[PATCH v4 1/7] usb: onboard-hub: Add reset-gpio support

[Venkatesh Yadav Abbarapu]

As part of the reset, sets the direction of the pin to output before
toggling the pin. Delay of millisecond is added in between low and
high to meet the setup and hold time requirement of the reset.

Signed-off-by: Venkatesh Yadav Abbarapu <venkatesh.abbar...@amd.com>
---
 common/usb_onboard_hub.c | 35 ++++++++++++++++++++++++++++++++++-
 1 file changed, 34 insertions(+), 1 deletion(-)

diff --git a/common/usb_onboard_hub.c b/common/usb_onboard_hub.c
index 68a04ac041..9ecc638c7a 100644
--- a/common/usb_onboard_hub.c
+++ b/common/usb_onboard_hub.c
@@ -7,16 +7,26 @@
  * Mostly inspired by Linux kernel v6.1 onboard_usb_hub driver
  */
 
+#include <asm/gpio.h>
 #include <dm.h>
 #include <dm/device_compat.h>
+#include <linux/delay.h>
 #include <power/regulator.h>
 
 struct onboard_hub {
        struct udevice *vdd;
+       struct gpio_desc *reset_gpio;
+};
+
+struct onboard_hub_data {
+       unsigned long reset_us;
+       unsigned long power_on_delay_us;
 };
 
 static int usb_onboard_hub_probe(struct udevice *dev)
 {
+       struct onboard_hub_data *data =
+               (struct onboard_hub_data *)dev_get_driver_data(dev);
        struct onboard_hub *hub = dev_get_priv(dev);
        int ret;
 
@@ -30,7 +40,24 @@ static int usb_onboard_hub_probe(struct udevice *dev)
        if (ret)
                dev_err(dev, "can't enable vdd-supply: %d\n", ret);
 
-       return ret;
+       hub->reset_gpio = devm_gpiod_get_optional(dev, "reset",
+                                                 GPIOD_IS_OUT | 
GPIOD_ACTIVE_LOW);
+       /* property is optional, don't return error! */
+       if (hub->reset_gpio) {
+               ret = dm_gpio_set_value(hub->reset_gpio, 1);
+               if (ret)
+                       return ret;
+
+               udelay(data->reset_us);
+
+               ret = dm_gpio_set_value(hub->reset_gpio, 0);
+               if (ret)
+                       return ret;
+
+               udelay(data->power_on_delay_us);
+       }
+
+       return 0;
 }
 
 static int usb_onboard_hub_remove(struct udevice *dev)
@@ -38,6 +65,12 @@ static int usb_onboard_hub_remove(struct udevice *dev)
        struct onboard_hub *hub = dev_get_priv(dev);
        int ret;
 
+       if (hub->reset_gpio) {
+               struct gpio_desc *hub_reset_gpio = hub->reset_gpio;
+
+               dm_gpio_free(hub_reset_gpio->dev, hub_reset_gpio);
+       }
+
        ret = regulator_set_enable_if_allowed(hub->vdd, false);
        if (ret)
                dev_err(dev, "can't disable vdd-supply: %d\n", ret);
-- 
2.17.1