[PATCH v2 0/8] can: rcar_canfd: Add support for Renesas RZ/G3S

[PATCH v2 0/8] can: rcar_canfd: Add support for Renesas RZ/G3S

[Claudiu Beznea]

From: Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>

Hi,

Series adds CAN support for the Renesas RZ/G3S SoC. Along with it a typo
fix patch was added on the CAN driver.

Thank you,
Claudiu

Changes in v2:
- collected tags
- addressed sashiko review comments

Claudiu Beznea (8):
  clk: r9a08g045-cpg: Add clocks and resets for CAN-FD
  dt-bindings: can: renesas,rcar-canfd: Document RZ/G3S SoC
  can: rcar_canfd: Fix typos in macro names
  can: rcar_canfd: Allow the CAN FD clock to be sourced from fck
  can: rcar_canfd: Do not set registers selecting the CAN mode
  can: rcar_canfd: Add support for Renesas RZ/G3S
  arm64: dts: renesas: r9a08g045: Add CAN-FD node
  arm64: dts: renesas: rzg3s-smarc: Enable CAN-FD

 .../bindings/net/can/renesas,rcar-canfd.yaml  | 20 +++++-
 arch/arm64/boot/dts/renesas/r9a08g045.dtsi    | 39 +++++++++++
 .../boot/dts/renesas/rzg3s-smarc-switches.h   | 12 ++++
 arch/arm64/boot/dts/renesas/rzg3s-smarc.dtsi  | 46 +++++++++++++
 drivers/clk/renesas/r9a08g045-cpg.c           |  9 +++
 drivers/net/can/rcar/rcar_canfd.c             | 64 +++++++++++++++----
 6 files changed, 177 insertions(+), 13 deletions(-)

-- 
2.43.0

[PATCH v2 1/8] clk: r9a08g045-cpg: Add clocks and resets for CAN-FD

[Claudiu Beznea]

From: Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>

Renesas RZ/G3S SoC has a CAN-FD IP. Add clocks and resets for it.

Reviewed-by: Biju Das <biju.das.jz@bp.renesas.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>
---

Changes in v2:
- used R9A08G045_CLK_P4 ID for P4 clock
- still collected the tags; Biju, Geert, please let me know if you consider
  otherwise

 drivers/clk/renesas/r9a08g045-cpg.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/drivers/clk/renesas/r9a08g045-cpg.c b/drivers/clk/renesas/r9a08g045-cpg.c
index 624fc5e6fb24..ea2a6a71aebd 100644
--- a/drivers/clk/renesas/r9a08g045-cpg.c
+++ b/drivers/clk/renesas/r9a08g045-cpg.c
@@ -77,6 +77,7 @@ enum clk_ids {
 	CLK_SEL_PLL4,
 	CLK_P1_DIV2,
 	CLK_P3_DIV2,
+	CLK_P4_DIV2,
 	CLK_SD0_DIV4,
 	CLK_SD1_DIV4,
 	CLK_SD2_DIV4,
@@ -172,6 +173,8 @@ static const struct cpg_core_clk r9a08g045_core_clks[] __initconst = {
 	DEF_G3S_DIV("P3", R9A08G045_CLK_P3, CLK_PLL3_DIV2_4, DIVPL3C, G3S_DIVPL3C_STS,
 		    dtable_1_32, 0, 0, 0, NULL),
 	DEF_FIXED("P3_DIV2", CLK_P3_DIV2, R9A08G045_CLK_P3, 1, 2),
+	DEF_FIXED("P4", R9A08G045_CLK_P4, CLK_PLL2_DIV2, 1, 5),
+	DEF_FIXED("P4_DIV2", CLK_P4_DIV2, R9A08G045_CLK_P4, 1, 2),
 	DEF_FIXED("P5", R9A08G045_CLK_P5, CLK_PLL2_DIV2, 1, 4),
 	DEF_FIXED("ZT", R9A08G045_CLK_ZT, CLK_PLL3_DIV2_8, 1, 1),
 	DEF_FIXED("S0", R9A08G045_CLK_S0, CLK_SEL_PLL4, 1, 2),
@@ -274,6 +277,10 @@ static const struct rzg2l_mod_clk r9a08g045_mod_clks[] = {
 					MSTOP(BUS_MCPU2, BIT(5))),
 	DEF_MOD("scif5_clk_pck",	R9A08G045_SCIF5_CLK_PCK, R9A08G045_CLK_P0, 0x584, 5,
 					MSTOP(BUS_MCPU3, BIT(4))),
+	DEF_MOD("canfd_pclk",		R9A08G045_CANFD_PCLK, CLK_P4_DIV2, 0x594, 0,
+					MSTOP(BUS_MCPU2, BIT(9))),
+	DEF_MOD("canfd_clk_ram",	R9A08G045_CANFD_CLK_RAM, R9A08G045_CLK_P4, 0x594, 1,
+					MSTOP(BUS_MCPU2, BIT(9))),
 	DEF_MOD("gpio_hclk",		R9A08G045_GPIO_HCLK, R9A08G045_OSCCLK, 0x598, 0,
 					MSTOP(BUS_PERI_CPU, BIT(6))),
 	DEF_MOD("adc_adclk",		R9A08G045_ADC_ADCLK, R9A08G045_CLK_TSU, 0x5a8, 0,
@@ -324,6 +331,8 @@ static const struct rzg2l_reset r9a08g045_resets[] = {
 	DEF_RST(R9A08G045_SCIF3_RST_SYSTEM_N, 0x884, 3),
 	DEF_RST(R9A08G045_SCIF4_RST_SYSTEM_N, 0x884, 4),
 	DEF_RST(R9A08G045_SCIF5_RST_SYSTEM_N, 0x884, 5),
+	DEF_RST(R9A08G045_CANFD_RSTP_N, 0x894, 0),
+	DEF_RST(R9A08G045_CANFD_RSTC_N, 0x894, 1),
 	DEF_RST(R9A08G045_GPIO_RSTN, 0x898, 0),
 	DEF_RST(R9A08G045_GPIO_PORT_RESETN, 0x898, 1),
 	DEF_RST(R9A08G045_GPIO_SPARE_RESETN, 0x898, 2),
-- 
2.43.0

Re: [PATCH v2 1/8] clk: r9a08g045-cpg: Add clocks and resets for CAN-FD

[Geert Uytterhoeven]

Hi Claudiu,

On Thu, 9 Jul 2026 at 20:23, Claudiu Beznea
<claudiu.beznea+renesas@tuxon.dev> wrote:
> From: Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>
>
> Renesas RZ/G3S SoC has a CAN-FD IP. Add clocks and resets for it.
>
> Reviewed-by: Biju Das <biju.das.jz@bp.renesas.com>
> Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
> Signed-off-by: Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>
> ---
>
> Changes in v2:
> - used R9A08G045_CLK_P4 ID for P4 clock
> - still collected the tags; Biju, Geert, please let me know if you consider
>   otherwise

Thanks, will queue this one instead of v1 in renesas-clk for v7.3.

