Hi Aswath!

See below.

On 2021-12-17 07:26, Peter Rosin wrote:

Hi again.

On 2021-12-17 06:57, Peter Rosin wrote:

quoted

Hi Aswath!

On 2021-12-02 13:40, Aswath Govindraju wrote:

quoted

The following series of patches add support for reading mux
state from the device tree.

changes since v1:
- Made grammer corrections and added more information
  on the usage for mux-states and mux-controls

Aswath Govindraju (2):
  dt-bindings: mux: Document mux-states property
  mux: Add support for reading mux state from consumer DT node

 .../devicetree/bindings/mux/gpio-mux.yaml     |  11 +-
 .../devicetree/bindings/mux/mux-consumer.yaml |  21 ++
 .../bindings/mux/mux-controller.yaml          |  26 ++-
 drivers/mux/core.c                            | 219 ++++++++++++++++--
 include/linux/mux/consumer.h                  |  19 +-
 5 files changed, 271 insertions(+), 25 deletions(-)

I finally found some time to have a last look at this (fingers crossed) and
pushed it out for testing in linux-next.

I did end up squashing in these trivial changes in patch 2/2, I hope that's
fine with you. Just holler if not...

Cheers,
Peter

diff --git a/Documentation/driver-api/driver-model/devres.rst b/Documentation/driver-api/driver-model/devres.rst
index 148e19381b79..5018403fe82f 100644
--- a/Documentation/driver-api/driver-model/devres.rst
+++ b/Documentation/driver-api/driver-model/devres.rst

@@ -368,6 +368,7 @@ MUX
   devm_mux_chip_alloc()
   devm_mux_chip_register()
   devm_mux_control_get()
+  devm_mux_state_get()
 
 NET
   devm_alloc_etherdev()

diff --git a/drivers/mux/core.c b/drivers/mux/core.c
index 7355c5ad41f7..bf448069ca85 100644
--- a/drivers/mux/core.c
+++ b/drivers/mux/core.c

@@ -30,12 +30,13 @@
 #define MUX_CACHE_UNKNOWN MUX_IDLE_AS_IS
 
 /**
- * struct mux_state -	Represents a mux controller specific to a given device
- * @mux:		Pointer to a mux controller
- * @state		State of the mux to be set
+ * struct mux_state -	Represents a mux controller state specific to a given
+ *			consumer.
+ * @mux:		Pointer to a mux controller.
+ * @state		State of the mux to be selected.
  *
- * This structure is specific to a device that acquires it and has information
- * specific to the device.
+ * This structure is specific to the consumer that acquires it and has
+ * information specific to that consumer.
  */
 struct mux_state {
 	struct mux_control *mux;

@@ -354,7 +355,8 @@ static void mux_control_delay(struct mux_control *mux, unsigned int delay_us)
  * On successfully selecting the mux-control state, it will be locked until
  * there is a call to mux_control_deselect(). If the mux-control is already
  * selected when mux_control_select() is called, the caller will be blocked
- * until mux_control_deselect() is called (by someone else).
+ * until mux_control_deselect() or mux_state_deselect() is called (by someone
+ * else).
  *
  * Therefore, make sure to call mux_control_deselect() when the operation is
  * complete and the mux-control is free for others to use, but do not call

@@ -384,16 +386,15 @@ int mux_control_select_delay(struct mux_control *mux, unsigned int state,
 EXPORT_SYMBOL_GPL(mux_control_select_delay);
 
 /**
- * mux_state_select_delay() - Select mux-state
- * @mstate: The mux-state to select
- * @delay_us: The time to delay (in microseconds) if the mux control
- *            changes state on select
+ * mux_state_select_delay() - Select the given multiplexer state.
+ * @mstate: The mux-state to select.
+ * @delay_us: The time to delay (in microseconds) if the mux state is changed.
  *
- * On successfully selecting the mux-state, it will be locked until
- * there is a call to mux_state_deselect() or mux_control_deselect().
- * If the mux-control is already selected when mux_state_select() is
- * called, the caller will be blocked until mux_state_deselect() or
- * mux_control_deselect() is called (by someone else).
+ * On successfully selecting the mux-state, its mux-control 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() or mux_control_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

