In some cases, we might need to provide the state of the mux to be set for
the operation of a given peripheral. Therefore, pass this information using
the second argument of the mux-controls property.
Signed-off-by: Aswath Govindraju <a-govindraju@xxxxxx>
---
drivers/mux/core.c | 146 ++++++++++++++++++++++++++++++++++-
include/linux/mux/consumer.h | 19 ++++-
include/linux/mux/driver.h | 13 ++++
3 files changed, 173 insertions(+), 5 deletions(-)
diff --git a/drivers/mux/core.c b/drivers/mux/core.c
index 22f4709768d1..9622b98f9818 100644
--- a/drivers/mux/core.c
+++ b/drivers/mux/core.c
@@ -370,6 +370,29 @@ int mux_control_select_delay(struct mux_control *mux, unsigned int state,
}
EXPORT_SYMBOL_GPL(mux_control_select_delay);
+/**
+ * mux_state_select_delay() - Select the enable state in mux-state
+ * @mux: The mux-state to request a change of state from.
+ * @delay_us: The time to delay (in microseconds) if the mux state is changed.
+ *
+ * On successfully selecting the enable state, it will be locked until
+ * there is a call to mux_state_deselect(). If the mux-control is already
+ * selected when mux_state_select() is called, the caller will be blocked
+ * until mux_state_deselect() is called (by someone else).
+ *
+ * Therefore, make sure to call mux_state_deselect() when the operation is
+ * complete and the mux-control is free for others to use, but do not call
+ * mux_state_deselect() if mux_state_select() fails.
+ *
+ * Return: 0 when the mux-state has the enable state or a negative
+ * errno on error.
+ */
+int mux_state_select_delay(struct mux_state *mux, unsigned int delay_us)
+{
+ return mux_control_select_delay(mux->mux, mux->enable_state, delay_us);
+}
+EXPORT_SYMBOL_GPL(mux_state_select_delay);
+
/**
* mux_control_try_select_delay() - Try to select the given multiplexer state.
* @mux: The mux-control to request a change of state from.
@@ -405,6 +428,27 @@ int mux_control_try_select_delay(struct mux_control *mux, unsigned int state,
}
EXPORT_SYMBOL_GPL(mux_control_try_select_delay);
+/**
+ * mux_state_try_select_delay() - Try to select the multiplexer enable state.
+ * @mux: The mux-control to request a change of state from.
+ * @delay_us: The time to delay (in microseconds) if the mux state is changed.
+ *
+ * On successfully selecting the enable state, it will be locked until
+ * mux_state_deselect() called.
+ *
+ * Therefore, make sure to call mux_state_deselect() when the operation is
+ * complete and the mux-control is free for others to use, but do not call
+ * mux_state_deselect() if mux_state_try_select() fails.
+ *
+ * Return: 0 when the mux-control state has the requested state or a negative
+ * errno on error. Specifically -EBUSY if the mux-control is contended.
+ */
+int mux_state_try_select_delay(struct mux_state *mux, unsigned int delay_us)
+{
+ return mux_control_try_select_delay(mux->mux, mux->enable_state, delay_us);
+}
+EXPORT_SYMBOL_GPL(mux_state_try_select_delay);
+
/**
* mux_control_deselect() - Deselect the previously selected multiplexer state.
* @mux: The mux-control to deselect.
@@ -431,6 +475,24 @@ int mux_control_deselect(struct mux_control *mux)
}
EXPORT_SYMBOL_GPL(mux_control_deselect);
+/**
+ * mux_state_deselect() - Deselect the previously selected multiplexer state.
+ * @mux: The mux-state to deselect.
+ *
+ * It is required that a single call is made to mux_state_deselect() for
+ * each and every successful call made to either of mux_state_select() or
+ * mux_state_try_select().
+ *
+ * Return: 0 on success and a negative errno on error. An error can only
+ * occur if the mux has an idle state. Note that even if an error occurs, the
+ * mux-control is unlocked and is thus free for the next access.
