linux-kernel - [PATCH v2 2/9] i2c: reject new transfers when adapters are suspended

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Date:   Sat, 22 Dec 2018 21:26:16 +0100
From:   Wolfram Sang <wsa+renesas@...g-engineering.com>
To:     linux-i2c@...r.kernel.org
Cc:     linux-renesas-soc@...r.kernel.org, linux-pm@...r.kernel.org,
        Hans de Goede <hdegoede@...hat.com>,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
        Wolfram Sang <wsa+renesas@...g-engineering.com>,
        Wolfram Sang <wsa@...-dreams.de>
Subject: [PATCH v2 2/9] i2c: reject new transfers when adapters are suspended

Using the 'is_suspended' flag from the PM core, we now reject new
transfers if the parent of the adapter is already marked suspended.

Signed-off-by: Wolfram Sang <wsa+renesas@...g-engineering.com>
---
 Documentation/i2c/fault-codes | 4 ++++
 drivers/i2c/i2c-core-base.c   | 3 +++
 drivers/i2c/i2c-core-smbus.c  | 4 ++++
 3 files changed, 11 insertions(+)

diff --git a/Documentation/i2c/fault-codes b/Documentation/i2c/fault-codes
index 47c25abb7d52..0cee0fc545b4 100644
--- a/Documentation/i2c/fault-codes
+++ b/Documentation/i2c/fault-codes
@@ -112,6 +112,10 @@ EPROTO
 	case is when the length of an SMBus block data response
 	(from the SMBus slave) is outside the range 1-32 bytes.
 
+ESHUTDOWN
+	Returned when a transfer was requested using an adapter
+	which is already suspended.
+
 ETIMEDOUT
 	This is returned by drivers when an operation took too much
 	time, and was aborted before it completed.
diff --git a/drivers/i2c/i2c-core-base.c b/drivers/i2c/i2c-core-base.c
index 28460f6a60cc..3ce238b782f3 100644
--- a/drivers/i2c/i2c-core-base.c
+++ b/drivers/i2c/i2c-core-base.c
@@ -1865,6 +1865,9 @@ int __i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
 
 	if (WARN_ON(!msgs || num < 1))
 		return -EINVAL;
+	if (WARN(device_is_suspended(adap->dev.parent),
+		 "Accessing already suspended I2C/SMBus adapter"))
+		return -ESHUTDOWN;
 
 	if (adap->quirks && i2c_check_for_quirks(adap, msgs, num))
 		return -EOPNOTSUPP;
diff --git a/drivers/i2c/i2c-core-smbus.c b/drivers/i2c/i2c-core-smbus.c
index 9cd66cabb84f..e0f7f22feabd 100644
--- a/drivers/i2c/i2c-core-smbus.c
+++ b/drivers/i2c/i2c-core-smbus.c
@@ -547,6 +547,10 @@ s32 __i2c_smbus_xfer(struct i2c_adapter *adapter, u16 addr,
 	int try;
 	s32 res;
 
+	if (WARN(device_is_suspended(adapter->dev.parent),
+		 "Accessing already suspended I2C/SMBus adapter"))
+		return -ESHUTDOWN;
+
 	/* If enabled, the following two tracepoints are conditional on
 	 * read_write and protocol.
 	 */
-- 
2.19.1