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Date: Thu, 25 Aug 2016 23:07:01 +0200
From: Peter Rosin <peda@...ntia.se>
To: <linux-kernel@...r.kernel.org>
CC: Peter Rosin <peda@...ntia.se>, David Airlie <airlied@...ux.ie>,
"Wolfram Sang" <wsa@...-dreams.de>,
<dri-devel@...ts.freedesktop.org>, <linux-i2c@...r.kernel.org>
Subject: [PATCH v2] i2c: move locking operations to their own struct
This makes it trivial to constify them, so do that.
Signed-off-by: Peter Rosin <peda@...ntia.se>
---
drivers/gpu/drm/drm_dp_helper.c | 10 +++++++---
drivers/i2c/i2c-core.c | 13 ++++++++-----
drivers/i2c/i2c-mux.c | 25 ++++++++++++++++---------
include/linux/i2c.h | 25 ++++++++++++++++++-------
4 files changed, 49 insertions(+), 24 deletions(-)
Changes since v1:
- Also fix the user in drivers/gpu (only compile-tested, but
it's simple enough...)
This takes care of the 0-day splat reported in:
http://marc.info/?l=linux-i2c&m=147215193023544&w=2
Cheers,
Peter
diff --git a/drivers/gpu/drm/drm_dp_helper.c b/drivers/gpu/drm/drm_dp_helper.c
index eae5ef963cb7..2bd064493ae7 100644
--- a/drivers/gpu/drm/drm_dp_helper.c
+++ b/drivers/gpu/drm/drm_dp_helper.c
@@ -790,6 +790,12 @@ static void unlock_bus(struct i2c_adapter *i2c, unsigned int flags)
mutex_unlock(&i2c_to_aux(i2c)->hw_mutex);
}
+static const struct i2c_lock_operations drm_dp_i2c_lock_ops = {
+ .lock_bus = lock_bus,
+ .trylock_bus = trylock_bus,
+ .unlock_bus = unlock_bus,
+};
+
/**
* drm_dp_aux_init() - minimally initialise an aux channel
* @aux: DisplayPort AUX channel
@@ -807,9 +813,7 @@ void drm_dp_aux_init(struct drm_dp_aux *aux)
aux->ddc.algo_data = aux;
aux->ddc.retries = 3;
- aux->ddc.lock_bus = lock_bus;
- aux->ddc.trylock_bus = trylock_bus;
- aux->ddc.unlock_bus = unlock_bus;
+ aux->ddc.lock_ops = &drm_dp_i2c_lock_ops;
}
EXPORT_SYMBOL(drm_dp_aux_init);
diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c
index 56e50ca905ba..0bdda24a10b2 100644
--- a/drivers/i2c/i2c-core.c
+++ b/drivers/i2c/i2c-core.c
@@ -1691,6 +1691,12 @@ static int __process_new_adapter(struct device_driver *d, void *data)
return i2c_do_add_adapter(to_i2c_driver(d), data);
}
+static const struct i2c_lock_operations i2c_adapter_lock_ops = {
+ .lock_bus = i2c_adapter_lock_bus,
+ .trylock_bus = i2c_adapter_trylock_bus,
+ .unlock_bus = i2c_adapter_unlock_bus,
+};
+
static int i2c_register_adapter(struct i2c_adapter *adap)
{
int res = -EINVAL;
@@ -1710,11 +1716,8 @@ static int i2c_register_adapter(struct i2c_adapter *adap)
goto out_list;
}
- if (!adap->lock_bus) {
- adap->lock_bus = i2c_adapter_lock_bus;
- adap->trylock_bus = i2c_adapter_trylock_bus;
- adap->unlock_bus = i2c_adapter_unlock_bus;
- }
+ if (!adap->lock_ops)
+ adap->lock_ops = &i2c_adapter_lock_ops;
rt_mutex_init(&adap->bus_lock);
rt_mutex_init(&adap->mux_lock);
diff --git a/drivers/i2c/i2c-mux.c b/drivers/i2c/i2c-mux.c
index 764f195795e4..14741ff31041 100644
--- a/drivers/i2c/i2c-mux.c
+++ b/drivers/i2c/i2c-mux.c
@@ -263,6 +263,18 @@ struct i2c_mux_core *i2c_mux_alloc(struct i2c_adapter *parent,
}
EXPORT_SYMBOL_GPL(i2c_mux_alloc);
+static const struct i2c_lock_operations i2c_mux_lock_ops = {
+ .lock_bus = i2c_mux_lock_bus,
+ .trylock_bus = i2c_mux_trylock_bus,
+ .unlock_bus = i2c_mux_unlock_bus,
+};
+
+static const struct i2c_lock_operations i2c_parent_lock_ops = {