+ */
+int mux_state_deselect(struct mux_state *mux)
+{
+ return mux_control_deselect(mux->mux);
+}
+EXPORT_SYMBOL_GPL(mux_state_deselect);
+
/* Note this function returns a reference to the mux_chip dev. */
static struct mux_chip *of_find_mux_chip_by_node(struct device_node *np)
{
@@ -442,13 +504,15 @@ static struct mux_chip *of_find_mux_chip_by_node(struct device_node *np)
}
/**
- * mux_control_get() - Get the mux-control for a device.
+ * mux_get() - Get the mux-control for a device.
* @dev: The device that needs a mux-control.
* @mux_name: The name identifying the mux-control.
+ * @enable_state: The variable to store the enable state for the requested device
*
* Return: A pointer to the mux-control, or an ERR_PTR with a negative errno.
*/
-struct mux_control *mux_control_get(struct device *dev, const char *mux_name)
+static struct mux_control *mux_get(struct device *dev, const char *mux_name,
+ unsigned int *enable_state)
{
struct device_node *np = dev->of_node;
struct of_phandle_args args;
@@ -481,8 +545,7 @@ struct mux_control *mux_control_get(struct device *dev, const char *mux_name)
if (!mux_chip)
return ERR_PTR(-EPROBE_DEFER);
- if (args.args_count > 1 ||
- (!args.args_count && (mux_chip->controllers > 1))) {
+ if (!args.args_count && mux_chip->controllers > 1) {
dev_err(dev, "%pOF: wrong #mux-control-cells for %pOF\n",
np, args.np);
put_device(&mux_chip->dev);
@@ -500,8 +563,25 @@ struct mux_control *mux_control_get(struct device *dev, const char *mux_name)
return ERR_PTR(-EINVAL);
}
+ if (args.args_count == 2)
+ *enable_state = args.args[1];
+
return &mux_chip->mux[controller];
}
+
+/**
+ * mux_control_get() - Get the mux-control for a device.
+ * @dev: The device that needs a mux-control.
+ * @mux_name: The name identifying the mux-control.
+ *
+ * Return: A pointer to the mux-control, or an ERR_PTR with a negative errno.
+ */
+struct mux_control *mux_control_get(struct device *dev, const char *mux_name)
+{
+ int state;
+
+ return mux_get(dev, mux_name, &state);
+}
EXPORT_SYMBOL_GPL(mux_control_get);
/**
@@ -523,6 +603,26 @@ static void devm_mux_control_release(struct device *dev, void *res)
mux_control_put(mux);
}
+/**
+ * mux_state_put() - Put away the mux-state for good.
+ * @mux: The mux-state to put away.
+ *
+ * mux_control_put() reverses the effects of mux_control_get().
+ */
+void mux_state_put(struct mux_state *mux_state)
+{
+ mux_control_put(mux_state->mux);
+ kfree(mux_state);
+}
+EXPORT_SYMBOL_GPL(mux_state_put);
+
+static void devm_mux_state_release(struct device *dev, void *res)
+{
+ struct mux_state *mux = *(struct mux_state **)res;
+
+ mux_state_put(mux);
+}
+
/**
* devm_mux_control_get() - Get the mux-control for a device, with resource
* management.
@@ -553,6 +653,44 @@ struct mux_control *devm_mux_control_get(struct device *dev,
}
EXPORT_SYMBOL_GPL(devm_mux_control_get);
+/**
+ * devm_mux_state_get() - Get the mux-state for a device, with resource
+ * management.
+ * @dev: The device that needs a mux-control.
+ * @mux_name: The name identifying the mux-control.
+ *
+ * Return: Pointer to the mux-state, or an ERR_PTR with a negative errno.
