Re: [PATCH] usb: host: ehci-platform: add support for optional external vbus supply

From: Roger Quadros
Date: Tue Feb 20 2018 - 04:27:43 EST


Hi,

On 20/02/18 11:11, Amelie Delaunay wrote:
> On some boards, especially when vbus supply requires large current,
> and the charge pump on the PHY isn't enough, an external vbus power switch
> may be used.
> Add support for this optional external vbus supply in ehci-platform.

Isn't this generic enough to be done for all *hci-platform drivers?

And if this is a VBUS supply to the port, the root hub driver should be controlling it
based on port power on/off commands to the port right?

>
> Signed-off-by: Amelie Delaunay <amelie.delaunay@xxxxxx>
> ---
> Documentation/devicetree/bindings/usb/usb-ehci.txt | 1 +
> drivers/usb/host/ehci-platform.c | 23 ++++++++++++++++++++++
> 2 files changed, 24 insertions(+)
>
> diff --git a/Documentation/devicetree/bindings/usb/usb-ehci.txt b/Documentation/devicetree/bindings/usb/usb-ehci.txt
> index 3efde12..fc480cd 100644
> --- a/Documentation/devicetree/bindings/usb/usb-ehci.txt
> +++ b/Documentation/devicetree/bindings/usb/usb-ehci.txt
> @@ -19,6 +19,7 @@ Optional properties:
> - phys : phandle + phy specifier pair
> - phy-names : "usb"
> - resets : phandle + reset specifier pair
> + - vbus-supply : phandle of regulator supplying vbus
>
> Example (Sequoia 440EPx):
> ehci@e0000300 {
> diff --git a/drivers/usb/host/ehci-platform.c b/drivers/usb/host/ehci-platform.c
> index b065a96..76cc781 100644
> --- a/drivers/usb/host/ehci-platform.c
> +++ b/drivers/usb/host/ehci-platform.c
> @@ -29,6 +29,7 @@
> #include <linux/of.h>
> #include <linux/phy/phy.h>
> #include <linux/platform_device.h>
> +#include <linux/regulator/consumer.h>
> #include <linux/reset.h>
> #include <linux/usb.h>
> #include <linux/usb/hcd.h>
> @@ -46,6 +47,7 @@ struct ehci_platform_priv {
> struct reset_control *rsts;
> struct phy **phys;
> int num_phys;
> + struct regulator *vbus_supply;
> bool reset_on_resume;
> };
>
> @@ -99,6 +101,15 @@ static int ehci_platform_power_on(struct platform_device *dev)
> }
> }
>
> + if (priv->vbus_supply) {
> + ret = regulator_enable(priv->vbus_supply);
> + if (ret) {
> + dev_err(&dev->dev,
> + "failed to enable vbus supply: %d\n", ret);
> + goto err_exit_phy;
> + }
> + }
> +
> return 0;
>
> err_exit_phy:
> @@ -119,6 +130,9 @@ static void ehci_platform_power_off(struct platform_device *dev)
> struct ehci_platform_priv *priv = hcd_to_ehci_priv(hcd);
> int clk, phy_num;
>
> + if (priv->vbus_supply)
> + regulator_disable(priv->vbus_supply);
> +

If we disable the VBUS here, which is being called during ehci_platform_suspend(),
how can we expect remote wakeup to work?
This is unconditionally powering down the port.

> for (phy_num = 0; phy_num < priv->num_phys; phy_num++) {
> phy_power_off(priv->phys[phy_num]);
> phy_exit(priv->phys[phy_num]);
> @@ -247,6 +261,15 @@ static int ehci_platform_probe(struct platform_device *dev)
> if (err)
> goto err_put_clks;
>
> + priv->vbus_supply = devm_regulator_get_optional(&dev->dev, "vbus");
> + if (IS_ERR(priv->vbus_supply)) {
> + err = PTR_ERR(priv->vbus_supply);
> + if (err == -ENODEV)
> + priv->vbus_supply = NULL;
> + else
> + goto err_reset;
> + }
> +
> if (pdata->big_endian_desc)
> ehci->big_endian_desc = 1;
> if (pdata->big_endian_mmio)
>

--
cheers,
-roger

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