linux-kernel - [PATCH 51/51] phy-twl4030-usb: initialize charging-related stuff via pm

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Date:   Wed, 14 Sep 2016 13:14:32 +0530
From:   Kishon Vijay Abraham I <kishon@...com>
To:     <gregkh@...uxfoundation.org>
CC:     <kishon@...com>, <linux-kernel@...r.kernel.org>
Subject: [PATCH 51/51] phy-twl4030-usb: initialize charging-related stuff via pm_runtime

From: Andreas Kemnade <andreas@...nade.info>

twl4030_phy_power_on() initializes some bits which are required for
charging. As they are not set in twl4030_usb_runtime_resume()
a call to pm_runtime_get_sync() is not sufficient to enable charging.

This patch moves the initialization to twl4030_usb_runtime_resume()
so everything needed for charging is initialized upon
pm_runtime_get_sync().

That also gives improved possibilities to debug problems in that area
because the relevant parts can be checked separately. Charging can be
enabled without having the musb subsystem active.

As a side effect this hides some bugs in musb which causes
unbalanced calls to phy_power_off()/phy_power_on() so that
phy->power_count becomes -1.

The result is that e.g. the GTA04 phone (dm3730 + twl4030) works
finally as a usb gadget again and charging is working.

Signed-off-by: Andreas Kemnade <andreas@...nade.info>
Acked-by: Tony Lindgren <tony@...mide.com>
Signed-off-by: Kishon Vijay Abraham I <kishon@...com>
---
 drivers/phy/phy-twl4030-usb.c |   16 +++++++++++-----
 1 file changed, 11 insertions(+), 5 deletions(-)

diff --git a/drivers/phy/phy-twl4030-usb.c b/drivers/phy/phy-twl4030-usb.c
index 81067b4..87e6334 100644
--- a/drivers/phy/phy-twl4030-usb.c
+++ b/drivers/phy/phy-twl4030-usb.c
@@ -440,6 +440,17 @@ static int __maybe_unused twl4030_usb_runtime_resume(struct device *dev)
 			  (PHY_CLK_CTRL_CLOCKGATING_EN |
 			   PHY_CLK_CTRL_CLK32K_EN));

+	twl4030_i2c_access(twl, 1);
+	twl4030_usb_set_mode(twl, twl->usb_mode);
+	if (twl->usb_mode == T2_USB_MODE_ULPI)
+		twl4030_i2c_access(twl, 0);
+	/*
+	 * According to the TPS65950 TRM, there has to be at least 50ms
+	 * delay between setting POWER_CTRL_OTG_ENAB and enabling charging
+	 * so wait here so that a fully enabled phy can be expected after
+	 * resume
+	 */
+	msleep(50);
 	return 0;
 }

@@ -460,11 +471,6 @@ static int twl4030_phy_power_on(struct phy *phy)

 	dev_dbg(twl->dev, "%s\n", __func__);
 	pm_runtime_get_sync(twl->dev);
-	twl4030_i2c_access(twl, 1);
-	twl4030_usb_set_mode(twl, twl->usb_mode);
-	if (twl->usb_mode == T2_USB_MODE_ULPI)
-		twl4030_i2c_access(twl, 0);
-	twl->linkstat = MUSB_UNKNOWN;
 	schedule_delayed_work(&twl->id_workaround_work, HZ);

 	return 0;
-- 
1.7.9.5