linux-kernel - Re: [PATCH v2 1/2] phy: add new phy_notify

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Message-ID: <e2lhm237c3xtbdjux2wuesq5fwu7nky3w7oq2fnsgn2pqcg5kh@xhxktriooyes>
Date: Tue, 22 Jul 2025 22:04:08 +0530
From: Manivannan Sadhasivam <mani@...nel.org>
To: Peter Griffin <peter.griffin@...aro.org>
Cc: Vinod Koul <vkoul@...nel.org>, 
	Kishon Vijay Abraham I <kishon@...nel.org>, André Draszik <andre.draszik@...aro.org>, 
	Tudor Ambarus <tudor.ambarus@...aro.org>, Alim Akhtar <alim.akhtar@...sung.com>, 
	Krzysztof Kozlowski <krzk@...nel.org>, linux-phy@...ts.infradead.org, linux-kernel@...r.kernel.org, 
	linux-arm-kernel@...ts.infradead.org, linux-samsung-soc@...r.kernel.org, kernel-team@...roid.com, 
	William Mcvicker <willmcvicker@...gle.com>
Subject: Re: [PATCH v2 1/2] phy: add new phy_notify_pmstate() api

On Thu, Jul 03, 2025 at 02:03:22PM GMT, Peter Griffin wrote:
> Add a new phy_notify_pmstate() api that notifies and configures a phy for a
> given PM link state transition.
> 
> This is intended to be by phy drivers which need to do some runtime
> configuration of parameters during the transition that can't be handled by
> phy_calibrate() or phy_power_{on|off}().
> 
> The first usage of this API is in the Samsung UFS phy that needs to issue
> some register writes when entering and exiting the hibernate link state.
> 
> Signed-off-by: Peter Griffin <peter.griffin@...aro.org>
> ---
>  drivers/phy/phy-core.c  | 25 +++++++++++++++++++++++++
>  include/linux/phy/phy.h | 25 +++++++++++++++++++++++++
>  2 files changed, 50 insertions(+)
> 
> diff --git a/drivers/phy/phy-core.c b/drivers/phy/phy-core.c
> index 04a5a34e7a950ae94fae915673c25d476fc071c1..0b29bc2c709890d7fc27d1480a35cda6a826fd30 100644
> --- a/drivers/phy/phy-core.c
> +++ b/drivers/phy/phy-core.c
> @@ -520,6 +520,31 @@ int phy_notify_disconnect(struct phy *phy, int port)
>  }
>  EXPORT_SYMBOL_GPL(phy_notify_disconnect);
>  
> +/**
> + * phy_notify_pmstate() - phy link state notification

'pmstate' doesn't correspond to 'link state'. So how about,
phy_notify_link_state()?

s/phy/PHY (here and below)

> + * @phy: the phy returned by phy_get()
> + * @state: the link state
> + *
> + * Notify the phy of some PM link state transition. Used to notify and

Link state change is common for the PHY. So remove 'PM'.

> + * configure the phy accordingly.
> + *
> + * Returns: %0 if successful, a negative error code otherwise
> + */
> +int phy_notify_pmstate(struct phy *phy, enum phy_linkstate state)

I think you need to use 'int state' and let drivers pass their own link state
values. You cannot have generic link states across all peripherals.

> +{
> +	int ret;
> +
> +	if (!phy || !phy->ops->notify_pmstate)
> +		return 0;
> +
> +	mutex_lock(&phy->mutex);
> +	ret = phy->ops->notify_pmstate(phy, state);

'notify_link_state'

> +	mutex_unlock(&phy->mutex);
> +
> +	return ret;
> +}
> +EXPORT_SYMBOL_GPL(phy_notify_pmstate);
> +
>  /**
>   * phy_configure() - Changes the phy parameters
>   * @phy: the phy returned by phy_get()
> diff --git a/include/linux/phy/phy.h b/include/linux/phy/phy.h
> index 13add0c2c40721fe9ca3f0350d13c035cd25af45..d904ec4edb7e2be41fcf6ab780d3148c2ee8a950 100644
> --- a/include/linux/phy/phy.h
> +++ b/include/linux/phy/phy.h
> @@ -53,6 +53,11 @@ enum phy_media {
>  	PHY_MEDIA_DAC,
>  };
>  
> +enum phy_linkstate {
> +	PHY_UFS_HIBERN8_ENTER,
> +	PHY_UFS_HIBERN8_EXIT,
> +};

Please move these to include/linux/phy/ufs.h as defines.

> +
>  /**
>   * union phy_configure_opts - Opaque generic phy configuration
>   *
> @@ -132,6 +137,18 @@ struct phy_ops {
>  	int	(*connect)(struct phy *phy, int port);
>  	int	(*disconnect)(struct phy *phy, int port);
>  
> +	/**
> +	 * @notify_pmstate:
> +	 *
> +	 * Optional.
> +	 *
> +	 * Used to notify and configure the phy for a PM link state
> +	 * transition.
> +	 *
> +	 * Returns: 0 if successful, an negative error code otherwise

I think you can drop the inline comment and just add to the top level
kernel-doc.

- Mani

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