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From:   nikitos.tr@gmail.com
To:     cw00.choi@samsung.com, myungjoo.ham@samsung.com
Cc:     linux-kernel@vger.kernel.org, stephan@gerhold.net,
        Nikita Travkin <nikitos.tr@gmail.com>
Subject: [PATCH] extcon: sm5502: Detect OTG when USB_ID is connected to ground
Date:   Tue, 19 Jan 2021 18:33:47 +0500
Message-Id: <20210119133347.42050-1-nikitos.tr@gmail.com>
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From: Nikita Travkin <nikitos.tr@gmail.com>

In it's curent state this driver ignores OTG adapters with ID pin
connected to ground. This commit adds a check to set extcon into
host mode when such OTG adapter is connected.

Signed-off-by: Nikita Travkin <nikitos.tr@gmail.com>

---

This issue was already reported in [1] and this behaviour appears
for both Samsung Galaxy A5 (2015) mentioned there and A3 that I was
working on. This patch allows OTG detection on A3.

[1]: https://lore.kernel.org/lkml/20191011145015.GA127238@gerhold.net/
---
 drivers/extcon/extcon-sm5502.c | 22 ++++++++++++++++++++--
 1 file changed, 20 insertions(+), 2 deletions(-)

diff --git a/drivers/extcon/extcon-sm5502.c b/drivers/extcon/extcon-sm5502.c
index 106d4da647bd..db41d1c58efd 100644
--- a/drivers/extcon/extcon-sm5502.c
+++ b/drivers/extcon/extcon-sm5502.c
@@ -144,6 +144,7 @@ enum sm5502_muic_acc_type {
 	SM5502_MUIC_ADC_AUDIO_TYPE1_FULL_REMOTE = 0x3e,	/* |      001|11110| */
 	SM5502_MUIC_ADC_AUDIO_TYPE1_SEND_END = 0x5e,	/* |      010|11110| */
 							/* |Dev Type1|--ADC| */
+	SM5502_MUIC_ADC_GROUND_USB_OTG = 0x80,		/* |      100|00000| */
 	SM5502_MUIC_ADC_OPEN_USB = 0x5f,		/* |      010|11111| */
 	SM5502_MUIC_ADC_OPEN_TA = 0xdf,			/* |      110|11111| */
 	SM5502_MUIC_ADC_OPEN_USB_OTG = 0xff,		/* |      111|11111| */
@@ -291,11 +292,27 @@ static unsigned int sm5502_muic_get_cable_type(struct sm5502_muic_info *info)
 	 * connected with to MUIC device.
 	 */
 	cable_type = adc & SM5502_REG_ADC_MASK;
-	if (cable_type == SM5502_MUIC_ADC_GROUND)
-		return SM5502_MUIC_ADC_GROUND;
 
 	switch (cable_type) {
 	case SM5502_MUIC_ADC_GROUND:
+		ret = regmap_read(info->regmap, SM5502_REG_DEV_TYPE1,
+				  &dev_type1);
+		if (ret) {
+			dev_err(info->dev, "failed to read DEV_TYPE1 reg\n");
+			return ret;
+		}
+
+		switch (dev_type1) {
+		case SM5502_REG_DEV_TYPE1_USB_OTG_MASK:
+			cable_type = SM5502_MUIC_ADC_GROUND_USB_OTG;
+			break;
+		default:
+			dev_dbg(info->dev,
+				"cannot identify the cable type: adc(0x%x), dev_type1(0x%x)\n",
+				adc, dev_type1);
+			return -EINVAL;
+		}
+		break;
 	case SM5502_MUIC_ADC_SEND_END_BUTTON:
 	case SM5502_MUIC_ADC_REMOTE_S1_BUTTON:
 	case SM5502_MUIC_ADC_REMOTE_S2_BUTTON:
@@ -396,6 +413,7 @@ static int sm5502_muic_cable_handler(struct sm5502_muic_info *info,
 		con_sw	= DM_DP_SWITCH_OPEN;
 		vbus_sw	= VBUSIN_SWITCH_VBUSOUT;
 		break;
+	case SM5502_MUIC_ADC_GROUND_USB_OTG:
 	case SM5502_MUIC_ADC_OPEN_USB_OTG:
 		id	= EXTCON_USB_HOST;
 		con_sw	= DM_DP_SWITCH_USB;
-- 
2.25.1