Re: [PATCH v3 04/15] can: grcan: Add clock handling

[Arun Muthusamy <arun.muthusamy@gaisler.com>]

On 1/23/26 14:44, Marc Kleine-Budde wrote:
> On 22.01.2026 13:10:27, Arun Muthusamy wrote:
>> 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 | 19 ++++++++++++++++---
>>   1 file changed, 16 insertions(+), 3 deletions(-)
>>
>> diff --git a/drivers/net/can/grcan.c b/drivers/net/can/grcan.c
>> index 3b1b09943436..538a9b4f82ab 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 +1664,20 @@ 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;
>> +		}
> I think devm_clk_get() either returns an error pointer or a valid clock
> pointer.
>
>> +		if (clk) {
>> +			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);
>>
you are correct, since devm_clk_get() returns either a valid clock pointer or an error pointer, "if (clk)" check is indeed redundant.