+ .lock_bus = i2c_parent_lock_bus,
+ .trylock_bus = i2c_parent_trylock_bus,
+ .unlock_bus = i2c_parent_unlock_bus,
+};
+
int i2c_mux_add_adapter(struct i2c_mux_core *muxc,
u32 force_nr, u32 chan_id,
unsigned int class)
@@ -312,15 +324,10 @@ int i2c_mux_add_adapter(struct i2c_mux_core *muxc,
priv->adap.retries = parent->retries;
priv->adap.timeout = parent->timeout;
priv->adap.quirks = parent->quirks;
- if (muxc->mux_locked) {
- priv->adap.lock_bus = i2c_mux_lock_bus;
- priv->adap.trylock_bus = i2c_mux_trylock_bus;
- priv->adap.unlock_bus = i2c_mux_unlock_bus;
- } else {
- priv->adap.lock_bus = i2c_parent_lock_bus;
- priv->adap.trylock_bus = i2c_parent_trylock_bus;
- priv->adap.unlock_bus = i2c_parent_unlock_bus;
- }
+ if (muxc->mux_locked)
+ priv->adap.lock_ops = &i2c_mux_lock_ops;
+ else
+ priv->adap.lock_ops = &i2c_parent_lock_ops;
/* Sanity check on class */
if (i2c_mux_parent_classes(parent) & class)
diff --git a/include/linux/i2c.h b/include/linux/i2c.h
index c1f60a345db7..616f67635734 100644
--- a/include/linux/i2c.h
+++ b/include/linux/i2c.h
@@ -427,6 +427,20 @@ struct i2c_algorithm {
};
/**
+ * struct i2c_lock_operations - represent I2C locking operations
+ * @lock_bus: Get exclusive access to an I2C bus segment
+ * @trylock_bus: Try to get exclusive access to an I2C bus segment
+ * @unlock_bus: Release exclusive access to an I2C bus segment
+ *
+ * The main operations are wrapped by i2c_lock_bus and i2c_unlock_bus.
+ */
+struct i2c_lock_operations {
+ void (*lock_bus)(struct i2c_adapter *, unsigned int flags);
+ int (*trylock_bus)(struct i2c_adapter *, unsigned int flags);
+ void (*unlock_bus)(struct i2c_adapter *, unsigned int flags);
+};
+
+/**
* struct i2c_timings - I2C timing information
* @bus_freq_hz: the bus frequency in Hz
* @scl_rise_ns: time SCL signal takes to rise in ns; t(r) in the I2C specification
@@ -536,6 +550,7 @@ struct i2c_adapter {
void *algo_data;
/* data fields that are valid for all devices */
+ const struct i2c_lock_operations *lock_ops;
struct rt_mutex bus_lock;
struct rt_mutex mux_lock;
@@ -552,10 +567,6 @@ struct i2c_adapter {
struct i2c_bus_recovery_info *bus_recovery_info;
const struct i2c_adapter_quirks *quirks;
-
- void (*lock_bus)(struct i2c_adapter *, unsigned int flags);
- int (*trylock_bus)(struct i2c_adapter *, unsigned int flags);
- void (*unlock_bus)(struct i2c_adapter *, unsigned int flags);
};
#define to_i2c_adapter(d) container_of(d, struct i2c_adapter, dev)
@@ -597,7 +608,7 @@ int i2c_for_each_dev(void *data, int (*fn)(struct device *, void *));
static inline void
i2c_lock_bus(struct i2c_adapter *adapter, unsigned int flags)
{
- adapter->lock_bus(adapter, flags);
+ adapter->lock_ops->lock_bus(adapter, flags);
}
/**
@@ -611,7 +622,7 @@ i2c_lock_bus(struct i2c_adapter *adapter, unsigned int flags)
static inline int
i2c_trylock_bus(struct i2c_adapter *adapter, unsigned int flags)
{
- return adapter->trylock_bus(adapter, flags);
+ return adapter->lock_ops->trylock_bus(adapter, flags);
}
/**
@@ -623,7 +634,7 @@ i2c_trylock_bus(struct i2c_adapter *adapter, unsigned int flags)
static inline void
i2c_unlock_bus(struct i2c_adapter *adapter, unsigned int flags)
{
- adapter->unlock_bus(adapter, flags);
+ adapter->lock_ops->unlock_bus(adapter, flags);
}
static inline void
--
2.1.4
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