linux-kernel - [PATCH 3/3] extcon: intel-cht-wc: Ignore failure to detect charger-type on host mode exit

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Date:   Mon,  3 Apr 2017 13:26:30 +0200
From:   Hans de Goede <hdegoede@...hat.com>
To:     MyungJoo Ham <myungjoo.ham@...sung.com>,
        Chanwoo Choi <cw00.choi@...sung.com>
Cc:     Hans de Goede <hdegoede@...hat.com>, Takashi Iwai <tiwai@...e.de>,
        linux-kernel@...r.kernel.org
Subject: [PATCH 3/3] extcon: intel-cht-wc: Ignore failure to detect charger-type on host mode exit

When we leave host-mode because the id-pin is no longer connected to
ground, the 5v boost converter is normally still on, so we will see
Vbus, but it is not from a charger (normally) so the charger-type
detection will fail.

This commit silences the cht_wc_extcon_get_charger() false-positive
errors when we're leaving host mode.

Signed-off-by: Hans de Goede <hdegoede@...hat.com>
---
 drivers/extcon/extcon-intel-cht-wc.c | 15 +++++++++++----
 1 file changed, 11 insertions(+), 4 deletions(-)

diff --git a/drivers/extcon/extcon-intel-cht-wc.c b/drivers/extcon/extcon-intel-cht-wc.c
index 8651f63..0e1f2c7 100644
--- a/drivers/extcon/extcon-intel-cht-wc.c
+++ b/drivers/extcon/extcon-intel-cht-wc.c
@@ -98,6 +98,7 @@ struct cht_wc_extcon_data {
 	struct regmap *regmap;
 	struct extcon_dev *edev;
 	unsigned int previous_cable;
+	bool usb_host;
 };
 
 static int cht_wc_extcon_get_id(struct cht_wc_extcon_data *ext, int pwrsrc_sts)
@@ -114,7 +115,8 @@ static int cht_wc_extcon_get_id(struct cht_wc_extcon_data *ext, int pwrsrc_sts)
 	return USB_ID_FLOAT;
 }
 
-static int cht_wc_extcon_get_charger(struct cht_wc_extcon_data *ext)
+static int cht_wc_extcon_get_charger(struct cht_wc_extcon_data *ext,
+				     bool ignore_errors)
 {
 	int ret, usbsrc, status;
 	unsigned long timeout;
@@ -137,6 +139,9 @@ static int cht_wc_extcon_get_charger(struct cht_wc_extcon_data *ext)
 	} while (time_before(jiffies, timeout));
 
 	if (status != CHT_WC_USBSRC_STS_SUCCESS) {
+		if (ignore_errors)
+			return EXTCON_CHG_USB_SDP; /* Save fallback */
+
 		if (status == CHT_WC_USBSRC_STS_FAIL)
 			dev_warn(ext->dev, "Could not detect charger type\n");
 		else
@@ -206,6 +211,8 @@ static void cht_wc_extcon_pwrsrc_event(struct cht_wc_extcon_data *ext)
 {
 	int ret, pwrsrc_sts, id;
 	unsigned int cable = EXTCON_NONE;
+	/* Ignore errors in host mode, as the 5v boost converter is on then */
+	bool ignore_get_charger_errors = ext->usb_host;
 
 	ret = regmap_read(ext->regmap, CHT_WC_PWRSRC_STS, &pwrsrc_sts);
 	if (ret) {
@@ -226,7 +233,7 @@ static void cht_wc_extcon_pwrsrc_event(struct cht_wc_extcon_data *ext)
 		goto set_state;
 	}
 
-	ret = cht_wc_extcon_get_charger(ext);
+	ret = cht_wc_extcon_get_charger(ext, ignore_get_charger_errors);
 	if (ret >= 0)
 		cable = ret;
 
@@ -241,8 +248,8 @@ static void cht_wc_extcon_pwrsrc_event(struct cht_wc_extcon_data *ext)
 		ext->previous_cable = cable;
 	}
 
-	extcon_set_state_sync(ext->edev, EXTCON_USB_HOST,
-			      id == USB_ID_GND || id == USB_RID_A);
+	ext->usb_host = id == USB_ID_GND || id == USB_RID_A;
+	extcon_set_state_sync(ext->edev, EXTCON_USB_HOST, ext->usb_host);
 }
 
 static irqreturn_t cht_wc_extcon_isr(int irq, void *data)
-- 
2.9.3