power: qpnp-smbcharger: Add extcon notifiers for USB

Allow charger to expose an extcon device which can emit
notification for USB and USB-HOST cable connection states.
The driver can correspondingly register interest in being
notified of these cable connection statuses.

This is intended to replace the power_supply_set_present()
and power_supply_set_usb_otg() mechanisms currently used.

Change-Id: I6c7cf971f59ac3f3075f5c8f13786306729f25a8
Signed-off-by: Jack Pham <jackp@codeaurora.org>

drivers/power/Kconfig

@@ -523,6 +523,7 @@ config AXP20X_POWER
 config QPNP_SMBCHARGER
 	tristate "QPNP SMB Charger driver"
 	depends on SPMI
+	depends on EXTCON
 	help
 	  Say Y here to enable the dual path switch mode battery charger which
 	  supports USB detection and battery charging up to 3A.

drivers/power/qpnp-smbcharger.c

@@ -40,6 +40,7 @@
 #include <linux/of_batterydata.h>
 #include <linux/msm_bcl.h>
 #include <linux/ktime.h>
+#include <linux/extcon.h>
 #include "pmic-voter.h"
 
 /* Mask/Bit helpers */
@@ -280,6 +281,9 @@ struct smbchg_chip {
 	struct votable			*hw_aicl_rerun_disable_votable;
 	struct votable			*hw_aicl_rerun_enable_indirect_votable;
 	struct votable			*aicl_deglitch_short_votable;
+
+	/* extcon for VBUS / ID notification to USB */
+	struct extcon_dev		*extcon;
 };
 
 enum qpnp_schg {
@@ -419,6 +423,13 @@ enum aicl_short_deglitch_voters {
 	HVDCP_SHORT_DEGLITCH_VOTER,
 	NUM_HW_SHORT_DEGLITCH_VOTERS,
 };
+
+static const unsigned int smbchg_extcon_cable[] = {
+	EXTCON_USB,
+	EXTCON_USB_HOST,
+	EXTCON_NONE,
+};
+
 static int smbchg_debug_mask;
 module_param_named(
 	debug_mask, smbchg_debug_mask, int, S_IRUSR | S_IWUSR
@@ -4524,6 +4535,7 @@ static void handle_usb_removal(struct smbchg_chip *chip)
 		power_supply_set_property(chip->usb_psy,
 				POWER_SUPPLY_PROP_PRESENT, &pval);
 	}
+	extcon_set_cable_state_(chip->extcon, EXTCON_USB, chip->usb_present);
 	set_usb_psy_dp_dm(chip, POWER_SUPPLY_DP_DM_DPR_DMR);
 	schedule_work(&chip->usb_set_online_work);
 
@@ -4615,6 +4627,12 @@ static void handle_usb_insertion(struct smbchg_chip *chip)
 				POWER_SUPPLY_PROP_PRESENT, &pval);
 	}
 
+	/* Only notify USB if it's not a charger */
+	if (usb_supply_type == POWER_SUPPLY_TYPE_USB ||
+			usb_supply_type == POWER_SUPPLY_TYPE_USB_CDP)
+		extcon_set_cable_state_(chip->extcon, EXTCON_USB,
+				chip->usb_present);
+
 	/* Notify the USB psy if OV condition is not present */
 	if (!chip->usb_ov_det) {
 		/*
@@ -5524,6 +5542,8 @@ static void update_typec_otg_status(struct smbchg_chip *chip, int mode,
 		pval.intval = 1;
 		power_supply_set_property(chip->usb_psy,
 				POWER_SUPPLY_PROP_USB_OTG, &pval);
+		extcon_set_cable_state_(chip->extcon, EXTCON_USB_HOST,
+				chip->typec_dfp);
 		/* update FG */
 		set_property_on_fg(chip, POWER_SUPPLY_PROP_STATUS,
 				get_prop_batt_status(chip));
@@ -5532,6 +5552,8 @@ static void update_typec_otg_status(struct smbchg_chip *chip, int mode,
 		pval.intval = 0;
 		power_supply_set_property(chip->usb_psy,
 				POWER_SUPPLY_PROP_USB_OTG, &pval);
+		extcon_set_cable_state_(chip->extcon, EXTCON_USB_HOST,
+				chip->typec_dfp);
 		/* update FG */
 		set_property_on_fg(chip, POWER_SUPPLY_PROP_STATUS,
 				get_prop_batt_status(chip));
@@ -6418,6 +6440,9 @@ static irqreturn_t usbid_change_handler(int irq, void *_chip)
 		power_supply_set_property(chip->usb_psy,
 				POWER_SUPPLY_PROP_USB_OTG, &pval);
 	}
+
+	extcon_set_cable_state_(chip->extcon, EXTCON_USB_HOST, otg_present);
+
 	if (otg_present)
 		pr_smb(PR_STATUS, "OTG detected\n");
 
@@ -8018,6 +8043,18 @@ static int smbchg_probe(struct platform_device *pdev)
 		return rc;
 	}
 
+	chip->extcon = devm_extcon_dev_allocate(chip->dev, smbchg_extcon_cable);
+	if (IS_ERR(chip->extcon)) {
+		dev_err(chip->dev, "failed to allocate extcon device\n");
+		return PTR_ERR(chip->extcon);
+	}
+
+	rc = devm_extcon_dev_register(chip->dev, chip->extcon);
+	if (rc) {
+		dev_err(chip->dev, "failed to register extcon device\n");
+		return rc;
+	}
+
 	rc = smbchg_hw_init(chip);
 	if (rc < 0) {
 		dev_err(&pdev->dev,