linux-kernel - [PATCH 2/2] extcon: axp288: Only reschedule charger-detection at boot when a SDP is detected

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Date:   Sun, 14 Jan 2018 16:10:21 +0100
From:   Hans de Goede <hdegoede@...hat.com>
To:     MyungJoo Ham <myungjoo.ham@...sung.com>,
        Chanwoo Choi <cw00.choi@...sung.com>,
        Chen-Yu Tsai <wens@...e.org>
Cc:     Hans de Goede <hdegoede@...hat.com>, linux-kernel@...r.kernel.org
Subject: [PATCH 2/2] extcon: axp288: Only reschedule charger-detection at boot when a SDP is detected

The only misdetection which can happen at boot due to data-lines mux issues
is detecting a non SDP as SDP, so we only need to retry if we detect a SDP
on our first detection.

Note Vbus misdetection is not a problem, as soon as the drivers controlling
the Vbus path set it correctly we will get an interrupt which reschedules
the charger-detection.

Also update the comment about the re-detection to reflect this.

Signed-off-by: Hans de Goede <hdegoede@...hat.com>
---
 drivers/extcon/extcon-axp288.c | 14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

diff --git a/drivers/extcon/extcon-axp288.c b/drivers/extcon/extcon-axp288.c
index 63b99d5becd7..17e6808af0d1 100644
--- a/drivers/extcon/extcon-axp288.c
+++ b/drivers/extcon/extcon-axp288.c
@@ -161,16 +161,16 @@ static void axp288_chrg_detect_complete(struct axp288_extcon_info *info,
 	/*
 	 * We depend on other drivers to do things like mux the data lines,
 	 * enable/disable vbus based on the id-pin, etc. Sometimes the BIOS has
-	 * not set these things up correctly resulting in the initial charger
-	 * cable type detection giving a wrong result and we end up not charging
-	 * or charging at only 0.5A.
+	 * not set these things up correctly resulting in a wrong result for the
+	 * initial charger type detection and we end up charging at only 0.5A.
 	 *
-	 * So we schedule a second cable type detection after 2 seconds to
-	 * give the other drivers time to load and do their thing.
+	 * If our first detect detects an SDP charger-type, we try again after
+	 * 2 seconds to give the other drivers time to load and do their thing.
 	 */
 	if (!info->first_detect_done) {
-		queue_delayed_work(system_wq, &info->det_work,
-				   msecs_to_jiffies(2000));
+		if (info->previous_cable == EXTCON_CHG_USB_SDP)
+			queue_delayed_work(system_wq, &info->det_work,
+					   msecs_to_jiffies(2000));
 		info->first_detect_done = true;
 	}
 
-- 
2.14.3