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

[Geert Uytterhoeven]

Hi Prabhakar,

On Mon, Jul 19, 2021 at 4:39 PM Lad Prabhakar
<prabhakar.mahadev-lad.rj@xxxxxxxxxxxxxx> 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@xxxxxxxxxxxxxx>
> Reviewed-by: Biju Das <biju.das.jz@xxxxxxxxxxxxxx>

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.

> +       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.

> +               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,

> +               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@xxxxxxxxxxxxxx

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