linux-kernel - [PATCH v2] USB: serial: cp210x: Fix GPIO in autosuspend

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Message-Id: <20190217175901.3986-1-pados@pados.hu>
Date:   Sun, 17 Feb 2019 18:59:01 +0100
From:   Karoly Pados <pados@...os.hu>
To:     "Johan Hovold" <johan@...nel.org>,
        "Greg Kroah-Hartman" <gregkh@...uxfoundation.org>,
        linux-usb@...r.kernel.org, linux-kernel@...r.kernel.org,
        "Loic Poulain" <loic.poulain@...aro.org>
Cc:     Karoly Pados <pados@...os.hu>
Subject: [PATCH v2] USB: serial: cp210x: Fix GPIO in autosuspend

Current GPIO code in cp210x fails to take USB autosuspend into account,
making it practically impossible to use GPIOs with autosuspend enabled
without user configuration. Fix this like for ftdi_sio in a previous patch.
Tested on a CP2102N.

Signed-off-by: Karoly Pados <pados@...os.hu>
---
Changelog:
- v2: Restrict new autopm calls to GPIO paths.
      Always check result of usb_autopm_get.
      Rebased to current usb_serial upstream.

 drivers/usb/serial/cp210x.c | 13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/drivers/usb/serial/cp210x.c b/drivers/usb/serial/cp210x.c
index fac7a4547523..f7aaecad6e21 100644
--- a/drivers/usb/serial/cp210x.c
+++ b/drivers/usb/serial/cp210x.c
@@ -1370,8 +1370,13 @@ static int cp210x_gpio_get(struct gpio_chip *gc, unsigned int gpio)
 	if (priv->partnum == CP210X_PARTNUM_CP2105)
 		req_type = REQTYPE_INTERFACE_TO_HOST;
 
+	result = usb_autopm_get_interface(serial->interface);
+	if (result)
+		return result;
+
 	result = cp210x_read_vendor_block(serial, req_type,
 					  CP210X_READ_LATCH, &buf, sizeof(buf));
+	usb_autopm_put_interface(serial->interface);
 	if (result < 0)
 		return result;
 
@@ -1392,6 +1397,10 @@ static void cp210x_gpio_set(struct gpio_chip *gc, unsigned int gpio, int value)
 
 	buf.mask = BIT(gpio);
 
+	result = usb_autopm_get_interface(serial->interface);
+	if (result)
+		goto out;
+
 	if (priv->partnum == CP210X_PARTNUM_CP2105) {
 		result = cp210x_write_vendor_block(serial,
 						   REQTYPE_HOST_TO_INTERFACE,
@@ -1399,7 +1408,6 @@ static void cp210x_gpio_set(struct gpio_chip *gc, unsigned int gpio, int value)
 						   sizeof(buf));
 	} else {
 		u16 wIndex = buf.state << 8 | buf.mask;
-
 		result = usb_control_msg(serial->dev,
 					 usb_sndctrlpipe(serial->dev, 0),
 					 CP210X_VENDOR_SPECIFIC,
@@ -1409,6 +1417,9 @@ static void cp210x_gpio_set(struct gpio_chip *gc, unsigned int gpio, int value)
 					 NULL, 0, USB_CTRL_SET_TIMEOUT);
 	}
 
+	usb_autopm_put_interface(serial->interface);
+
+out:
 	if (result < 0) {
 		dev_err(&serial->interface->dev, "failed to set GPIO value: %d\n",
 				result);
-- 
2.20.1