[PATCH 2/2] can: flexcan: allow the control of the STB CAN transceiver pin

[Fabio Estevam <festevam@xxxxxxxxx>]

It is very common to have an STB pin in CAN transceivers, which allows
putting the transceiver in standby or normal operation mode.

Add support for handling the STB pin.

Signed-off-by: Fabio Estevam <festevam@xxxxxxxxx>
---
 drivers/net/can/flexcan.c | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/drivers/net/can/flexcan.c b/drivers/net/can/flexcan.c
index 038fe1036df2..094050b4b461 100644
--- a/drivers/net/can/flexcan.c
+++ b/drivers/net/can/flexcan.c
@@ -17,6 +17,7 @@
 #include <linux/can/rx-offload.h>
 #include <linux/clk.h>
 #include <linux/delay.h>
+#include <linux/gpio/consumer.h>
 #include <linux/interrupt.h>
 #include <linux/io.h>
 #include <linux/mfd/syscon.h>
@@ -358,6 +359,8 @@ struct flexcan_priv {
 	struct regulator *reg_xceiver;
 	struct flexcan_stop_mode stm;
 
+	struct gpio_desc *stb;
+
 	/* Read and Write APIs */
 	u32 (*read)(void __iomem *addr);
 	void (*write)(u32 val, void __iomem *addr);
@@ -617,6 +620,8 @@ static void flexcan_clks_disable(const struct flexcan_priv *priv)
 
 static inline int flexcan_transceiver_enable(const struct flexcan_priv *priv)
 {
+	gpiod_set_value_cansleep(priv->stb, 0);
+
 	if (!priv->reg_xceiver)
 		return 0;
 
@@ -625,6 +630,8 @@ static inline int flexcan_transceiver_enable(const struct flexcan_priv *priv)
 
 static inline int flexcan_transceiver_disable(const struct flexcan_priv *priv)
 {
+	gpiod_set_value_cansleep(priv->stb, 1);
+
 	if (!priv->reg_xceiver)
 		return 0;
 
@@ -2044,6 +2051,10 @@ static int flexcan_probe(struct platform_device *pdev)
 		priv->can.bittiming_const = &flexcan_bittiming_const;
 	}
 
+	priv->stb = devm_gpiod_get_optional(&pdev->dev, "stb", GPIOD_OUT_HIGH);
+	if (IS_ERR(priv->stb))
+		return PTR_ERR(priv->stb);
+
 	pm_runtime_get_noresume(&pdev->dev);
 	pm_runtime_set_active(&pdev->dev);
 	pm_runtime_enable(&pdev->dev);
-- 
2.17.1