@@ -415,7 +416,7 @@ EXPORT_SYMBOL_GPL(mux_state_select_delay);
  * @delay_us: The time to delay (in microseconds) if the mux state is changed.
  *
  * On successfully selecting the mux-control state, it will be locked until
- * mux_control_deselect() or mux_state_deselect() called.
+ * mux_control_deselect() called.
  *
  * Therefore, make sure to call mux_control_deselect() when the operation is
  * complete and the mux-control is free for others to use, but do not call

@@ -444,12 +445,12 @@ 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 mux-state.
- * @mstate: The mux-state to select
+ * mux_state_try_select_delay() - Try to select the given multiplexer state.
+ * @mstate: The mux-state to select.
  * @delay_us: The time to delay (in microseconds) if the mux state is changed.
  *
- * On successfully selecting the mux-state, it will be locked until
- * mux_state_deselect() or mux_control_deselect() is called.
+ * On successfully selecting the mux-state, its mux-control will be locked
+ * until mux_state_deselect() is 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

@@ -642,26 +643,6 @@ 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.
- * @mstate: The mux-state to put away.
- *
- * mux_control_put() reverses the effects of mux_control_get().
- */
-void mux_state_put(struct mux_state *mstate)
-{
-	mux_control_put(mstate->mux);
-	kfree(mstate);
-}
-EXPORT_SYMBOL_GPL(mux_state_put);
-
-static void devm_mux_state_release(struct device *dev, void *res)
-{
-	struct mux_state *mstate = *(struct mux_state **)res;
-
-	mux_state_put(mstate);
-}
-
 /**
  * devm_mux_control_get() - Get the mux-control for a device, with resource
  *			    management.

@@ -692,6 +673,26 @@ struct mux_control *devm_mux_control_get(struct device *dev,
 }
 EXPORT_SYMBOL_GPL(devm_mux_control_get);
 
+/**
+ * mux_state_put() - Put away the mux-state for good.
+ * @mstate: The mux-state to put away.
+ *
+ * mux_control_put() reverses the effects of mux_control_get().

And, a couple of minutes later, I squashed in this on top:

- * mux_control_put() reverses the effects of mux_control_get().
+ * mux_state_put() reverses the effects of mux_state_get().

And now I notice that there is no mux_state_get. There should be one,
in my opinion, at least if there is an exported mux_state_put.

So, Aswath, can you please test the patch that's coming as a reply
to this message on top of what is currently on its way into linux-next?

I.e. wait for the next linux-next to be released, or
https://gitlab.com/peda-linux/mux.git#for-next

Or, optionally, just grab the mux-state-get branch:

https://gitlab.com/peda-linux/mux.git#mux-state-get

Cheers,
Peter

quoted

+ */
+void mux_state_put(struct mux_state *mstate)
+{
+	mux_control_put(mstate->mux);
+	kfree(mstate);
+}
+EXPORT_SYMBOL_GPL(mux_state_put);
+
+static void devm_mux_state_release(struct device *dev, void *res)
+{
+	struct mux_state *mstate = *(struct mux_state **)res;
+
+	mux_state_put(mstate);
+}
+
 /**
  * devm_mux_state_get() - Get the mux-state for a device, with resource
  *			  management.

diff --git a/include/linux/mux/consumer.h b/include/linux/mux/consumer.h
index bf5abf062c21..babf2a744056 100644
--- a/include/linux/mux/consumer.h
+++ b/include/linux/mux/consumer.h

@@ -27,6 +27,7 @@ int __must_check mux_control_try_select_delay(struct mux_control *mux,
 					      unsigned int delay_us);
 int __must_check mux_state_try_select_delay(struct mux_state *mstate,
 					    unsigned int delay_us);
+
 static inline int __must_check mux_control_select(struct mux_control *mux,
 						  unsigned int state)
 {

@@ -37,6 +38,7 @@ static inline int __must_check mux_state_select(struct mux_state *mstate)
 {
 	return mux_state_select_delay(mstate, 0);
 }
+
 static inline int __must_check mux_control_try_select(struct mux_control *mux,
 						      unsigned int state)
 {