kernel: dwc2: add support for host mode external vbus supply

Backport patch adding support for the vbus-supply devicetree property,
which allows to specific GPIOs (via fixed regulators) to enable
vbus/usb power.

Signed-off-by: Mathias Kresin <dev@kresin.me>

2 files changed, 164 insertions, 0 deletions

diff --git a/target/linux/generic/backport-4.14/030-v4.17-0001-usb-dwc2-add-support-for-host-mode-external-vbus-sup.patch b/target/linux/generic/backport-4.14/030-v4.17-0001-usb-dwc2-add-support-for-host-mode-external-vbus-sup.patch
new file mode 100644
index 0000000000..f490639f39
--- /dev/null
+++ b/target/linux/generic/backport-4.14/030-v4.17-0001-usb-dwc2-add-support-for-host-mode-external-vbus-sup.patch
@@ -0,0 +1,109 @@
+From 531ef5ebea96394ddb7f554d4d88e017dde30a59 Mon Sep 17 00:00:00 2001
+From: Amelie Delaunay <amelie.delaunay@st.com>
+Date: Tue, 13 Feb 2018 09:28:12 +0100
+Subject: [PATCH] usb: dwc2: add support for host mode external vbus supply
+
+This patch adds a way to enable an external vbus supply in host mode,
+when dwc2 drvvbus signal is not used.
+
+This patch is very similar to the one done in U-Boot dwc2 driver [1]. It
+also adds dynamic vbus supply management depending on the role and state
+of the core.
+
+[1] https://lists.denx.de/pipermail/u-boot/2017-March/283434.html
+
+Signed-off-by: Amelie Delaunay <amelie.delaunay@st.com>
+Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>
+---
+ drivers/usb/dwc2/core.h |  2 ++
+ drivers/usb/dwc2/hcd.c  | 26 ++++++++++++++++++++++++++
+ 2 files changed, 28 insertions(+)
+
+--- a/drivers/usb/dwc2/core.h
++++ b/drivers/usb/dwc2/core.h
+@@ -777,6 +777,7 @@ struct dwc2_hregs_backup {
+  * @plat:               The platform specific configuration data. This can be
+  *                      removed once all SoCs support usb transceiver.
+  * @supplies:           Definition of USB power supplies
++ * @vbus_supply:        Regulator supplying vbus.
+  * @phyif:              PHY interface width
+  * @lock:		Spinlock that protects all the driver data structures
+  * @priv:		Stores a pointer to the struct usb_hcd
+@@ -913,6 +914,7 @@ struct dwc2_hsotg {
+ 	struct usb_phy *uphy;
+ 	struct dwc2_hsotg_plat *plat;
+ 	struct regulator_bulk_data supplies[DWC2_NUM_SUPPLIES];
++	struct regulator *vbus_supply;
+ 	u32 phyif;
+ 
+ 	spinlock_t lock;
+--- a/drivers/usb/dwc2/hcd.c
++++ b/drivers/usb/dwc2/hcd.c
+@@ -359,6 +359,23 @@ static void dwc2_gusbcfg_init(struct dwc
+ 	dwc2_writel(usbcfg, hsotg->regs + GUSBCFG);
+ }
+ 
++static int dwc2_vbus_supply_init(struct dwc2_hsotg *hsotg)
++{
++	hsotg->vbus_supply = devm_regulator_get_optional(hsotg->dev, "vbus");
++	if (IS_ERR(hsotg->vbus_supply))
++		return 0;
++
++	return regulator_enable(hsotg->vbus_supply);
++}
++
++static int dwc2_vbus_supply_exit(struct dwc2_hsotg *hsotg)
++{
++	if (hsotg->vbus_supply)
++		return regulator_disable(hsotg->vbus_supply);
++
++	return 0;
++}
++
+ /**
+  * dwc2_enable_host_interrupts() - Enables the Host mode interrupts
+  *
+@@ -3246,6 +3263,7 @@ static void dwc2_conn_id_status_change(s
+ 
+ 	/* B-Device connector (Device Mode) */
+ 	if (gotgctl & GOTGCTL_CONID_B) {
++		dwc2_vbus_supply_exit(hsotg);
+ 		/* Wait for switch to device mode */
+ 		dev_dbg(hsotg->dev, "connId B\n");
