Re: [PATCH v9 4/4] can: m_can: Support pinctrl wakeup state

[Kendall Willis <k-willis@ti.com>]

On 9/4/25 04:05, Dhruva Gole wrote:
> On Aug 20, 2025 at 14:42:28 +0200, Markus Schneider-Pargmann wrote:
>> am62 requires a wakeup flag being set in pinctrl when mcan pins acts as
> 
> Let's call it "TI AM62x SoC" or TI K3 SoCs? This commit goes into a driver so let's not assume
> everyone knows what am62 means ;)
> 
> Also nit: s/"mcan pins acts"/"mcan pins act"/
> 
>> a wakeup source. Add support to select the wakeup state if WOL is
>> enabled.
>>
>> Signed-off-by: Markus Schneider-Pargmann <msp@baylibre.com>
>> ---
>>   drivers/net/can/m_can/m_can.c | 69 +++++++++++++++++++++++++++++++++++++++++--
>>   drivers/net/can/m_can/m_can.h |  3 ++
>>   2 files changed, 70 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/net/can/m_can/m_can.c b/drivers/net/can/m_can/m_can.c
>> index e08fae5ddf5efa8345670dd50d50954ec5d52b29..a1fa4b2f6b6cc94e5e10259cca53bd931ab238c8 100644
>> --- a/drivers/net/can/m_can/m_can.c
>> +++ b/drivers/net/can/m_can/m_can.c
>> @@ -2249,7 +2249,26 @@ static int m_can_set_wol(struct net_device *dev, struct ethtool_wolinfo *wol)
>>   		return ret;
>>   	}
>>   
>> +	if (!IS_ERR_OR_NULL(cdev->pinctrl_state_wakeup)) {
>> +		if (wol_enable)
>> +			ret = pinctrl_select_state(cdev->pinctrl, cdev->pinctrl_state_wakeup);
>> +		else
>> +			ret = pinctrl_pm_select_default_state(cdev->dev);
>> +
>> +		if (ret) {
>> +			netdev_err(cdev->net, "Failed to select pinctrl state %pE\n",
>> +				   ERR_PTR(ret));
>> +			goto err_wakeup_enable;
>> +		}
>> +	}
>> +
>>   	return 0;
>> +
>> +err_wakeup_enable:
>> +	/* Revert wakeup enable */
>> +	device_set_wakeup_enable(cdev->dev, !wol_enable);
>> +
>> +	return ret;
>>   }
>>   
>>   static const struct ethtool_ops m_can_ethtool_ops_coalescing = {
>> @@ -2377,6 +2396,42 @@ int m_can_class_get_clocks(struct m_can_classdev *cdev)
>>   }
>>   EXPORT_SYMBOL_GPL(m_can_class_get_clocks);
>>   
>> +static bool m_can_class_wakeup_pinctrl_enabled(struct m_can_classdev *class_dev)
>> +{
>> +	return device_may_wakeup(class_dev->dev) && class_dev->pinctrl_state_wakeup;
>> +}
>> +
>> +static int m_can_class_setup_optional_pinctrl(struct m_can_classdev *class_dev)
>> +{
>> +	struct device *dev = class_dev->dev;
>> +	int ret;
>> +
>> +	class_dev->pinctrl = devm_pinctrl_get(dev);
>> +	if (IS_ERR(class_dev->pinctrl)) {
>> +		ret = PTR_ERR(class_dev->pinctrl);
>> +		class_dev->pinctrl = NULL;
>> +
>> +		if (ret == -ENODEV)
>> +			return 0;
>> +
>> +		return dev_err_probe(dev, ret, "Failed to get pinctrl\n");
>> +	}
>> +
>> +	class_dev->pinctrl_state_wakeup =
>> +		pinctrl_lookup_state(class_dev->pinctrl, "wakeup");
>> +	if (IS_ERR(class_dev->pinctrl_state_wakeup)) {
>> +		ret = PTR_ERR(class_dev->pinctrl_state_wakeup);
>> +		class_dev->pinctrl_state_wakeup = NULL;
>> +
>> +		if (ret == -ENODEV)
>> +			return 0;
>> +
>> +		return dev_err_probe(dev, ret, "Failed to lookup pinctrl wakeup state\n");
>> +	}
>> +
>> +	return 0;
>> +}
>> +
>>   struct m_can_classdev *m_can_class_allocate_dev(struct device *dev,
>>   						int sizeof_priv)
>>   {
>> @@ -2418,7 +2473,15 @@ struct m_can_classdev *m_can_class_allocate_dev(struct device *dev,
>>   	m_can_of_parse_mram(class_dev, mram_config_vals);
>>   	spin_lock_init(&class_dev->tx_handling_spinlock);
>>   
>> +	ret = m_can_class_setup_optional_pinctrl(class_dev);
> 
> optional makes it sound a little confusing IMO, might make sense to call
> it something like m_can_class_configure_pinctrl or m_can_class_setup_wakeup_pinctrl

I agree it should be changed to something different. Maybe you could add 
a comment or add in the commit message denoting that configuring the 
pinctrl is optional?

> 
>> +	if (ret)
>> +		goto err_free_candev;
>> +
>>   	return class_dev;
>> +
>> +err_free_candev:
>> +	free_candev(net_dev);
>> +	return ERR_PTR(ret);
>>   }
>>   EXPORT_SYMBOL_GPL(m_can_class_allocate_dev);
>>   
>> @@ -2533,7 +2596,8 @@ int m_can_class_suspend(struct device *dev)
>>   		m_can_clk_stop(cdev);
>>   	}
>>   
>> -	pinctrl_pm_select_sleep_state(dev);
>> +	if (!m_can_class_wakeup_pinctrl_enabled(cdev))
>> +		pinctrl_pm_select_sleep_state(dev);
>>   
>>   	cdev->can.state = CAN_STATE_SLEEPING;
>>   
>> @@ -2547,7 +2611,8 @@ int m_can_class_resume(struct device *dev)
>>   	struct net_device *ndev = cdev->net;
>>   	int ret = 0;
>>   
>> -	pinctrl_pm_select_default_state(dev);
>> +	if (!m_can_class_wakeup_pinctrl_enabled(cdev))
>> +		pinctrl_pm_select_default_state(dev);
>>   
>>   	cdev->can.state = CAN_STATE_ERROR_ACTIVE;
>>   
>> diff --git a/drivers/net/can/m_can/m_can.h b/drivers/net/can/m_can/m_can.h
>> index bd4746c63af3f0a032910644dfd48a9ebb3a6168..583c7f1d005d61b3fc8587697388522993ff11a8 100644
>> --- a/drivers/net/can/m_can/m_can.h
>> +++ b/drivers/net/can/m_can/m_can.h
>> @@ -128,6 +128,9 @@ struct m_can_classdev {
>>   	struct mram_cfg mcfg[MRAM_CFG_NUM];
>>   
>>   	struct hrtimer hrtimer;
>> +
>> +	struct pinctrl *pinctrl;
>> +	struct pinctrl_state *pinctrl_state_wakeup;
>>   };
>>   
>>   struct m_can_classdev *m_can_class_allocate_dev(struct device *dev, int sizeof_priv);
>>
>> -- 
>> 2.50.1
>>
>