linux-kernel - [PATCH v2 1/4] i2c: export i2c_adapter

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Date:   Fri, 16 Sep 2016 18:02:42 +0200
From:   Bartosz Golaszewski <bgolaszewski@...libre.com>
To:     Linus Walleij <linus.walleij@...aro.org>,
        Alexandre Courbot <gnurou@...il.com>,
        Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
        Vignesh R <vigneshr@...com>, Yong Li <yong.b.li@...el.com>,
        Geert Uytterhoeven <geert+renesas@...der.be>,
        Peter Zijlstra <peterz@...radead.org>,
        Ingo Molnar <mingo@...hat.com>,
        Wolfram Sang <wsa@...-dreams.de>, Peter Rosin <peda@...ntia.se>
Cc:     linux-i2c <linux-i2c@...r.kernel.org>,
        linux-gpio <linux-gpio@...r.kernel.org>,
        LKML <linux-kernel@...r.kernel.org>,
        Bartosz Golaszewski <bgolaszewski@...libre.com>
Subject: [PATCH v2 1/4] i2c: export i2c_adapter_depth()

For crazy setups in which an i2c gpio expander is behind an i2c gpio
multiplexer controlled by a gpio provided a second expander using the
same device driver we need to explicitly tell lockdep how to handle
nested locking.

Export i2c_adapter_depth() as public API to be reused outside of i2c
core code.

Signed-off-by: Bartosz Golaszewski <bgolaszewski@...libre.com>
---
 drivers/i2c/i2c-core.c | 9 ++-------
 include/linux/i2c.h    | 1 +
 2 files changed, 3 insertions(+), 7 deletions(-)

diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c
index da3a02e..c9b8df8 100644
--- a/drivers/i2c/i2c-core.c
+++ b/drivers/i2c/i2c-core.c
@@ -1335,13 +1335,7 @@ static void i2c_adapter_dev_release(struct device *dev)
 	complete(&adap->dev_released);
 }
 
-/*
- * This function is only needed for mutex_lock_nested, so it is never
- * called unless locking correctness checking is enabled. Thus we
- * make it inline to avoid a compiler warning. That's what gcc ends up
- * doing anyway.
- */
-static inline unsigned int i2c_adapter_depth(struct i2c_adapter *adapter)
+unsigned int i2c_adapter_depth(struct i2c_adapter *adapter)
 {
 	unsigned int depth = 0;
 
@@ -1350,6 +1344,7 @@ static inline unsigned int i2c_adapter_depth(struct i2c_adapter *adapter)
 
 	return depth;
 }
+EXPORT_SYMBOL_GPL(i2c_adapter_depth);
 
 /*
  * Let users instantiate I2C devices through sysfs. This can be used when
diff --git a/include/linux/i2c.h b/include/linux/i2c.h
index fffdc27..cfacc03 100644
--- a/include/linux/i2c.h
+++ b/include/linux/i2c.h
@@ -673,6 +673,7 @@ extern void i2c_clients_command(struct i2c_adapter *adap,
 
 extern struct i2c_adapter *i2c_get_adapter(int nr);
 extern void i2c_put_adapter(struct i2c_adapter *adap);
+extern unsigned int i2c_adapter_depth(struct i2c_adapter *adapter);
 
 void i2c_parse_fw_timings(struct device *dev, struct i2c_timings *t, bool use_defaults);
 
-- 
2.7.4