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SubjectRe: [PATCH v3] usb: host: ehci-platform: add support for optional external vbus supply
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Hi Amelie,

Just a couple of drive-by coding style comments...

On 23/02/18 13:46, 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 optional external vbus supply per port in ehci-platform.
>
> Signed-off-by: Amelie Delaunay <amelie.delaunay@st.com>
>
> ---
> Changes in v3:
> * Address Felipe Balbi comments: reduce indentation in
> ehci_platform_port_power.
> * Address Roger Quadros and Alan Stern comments: platforms can have one
> external vbus supply per port, so add support to get as many optional
> regulator as implemented ports on the host controller.
>
> Changes in v2:
> * Address Roger Quadros comments: move regulator_enable/disable from
> ehci_platform_power_on/off to ehci_platform_port_power.
> ---
> Documentation/devicetree/bindings/usb/usb-ehci.txt | 1 +
> drivers/usb/host/ehci-platform.c | 52 +++++++++++++++++++++-
> 2 files changed, 52 insertions(+), 1 deletion(-)
>
> diff --git a/Documentation/devicetree/bindings/usb/usb-ehci.txt b/Documentation/devicetree/bindings/usb/usb-ehci.txt
> index 3efde12..cd576db 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
> + - portN_vbus-supply : phandle of regulator supplying vbus for port N
>
> Example (Sequoia 440EPx):
> ehci@e0000300 {
> diff --git a/drivers/usb/host/ehci-platform.c b/drivers/usb/host/ehci-platform.c
> index b065a96..8e9f201 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_supplies;
> bool reset_on_resume;
> };
>
> @@ -56,7 +58,8 @@ static int ehci_platform_reset(struct usb_hcd *hcd)
> struct platform_device *pdev = to_platform_device(hcd->self.controller);
> struct usb_ehci_pdata *pdata = dev_get_platdata(&pdev->dev);
> struct ehci_hcd *ehci = hcd_to_ehci(hcd);
> - int retval;
> + struct ehci_platform_priv *priv = hcd_to_ehci_priv(hcd);
> + int portnum, n_ports, retval;
>
> ehci->has_synopsys_hc_bug = pdata->has_synopsys_hc_bug;
>
> @@ -71,11 +74,57 @@ static int ehci_platform_reset(struct usb_hcd *hcd)
> if (retval)
> return retval;
>
> + n_ports = HCS_N_PORTS(ehci->hcs_params);
> + priv->vbus_supplies = devm_kcalloc(&pdev->dev, n_ports,
> + sizeof(struct regulator *),

Using "sizeof(*priv->vbus_supplies)" here will prevent people sending
annoying cleanup patches later.

> + GFP_KERNEL);
> + if (!priv->vbus_supplies)
> + return -ENOMEM;
> +
> + for (portnum = 0; portnum < n_ports; portnum++) {
> + struct regulator *vbus_supply;
> + char id[20];
> +
> + sprintf(id, "port%d_vbus", portnum);
> +
> + vbus_supply = devm_regulator_get_optional(&pdev->dev, id);
> + if (IS_ERR(vbus_supply)) {
> + retval = PTR_ERR(vbus_supply);
> + if (retval == -ENODEV)
> + priv->vbus_supplies[portnum] = NULL;

The array element here hasn't yet been assigned to since kcalloc()
initially zeroed it, so this is entirely redundant - you can simply make
the comparison a "!=" and remove the "else" case.

Robin.

> + else
> + return retval;
> + } else {
> + priv->vbus_supplies[portnum] = vbus_supply;
> + }
> + }
> +
> if (pdata->no_io_watchdog)
> ehci->need_io_watchdog = 0;
> return 0;
> }
>
> +static int ehci_platform_port_power(struct usb_hcd *hcd, int portnum,
> + bool enable)
> +{
> + struct ehci_platform_priv *priv = hcd_to_ehci_priv(hcd);
> + int ret;
> +
> + if (!priv->vbus_supplies[portnum])
> + return 0;
> +
> + if (enable)
> + ret = regulator_enable(priv->vbus_supplies[portnum]);
> + else
> + ret = regulator_disable(priv->vbus_supplies[portnum]);
> + if (ret)
> + dev_err(hcd->self.controller,
> + "failed to %s vbus supply for port %d: %d\n",
> + enable ? "enable" : "disable", portnum, ret);
> +
> + return ret;
> +}
> +
> static int ehci_platform_power_on(struct platform_device *dev)
> {
> struct usb_hcd *hcd = platform_get_drvdata(dev);
> @@ -134,6 +183,7 @@ static struct hc_driver __read_mostly ehci_platform_hc_driver;
> static const struct ehci_driver_overrides platform_overrides __initconst = {
> .reset = ehci_platform_reset,
> .extra_priv_size = sizeof(struct ehci_platform_priv),
> + .port_power = ehci_platform_port_power,
> };
>
> static struct usb_ehci_pdata ehci_platform_defaults = {
>

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