[PATCH v4] phy: mvebu-cp110-utmi: support swapping d+/d- lanes by dts property

[Josua Mayer]

CP11x UTMI PHY supports swapping D+/D- signals via digital control
register 1.

Add support for the "swap-dx-lanes" device-tree property, which lists
the port-ids that should swap D+ and D-.
The property is evaluated in probe and applied before power-on
during mvebu_cp110_utmi_port_setup.

Signed-off-by: Josua Mayer <josua at solid-run.com>
---
Changes in v4:
- rebased on v6.12-rc1
- Link to v3: https://lore.kernel.org/r/20240908-mvebu-utmi-phy-v3-1-88c50950e7d2@solid-run.com

Changes in v3:
- add description for new struct member
  (Reported-by: kernel test robot <lkp at intel.com>)
- Link to v2: https://lore.kernel.org/r/20240903-mvebu-utmi-phy-v2-1-7f49c131fad0@solid-run.com

Changes in v2:
- fixed compile error introduced with v6.11-rc1:
  parameters of of_property_for_each_u32 were changed from 5 to 3.
  (Reported-by: Vinod Koul <vkoul at kernel.org>)
- rebased on v6.11-rc1
- Link to v1: https://lore.kernel.org/r/20240704-mvebu-utmi-phy-v1-1-9d3c8eea46e5@solid-run.com
---
 drivers/phy/marvell/phy-mvebu-cp110-utmi.c | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/drivers/phy/marvell/phy-mvebu-cp110-utmi.c b/drivers/phy/marvell/phy-mvebu-cp110-utmi.c
index 4922a5f3327d..59903f86b13f 100644
--- a/drivers/phy/marvell/phy-mvebu-cp110-utmi.c
+++ b/drivers/phy/marvell/phy-mvebu-cp110-utmi.c
@@ -62,6 +62,8 @@
 #define   SQ_AMP_CAL_MASK			GENMASK(2, 0)
 #define   SQ_AMP_CAL_VAL			1
 #define   SQ_AMP_CAL_EN				BIT(3)
+#define UTMI_DIG_CTRL1_REG			0x20
+#define   SWAP_DPDM				BIT(15)
 #define UTMI_CTRL_STATUS0_REG			0x24
 #define   SUSPENDM				BIT(22)
 #define   TEST_SEL				BIT(25)
@@ -99,11 +101,13 @@ struct mvebu_cp110_utmi {
  * @priv: PHY driver data
  * @id: PHY port ID
  * @dr_mode: PHY connection: USB_DR_MODE_HOST or USB_DR_MODE_PERIPHERAL
+ * @swap_dx: whether to swap d+/d- signals
  */
 struct mvebu_cp110_utmi_port {
 	struct mvebu_cp110_utmi *priv;
 	u32 id;
 	enum usb_dr_mode dr_mode;
+	bool swap_dx;
 };
 
 static void mvebu_cp110_utmi_port_setup(struct mvebu_cp110_utmi_port *port)
@@ -159,6 +163,13 @@ static void mvebu_cp110_utmi_port_setup(struct mvebu_cp110_utmi_port *port)
 	reg &= ~(VDAT_MASK | VSRC_MASK);
 	reg |= (VDAT_VAL << VDAT_OFFSET) | (VSRC_VAL << VSRC_OFFSET);
 	writel(reg, PORT_REGS(port) + UTMI_CHGDTC_CTRL_REG);
+
+	/* Swap D+/D- */
+	reg = readl(PORT_REGS(port) + UTMI_DIG_CTRL1_REG);
+	reg &= ~(SWAP_DPDM);
+	if (port->swap_dx)
+		reg |= SWAP_DPDM;
+	writel(reg, PORT_REGS(port) + UTMI_DIG_CTRL1_REG);
 }
 
 static int mvebu_cp110_utmi_phy_power_off(struct phy *phy)
@@ -286,6 +297,7 @@ static int mvebu_cp110_utmi_phy_probe(struct platform_device *pdev)
 	struct phy_provider *provider;
 	struct device_node *child;
 	u32 usb_devices = 0;
+	u32 swap_dx = 0;
 
 	utmi = devm_kzalloc(dev, sizeof(*utmi), GFP_KERNEL);
 	if (!utmi)
@@ -345,6 +357,10 @@ static int mvebu_cp110_utmi_phy_probe(struct platform_device *pdev)
 			}
 		}
 
+		of_property_for_each_u32(dev->of_node, "swap-dx-lanes", swap_dx)
+			if (swap_dx == port_id)
+				port->swap_dx = 1;
+
 		/* Retrieve PHY capabilities */
 		utmi->ops = &mvebu_cp110_utmi_phy_ops;
 

---
base-commit: 9852d85ec9d492ebef56dc5f229416c925758edc
change-id: 20240704-mvebu-utmi-phy-84aa3bf3957d

Best regards,
-- 
Josua Mayer <josua at solid-run.com>