can: tcan4x5x: add option for selecting nWKRQ voltage

The nWKRQ pin supports an output voltage of either the internal reference
voltage (3.6V) or the reference voltage of
the digital interface 0-6V (VIO).
Add the devicetree option ti,nwkrq-voltage-vio to set it to VIO.

If this property is omitted the reset default, the internal reference
voltage, is used.

Signed-off-by: Sean Nyekjaer <[email protected]>
Reviewed-by: Marc Kleine-Budde <[email protected]>
Reviewed-by: Vincent Mailhol <[email protected]>
Link: https://patch.msgid.link/[email protected]
[mkl: remove unused variable in tcan4x5x_get_dt_data()]
Signed-off-by: Marc Kleine-Budde <[email protected]>

Author: sknsean

drivers/net/can/m_can/tcan4x5x-core.c

@@ -92,6 +92,8 @@
 #define TCAN4X5X_MODE_STANDBY BIT(6)
 #define TCAN4X5X_MODE_NORMAL BIT(7)
 
+#define TCAN4X5X_NWKRQ_VOLTAGE_VIO BIT(19)
+
 #define TCAN4X5X_DISABLE_WAKE_MSK	(BIT(31) | BIT(30))
 #define TCAN4X5X_DISABLE_INH_MSK	BIT(9)
 
@@ -267,6 +269,13 @@ static int tcan4x5x_init(struct m_can_classdev *cdev)
 	if (ret)
 		return ret;
 
+	if (tcan4x5x->nwkrq_voltage_vio) {
+		ret = regmap_set_bits(tcan4x5x->regmap, TCAN4X5X_CONFIG,
+				      TCAN4X5X_NWKRQ_VOLTAGE_VIO);
+		if (ret)
+			return ret;
+	}
+
 	return ret;
 }
 
@@ -318,6 +327,14 @@ static const struct tcan4x5x_version_info
 	return &tcan4x5x_versions[TCAN4X5X];
 }
 
+static void tcan4x5x_get_dt_data(struct m_can_classdev *cdev)
+{
+	struct tcan4x5x_priv *tcan4x5x = cdev_to_priv(cdev);
+
+	tcan4x5x->nwkrq_voltage_vio =
+		of_property_read_bool(cdev->dev->of_node, "ti,nwkrq-voltage-vio");
+}
+
 static int tcan4x5x_get_gpios(struct m_can_classdev *cdev,
 			      const struct tcan4x5x_version_info *version_info)
 {
@@ -453,6 +470,8 @@ static int tcan4x5x_can_probe(struct spi_device *spi)
 		goto out_power;
 	}
 
+	tcan4x5x_get_dt_data(mcan_class);
+
 	tcan4x5x_check_wake(priv);
 
 	ret = tcan4x5x_write_tcan_reg(mcan_class, TCAN4X5X_INT_EN, 0);

drivers/net/can/m_can/tcan4x5x.h

@@ -42,6 +42,8 @@ struct tcan4x5x_priv {
 
 	struct tcan4x5x_map_buf map_buf_rx;
 	struct tcan4x5x_map_buf map_buf_tx;
+
+	bool nwkrq_voltage_vio;
 };
 
 static inline void