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

[PATCH v2 2/8] dt-bindings: can: renesas,rcar-canfd: Document RZ/G3S SoC

[Claudiu Beznea]

From: Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>

The CAN FD controller found on the Renesas RZ/G3S SoC is largely compatible
with the variant present on the RZ/G3E SoC. The main differences are:
- the RZ/G3S provides only two CAN FD channels
- the RZ/G3S supports only CAN FD operation; the Channel n CAN FD
  Configuration Register does not implement the bits used to select
  classical CAN-only mode (bit 30) or CAN FD-only mode (bit 28);
  consequently, bit 31 (CAN FD Frame Distinction Enable) of the same
  register is also not implemented
- some bits in several registers (mainly reserved or status bits) are
  read-write on the RZ/G3S but read-only on the RZ/G3E; their behavior is
  otherwise identical: the bits read back as 0 on both SoCs and software
  is allowed to write only 0 to them on the RZ/G3S
- the RZ/G3S provides 128 acceptance filters, compared to 64 on the
  RZ/G3E
- the RZ/G3S can use PCLK clock as the CAN FD clock source through an
  internal clock divider, while also supporting an external CAN FD clock
  source

Since:
- the SoC clock generator provides to the CAN IP only the peripheral and
  the RAM clocks
- when sourced from the peripheral clock, the CAN-FD clock is obtained
  inside the IP itself by dividing the peripheral clock
- the assigned-clocks and assigned-clock-rates properties are specific to
  the CAN-FD clock
the assigned-clocks and assigned-clock-rates properties were dropped from
the required properties list of the Renesas RZ/G3S SoC.

Add documentation for the Renesas RZ/G3S SoC.

Signed-off-by: Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>
---

Changes in v2:
- forbid renesas,no-can-fd and renesas,fd-only since the IP supports
  only CAN-FD; for this didn't collect Biju's tag

 .../bindings/net/can/renesas,rcar-canfd.yaml  | 20 +++++++++++++++++--
 1 file changed, 18 insertions(+), 2 deletions(-)

diff --git a/Documentation/devicetree/bindings/net/can/renesas,rcar-canfd.yaml b/Documentation/devicetree/bindings/net/can/renesas,rcar-canfd.yaml
index b9d9dd7a7967..43ebfd73f5bf 100644
--- a/Documentation/devicetree/bindings/net/can/renesas,rcar-canfd.yaml
+++ b/Documentation/devicetree/bindings/net/can/renesas,rcar-canfd.yaml
@@ -13,6 +13,7 @@ properties:
   compatible:
     oneOf:
       - enum:
+          - renesas,r9a08g045-canfd        # RZ/G3S
           - renesas,r9a09g047-canfd        # RZ/G3E
           - renesas,r9a09g077-canfd        # RZ/T2H
 
@@ -185,8 +186,6 @@ required:
   - clocks
   - clock-names
   - power-domains
-  - assigned-clocks
-  - assigned-clock-rates
   - channel0
   - channel1
 
@@ -198,6 +197,7 @@ allOf:
         compatible:
           contains:
             enum:
+              - renesas,r9a08g045-canfd
               - renesas,rzg2l-canfd
     then:
       properties:
@@ -267,6 +267,7 @@ allOf:
           contains:
             enum:
               - renesas,r9a09g077-canfd
+              - renesas,r9a08g045-canfd
               - renesas,rcar-gen3-canfd
               - renesas,rzg2l-canfd
     then:
@@ -330,6 +331,7 @@ allOf:
         compatible:
           contains:
             enum:
+              - renesas,r9a08g045-canfd
               - renesas,r9a09g047-canfd
               - renesas,rzg2l-canfd
     then:
@@ -350,6 +352,20 @@ allOf:
       properties:
         reset-names: false
 
+  - if:
+      properties:
+        compatible:
+          contains:
+            const: renesas,r9a08g045-canfd
+    then:
+      properties:
+        renesas,no-can-fd: false
+        renesas,fd-only: false
+    else:
+      required:
+        - assigned-clocks
+        - assigned-clock-rates
+
 unevaluatedProperties: false
 
 examples:
-- 
2.43.0

Re: [PATCH v2 2/8] dt-bindings: can: renesas,rcar-canfd: Document RZ/G3S SoC

[Geert Uytterhoeven]

Hi Claudiu,

On Thu, 9 Jul 2026 at 20:23, Claudiu Beznea
<claudiu.beznea+renesas@tuxon.dev> wrote:
> From: Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>
>
> The CAN FD controller found on the Renesas RZ/G3S SoC is largely compatible
> with the variant present on the RZ/G3E SoC. The main differences are:
> - the RZ/G3S provides only two CAN FD channels
> - the RZ/G3S supports only CAN FD operation; the Channel n CAN FD
>   Configuration Register does not implement the bits used to select
>   classical CAN-only mode (bit 30) or CAN FD-only mode (bit 28);
>   consequently, bit 31 (CAN FD Frame Distinction Enable) of the same
>   register is also not implemented
> - some bits in several registers (mainly reserved or status bits) are
>   read-write on the RZ/G3S but read-only on the RZ/G3E; their behavior is
>   otherwise identical: the bits read back as 0 on both SoCs and software
>   is allowed to write only 0 to them on the RZ/G3S
> - the RZ/G3S provides 128 acceptance filters, compared to 64 on the
>   RZ/G3E
> - the RZ/G3S can use PCLK clock as the CAN FD clock source through an
>   internal clock divider, while also supporting an external CAN FD clock
>   source
>
> Since:
> - the SoC clock generator provides to the CAN IP only the peripheral and
>   the RAM clocks
> - when sourced from the peripheral clock, the CAN-FD clock is obtained
>   inside the IP itself by dividing the peripheral clock
> - the assigned-clocks and assigned-clock-rates properties are specific to
>   the CAN-FD clock
> the assigned-clocks and assigned-clock-rates properties were dropped from
> the required properties list of the Renesas RZ/G3S SoC.
>
> Add documentation for the Renesas RZ/G3S SoC.
>
> Signed-off-by: Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>
> ---
>
> Changes in v2:
> - forbid renesas,no-can-fd and renesas,fd-only since the IP supports
>   only CAN-FD; for this didn't collect Biju's tag

Thanks for the update!

