linux-kernel - [PATCH v2] phy: phy-twl4030-usb: fix denied runtime access

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Message-Id: <20180922094405.4067-1-andreas@kemnade.info>
Date:   Sat, 22 Sep 2018 11:44:05 +0200
From:   Andreas Kemnade <andreas@...nade.info>
To:     Dmitry Torokhov <dmitry.torokhov@...il.com>, kishon@...com,
        lee.jones@...aro.org, daniel.thompson@...aro.org,
        wsa@...-dreams.de, linux-omap@...r.kernel.org,
        linux-kernel@...r.kernel.org,
        Discussions about the Letux Kernel 
        <letux-kernel@...nphoenux.org>
Cc:     Andreas Kemnade <andreas@...nade.info>
Subject: [PATCH v2] phy: phy-twl4030-usb: fix denied runtime access

When runtime is not enabled, pm_runtime_get_sync() returns -EACCESS,
the counter will be incremented but the resume callback not called,
so enumeration and charging will not start properly.
To avoid that happen, disable irq on suspend and recheck on resume.

Practically this happens when the device is woken up from suspend by
plugging in usb.

Signed-off-by: Andreas Kemnade <andreas@...nade.info>
---
Changes in v2:
* use pm suspend/resume callback instead of delayed_work
  as suggested by Dmitry

 drivers/phy/ti/phy-twl4030-usb.c | 29 +++++++++++++++++++++++++++++
 1 file changed, 29 insertions(+)

diff --git a/drivers/phy/ti/phy-twl4030-usb.c b/drivers/phy/ti/phy-twl4030-usb.c
index a44680d64f9b..c267afb68f07 100644
--- a/drivers/phy/ti/phy-twl4030-usb.c
+++ b/drivers/phy/ti/phy-twl4030-usb.c
@@ -144,6 +144,7 @@
 #define PMBR1				0x0D
 #define GPIO_USB_4PIN_ULPI_2430C	(3 << 0)
 
+static irqreturn_t twl4030_usb_irq(int irq, void *_twl);
 /*
  * If VBUS is valid or ID is ground, then we know a
  * cable is present and we need to be runtime-enabled
@@ -395,6 +396,33 @@ static void __twl4030_phy_power(struct twl4030_usb *twl, int on)
 	WARN_ON(twl4030_usb_write_verify(twl, PHY_PWR_CTRL, pwr) < 0);
 }
 
+static int __maybe_unused twl4030_usb_suspend(struct device *dev)
+{
+	struct twl4030_usb *twl = dev_get_drvdata(dev);
+
+	/*
+	 * we need enabled runtime on resume,
+	 * so turn irq off here, so we do not get it early
+	 * note: wakeup on usb plug works independently of this
+	 */
+	dev_dbg(twl->dev, "%s\n", __func__);
+	disable_irq(twl->irq);
+
+	return 0;
+}
+
+static int __maybe_unused twl4030_usb_resume(struct device *dev)
+{
+	struct twl4030_usb *twl = dev_get_drvdata(dev);
+
+	dev_dbg(twl->dev, "%s\n", __func__);
+	enable_irq(twl->irq);
+	/* check whether cable status changed */
+	twl4030_usb_irq(0, twl);
+
+	return 0;
+}
+
 static int __maybe_unused twl4030_usb_runtime_suspend(struct device *dev)
 {
 	struct twl4030_usb *twl = dev_get_drvdata(dev);
@@ -655,6 +683,7 @@ static const struct phy_ops ops = {
 static const struct dev_pm_ops twl4030_usb_pm_ops = {
 	SET_RUNTIME_PM_OPS(twl4030_usb_runtime_suspend,
 			   twl4030_usb_runtime_resume, NULL)
+	SET_SYSTEM_SLEEP_PM_OPS(twl4030_usb_suspend, twl4030_usb_resume)
 };
 
 static int twl4030_usb_probe(struct platform_device *pdev)
-- 
2.11.0