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

Arun Muthusamy
2026-01-27T13:27:41Z

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.