> --- a/Documentation/devicetree/bindings/net/can/renesas,rcar-canfd.yaml
> +++ b/Documentation/devicetree/bindings/net/can/renesas,rcar-canfd.yaml
> @@ -267,6 +267,7 @@ allOf:
>            contains:
>              enum:
>                - renesas,r9a09g077-canfd
> +              - renesas,r9a08g045-canfd

Please preserve sort order (alphabetical).

>                - renesas,rcar-gen3-canfd
>                - renesas,rzg2l-canfd
>      then:

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

[PATCH v2 3/8] can: rcar_canfd: Fix typos in macro names

[Claudiu Beznea]

From: Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>

The bits 1..0 of the Channel n Control Register are named CHMDC (Channel
Mode select). Fix typos in macro names by replacing DMC with MDC.

Reviewed-by: Biju Das <biju.das.jz@bp.renesas.com>
Signed-off-by: Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>
---

Changes in v2:
- collected tags

 drivers/net/can/rcar/rcar_canfd.c | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/drivers/net/can/rcar/rcar_canfd.c b/drivers/net/can/rcar/rcar_canfd.c
index 4ee108abffb8..879f31c97276 100644
--- a/drivers/net/can/rcar/rcar_canfd.c
+++ b/drivers/net/can/rcar/rcar_canfd.c
@@ -132,9 +132,9 @@
 #define RCANFD_CCTR_BEIE		BIT(8)
 #define RCANFD_CCTR_CSLPR		BIT(2)
 #define RCANFD_CCTR_CHMDC_MASK		(0x3)
-#define RCANFD_CCTR_CHDMC_COPM		(0x0)
-#define RCANFD_CCTR_CHDMC_CRESET	(0x1)
-#define RCANFD_CCTR_CHDMC_CHLT		(0x2)
+#define RCANFD_CCTR_CHMDC_COPM		(0x0)
+#define RCANFD_CCTR_CHMDC_CRESET	(0x1)
+#define RCANFD_CCTR_CHMDC_CHLT		(0x2)
 
 /* RSCFDnCFDCmSTS / RSCFDnCmSTS */
 #define RCANFD_CSTS_COMSTS		BIT(7)
@@ -828,7 +828,7 @@ static int rcar_canfd_reset_controller(struct rcar_canfd_global *gpriv)
 
 		rcar_canfd_update_bit(gpriv->base, RCANFD_CCTR(ch),
 				      RCANFD_CCTR_CHMDC_MASK,
-				      RCANFD_CCTR_CHDMC_CRESET);
+				      RCANFD_CCTR_CHMDC_CRESET);
 
 		/* Ensure Channel reset mode */
 		err = readl_poll_timeout((gpriv->base + RCANFD_CSTS(ch)), sts,
@@ -1504,7 +1504,7 @@ static int rcar_canfd_start(struct net_device *ndev)
 
 	/* Set channel to Operational mode */
 	rcar_canfd_update_bit(priv->base, RCANFD_CCTR(ch),
-			      RCANFD_CCTR_CHMDC_MASK, RCANFD_CCTR_CHDMC_COPM);
+			      RCANFD_CCTR_CHMDC_MASK, RCANFD_CCTR_CHMDC_COPM);
 
 	/* Verify channel mode change */
 	err = readl_poll_timeout((priv->base + RCANFD_CSTS(ch)), sts,
@@ -1578,7 +1578,7 @@ static void rcar_canfd_stop(struct net_device *ndev)
 
 	/* Transition to channel reset mode  */
 	rcar_canfd_update_bit(priv->base, RCANFD_CCTR(ch),
-			      RCANFD_CCTR_CHMDC_MASK, RCANFD_CCTR_CHDMC_CRESET);
+			      RCANFD_CCTR_CHMDC_MASK, RCANFD_CCTR_CHMDC_CRESET);
 
 	/* Check Channel reset mode */
 	err = readl_poll_timeout((priv->base + RCANFD_CSTS(ch)), sts,
-- 
2.43.0

[PATCH v2 4/8] can: rcar_canfd: Allow the CAN FD clock to be sourced from fck

[Claudiu Beznea]

From: Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>

On the Renesas RZ/G3S, the CAN FD clock can be sourced either from fck
(the peripheral clock) or from an external clock (can_clk). When fck is
used, it is divided internally by the CAN FD controller.

Adjust the existing canfd clock handling code to support the RZ/G3S CAN.

The existing struct rcar_canfd_hw_info instances were updated to address
the request in the Link discussion.

Link: https://lore.kernel.org/all/1d9719e3-10ff-4cd8-b729-55fea93c37ce@wanadoo.fr
Signed-off-by: Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>
---

Changes in v2:
- changed the logic to request canfd only if info->fcan_pclk and contrary
  get the fcan clock from pclk; for this didn't collect the Rb tag

 drivers/net/can/rcar/rcar_canfd.c | 22 +++++++++++++++++-----
 1 file changed, 17 insertions(+), 5 deletions(-)

diff --git a/drivers/net/can/rcar/rcar_canfd.c b/drivers/net/can/rcar/rcar_canfd.c
index 879f31c97276..b66f72de46c9 100644
--- a/drivers/net/can/rcar/rcar_canfd.c
+++ b/drivers/net/can/rcar/rcar_canfd.c
@@ -444,6 +444,7 @@ struct rcar_canfd_hw_info {
 	unsigned ch_interface_mode:1;	/* Has channel interface mode */
 	unsigned shared_can_regs:1;	/* Has shared classical can registers */
 	unsigned external_clk:1;	/* Has external clock */
+	unsigned fcan_pclk:1;		/* Has fcan sourced from pclk. */
 };
 
