linux-kernel - [PATCH v2 3/7] can: rcar_canfd: Move enabling of RAM clk from probe()

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Message-ID: <20250912104733.173281-4-biju.das.jz@bp.renesas.com>
Date: Fri, 12 Sep 2025 11:47:21 +0100
From: Biju <biju.das.au@...il.com>
To: Marc Kleine-Budde <mkl@...gutronix.de>,
	Vincent Mailhol <mailhol.vincent@...adoo.fr>,
	Geert Uytterhoeven <geert+renesas@...der.be>,
	Magnus Damm <magnus.damm@...il.com>
Cc: Biju Das <biju.das.jz@...renesas.com>,
	linux-can@...r.kernel.org,
	linux-renesas-soc@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	Prabhakar Mahadev Lad <prabhakar.mahadev-lad.rj@...renesas.com>,
	Biju Das <biju.das.au@...il.com>
Subject: [PATCH v2 3/7] can: rcar_canfd: Move enabling of RAM clk from probe()

From: Biju Das <biju.das.jz@...renesas.com>

The RAM clk needs to be enabled in resume for proper operation in STR mode
for RZ/G3E SoC. This change also result in less power consumption.

Signed-off-by: Biju Das <biju.das.jz@...renesas.com>
---
v2:
 * New patch.
---
 drivers/net/can/rcar/rcar_canfd.c | 23 +++++++++++++++++------
 1 file changed, 17 insertions(+), 6 deletions(-)

diff --git a/drivers/net/can/rcar/rcar_canfd.c b/drivers/net/can/rcar/rcar_canfd.c
index 460bb62bbd08..da469595be74 100644
--- a/drivers/net/can/rcar/rcar_canfd.c
+++ b/drivers/net/can/rcar/rcar_canfd.c
@@ -468,6 +468,7 @@ struct rcar_canfd_global {
 	struct platform_device *pdev;	/* Respective platform device */
 	struct clk *clkp;		/* Peripheral clock */
 	struct clk *can_clk;		/* fCAN clock */
+	struct clk *clk_ram;		/* Clock RAM */
 	unsigned long channels_mask;	/* Enabled channels mask */
 	bool extclk;			/* CANFD or Ext clock */
 	bool fdmode;			/* CAN FD or Classical CAN only mode */
@@ -1975,7 +1976,6 @@ static int rcar_canfd_probe(struct platform_device *pdev)
 	u32 rule_entry = 0;
 	bool fdmode = true;			/* CAN FD only mode - default */
 	char name[9] = "channelX";
-	struct clk *clk_ram;
 	int i;
 
 	info = of_device_get_match_data(dev);
@@ -2065,10 +2065,10 @@ static int rcar_canfd_probe(struct platform_device *pdev)
 		gpriv->extclk = gpriv->info->external_clk;
 	}
 
-	clk_ram = devm_clk_get_optional_enabled(dev, "ram_clk");
-	if (IS_ERR(clk_ram))
-		return dev_err_probe(dev, PTR_ERR(clk_ram),
-				     "cannot get enabled ram clock\n");
+	gpriv->clk_ram = devm_clk_get_optional(dev, "ram_clk");
+	if (IS_ERR(gpriv->clk_ram))
+		return dev_err_probe(dev, PTR_ERR(gpriv->clk_ram),
+				     "cannot get ram clock\n");
 
 	addr = devm_platform_ioremap_resource(pdev, 0);
 	if (IS_ERR(addr)) {
@@ -2134,10 +2134,18 @@ static int rcar_canfd_probe(struct platform_device *pdev)
 		goto fail_reset;
 	}
 
+	/* Enable RAM clock  */
+	err = clk_prepare_enable(gpriv->clk_ram);
+	if (err) {
+		dev_err(dev, "failed to enable RAM clock: %pe\n",
+			ERR_PTR(err));
+		goto fail_clk;
+	}
+
 	err = rcar_canfd_reset_controller(gpriv);
 	if (err) {
 		dev_err(dev, "reset controller failed: %pe\n", ERR_PTR(err));
-		goto fail_clk;
+		goto fail_ram_clk;
 	}
 
 	/* Controller in Global reset & Channel reset mode */
@@ -2189,6 +2197,8 @@ static int rcar_canfd_probe(struct platform_device *pdev)
 		rcar_canfd_channel_remove(gpriv, ch);
 fail_mode:
 	rcar_canfd_disable_global_interrupts(gpriv);
+fail_ram_clk:
+	clk_disable_unprepare(gpriv->clk_ram);
 fail_clk:
 	clk_disable_unprepare(gpriv->clkp);
 fail_reset:
@@ -2213,6 +2223,7 @@ static void rcar_canfd_remove(struct platform_device *pdev)
 
 	/* Enter global sleep mode */
 	rcar_canfd_set_bit(gpriv->base, RCANFD_GCTR, RCANFD_GCTR_GSLPR);
+	clk_disable_unprepare(gpriv->clk_ram);
 	clk_disable_unprepare(gpriv->clkp);
 	reset_control_assert(gpriv->rstc2);
 	reset_control_assert(gpriv->rstc1);
-- 
2.43.0