[PATCH 1/2] usb: dwc3: add a power supply for current control

[Ray Chi <raychi@google.com>]

Currently, VBUS draw callback does no action when the
generic PHYs are used. This patch adds an additional
path to control charging current through power supply
interface.

Signed-off-by: Ray Chi <raychi@google.com>
---
 drivers/usb/dwc3/core.c | 15 +++++++++++++++
 drivers/usb/dwc3/core.h |  4 ++++
 2 files changed, 19 insertions(+)

diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c
index f2448d0a9d39..d15f065849cd 100644
--- a/drivers/usb/dwc3/core.c
+++ b/drivers/usb/dwc3/core.c
@@ -1238,6 +1238,8 @@ static void dwc3_get_properties(struct dwc3 *dwc)
 	u8			rx_max_burst_prd;
 	u8			tx_thr_num_pkt_prd;
 	u8			tx_max_burst_prd;
+	const char		*usb_psy_name;
+	int			ret;
 
 	/* default to highest possible threshold */
 	lpm_nyet_threshold = 0xf;
@@ -1263,6 +1265,13 @@ static void dwc3_get_properties(struct dwc3 *dwc)
 	else
 		dwc->sysdev = dwc->dev;
 
+	ret = device_property_read_string(dev, "usb-psy-name", &usb_psy_name);
+	if (ret >= 0) {
+		dwc->usb_psy = power_supply_get_by_name(usb_psy_name);
+		if (!dwc->usb_psy)
+			dev_err(dev, "couldn't get usb power supply\n");
+	}
+
 	dwc->has_lpm_erratum = device_property_read_bool(dev,
 				"snps,has-lpm-erratum");
 	device_property_read_u8(dev, "snps,lpm-nyet-threshold",
@@ -1619,6 +1628,9 @@ static int dwc3_probe(struct platform_device *pdev)
 assert_reset:
 	reset_control_assert(dwc->reset);
 
+	if (!dwc->usb_psy)
+		power_supply_put(dwc->usb_psy);
+
 	return ret;
 }
 
@@ -1641,6 +1653,9 @@ static int dwc3_remove(struct platform_device *pdev)
 	dwc3_free_event_buffers(dwc);
 	dwc3_free_scratch_buffers(dwc);
 
+	if (!dwc->usb_psy)
+		power_supply_put(dwc->usb_psy);
+
 	return 0;
 }
 
diff --git a/drivers/usb/dwc3/core.h b/drivers/usb/dwc3/core.h
index 052b20d52651..6708fdf358b3 100644
--- a/drivers/usb/dwc3/core.h
+++ b/drivers/usb/dwc3/core.h
@@ -30,6 +30,8 @@
 
 #include <linux/phy/phy.h>
 
+#include <linux/power_supply.h>
+
 #define DWC3_MSG_MAX	500
 
 /* Global constants */
@@ -1125,6 +1127,8 @@ struct dwc3 {
 	struct usb_role_switch	*role_sw;
 	enum usb_dr_mode	role_switch_default_mode;
 
+	struct power_supply	*usb_psy;
+
 	u32			fladj;
 	u32			irq_gadget;
 	u32			otg_irq;
-- 
2.30.0.617.g56c4b15f3c-goog