 /* Channel priv data */
@@ -617,6 +618,7 @@ static const struct rcar_canfd_hw_info rcar_gen3_hw_info = {
 	.ch_interface_mode = 0,
 	.shared_can_regs = 0,
 	.external_clk = 1,
+	.fcan_pclk = 0,
 };
 
 static const struct rcar_canfd_hw_info rcar_gen4_hw_info = {
@@ -634,6 +636,7 @@ static const struct rcar_canfd_hw_info rcar_gen4_hw_info = {
 	.ch_interface_mode = 1,
 	.shared_can_regs = 1,
 	.external_clk = 1,
+	.fcan_pclk = 0,
 };
 
 static const struct rcar_canfd_hw_info rzg2l_hw_info = {
@@ -651,6 +654,7 @@ static const struct rcar_canfd_hw_info rzg2l_hw_info = {
 	.ch_interface_mode = 0,
 	.shared_can_regs = 0,
 	.external_clk = 1,
+	.fcan_pclk = 0,
 };
 
 static const struct rcar_canfd_hw_info r9a09g047_hw_info = {
@@ -668,6 +672,7 @@ static const struct rcar_canfd_hw_info r9a09g047_hw_info = {
 	.ch_interface_mode = 1,
 	.shared_can_regs = 1,
 	.external_clk = 0,
+	.fcan_pclk = 0,
 };
 
 static const struct rcar_canfd_hw_info r9a09g077_hw_info = {
@@ -685,6 +690,7 @@ static const struct rcar_canfd_hw_info r9a09g077_hw_info = {
 	.ch_interface_mode = 1,
 	.shared_can_regs = 1,
 	.external_clk = 1,
+	.fcan_pclk = 0,
 };
 
 /* Helper functions */
@@ -2191,13 +2197,19 @@ static int rcar_canfd_probe(struct platform_device *pdev)
 	 */
 	gpriv->can_clk = devm_clk_get(dev, "can_clk");
 	if (IS_ERR(gpriv->can_clk) || (clk_get_rate(gpriv->can_clk) == 0)) {
-		gpriv->can_clk = devm_clk_get(dev, "canfd");
-		if (IS_ERR(gpriv->can_clk))
-			return dev_err_probe(dev, PTR_ERR(gpriv->can_clk),
-					     "cannot get canfd clock\n");
+		if (info->fcan_pclk) {
+			fcan_freq = clk_get_rate(gpriv->clkp);
+		} else {
+			gpriv->can_clk = devm_clk_get(dev, "canfd");
+			if (IS_ERR(gpriv->can_clk))
+				return dev_err_probe(dev, PTR_ERR(gpriv->can_clk),
+						     "cannot get canfd clock\n");
+
+			fcan_freq = clk_get_rate(gpriv->can_clk);
+		}
 
 		/* CANFD clock may be further divided within the IP */
-		fcan_freq = clk_get_rate(gpriv->can_clk) / info->postdiv;
+		fcan_freq /= info->postdiv;
 	} else {
 		fcan_freq = clk_get_rate(gpriv->can_clk);
 		gpriv->extclk = gpriv->info->external_clk;
-- 
2.43.0

Re: [PATCH v2 4/8] can: rcar_canfd: Allow the CAN FD clock to be sourced from fck

[sashiko-bot]

Thank you for your contribution! Sashiko AI review found 2 potential issue(s) to consider:

New issues:
- [High] Unhandled ERR_PTR dereference leading to kernel panic in clock API.

Pre-existing issues:
- [High] Use-After-Free and Double Free on probe error path.
--

--- Patch [4]: [PATCH v2 4/8] can: rcar_canfd: Allow the CAN FD clock to be sourced from fck ---
commit 4210af3a91e163ec149ddcdedbbe130decc7d427
Author: Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>

can: rcar_canfd: Allow the CAN FD clock to be sourced from fck

Adjust the existing canfd clock handling code to support the RZ/G3S CAN.
When fck is used, it is divided internally by the CAN FD controller.

Link: https://lore.kernel.org/all/1d9719e3-10ff-4cd8-b729-55fea93c37ce@wanadoo.fr

> diff --git a/drivers/net/can/rcar/rcar_canfd.c b/drivers/net/can/rcar/rcar_canfd.c
> index b40ae5998c1da..0283620ebcf8d 100644
> --- a/drivers/net/can/rcar/rcar_canfd.c
> +++ b/drivers/net/can/rcar/rcar_canfd.c
[ ... ]
> @@ -2190,13 +2196,19 @@ static int rcar_canfd_probe(struct platform_device *pdev)
>  	 */
>  	gpriv->can_clk = devm_clk_get(dev, "can_clk");
>  	if (IS_ERR(gpriv->can_clk) || (clk_get_rate(gpriv->can_clk) == 0)) {
> -		gpriv->can_clk = devm_clk_get(dev, "canfd");
> -		if (IS_ERR(gpriv->can_clk))
> -			return dev_err_probe(dev, PTR_ERR(gpriv->can_clk),
> -					     "cannot get canfd clock\n");
> +		if (info->fcan_pclk) {
> +			fcan_freq = clk_get_rate(gpriv->clkp);
> +		} else {

[Severity: High]
If info->fcan_pclk is true and can_clk is not present, gpriv->can_clk
retains an ERR_PTR value here.

When the interface is brought up later, rcar_canfd_open() calls
clk_prepare_enable(gpriv->can_clk):

drivers/net/can/rcar/rcar_canfd.c:rcar_canfd_open() {
    ...
	/* Peripheral clock is already enabled in probe */
	err = clk_prepare_enable(gpriv->can_clk);
	if (err) {
    ...
}

Because clk_prepare_enable() checks for NULL but not for IS_ERR(), will
this dereference the error pointer and cause a kernel panic? Should
gpriv->can_clk be explicitly set to NULL when using the fcan_pclk fallback?

> +			gpriv->can_clk = devm_clk_get(dev, "canfd");
> +			if (IS_ERR(gpriv->can_clk))
> +				return dev_err_probe(dev, PTR_ERR(gpriv->can_clk),
> +						     "cannot get canfd clock\n");
> +
> +			fcan_freq = clk_get_rate(gpriv->can_clk);
> +		}
>  
>  		/* CANFD clock may be further divided within the IP */
> -		fcan_freq = clk_get_rate(gpriv->can_clk) / info->postdiv;
> +		fcan_freq /= info->postdiv;
>  	} else {
>  		fcan_freq = clk_get_rate(gpriv->can_clk);
>  		gpriv->extclk = gpriv->info->external_clk;

[Severity: High]
This is a pre-existing issue, but there is a use-after-free and double
free on the probe error path.

