can: rcar_canfd: Add support for FD-Only mode

The RZ/{G2L,G3E} and R-Car Gen4 SoCs support additional CAN FD mode called
FD-only mode. In this mode, communication in Classical CAN frame format is
disabled.

Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>
Link: https://patch.msgid.link/20251126155911.320563-3-biju.das.jz@bp.renesas.com
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

diff --git a/drivers/net/can/rcar/rcar_canfd.c b/drivers/net/can/rcar/rcar_canfd.c
index 7895e1fdea1c6d572413e3fbf286bbfc371d4814..4a653d8978baf934d1bf30296153dac55902985a 100644 (file)
--- a/drivers/net/can/rcar/rcar_canfd.c
+++ b/drivers/net/can/rcar/rcar_canfd.c
@@ -472,6 +472,7 @@ struct rcar_canfd_global {
        unsigned long channels_mask;    /* Enabled channels mask */
        bool extclk;                    /* CANFD or Ext clock */
        bool fdmode;                    /* CAN FD or Classical CAN only mode */
+       bool fd_only_mode;              /* FD-Only mode for CAN-FD */
        struct reset_control *rstc1;
        struct reset_control *rstc2;
        const struct rcar_canfd_hw_info *info;
@@ -829,12 +830,20 @@ static int rcar_canfd_reset_controller(struct rcar_canfd_global *gpriv)
                                                         RCANFD_GEN4_FDCFG_FDOE);
                                rcar_canfd_set_bit_reg(&gpriv->fcbase[ch].cfdcfg,
                                                       RCANFD_GEN4_FDCFG_CLOE);
+                       } else if (gpriv->fd_only_mode) {
+                               rcar_canfd_clear_bit_reg(&gpriv->fcbase[ch].cfdcfg,
+                                                        RCANFD_GEN4_FDCFG_CLOE);
+                               rcar_canfd_set_bit_reg(&gpriv->fcbase[ch].cfdcfg,
+                                                      RCANFD_GEN4_FDCFG_FDOE);
                        } else {
                                rcar_canfd_clear_bit_reg(&gpriv->fcbase[ch].cfdcfg,
                                                         RCANFD_GEN4_FDCFG_FDOE);
                                rcar_canfd_clear_bit_reg(&gpriv->fcbase[ch].cfdcfg,
                                                         RCANFD_GEN4_FDCFG_CLOE);
                        }
+               } else if (gpriv->fd_only_mode) {
+                       rcar_canfd_set_bit_reg(&gpriv->fcbase[ch].cfdcfg,
+                                              RCANFD_GEN4_FDCFG_FDOE);
                }
        }
 
@@ -2140,6 +2149,9 @@ static int rcar_canfd_probe(struct platform_device *pdev)
        gpriv->fdmode = fdmode;
        gpriv->info = info;
 
+       if (of_property_read_bool(dev->of_node, "renesas,fd-only"))
+               gpriv->fd_only_mode = true; /* FD-Only mode for CAN-FD */
+
        gpriv->rstc1 = devm_reset_control_get_optional_exclusive(dev, "rstp_n");
        if (IS_ERR(gpriv->rstc1))
                return dev_err_probe(dev, PTR_ERR(gpriv->rstc1),
@@ -2239,7 +2251,7 @@ static int rcar_canfd_probe(struct platform_device *pdev)
        platform_set_drvdata(pdev, gpriv);
        dev_info(dev, "global operational state (%s clk, %s mode)\n",
                 gpriv->extclk ? "ext" : "canfd",
-                gpriv->fdmode ? "fd" : "classical");
+                gpriv->fdmode ? (gpriv->fd_only_mode ? "fd-only" : "fd") : "classical");
        return 0;
 
 fail_channel: