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

["Lad, Prabhakar" <prabhakar.csengg@gmail.com>]

Hi Geert,

Thank you for the review.

On Tue, Jul 20, 2021 at 11:31 AM Geert Uytterhoeven
<geert@linux-m68k.org> wrote:
>
> Hi Prabhakar,
>
> On Mon, Jul 19, 2021 at 4:39 PM Lad Prabhakar
> <prabhakar.mahadev-lad.rj@bp.renesas.com> 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>
>
> Thanks for your patch!
>
> > --- a/drivers/net/can/rcar/rcar_canfd.c
> > +++ b/drivers/net/can/rcar/rcar_canfd.c
> > @@ -37,9 +37,15 @@
> >  #include <linux/bitmap.h>
> >  #include <linux/bitops.h>
> >  #include <linux/iopoll.h>
> > +#include <linux/reset.h>
> >
> >  #define RCANFD_DRV_NAME                        "rcar_canfd"
> >
> > +enum rcanfd_chip_id {
> > +       RENESAS_RCAR_GEN3 = 0,
> > +       RENESAS_RZG2L,
> > +};
> > +
> >  /* Global register bits */
> >
> >  /* RSCFDnCFDGRMCFG */
> > @@ -513,6 +519,9 @@ struct rcar_canfd_global {
> >         enum rcar_canfd_fcanclk fcan;   /* CANFD or Ext clock */
> >         unsigned long channels_mask;    /* Enabled channels mask */
> >         bool fdmode;                    /* CAN FD or Classical CAN only mode */
> > +       struct reset_control *rstc1;     /* Pointer to reset source1 */
> > +       struct reset_control *rstc2;     /* Pointer to reset source2 */
>
> Are these comments helpful? IMHO they're stating the obvious.
>
No :D will drop those.

> > +       enum rcanfd_chip_id chip_id;
> >  };
> >
> >  /* CAN FD mode nominal rate constants */
> > @@ -1577,6 +1586,45 @@ static int rcar_canfd_channel_probe(struct rcar_canfd_global *gpriv, u32 ch,
> >         priv->can.clock.freq = fcan_freq;
> >         dev_info(&pdev->dev, "can_clk rate is %u\n", priv->can.clock.freq);
> >
> > +       if (gpriv->chip_id == RENESAS_RZG2L) {
> > +               char *irq_name;
> > +               int err_irq;
> > +               int tx_irq;
> > +
> > +               err_irq = platform_get_irq_byname(pdev, ch == 0 ? "can0_error" : "can1_error");
> > +               if (err_irq < 0) {
> > +                       err = err_irq;
> > +                       goto fail;
> > +               }
> > +
> > +               tx_irq = platform_get_irq_byname(pdev, ch == 0 ? "can0_tx" : "can1_tx");
> > +               if (tx_irq < 0) {
> > +                       err = tx_irq;
> > +                       goto fail;
> > +               }
> > +
> > +               irq_name = devm_kasprintf(&pdev->dev, GFP_KERNEL,
> > +                                         "canfd.chnerr%d", ch);
>
> if (!irq_name) {
>     ret = -ENOMEM;
>     goto fail;
> }
>
> > +               err = devm_request_irq(&pdev->dev, err_irq,
> > +                                      rcar_canfd_channel_interrupt, 0,
> > +                                      irq_name, gpriv);
> > +               if (err) {
> > +                       dev_err(&pdev->dev, "devm_request_irq CH Err(%d) failed, error %d\n",
> > +                               err_irq, err);
> > +                       goto fail;
> > +               }
> > +               irq_name = devm_kasprintf(&pdev->dev, GFP_KERNEL,
> > +                                         "canfd.chntx%d", ch);
>
> Likewise.
>
> > +               err = devm_request_irq(&pdev->dev, tx_irq,
> > +                                      rcar_canfd_channel_interrupt, 0,
> > +                                      irq_name, gpriv);
> > +               if (err) {
> > +                       dev_err(&pdev->dev, "devm_request_irq Tx (%d) failed, error %d\n",
> > +                               tx_irq, err);
> > +                       goto fail;
> > +               }
> > +       }
> > +
> >         if (gpriv->fdmode) {
> >                 priv->can.bittiming_const = &rcar_canfd_nom_bittiming_const;
> >                 priv->can.data_bittiming_const =
>
> > @@ -1649,27 +1700,64 @@ static int rcar_canfd_probe(struct platform_device *pdev)
> >         if (of_child && of_device_is_available(of_child))
> >                 channels_mask |= BIT(1);        /* Channel 1 */
> >
> > -       ch_irq = platform_get_irq(pdev, 0);
> > -       if (ch_irq < 0) {
> > -               err = ch_irq;
> > -               goto fail_dev;
> > -       }
> > +       if (chip_id == RENESAS_RCAR_GEN3) {
> > +               ch_irq = platform_get_irq_byname(pdev, "ch_int");
>
> platform_get_irq_byname_optional()?
> Unless you want to urge people to update their DTB.
>
Good point will change it to platform_get_irq_byname_optional().

> > +               if (ch_irq < 0) {
> > +                       /* For backward compatibility get irq by index */
> > +                       ch_irq = platform_get_irq(pdev, 0);
> > +                       if (ch_irq < 0)
> > +                               return ch_irq;
> > +               }
> >
> > -       g_irq = platform_get_irq(pdev, 1);
> > -       if (g_irq < 0) {
> > -               err = g_irq;
> > -               goto fail_dev;
> > +               g_irq = platform_get_irq_byname(pdev, "g_int");
>
> Likewise,
>
agreed

Cheers,
Prabhakar

> > +               if (g_irq < 0) {
> > +                       /* For backward compatibility get irq by index */
> > +                       g_irq = platform_get_irq(pdev, 1);
> > +                       if (g_irq < 0)
> > +                               return g_irq;
> > +               }
> > +       } else {
> > +               g_irq = platform_get_irq_byname(pdev, "g_error");
> > +               if (g_irq < 0)
> > +                       return g_irq;
> > +
> > +               g_rx_irq = platform_get_irq_byname(pdev, "g_rx_fifo");
> > +               if (g_rx_irq < 0)
> > +                       return g_rx_irq;
> >         }
> >
>
> Gr{oetje,eeting}s,
>
>                         Geert
>
> --
> Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org
>
> In personal conversations with technical people, I call myself a hacker. But
> when I'm talking to journalists I just say "programmer" or something like that.
>                                 -- Linus Torvalds