In rcar_canfd_channel_probe():

drivers/net/can/rcar/rcar_canfd.c:rcar_canfd_channel_probe() {
    ...
	gpriv->ch[priv->channel] = priv;
	err = register_candev(ndev);
	if (err) {
		dev_err(dev, "register_candev() failed: %pe\n", ERR_PTR(err));
		goto fail_candev;
	}
    ...
fail_candev:
	netif_napi_del(&priv->napi);
fail:
	free_candev(ndev);
	return err;
}

If register_candev() fails, ndev (which contains priv) is freed via
free_candev(), but the global pointer gpriv->ch[priv->channel] is not
cleared.

Then in the parent rcar_canfd_probe(), the error handler cleans up:

drivers/net/can/rcar/rcar_canfd.c:rcar_canfd_probe() {
    ...
fail_channel:
	for_each_set_bit(ch, &gpriv->channels_mask, info->max_channels)
		rcar_canfd_channel_remove(gpriv, ch);
    ...
}

And rcar_canfd_channel_remove() bypasses the NULL check:

drivers/net/can/rcar/rcar_canfd.c:rcar_canfd_channel_remove() {
	struct rcar_canfd_channel *priv = gpriv->ch[ch];

	if (priv) {
		unregister_candev(priv->ndev);
		netif_napi_del(&priv->napi);
		free_candev(priv->ndev);
	}
}

Will this cause unregister_candev() to be called on an already freed device,
followed by a second free_candev()?

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260709182332.876408-1-claudiu.beznea+renesas@tuxon.dev?part=4

[PATCH v2 5/8] can: rcar_canfd: Do not set registers selecting the CAN mode

[Claudiu Beznea]

From: Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>

The bits 30 (classical CAN-only mode) and 28 (FD-only enable) of the
Channel n CAN-FD Configuration Register of the Renesas RZ/G3S SoC are not
available. The IP supports only CAN-FD mode. RZ/G3S HW manual (revision
1.30) specify the bits are read as zero and the write value should always
be zero.

Add the mode_select_na flag in struct rcar_canfd_hw_info to cover RZ/G3S
and avoid writing to unavailable bits.

The existing struct rcar_canfd_hw_info instances were updated to address
the request in the Link discussion.

Commit prepares for the addition of the Renesas RZ/G3S SoC.

Link: https://lore.kernel.org/all/1d9719e3-10ff-4cd8-b729-55fea93c37ce@wanadoo.fr
Reviewed-by: Biju Das <biju.das.jz@bp.renesas.com>
Signed-off-by: Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>
---

Changes in v2:
- collected the tags
- updated patch description to reflect this is a preparatory commit

 drivers/net/can/rcar/rcar_canfd.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/drivers/net/can/rcar/rcar_canfd.c b/drivers/net/can/rcar/rcar_canfd.c
index b66f72de46c9..112aa9024487 100644
--- a/drivers/net/can/rcar/rcar_canfd.c
+++ b/drivers/net/can/rcar/rcar_canfd.c
@@ -445,6 +445,7 @@ struct rcar_canfd_hw_info {
 	unsigned shared_can_regs:1;	/* Has shared classical can registers */
 	unsigned external_clk:1;	/* Has external clock */
 	unsigned fcan_pclk:1;		/* Has fcan sourced from pclk. */
+	unsigned mode_select_na:1;	/* Has no bits for selecting the mode. */
 };
 
 /* Channel priv data */
@@ -619,6 +620,7 @@ static const struct rcar_canfd_hw_info rcar_gen3_hw_info = {
 	.shared_can_regs = 0,
 	.external_clk = 1,
 	.fcan_pclk = 0,
+	.mode_select_na = 0,
 };
 
 static const struct rcar_canfd_hw_info rcar_gen4_hw_info = {
@@ -637,6 +639,7 @@ static const struct rcar_canfd_hw_info rcar_gen4_hw_info = {
 	.shared_can_regs = 1,
 	.external_clk = 1,
 	.fcan_pclk = 0,
+	.mode_select_na = 0,
 };
 
 static const struct rcar_canfd_hw_info rzg2l_hw_info = {
@@ -655,6 +658,7 @@ static const struct rcar_canfd_hw_info rzg2l_hw_info = {
 	.shared_can_regs = 0,
 	.external_clk = 1,
 	.fcan_pclk = 0,
+	.mode_select_na = 0,
 };
 
 static const struct rcar_canfd_hw_info r9a09g047_hw_info = {
@@ -673,6 +677,7 @@ static const struct rcar_canfd_hw_info r9a09g047_hw_info = {
 	.shared_can_regs = 1,
 	.external_clk = 0,
 	.fcan_pclk = 0,
+	.mode_select_na = 0,
 };
 
 static const struct rcar_canfd_hw_info r9a09g077_hw_info = {
@@ -691,6 +696,7 @@ static const struct rcar_canfd_hw_info r9a09g077_hw_info = {
 	.shared_can_regs = 1,
 	.external_clk = 1,
 	.fcan_pclk = 0,
+	.mode_select_na = 0,
 };
 
 /* Helper functions */
@@ -846,6 +852,9 @@ static int rcar_canfd_reset_controller(struct rcar_canfd_global *gpriv)
 		}
 
 		/* Set the controller into appropriate mode */
+		if (gpriv->info->mode_select_na)
+			continue;
+
 		if (gpriv->info->ch_interface_mode) {
 			/* Do not set CLOE and FDOE simultaneously */
 			if (!gpriv->fdmode) {
-- 
2.43.0

[PATCH v2 6/8] can: rcar_canfd: Add support for Renesas RZ/G3S

[Claudiu Beznea]

From: Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>

Add support for Renesas RZ/G3S

The Renesas RZ/G3S CAN-FD controller is largely compatible with the
variant found on the Renesas RZ/G3E. The main differences are:
- the RZ/G3S provides 128 acceptance filters
- the RZ/G3S supports only two channels
- the RZ/G3S supports only CAN-FD operation and does not implement the
  bits used to select between classical CAN-only and CAN FD-only modes.
- the RZ/G3S includes an internal divider that allows the peripheral
  clock to be used as the CAN FD clock source.

