[PATCH v1] can: mcp251xfd: Enable transceiver using gpio

[Anup Kulkarni <quic_anupkulk@xxxxxxxxxxx>]

Ensure the CAN transceiver is active during mcp251xfd_open() and
inactive during mcp251xfd_close() by utilizing
mcp251xfd_transceiver_mode(). Adjust GPIO_0 to switch between
NORMAL and STANDBY modes of transceiver.

Signed-off-by: Anup Kulkarni <quic_anupkulk@xxxxxxxxxxx>
---
 .../net/can/spi/mcp251xfd/mcp251xfd-core.c    | 32 +++++++++++++++++++
 drivers/net/can/spi/mcp251xfd/mcp251xfd.h     |  7 ++++
 2 files changed, 39 insertions(+)

diff --git a/drivers/net/can/spi/mcp251xfd/mcp251xfd-core.c b/drivers/net/can/spi/mcp251xfd/mcp251xfd-core.c
index 3e7526274e34..3b56dc1721a5 100644
--- a/drivers/net/can/spi/mcp251xfd/mcp251xfd-core.c
+++ b/drivers/net/can/spi/mcp251xfd/mcp251xfd-core.c
@@ -153,6 +153,25 @@ static inline int mcp251xfd_vdd_disable(const struct mcp251xfd_priv *priv)
 	return regulator_disable(priv->reg_vdd);
 }
 
+static int
+mcp251xfd_transceiver_mode(const struct mcp251xfd_priv *priv,
+			   const enum mcp251xfd_xceiver_mode mode)
+{
+	int val, pmode, latch;
+
+	if (mode == MCP251XFD_XCVR_NORMAL_MODE) {
+		pmode = MCP251XFD_REG_IOCON_PM0;
+		latch = 0;
+	} else if (mode == MCP251XFD_XCVR_STBY_MODE) {
+		pmode = MCP251XFD_REG_IOCON_PM0;
+		latch = MCP251XFD_REG_IOCON_LAT0;
+	} else {
+		return -EINVAL;
+	}
+	val = (pmode | latch) << priv->transceiver_pin;
+	return regmap_write(priv->map_reg, MCP251XFD_REG_IOCON, val);
+}
+
 static inline int
 mcp251xfd_transceiver_enable(const struct mcp251xfd_priv *priv)
 {
@@ -1620,6 +1639,10 @@ static int mcp251xfd_open(struct net_device *ndev)
 	if (err)
 		goto out_transceiver_disable;
 
+	err = mcp251xfd_transceiver_mode(priv, MCP251XFD_XCVR_NORMAL_MODE);
+	if (err)
+		goto out_transceiver_disable;
+
 	clear_bit(MCP251XFD_FLAGS_DOWN, priv->flags);
 	can_rx_offload_enable(&priv->offload);
 
@@ -1668,6 +1691,7 @@ static int mcp251xfd_open(struct net_device *ndev)
 
 static int mcp251xfd_stop(struct net_device *ndev)
 {
+	int err;
 	struct mcp251xfd_priv *priv = netdev_priv(ndev);
 
 	netif_stop_queue(ndev);
@@ -1678,6 +1702,9 @@ static int mcp251xfd_stop(struct net_device *ndev)
 	free_irq(ndev->irq, priv);
 	destroy_workqueue(priv->wq);
 	can_rx_offload_disable(&priv->offload);
+	err = mcp251xfd_transceiver_mode(priv, MCP251XFD_XCVR_STBY_MODE);
+	if (err)
+		return err;
 	mcp251xfd_chip_stop(priv, CAN_STATE_STOPPED);
 	mcp251xfd_transceiver_disable(priv);
 	mcp251xfd_ring_free(priv);
@@ -2051,6 +2078,11 @@ static int mcp251xfd_probe(struct spi_device *spi)
 					     "Failed to get clock-frequency!\n");
 	}
 
+	err = device_property_read_u32(&spi->dev, "gpio-transceiver-pin", &priv->transceiver_pin);
+		if (err)
+			return dev_err_probe(&spi->dev, err,
+					     "Failed to get gpio transceiver pin!\n");
+
 	/* Sanity check */
 	if (freq < MCP251XFD_SYSCLOCK_HZ_MIN ||
 	    freq > MCP251XFD_SYSCLOCK_HZ_MAX) {
diff --git a/drivers/net/can/spi/mcp251xfd/mcp251xfd.h b/drivers/net/can/spi/mcp251xfd/mcp251xfd.h
index dcbbd2b2fae8..14b086814bdb 100644
--- a/drivers/net/can/spi/mcp251xfd/mcp251xfd.h
+++ b/drivers/net/can/spi/mcp251xfd/mcp251xfd.h
@@ -614,6 +614,12 @@ enum mcp251xfd_flags {
 	__MCP251XFD_FLAGS_SIZE__
 };
 
+enum mcp251xfd_xceiver_mode {
+	MCP251XFD_XCVR_NORMAL_MODE,
+	MCP251XFD_XCVR_STBY_MODE,
+	MCP251XFD_XCVR_MODE_NONE
+};
+
 struct mcp251xfd_priv {
 	struct can_priv can;
 	struct can_rx_offload offload;
@@ -670,6 +676,7 @@ struct mcp251xfd_priv {
 
 	struct mcp251xfd_devtype_data devtype_data;
 	struct can_berr_counter bec;
+	u32 transceiver_pin;
 };
 
 #define MCP251XFD_IS(_model) \
-- 
2.25.1