[PATCH 6.6.y] can: rcar_canfd: change the initializing flow for clocks and resets

From: Tu Nguyen <[email protected]>

[ Upstream commit bef9004c5b91debfceaea2841855a4ebe81ff2b3 ]

Testing CANFD on RZ/G3E shows that many registers do not reset to their
initial values with the current flow of deasserting resets first and then
enabling clocks.

Based on the HW manual, clocks should be supplied first and the
resets deasserted afterward.

 section 7.4.3 Procedure for Activating Modules: RZ/G2L
 section 4.4.9.3 Procedure for Starting up Units: RZ/G3E

So, update the order of the initializing flow for resets and clocks
to match the hardware manual, resetting all CANFD registers to their
initial values. Also update rcar_canfd_global_deinit() to assert
resets before disabling clocks, so the teardown path mirrors the new
init ordering.

Fixes: 76e9353a80e9 ("can: rcar_canfd: Add support for RZ/G2L family")
Signed-off-by: Tu Nguyen <[email protected]>
Signed-off-by: Biju Das <[email protected]>
Tested-by: Claudiu Beznea <[email protected]>
Reviewed-by: Geert Uytterhoeven <[email protected]>
Reviewed-by: Vincent Mailhol <[email protected]>
Link: https://patch.msgid.link/[email protected]
Cc: [email protected]
Signed-off-by: Marc Kleine-Budde <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>
---
 drivers/net/can/rcar/rcar_canfd.c | 28 ++++++++++++++--------------
 1 file changed, 14 insertions(+), 14 deletions(-)

diff --git a/drivers/net/can/rcar/rcar_canfd.c b/drivers/net/can/rcar/rcar_canfd.c
index 5a30667001c94..0a2dc41d40d4f 100644
--- a/drivers/net/can/rcar/rcar_canfd.c
+++ b/drivers/net/can/rcar/rcar_canfd.c
@@ -1999,27 +1999,27 @@ static int rcar_canfd_probe(struct platform_device *pdev)
 		}
 	}
 
-	err = reset_control_reset(gpriv->rstc1);
-	if (err)
-		goto fail_dev;
-	err = reset_control_reset(gpriv->rstc2);
-	if (err) {
-		reset_control_assert(gpriv->rstc1);
-		goto fail_dev;
-	}
-
 	/* Enable peripheral clock for register access */
 	err = clk_prepare_enable(gpriv->clkp);
 	if (err) {
 		dev_err(dev, "failed to enable peripheral clock: %pe\n",
 			ERR_PTR(err));
-		goto fail_reset;
+		goto fail_dev;
+	}
+
+	err = reset_control_reset(gpriv->rstc1);
+	if (err)
+		goto fail_clk;
+	err = reset_control_reset(gpriv->rstc2);
+	if (err) {
+		reset_control_assert(gpriv->rstc1);
+		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_reset;
 	}
 
 	/* Controller in Global reset & Channel reset mode */
@@ -2070,11 +2070,11 @@ static int rcar_canfd_probe(struct platform_device *pdev)
 		rcar_canfd_channel_remove(gpriv, ch);
 fail_mode:
 	rcar_canfd_disable_global_interrupts(gpriv);
-fail_clk:
-	clk_disable_unprepare(gpriv->clkp);
 fail_reset:
 	reset_control_assert(gpriv->rstc1);
 	reset_control_assert(gpriv->rstc2);
+fail_clk:
+	clk_disable_unprepare(gpriv->clkp);
 fail_dev:
 	return err;
 }
@@ -2094,9 +2094,9 @@ 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->clkp);
 	reset_control_assert(gpriv->rstc1);
 	reset_control_assert(gpriv->rstc2);
+	clk_disable_unprepare(gpriv->clkp);
 }
 
 static int __maybe_unused rcar_canfd_suspend(struct device *dev)
-- 
2.53.0