Add support for the Renesas RZ/G3S.

Reviewed-by: Biju Das <biju.das.jz@bp.renesas.com>
Signed-off-by: Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>
---

Changes in v2:
- initialized shared_global_irqs = 0 for RZ/G3S, to follow the request
  from https://lore.kernel.org/all/1d9719e3-10ff-4cd8-b729-55fea93c37ce@wanadoo.fr
- collected tags

 drivers/net/can/rcar/rcar_canfd.c | 21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)

diff --git a/drivers/net/can/rcar/rcar_canfd.c b/drivers/net/can/rcar/rcar_canfd.c
index 112aa9024487..a3a1ac10fe7a 100644
--- a/drivers/net/can/rcar/rcar_canfd.c
+++ b/drivers/net/can/rcar/rcar_canfd.c
@@ -661,6 +661,26 @@ static const struct rcar_canfd_hw_info rzg2l_hw_info = {
 	.mode_select_na = 0,
 };
 
+static const struct rcar_canfd_hw_info r9a08g045_hw_info = {
+	.nom_bittiming = &rcar_canfd_gen4_nom_bittiming_const,
+	.data_bittiming = &rcar_canfd_gen4_data_bittiming_const,
+	.tdc_const = &rcar_canfd_gen4_tdc_const,
+	.regs = &rcar_gen4_regs,
+	.sh = &rcar_gen4_shift_data,
+	.rnc_field_width = 16,
+	.max_aflpn = 127,
+	.max_cftml = 31,
+	.max_channels = 2,
+	.postdiv = 2,
+	.shared_global_irqs = 0,
+	.multi_channel_irqs = 1,
+	.ch_interface_mode = 1,
+	.shared_can_regs = 1,
+	.external_clk = 1,
+	.fcan_pclk = 1,
+	.mode_select_na = 1,
+};
+
 static const struct rcar_canfd_hw_info r9a09g047_hw_info = {
 	.nom_bittiming = &rcar_canfd_gen4_nom_bittiming_const,
 	.data_bittiming = &rcar_canfd_gen4_data_bittiming_const,
@@ -2383,6 +2403,7 @@ static DEFINE_SIMPLE_DEV_PM_OPS(rcar_canfd_pm_ops, rcar_canfd_suspend,
 
 static const __maybe_unused struct of_device_id rcar_canfd_of_table[] = {
 	{ .compatible = "renesas,r8a779a0-canfd", .data = &rcar_gen4_hw_info },
+	{ .compatible = "renesas,r9a08g045-canfd", .data = &r9a08g045_hw_info },
 	{ .compatible = "renesas,r9a09g047-canfd", .data = &r9a09g047_hw_info },
 	{ .compatible = "renesas,r9a09g077-canfd", .data = &r9a09g077_hw_info },
 	{ .compatible = "renesas,rcar-gen3-canfd", .data = &rcar_gen3_hw_info },
-- 
2.43.0

Re: [PATCH v2 6/8] can: rcar_canfd: Add support for Renesas RZ/G3S

[sashiko-bot]

Thank you for your contribution! Sashiko AI review found 2 potential issue(s) to consider:

New issues:
- [Low] The `max_aflpn` field is incorrectly configured to 127, modeling 2048 acceptance filter rules instead of the hardware's 128 rules.

Pre-existing issues:
- [High] Silent data truncation of received CAN FD frames when the interface is configured in Classical CAN mode.
--

--- Patch [6]: [PATCH v2 6/8] can: rcar_canfd: Add support for Renesas RZ/G3S ---
commit dd7ffbc8ce8271e811932ba34aecef0183db4270
Author: Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>

can: rcar_canfd: Add support for Renesas RZ/G3S

The Renesas RZ/G3S CAN-FD controller is largely compatible with the
variant found on the Renesas RZ/G3E. The main differences are:
- the RZ/G3S provides 128 acceptance filters
- the RZ/G3S supports only two channels
- the RZ/G3S supports only CAN-FD operation and does not implement the
  bits used to select between classical CAN-only and CAN FD-only modes.
- the RZ/G3S includes an internal divider that allows the peripheral
  clock to be used as the CAN FD clock source.

Reviewed-by: Biju Das <biju.das.jz@bp.renesas.com>
Signed-off-by: Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>

> diff --git a/drivers/net/can/rcar/rcar_canfd.c b/drivers/net/can/rcar/rcar_canfd.c
> index 22f87491cd913..e74b72e60272e 100644
> --- a/drivers/net/can/rcar/rcar_canfd.c
> +++ b/drivers/net/can/rcar/rcar_canfd.c
> @@ -661,6 +661,26 @@ static const struct rcar_canfd_hw_info rzg2l_hw_info = {
>  	.mode_select_na = 0,
>  };
>  
> +static const struct rcar_canfd_hw_info r9a08g045_hw_info = {
> +	.nom_bittiming = &rcar_canfd_gen4_nom_bittiming_const,
> +	.data_bittiming = &rcar_canfd_gen4_data_bittiming_const,
> +	.tdc_const = &rcar_canfd_gen4_tdc_const,
> +	.regs = &rcar_gen4_regs,
> +	.sh = &rcar_gen4_shift_data,
> +	.rnc_field_width = 16,
> +	.max_aflpn = 127,

[Severity: Low]
Is this max_aflpn value correct for the RZ/G3S hardware?

The commit message mentions the RZ/G3S provides 128 acceptance filters.
Setting max_aflpn to 127 configures a mask for up to 128 pages (2048 rules).

Should this mask be 7 (for 8 pages / 128 filters) to match the hardware
specification?

> +	.max_cftml = 31,
> +	.max_channels = 2,
> +	.postdiv = 2,
> +	.shared_global_irqs = 0,
> +	.multi_channel_irqs = 1,
> +	.ch_interface_mode = 1,
> +	.shared_can_regs = 1,
> +	.external_clk = 1,
> +	.fcan_pclk = 1,
> +	.mode_select_na = 1,

[Severity: High]
This is a pre-existing issue, but does adding a controller with 
mode_select_na = 1 expose a silent data truncation issue?

