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

[Dhruva Gole <d-gole@ti.com>]

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

> +	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
> 

-- 
Best regards,
Dhruva Gole
Texas Instruments Incorporated