[PATCH v2] phy: renesas: rcar-gen3-usb2: Simplify ID/VBUS detection logic

Prabhakar prabhakar.csengg at gmail.com
Wed Mar 25 04:20:39 PDT 2026


From: Lad Prabhakar <prabhakar.mahadev-lad.rj at bp.renesas.com>

Read USB2_ADPCTRL once in rcar_gen3_check_id() instead of issuing
multiple MMIO reads, and derive both IDDIG and VBUSVALID from the same
value.

Drop the redundant !! operator, as assigning a masked u32 value to a
bool already performs the required normalization. Simplify the logic by
comparing the ID and VBUS status directly, which is equivalent to the
previous conditional but easier to follow.

Reported-by: Pavel Machek <pavel at nabladev.com>
Closes: https://lore.kernel.org/all/acJVCOdlchLiSe5n@duo.ucw.cz/
Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj at bp.renesas.com>
---
v1->v2:
- Rebased on top of latest next-20260324
- Combined variable declarations and assignments and dropped
  redundant !! operator
- Updated commit message
- Corrected the link for closes tag
---
 drivers/phy/renesas/phy-rcar-gen3-usb2.c | 10 ++++------
 1 file changed, 4 insertions(+), 6 deletions(-)

diff --git a/drivers/phy/renesas/phy-rcar-gen3-usb2.c b/drivers/phy/renesas/phy-rcar-gen3-usb2.c
index 79e820e2fe55..9a45d840efeb 100644
--- a/drivers/phy/renesas/phy-rcar-gen3-usb2.c
+++ b/drivers/phy/renesas/phy-rcar-gen3-usb2.c
@@ -314,13 +314,11 @@ static void rcar_gen3_init_from_a_peri_to_a_host(struct rcar_gen3_chan *ch)
 static bool rcar_gen3_check_id(struct rcar_gen3_chan *ch)
 {
 	if (ch->phy_data->vblvl_ctrl) {
-		bool vbus_valid;
-		bool device;
+		u32 val = readl(ch->base + USB2_ADPCTRL);
+		bool vbus_valid = val & USB2_ADPCTRL_VBUSVALID;
+		bool device = val & USB2_ADPCTRL_IDDIG;
 
-		device = !!(readl(ch->base + USB2_ADPCTRL) & USB2_ADPCTRL_IDDIG);
-		vbus_valid = !!(readl(ch->base + USB2_ADPCTRL) & USB2_ADPCTRL_VBUSVALID);
-
-		return vbus_valid ? device : !device;
+		return device == vbus_valid;
 	}
 
 	if (!ch->uses_otg_pins)
-- 
2.53.0




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