-Budde <mkl@pengutronix.de>,
	"David S. Miller" <davem@davemloft.net>,
	Jakub Kicinski <kuba@kernel.org>,
	Michael Turquette <mturquette@baylibre.com>,
	Stephen Boyd <sboyd@kernel.org>,
	linux-can@vger.kernel.org, netdev <netdev@vger.kernel.org>,
	"open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" 
	<devicetree@vger.kernel.org>,
	linux-clk <linux-clk@vger.kernel.org>,
	LKML <linux-kernel@vger.kernel.org>,
	Linux-Renesas <linux-renesas-soc@vger.kernel.org>,
	Biju Das <biju.das.jz@bp.renesas.com>
Subject: Re: [PATCH v2 2/5] can: rcar_canfd: Add support for RZ/G2L family
Date: Tue, 20 Jul 2021 15:57:40 +0100	[thread overview]
Message-ID: <CA+V-a8vgQ1-tUOw2o3E39reZmnLGFVN_HEvZeH-x5cj01x-Pzg@mail.gmail.com> (raw)
In-Reply-To: <c8ec5fe0c8eb86898416edb7c68dcf0eeeaccf54.camel@pengutronix.de>

Hi Philipp,

Thank you for the review.

On Tue, Jul 20, 2021 at 11:23 AM Philipp Zabel <p.zabel@pengutronix.de> wrote:
>
> On Mon, 2021-07-19 at 15:38 +0100, Lad Prabhakar wrote:
> > CANFD block on RZ/G2L SoC is almost identical to one found on
> > R-Car Gen3 SoC's. On RZ/G2L SoC interrupt sources for each channel
> > are split into different sources and the IP doesn't divide (1/2)
> > CANFD clock within the IP.
> >
> > This patch adds compatible string for RZ/G2L family and registers
> > the irq handlers required for CANFD operation. IRQ numbers are now
> > fetched based on names instead of indices. For backward compatibility
> > on non RZ/G2L SoC's we fallback reading based on indices.
> >
> > Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
> > Reviewed-by: Biju Das <biju.das.jz@bp.renesas.com>
> > ---
> >  drivers/net/can/rcar/rcar_canfd.c | 178 ++++++++++++++++++++++++------
> >  1 file changed, 147 insertions(+), 31 deletions(-)
> >
> > diff --git a/drivers/net/can/rcar/rcar_canfd.c b/drivers/net/can/rcar/rcar_canfd.c
> > index 311e6ca3bdc4..d4affc002fb3 100644
> > --- a/drivers/net/can/rcar/rcar_canfd.c
> > +++ b/drivers/net/can/rcar/rcar_canfd.c
> > @@ -37,9 +37,15 @@
> [...]
> > +     if (gpriv->chip_id == RENESAS_RZG2L) {
> > +             gpriv->rstc1 = devm_reset_control_get_exclusive_by_index(&pdev->dev, 0);
> > +             if (IS_ERR(gpriv->rstc1)) {
> > +                     dev_err(&pdev->dev, "failed to get reset index 0\n");
>
> Please consider requesting the reset controls by name instead of by
> index. See also my reply to the binding patch.
>
Will do.

> > +                     return PTR_ERR(gpriv->rstc1);
> > +             }
> > +
> > +             err = reset_control_reset(gpriv->rstc1);
> > +             if (err)
> > +                     return err;
>
> I suggest to wait until after all resource requests have succeeded
> before triggering the resets, i.e. first get all reset controls and
> clocks, etc., and only then trigger resets, enable clocks, and so on.
>
> That way there will be no spurious resets in case of probe deferrals.
>
Agreed, will update the code.

Cheers,
Prabhakar

> regards
> Philipp