On Thu, Nov 23, 2023 at 02:47:20PM +0100, Frieder Schrempf wrote:
> From: Frieder Schrempf <frieder.schrempf@xxxxxxxxxx>
>
> Most onboard USB hubs have a dedicated crystal oscillator but on some
> boards the clock signal for the hub is provided by the SoC.
>
> In order to support this, we add the possibility of specifying a
> clock in the devicetree that gets enabled/disabled when the hub
> is powered up/down.
>
> Signed-off-by: Frieder Schrempf <frieder.schrempf@xxxxxxxxxx>
> ---
> drivers/usb/misc/onboard_usb_hub.c | 14 ++++++++++++++
> 1 file changed, 14 insertions(+)
>
> diff --git a/drivers/usb/misc/onboard_usb_hub.c b/drivers/usb/misc/onboard_usb_hub.c
> index a341b2fbb7b44..e710e3c82ba9b 100644
> --- a/drivers/usb/misc/onboard_usb_hub.c
> +++ b/drivers/usb/misc/onboard_usb_hub.c
> @@ -5,6 +5,7 @@
> * Copyright (c) 2022, Google LLC
> */
>
> +#include <linux/clk.h>
> #include <linux/device.h>
> #include <linux/export.h>
> #include <linux/gpio/consumer.h>
> @@ -60,12 +61,19 @@ struct onboard_hub {
> bool going_away;
> struct list_head udev_list;
> struct mutex lock;
> + struct clk *clk;
> };
>
> static int onboard_hub_power_on(struct onboard_hub *hub)
> {
> int err;
>
> + err = clk_prepare_enable(hub->clk);
> + if (err) {
> + dev_err(hub->dev, "failed to enable clock: %d\n", err);
> + return err;
> + }
But what happens if clk is not set here?
And doesn't clk_prepare_enable() print out a message if it fails?
thanks,
greg k-h
