can: m_can: Add support for transceiver as phy

Add support for implementing transceiver node as phy. The max_bitrate
is obtained by getting a phy attribute.

Link: https://lore.kernel.org/r/20210724174001.553047-1-mkl@pengutronix.deSigned-off-by: Faiz Abbas <faiz_abbas@ti.com>
Signed-off-by: Aswath Govindraju <a-govindraju@ti.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

drivers/net/can/m_can/m_can.c

@@ -21,6 +21,7 @@
 #include <linux/iopoll.h>
 #include <linux/can/dev.h>
 #include <linux/pinctrl/consumer.h>
+#include <linux/phy/phy.h>
 
 #include "m_can.h"
 
@@ -1521,6 +1522,8 @@ static int m_can_close(struct net_device *dev)
 	close_candev(dev);
 	can_led_event(dev, CAN_LED_EVENT_STOP);
 
+	phy_power_off(cdev->transceiver);
+
 	return 0;
 }
 
@@ -1706,10 +1709,14 @@ static int m_can_open(struct net_device *dev)
 	struct m_can_classdev *cdev = netdev_priv(dev);
 	int err;
 
-	err = m_can_clk_start(cdev);
+	err = phy_power_on(cdev->transceiver);
 	if (err)
 		return err;
 
+	err = m_can_clk_start(cdev);
+	if (err)
+		goto out_phy_power_off;
+
 	/* open the can device */
 	err = open_candev(dev);
 	if (err) {
@@ -1766,6 +1773,8 @@ static int m_can_open(struct net_device *dev)
 	close_candev(dev);
 exit_disable_clks:
 	m_can_clk_stop(cdev);
+out_phy_power_off:
+	phy_power_off(cdev->transceiver);
 	return err;
 }
 

drivers/net/can/m_can/m_can.h

@@ -28,6 +28,7 @@
 #include <linux/iopoll.h>
 #include <linux/can/dev.h>
 #include <linux/pinctrl/consumer.h>
+#include <linux/phy/phy.h>
 
 /* m_can lec values */
 enum m_can_lec_type {
@@ -82,6 +83,7 @@ struct m_can_classdev {
 	struct workqueue_struct *tx_wq;
 	struct work_struct tx_work;
 	struct sk_buff *tx_skb;
+	struct phy *transceiver;
 
 	struct can_bittiming_const *bit_timing;
 	struct can_bittiming_const *data_timing;

drivers/net/can/m_can/m_can_platform.c

@@ -6,6 +6,7 @@
 // Copyright (C) 2018-19 Texas Instruments Incorporated - http://www.ti.com/
 
 #include <linux/platform_device.h>
+#include <linux/phy/phy.h>
 
 #include "m_can.h"
 
@@ -67,6 +68,7 @@ static int m_can_plat_probe(struct platform_device *pdev)
 	struct resource *res;
 	void __iomem *addr;
 	void __iomem *mram_addr;
+	struct phy *transceiver;
 	int irq, ret = 0;
 
 	mcan_class = m_can_class_allocate_dev(&pdev->dev,
@@ -101,6 +103,16 @@ static int m_can_plat_probe(struct platform_device *pdev)
 		goto probe_fail;
 	}
 
+	transceiver = devm_phy_optional_get(&pdev->dev, NULL);
+	if (IS_ERR(transceiver)) {
+		ret = PTR_ERR(transceiver);
+		dev_err_probe(&pdev->dev, ret, "failed to get phy\n");
+		goto probe_fail;
+	}
+
+	if (transceiver)
+		mcan_class->can.bitrate_max = transceiver->attrs.max_link_rate;
+
 	priv->base = addr;
 	priv->mram_base = mram_addr;
 
@@ -108,6 +120,7 @@ static int m_can_plat_probe(struct platform_device *pdev)
 	mcan_class->pm_clock_support = 1;
 	mcan_class->can.clock.freq = clk_get_rate(mcan_class->cclk);
 	mcan_class->dev = &pdev->dev;
+	mcan_class->transceiver = transceiver;
 
 	mcan_class->ops = &m_can_plat_ops;