If a user requests Classical CAN mode via the DT property renesas,no-can-fd,
the controller will still receive FD frames because mode_select_na prevents
hardware-level Classical CAN mode on this SoC.

When a CAN FD frame is received, rcar_canfd_rx_pkt() checks the ctrlmode:

drivers/net/can/rcar/rcar_canfd.c:rcar_canfd_rx_pkt() {
    if ((priv->can.ctrlmode & CAN_CTRLMODE_FD) &&
        sts & RCANFD_RFFDSTS_RFFDF)
        skb = alloc_canfd_skb(ndev, &cf);
    else
        skb = alloc_can_skb(ndev, (struct can_frame **)&cf);
    ...
}

Since CAN_CTRLMODE_FD is disabled, it allocates a Classical CAN skb instead
of dropping the unsupported FD frame. It then truncates the DLC and copies
up to 8 bytes:

drivers/net/can/rcar/rcar_canfd.c:rcar_canfd_rx_pkt() {
    ...
    } else {
        cf->len = can_cc_dlc2len(RCANFD_RFPTR_RFDLC(dlc));
        if (id & RCANFD_RFID_RFRTR)
            cf->can_id |= CAN_RTR_FLAG;
        else if (gpriv->info->shared_can_regs)
            rcar_canfd_get_data(priv, cf, RCANFD_F_RFDF(gpriv, ridx, 0));
    ...
}

Can this cause an FD frame to be silently truncated and passed to userspace
as a valid Classical CAN frame?

> +};
> +

[ ... ]

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260709182332.876408-1-claudiu.beznea+renesas@tuxon.dev?part=6

[PATCH v2 7/8] arm64: dts: renesas: r9a08g045: Add CAN-FD node

[Claudiu Beznea]

From: Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>

The Renesas RZ/G3S SoC includes a CAN-FD controller with two channels.
Add the corresponding device tree node.

Reviewed-by: Biju Das <biju.das.jz@bp.renesas.com>
Signed-off-by: Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>
---

Changes in v2:
- collected tags

 arch/arm64/boot/dts/renesas/r9a08g045.dtsi | 39 ++++++++++++++++++++++
 1 file changed, 39 insertions(+)

diff --git a/arch/arm64/boot/dts/renesas/r9a08g045.dtsi b/arch/arm64/boot/dts/renesas/r9a08g045.dtsi
index 3a69bb246bab..fe46f3d9c7cc 100644
--- a/arch/arm64/boot/dts/renesas/r9a08g045.dtsi
+++ b/arch/arm64/boot/dts/renesas/r9a08g045.dtsi
@@ -29,6 +29,13 @@ audio_clk2: audio2-clk {
 		clock-frequency = <0>;
 	};
 
+	can_clk: can-clk {
+		compatible = "fixed-clock";
+		#clock-cells = <0>;
+		/* This value must be overridden by boards that provide it. */
+		clock-frequency = <0>;
+	};
+
 	cluster0_opp: opp-table-0 {
 		compatible = "operating-points-v2";
 		opp-shared;
@@ -498,6 +505,38 @@ ssi3: ssi@100a8c00 {
 			status = "disabled";
 		};
 
+		canfd: can@100c0000 {
+			compatible = "renesas,r9a08g045-canfd";
+			reg = <0 0x100c0000 0 0x20000>;
+			interrupts = <GIC_SPI 373 IRQ_TYPE_LEVEL_HIGH>,
+				     <GIC_SPI 374 IRQ_TYPE_LEVEL_HIGH>,
+				     <GIC_SPI 377 IRQ_TYPE_LEVEL_HIGH>,
+				     <GIC_SPI 375 IRQ_TYPE_LEVEL_HIGH>,
+				     <GIC_SPI 379 IRQ_TYPE_LEVEL_HIGH>,
+				     <GIC_SPI 378 IRQ_TYPE_LEVEL_HIGH>,
+				     <GIC_SPI 376 IRQ_TYPE_LEVEL_HIGH>,
+				     <GIC_SPI 380 IRQ_TYPE_LEVEL_HIGH>;
+			interrupt-names = "g_err", "g_recc",
+					  "ch0_err", "ch0_rec", "ch0_trx",
+					  "ch1_err", "ch1_rec", "ch1_trx";
+			clocks = <&cpg CPG_MOD R9A08G045_CANFD_PCLK>,
+				 <&cpg CPG_MOD R9A08G045_CANFD_CLK_RAM>,
+				 <&can_clk>;
+			clock-names = "fck", "ram_clk", "can_clk";
+			resets = <&cpg R9A08G045_CANFD_RSTP_N>,
+				 <&cpg R9A08G045_CANFD_RSTC_N>;
+			reset-names = "rstp_n", "rstc_n";
+			power-domains = <&cpg>;
+			status = "disabled";
+
+			channel0 {
+				status = "disabled";
+			};
+			channel1 {
+				status = "disabled";
+			};
+		};
+
 		cpg: clock-controller@11010000 {
 			compatible = "renesas,r9a08g045-cpg";
 			reg = <0 0x11010000 0 0x10000>;
-- 
2.43.0

[PATCH v2 8/8] arm64: dts: renesas: rzg3s-smarc: Enable CAN-FD

[Claudiu Beznea]

From: Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>

The two CAN FD channels available on the Renesas RZ/G3S SoC are routed
through the Renesas SMARC Carrier II board when used with the Renesas
RZ/G3S SMARC Module.

The CAN transceiver on the Carrier II board has its standby pins connected
to GPIOs that are selected through the SW_GPIO_CAN_PMOD switches. By
default, these switches route the GPIOs to the PMOD interfaces.

Enable the CAN FD controller and its two available channels.

