linux-kernel - Re: [Patch V3 04/18] phy: tegra: xusb: Add usb-phy support

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Date:   Tue, 28 Jan 2020 18:38:40 +0100
From:   Thierry Reding <thierry.reding@...il.com>
To:     Nagarjuna Kristam <nkristam@...dia.com>
Cc:     balbi@...nel.org, gregkh@...uxfoundation.org, jonathanh@...dia.com,
        mark.rutland@....com, robh+dt@...nel.org, kishon@...com,
        devicetree@...r.kernel.org, linux-tegra@...r.kernel.org,
        linux-usb@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [Patch V3 04/18] phy: tegra: xusb: Add usb-phy support

On Mon, Dec 30, 2019 at 04:39:41PM +0530, Nagarjuna Kristam wrote:
> For USB 2 ports that has usb-role-switch enabled, add usb-phy for
> corresponding USB 2 phy. USB role changes from role switch are then
> updated to corresponding host and device mode drivers via usb-phy notifier
> block.
> 
> Signed-off-by: Nagarjuna Kristam <nkristam@...dia.com>
> ---
> V3:
>  - Updated arguments and variable allignments as per Thierry inputs.
> ---
> V2:
>  - Added dev_set_drvdata for port->dev.
> ---
>  drivers/phy/tegra/xusb.c | 71 ++++++++++++++++++++++++++++++++++++++++++++++++
>  drivers/phy/tegra/xusb.h |  2 ++
>  2 files changed, 76 insertions(+)
> 
> diff --git a/drivers/phy/tegra/xusb.c b/drivers/phy/tegra/xusb.c
> index 11ea9b5..536b2fc 100644
> --- a/drivers/phy/tegra/xusb.c
> +++ b/drivers/phy/tegra/xusb.c
> @@ -533,6 +533,8 @@ static int tegra_xusb_port_init(struct tegra_xusb_port *port,
>  	if (err < 0)
>  		goto unregister;
>  
> +	dev_set_drvdata(&port->dev, port);
> +
>  	return 0;
>  
>  unregister:
> @@ -545,6 +547,8 @@ static void tegra_xusb_port_unregister(struct tegra_xusb_port *port)
>  	if (!IS_ERR_OR_NULL(port->usb_role_sw)) {
>  		of_platform_depopulate(&port->dev);
>  		usb_role_switch_unregister(port->usb_role_sw);
> +		cancel_work_sync(&port->usb_phy_work);
> +		usb_remove_phy(&port->usb_phy);
>  	}
>  
>  	device_unregister(&port->dev);
> @@ -563,15 +567,62 @@ static const char * const usb_roles[] = {
>  	[USB_ROLE_DEVICE]	= "device",
>  };
>  
> +static void tegra_xusb_usb_phy_work(struct work_struct *work)
> +{
> +	struct tegra_xusb_port *port = container_of(work,
> +						    struct tegra_xusb_port,
> +						    usb_phy_work);
> +	enum usb_role role = usb_role_switch_get_role(port->usb_role_sw);
> +
> +	dev_dbg(&port->dev, "%s: calling notifier for role %s\n", __func__,
> +		usb_roles[role]);

Nit: I'd add parentheses into the above message, after %s, to highlight
that this is the name of a function.

> +
> +	atomic_notifier_call_chain(&port->usb_phy.notifier, role,
> +				   &port->usb_phy);
> +}
> +
>  static int tegra_xusb_role_sw_set(struct device *dev, enum usb_role role)
>  {
> +	struct tegra_xusb_port *port = dev_get_drvdata(dev);
> +
>  	dev_dbg(dev, "%s: role %s\n", __func__, usb_roles[role]);
>  
> +	schedule_work(&port->usb_phy_work);
> +
>  	return 0;
>  }
>  
> +static int tegra_xusb_set_peripheral(struct usb_otg *otg,
> +				     struct usb_gadget *gadget)
> +{
> +	struct tegra_xusb_port *port = container_of(otg->usb_phy,
> +						    struct tegra_xusb_port,
> +						    usb_phy);
> +
> +	if (gadget != NULL)
> +		schedule_work(&port->usb_phy_work);
> +
> +	return 0;
> +}
> +
> +static int tegra_xusb_set_host(struct usb_otg *otg, struct usb_bus *host)
> +{
> +	struct tegra_xusb_port *port = container_of(otg->usb_phy,
> +						    struct tegra_xusb_port,
> +						    usb_phy);
> +
> +	if (host != NULL)
> +		schedule_work(&port->usb_phy_work);
> +
> +	return 0;
> +}
> +
> +
>  static int tegra_xusb_setup_usb_role_switch(struct tegra_xusb_port *port)
>  {
> +	struct tegra_xusb_lane *lane = tegra_xusb_find_lane(port->padctl,
> +							    "usb2",
> +							    port->index);

Nit: This looks slightly awkward. It might be worth just declaring the
variable here and move the initialization to a separate line following
the declarations because then it fits on a single line.

>  	struct usb_role_switch_desc role_sx_desc = {
>  		.fwnode = dev_fwnode(&port->dev),
>  		.set = tegra_xusb_role_sw_set,
> @@ -587,6 +638,29 @@ static int tegra_xusb_setup_usb_role_switch(struct tegra_xusb_port *port)
>  		return err;
>  	}
>  
> +	INIT_WORK(&port->usb_phy_work, tegra_xusb_usb_phy_work);
> +
> +	port->usb_phy.otg = devm_kzalloc(&port->dev,
> +					 sizeof(struct usb_otg), GFP_KERNEL);

Nit: typically you try to fill up a line as much as possible before you
wrap, so the sizeof(...) can go onto the first line.

> +	if (!port->usb_phy.otg)
> +		return -ENOMEM;
> +
> +	/*
> +	 * Assign phy dev to usb-phy dev. Host/device drivers can use phy
> +	 * reference to retrieve usb-phy details.
> +	 */
> +	port->usb_phy.dev = &lane->pad->lanes[port->index]->dev;
> +	port->usb_phy.dev->driver = port->padctl->dev->driver;
> +	port->usb_phy.otg->usb_phy = &port->usb_phy;
> +	port->usb_phy.otg->set_peripheral = tegra_xusb_set_peripheral;
> +	port->usb_phy.otg->set_host = tegra_xusb_set_host;
> +
> +	err = usb_add_phy_dev(&port->usb_phy);
> +	if (err < 0) {
> +		dev_err(&port->dev, "Failed to add usbphy: %d\n", err);

Nit: "failed to add USB PHY: %d\n", to make this more consistent with
the existing error messages.

Other than that, looks great:

Acked-by: Thierry Reding <treding@...dia.com>

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