+ 		if (hsotg->bus_suspended) {
+@@ -4352,6 +4370,9 @@ static int _dwc2_hcd_start(struct usb_hc
+ 	}
+ 
+ 	spin_unlock_irqrestore(&hsotg->lock, flags);
++
++	dwc2_vbus_supply_init(hsotg);
++
+ 	return 0;
+ }
+ 
+@@ -4379,6 +4400,8 @@ static void _dwc2_hcd_stop(struct usb_hc
+ 	clear_bit(HCD_FLAG_HW_ACCESSIBLE, &hcd->flags);
+ 	spin_unlock_irqrestore(&hsotg->lock, flags);
+ 
++	dwc2_vbus_supply_exit(hsotg);
++
+ 	usleep_range(1000, 3000);
+ }
+ 
+@@ -4415,6 +4438,7 @@ static int _dwc2_hcd_suspend(struct usb_
+ 		hprt0 |= HPRT0_SUSP;
+ 		hprt0 &= ~HPRT0_PWR;
+ 		dwc2_writel(hprt0, hsotg->regs + HPRT0);
++		dwc2_vbus_supply_exit(hsotg);
+ 	}
+ 
+ 	/* Enter hibernation */
+@@ -4495,6 +4519,8 @@ static int _dwc2_hcd_resume(struct usb_h
+ 		spin_unlock_irqrestore(&hsotg->lock, flags);
+ 		dwc2_port_resume(hsotg);
+ 	} else {
++		dwc2_vbus_supply_init(hsotg);
++
+ 		/* Wait for controller to correctly update D+/D- level */
+ 		usleep_range(3000, 5000);
+ 
diff --git a/target/linux/generic/backport-4.14/030-v4.17-0002-usb-dwc2-dwc2_vbus_supply_init-fix-error-check.patch b/target/linux/generic/backport-4.14/030-v4.17-0002-usb-dwc2-dwc2_vbus_supply_init-fix-error-check.patch
new file mode 100644
index 0000000000..f3f93af68d
--- /dev/null
+++ b/target/linux/generic/backport-4.14/030-v4.17-0002-usb-dwc2-dwc2_vbus_supply_init-fix-error-check.patch
@@ -0,0 +1,55 @@
+From 438fea2a6325933868aebc20279e2669c9a21207 Mon Sep 17 00:00:00 2001
+From: Tomeu Vizoso <tomeu.vizoso@collabora.com>
+Date: Mon, 26 Mar 2018 11:00:01 +0200
+Subject: [PATCH] usb: dwc2: dwc2_vbus_supply_init: fix error check
+
+devm_regulator_get_optional returns -ENODEV if the regulator isn't
+there, so if that's the case we have to make sure not to leave -ENODEV
+in the regulator pointer.
+
+Also, make sure we return 0 in that case, but correctly propagate any
+other errors. Also propagate the error from _dwc2_hcd_start.
+
+Fixes: 531ef5ebea96 ("usb: dwc2: add support for host mode external vbus supply")
+Cc: Amelie Delaunay <amelie.delaunay@st.com>
+Reviewed-by: Amelie Delaunay <amelie.delaunay@st.com>
+Reviewed-by: Heiko Stuebner <heiko@sntech.de>
+Reviewed-by: Grigor Tovmasyan <tovmasya@synopsys.com>
+Tested-by: Heiko Stuebner <heiko@sntech.de>
+Acked-by: Minas Harutyunyan <hminas@synopsys.com>
+Signed-off-by: Tomeu Vizoso <tomeu.vizoso@collabora.com>
+Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>
+---
+ drivers/usb/dwc2/hcd.c | 13 ++++++++-----
+ 1 file changed, 8 insertions(+), 5 deletions(-)
+
+--- a/drivers/usb/dwc2/hcd.c
++++ b/drivers/usb/dwc2/hcd.c
+@@ -361,9 +361,14 @@ static void dwc2_gusbcfg_init(struct dwc
+ 
+ static int dwc2_vbus_supply_init(struct dwc2_hsotg *hsotg)
+ {
++	int ret;
++
+ 	hsotg->vbus_supply = devm_regulator_get_optional(hsotg->dev, "vbus");
+-	if (IS_ERR(hsotg->vbus_supply))
+-		return 0;
++	if (IS_ERR(hsotg->vbus_supply)) {
++		ret = PTR_ERR(hsotg->vbus_supply);
++		hsotg->vbus_supply = NULL;
++		return ret == -ENODEV ? 0 : ret;
++	}
+ 
+ 	return regulator_enable(hsotg->vbus_supply);
+ }
+@@ -4371,9 +4376,7 @@ static int _dwc2_hcd_start(struct usb_hc
+ 
+ 	spin_unlock_irqrestore(&hsotg->lock, flags);
+ 
+-	dwc2_vbus_supply_init(hsotg);
+-
+-	return 0;
++	return dwc2_vbus_supply_init(hsotg);
+ }
+ 
+ /*