From: Daniel Hellstrom <daniel@gaisler.com>

Add clock handling and add error messages for missing 'freq' DT property.

Signed-off-by: Daniel Hellstrom <daniel@gaisler.com>
Signed-off-by: Arun Muthusamy <arun.muthusamy@gaisler.com>
---
 drivers/net/can/grcan.c | 18 +++++++++++++++---
 1 file changed, 15 insertions(+), 3 deletions(-)

diff --git a/drivers/net/can/grcan.c b/drivers/net/can/grcan.c
index 3b1b09943436..f3821e224f4f 100644
--- a/drivers/net/can/grcan.c
+++ b/drivers/net/can/grcan.c
@@ -34,7 +34,7 @@
 #include <linux/spinlock.h>
 #include <linux/of.h>
 #include <linux/of_irq.h>
-
+#include <linux/clk.h>
 #include <linux/dma-mapping.h>

 #define DRV_NAME	"grcan"
@@ -1644,6 +1644,7 @@ static int grcan_probe(struct platform_device *ofdev)
 {
 	struct device_node *np = ofdev->dev.of_node;
 	struct device_node *sysid_parent;
+	struct clk *clk;
 	u32 sysid, ambafreq;
 	int irq, err;
 	void __iomem *base;
@@ -1663,8 +1664,19 @@ static int grcan_probe(struct platform_device *ofdev)

 	err = of_property_read_u32(np, "freq", &ambafreq);
 	if (err) {
-		dev_err(&ofdev->dev, "unable to fetch \"freq\" property\n");
-		goto exit_error;
+		clk = devm_clk_get(&ofdev->dev, NULL);
+		if (IS_ERR(clk)) {
+			dev_err_probe(&ofdev->dev, PTR_ERR(clk),
+				      "Failed both to get \"freq\" property and clock for fallback\n");
+			err = PTR_ERR(clk);
+			goto exit_error;
+		}
+
+		ambafreq = clk_get_rate(clk);
+		if (!ambafreq) {
+			dev_err(&ofdev->dev, "Invalid or Uninitialized clock\n");
+			return -EINVAL;
+		}
 	}

 	base = devm_platform_ioremap_resource(ofdev, 0);
--
2.51.0