Reviewed-by: Biju Das <biju.das.jz@bp.renesas.com>
Signed-off-by: Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>
---

Changes in v2:
- collected tags

 .../boot/dts/renesas/rzg3s-smarc-switches.h   | 12 +++++
 arch/arm64/boot/dts/renesas/rzg3s-smarc.dtsi  | 46 +++++++++++++++++++
 2 files changed, 58 insertions(+)

diff --git a/arch/arm64/boot/dts/renesas/rzg3s-smarc-switches.h b/arch/arm64/boot/dts/renesas/rzg3s-smarc-switches.h
index bbf908a5322c..198874ad9a65 100644
--- a/arch/arm64/boot/dts/renesas/rzg3s-smarc-switches.h
+++ b/arch/arm64/boot/dts/renesas/rzg3s-smarc-switches.h
@@ -37,4 +37,16 @@
  */
 #define SW_OPT_MUX4	SW_ON
 
+/*
+ * SW_GPIO_CAN_PMOD[x] switches' states:
+ * @SW_GPIO_CAN_PMOD1:
+ *	SW_OFF - GPIO8 connected to CAN0_STB (position 1-2)
+ *	SW_ON  - GPIO8 connected to PMOD1 (position 2-3)
+ * @SW_GPIO_CAN_PMOD2:
+ *	SW_OFF - GPIO9 connected to CAN1_STB (position 4-5)
+ *	SW_ON  - GPIO9 connected to PMOD1 (position 5-6)
+ */
+#define SW_GPIO_CAN_PMOD1	SW_ON
+#define SW_GPIO_CAN_PMOD2	SW_ON
+
 #endif /* __RZG3S_SMARC_SWITCHES_H__ */
diff --git a/arch/arm64/boot/dts/renesas/rzg3s-smarc.dtsi b/arch/arm64/boot/dts/renesas/rzg3s-smarc.dtsi
index 70af605168b0..2be684f55914 100644
--- a/arch/arm64/boot/dts/renesas/rzg3s-smarc.dtsi
+++ b/arch/arm64/boot/dts/renesas/rzg3s-smarc.dtsi
@@ -68,6 +68,24 @@ codec_dai: simple-audio-card,codec {
 		};
 	};
 
+	can_transceiver0: can-phy0 {
+		compatible = "ti,tcan1042";
+		#phy-cells = <0>;
+		max-bitrate = <8000000>;
+#if SW_GPIO_CAN_PMOD1 == SW_OFF
+		standby-gpios = <&pinctrl RZG2L_GPIO(13, 0) GPIO_ACTIVE_HIGH>;
+#endif
+	};
+
+	can_transceiver1: can-phy1 {
+		compatible = "ti,tcan1042";
+		#phy-cells = <0>;
+		max-bitrate = <8000000>;
+#if SW_GPIO_CAN_PMOD2 == SW_OFF
+		standby-gpios = <&pinctrl RZG2L_GPIO(13, 1) GPIO_ACTIVE_HIGH>;
+#endif
+	};
+
 	vcc_sdhi1: regulator-vcc-sdhi1 {
 		compatible = "regulator-fixed";
 		regulator-name = "SDHI1 Vcc";
@@ -92,6 +110,22 @@ &audio_clk2 {
 	clock-frequency = <12288000>;
 };
 
+&canfd {
+	pinctrl-0 = <&canfd_pins>;
+	pinctrl-names = "default";
+	status = "okay";
+
+	channel0 {
+		phys = <&can_transceiver0>;
+		status = "okay";
+	};
+
+	channel1 {
+		phys = <&can_transceiver1>;
+		status = "okay";
+	};
+};
+
 &ehci0 {
 	dr_mode = "otg";
 	status = "okay";
@@ -171,6 +205,18 @@ audio_clock_pins: audio-clock {
 		input-enable;
 	};
 
+	canfd_pins: canfd {
+		can0_pins: can0 {
+			pinmux = <RZG2L_PORT_PINMUX(6, 1, 3)>, /* CAN0_TX */
+				 <RZG2L_PORT_PINMUX(6, 2, 3)>; /* CAN0_RX */
+		};
+
+		can1_pins: can1 {
+			pinmux = <RZG2L_PORT_PINMUX(17, 0, 3)>, /* CAN1_TX */
+				 <RZG2L_PORT_PINMUX(17, 1, 3)>; /* CAN1_RX */
+		};
+	};
+
 	key-1-gpio-hog {
 		gpio-hog;
 		gpios = <RZG2L_GPIO(18, 0) GPIO_ACTIVE_LOW>;
-- 
2.43.0

Re: [PATCH v2 8/8] arm64: dts: renesas: rzg3s-smarc: Enable CAN-FD

[sashiko-bot]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Medium] CAN channels are enabled unconditionally even when their transceiver standby pins are disconnected by hardware switches, rendering the CAN bus physically inoperable.
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--- Patch [8]: [PATCH v2 8/8] arm64: dts: renesas: rzg3s-smarc: Enable CAN-FD ---
commit f8b012ec526a1699faa0dea73b3d5f10dc6c3d9d
Author: Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>

arm64: dts: renesas: rzg3s-smarc: Enable CAN-FD

This commit enables the CAN FD controller and its two channels on the
Renesas RZ/G3S SMARC Module. It conditionally sets up the standby GPIOs
for the CAN transceivers based on the states of the SW_GPIO_CAN_PMOD
switches.

> diff --git a/arch/arm64/boot/dts/renesas/rzg3s-smarc.dtsi b/arch/arm64/boot/dts/renesas/rzg3s-smarc.dtsi
> index 70af605168b07..2be684f559144 100644
> --- a/arch/arm64/boot/dts/renesas/rzg3s-smarc.dtsi
> +++ b/arch/arm64/boot/dts/renesas/rzg3s-smarc.dtsi
[ ... ]
> @@ -92,6 +110,22 @@ &audio_clk2 {
>  	clock-frequency = <12288000>;
>  };
>  
> +&canfd {
> +	pinctrl-0 = <&canfd_pins>;
> +	pinctrl-names = "default";
> +	status = "okay";
> +
> +	channel0 {
> +		phys = <&can_transceiver0>;
> +		status = "okay";
> +	};
> +
> +	channel1 {
> +		phys = <&can_transceiver1>;
> +		status = "okay";
> +	};
> +};

[Severity: Medium]
Since SW_GPIO_CAN_PMOD1 and SW_GPIO_CAN_PMOD2 are SW_ON by default, the
transceiver standby pins are disconnected from the SoC GPIOs. Because the
TCAN1042 PHY has an internal pull-up on the STB pin, leaving it floating
forces the transceiver into standby mode.

Does setting status = "okay" here unconditionally expose inoperable CAN bus
interfaces to userspace? Should the channel status be guarded by the same
switch macros used for the standby-gpios properties?

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260709182332.876408-1-claudiu.beznea+renesas@tuxon.dev?part=8