+ */
+struct mux_state *devm_mux_state_get(struct device *dev,
+ const char *mux_name)
+{
+ struct mux_state **ptr, *mux_state;
+ struct mux_control *mux_ctrl;
+ int enable_state;
+
+ mux_state = devm_kzalloc(dev, sizeof(struct mux_state), GFP_KERNEL);
+ if (!mux_state)
+ return ERR_PTR(-ENOMEM);
+
+ ptr = devres_alloc(devm_mux_state_release, sizeof(*ptr), GFP_KERNEL);
+ if (!ptr)
+ return ERR_PTR(-ENOMEM);
+
+ mux_ctrl = mux_get(dev, mux_name, &enable_state);
+ if (IS_ERR(mux_ctrl)) {
+ devres_free(ptr);
+ return (struct mux_state *)mux_ctrl;
+ }
+
+ mux_state->mux = mux_ctrl;
+ mux_state->enable_state = enable_state;
+ *ptr = mux_state;
+ devres_add(dev, ptr);
+
+ return mux_state;
+}
+EXPORT_SYMBOL_GPL(devm_mux_state_get);
+
/*
* Using subsys_initcall instead of module_init here to try to ensure - for
* the non-modular case - that the subsystem is initialized when mux consumers
diff --git a/include/linux/mux/consumer.h b/include/linux/mux/consumer.h
index 7a09b040ac39..d0f3242e148d 100644
--- a/include/linux/mux/consumer.h
+++ b/include/linux/mux/consumer.h
@@ -14,33 +14,50 @@
struct device;
struct mux_control;
+struct mux_state;
unsigned int mux_control_states(struct mux_control *mux);
int __must_check mux_control_select_delay(struct mux_control *mux,
unsigned int state,
unsigned int delay_us);
+int __must_check mux_state_select_delay(struct mux_state *mux,
+ unsigned int delay_us);
int __must_check mux_control_try_select_delay(struct mux_control *mux,
unsigned int state,
unsigned int delay_us);
-
+int __must_check mux_state_try_select_delay(struct mux_state *mux,
+ unsigned int delay_us);
static inline int __must_check mux_control_select(struct mux_control *mux,
unsigned int state)
{
return mux_control_select_delay(mux, state, 0);
}
+static inline int __must_check mux_state_select(struct mux_state *mux)
+{
+ return mux_state_select_delay(mux, 0);
+}
static inline int __must_check mux_control_try_select(struct mux_control *mux,
unsigned int state)
{
return mux_control_try_select_delay(mux, state, 0);
}
+static inline int __must_check mux_state_try_select(struct mux_state *mux)
+{
+ return mux_state_try_select_delay(mux, 0);
+}
+
int mux_control_deselect(struct mux_control *mux);
+int mux_state_deselect(struct mux_state *mux);
struct mux_control *mux_control_get(struct device *dev, const char *mux_name);
void mux_control_put(struct mux_control *mux);
+void mux_state_put(struct mux_state *mux);
struct mux_control *devm_mux_control_get(struct device *dev,
const char *mux_name);
+struct mux_state *devm_mux_state_get(struct device *dev,
+ const char *mux_name);
#endif /* _LINUX_MUX_CONSUMER_H */
diff --git a/include/linux/mux/driver.h b/include/linux/mux/driver.h
index 18824064f8c0..c7236f307fbd 100644
--- a/include/linux/mux/driver.h
+++ b/include/linux/mux/driver.h
@@ -53,6 +53,19 @@ struct mux_control {
ktime_t last_change;
};
+/**
+ * struct mux_state - Represents a mux controller specific to a given device
+ * @mux: Pointer to a mux controller
+ * @enable_state State of the mux to be set for enabling a device
+ *
+ * This structure is specific to a device that acquires it and has information
+ * specific to the device.
+ */
+struct mux_state {
+ struct mux_control *mux;
+ unsigned int enable_state;
+};
+
/**
* struct mux_chip - Represents a chip holding mux controllers.
* @controllers: Number of mux controllers handled by the chip.
--
2.17.1
