usb: misc: onboard_usb_hub: Add support for clock input

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@kontron.de>
Link: https://lore.kernel.org/r/20231127112234.109073-2-frieder@fris.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/usb/misc/onboard_usb_hub.c b/drivers/usb/misc/onboard_usb_hub.c
index 6d122772a9706475a95cd370ffb70bfb1b76e756..3b209104f648fd765b4b3a0532732546b45b8a84 100644 (file)
--- 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/err.h>
@@ -61,12 +62,19 @@ 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: %pe\n", ERR_PTR(err));
+               return err;
+       }
+
        err = regulator_bulk_enable(hub->pdata->num_supplies, hub->supplies);
        if (err) {
                dev_err(hub->dev, "failed to enable supplies: %pe\n", ERR_PTR(err));
@@ -93,6 +101,8 @@ static int onboard_hub_power_off(struct onboard_hub *hub)
                return err;
        }
 
+       clk_disable_unprepare(hub->clk);
+
        hub->is_powered_on = false;
 
        return 0;
@@ -267,6 +277,10 @@ static int onboard_hub_probe(struct platform_device *pdev)
                return err;
        }
 
+       hub->clk = devm_clk_get_optional(dev, NULL);
+       if (IS_ERR(hub->clk))
+               return dev_err_probe(dev, PTR_ERR(hub->clk), "failed to get clock\n");
+
        hub->reset_gpio = devm_gpiod_get_optional(dev, "reset",
                                                  GPIOD_OUT_HIGH);
        if (IS_ERR(hub->reset_gpio))