diff mbox series

[04/12] i2c: mux: populate the new *_atomic callbacks

Message ID 20190403124019.8947-5-wsa+renesas@sang-engineering.com
State Deferred
Headers show
Series i2c: core: introduce atomic transfers | expand

Commit Message

Wolfram Sang April 3, 2019, 12:40 p.m. UTC
If the parent adapter has atomic_xfer callbacks, populate them for the
mux adapter as well. We can use the same translation function as for the
non-atomic xfer callback.

Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
---
 drivers/i2c/i2c-mux.c | 6 ++++++
 1 file changed, 6 insertions(+)

Comments

Peter Rosin April 3, 2019, 3:17 p.m. UTC | #1
On 2019-04-03 14:40, Wolfram Sang wrote:
> If the parent adapter has atomic_xfer callbacks, populate them for the
> mux adapter as well. We can use the same translation function as for the
> non-atomic xfer callback.
> 
> Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
> ---
>  drivers/i2c/i2c-mux.c | 6 ++++++
>  1 file changed, 6 insertions(+)
> 
> diff --git a/drivers/i2c/i2c-mux.c b/drivers/i2c/i2c-mux.c
> index f330690b4125..603252fa1284 100644
> --- a/drivers/i2c/i2c-mux.c
> +++ b/drivers/i2c/i2c-mux.c
> @@ -310,12 +310,18 @@ int i2c_mux_add_adapter(struct i2c_mux_core *muxc,
>  		else
>  			priv->algo.master_xfer = __i2c_mux_master_xfer;
>  	}
> +	if (parent->algo->master_xfer_atomic)
> +		priv->algo.master_xfer_atomic = priv->algo.master_xfer;
> +
>  	if (parent->algo->smbus_xfer) {
>  		if (muxc->mux_locked)
>  			priv->algo.smbus_xfer = i2c_mux_smbus_xfer;
>  		else
>  			priv->algo.smbus_xfer = __i2c_mux_smbus_xfer;
>  	}
> +	if (parent->algo->smbus_xfer_atomic)
> +		priv->algo.smbus_xfer_atomic = priv->algo.smbus_xfer;
> +
>  	priv->algo.functionality = i2c_mux_functionality;
>  
>  	/* Now fill out new adapter structure */
> 

Hmmm, what happens if a driver implements .master_xfer and relies on
emulation for SMBus, and then someone implements .smbus_xfer_atomic
to handle some corner case at power-down?

Then someone hides the power-down device behind a mux. That would end
with xfers destined for .smbus_xfer_atomic being emulated by the
non-atomic .master_xfer, no?

Maybe too weird to care about?

I guess the question is if it is allowed to have .master_xfer_atomic
but not .master_xfer (and similarly for .smbus_xfer{,_atomic})? Maybe
that decision should be made explicit? And perhaps enforced?

I don't care deeply about the above though, so feel free to do
something about it, or

Reviewed-by: Peter Rosin <peda@axentia.se>

Cheers,
Peter
Wolfram Sang April 15, 2019, 12:04 p.m. UTC | #2
> I guess the question is if it is allowed to have .master_xfer_atomic
> but not .master_xfer (and similarly for .smbus_xfer{,_atomic})? Maybe
> that decision should be made explicit? And perhaps enforced?

xfer_atomic callbacks are optional. One xfer callback is mandatory. I
did a check for falling back to master_xfer_atomic if there is no
suitable smbus_xfer_atomic. I will think about the vice-versa case you
mentioned. Yet, this is indeed a super corner case, so I prefer to fix
this incrementally.

> I don't care deeply about the above though, so feel free to do
> something about it, or
> 
> Reviewed-by: Peter Rosin <peda@axentia.se>

Thanks for the review!
Andy Shevchenko April 15, 2019, 12:44 p.m. UTC | #3
On Wed, Apr 3, 2019 at 3:42 PM Wolfram Sang
<wsa+renesas@sang-engineering.com> wrote:
>
> If the parent adapter has atomic_xfer callbacks, populate them for the
> mux adapter as well. We can use the same translation function as for the
> non-atomic xfer callback.
>

Reviewed-by Andy Shevchenko <andriy.shevchenko@linux.intel.com>


> Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
> ---
>  drivers/i2c/i2c-mux.c | 6 ++++++
>  1 file changed, 6 insertions(+)
>
> diff --git a/drivers/i2c/i2c-mux.c b/drivers/i2c/i2c-mux.c
> index f330690b4125..603252fa1284 100644
> --- a/drivers/i2c/i2c-mux.c
> +++ b/drivers/i2c/i2c-mux.c
> @@ -310,12 +310,18 @@ int i2c_mux_add_adapter(struct i2c_mux_core *muxc,
>                 else
>                         priv->algo.master_xfer = __i2c_mux_master_xfer;
>         }
> +       if (parent->algo->master_xfer_atomic)
> +               priv->algo.master_xfer_atomic = priv->algo.master_xfer;
> +
>         if (parent->algo->smbus_xfer) {
>                 if (muxc->mux_locked)
>                         priv->algo.smbus_xfer = i2c_mux_smbus_xfer;
>                 else
>                         priv->algo.smbus_xfer = __i2c_mux_smbus_xfer;
>         }
> +       if (parent->algo->smbus_xfer_atomic)
> +               priv->algo.smbus_xfer_atomic = priv->algo.smbus_xfer;
> +
>         priv->algo.functionality = i2c_mux_functionality;
>
>         /* Now fill out new adapter structure */
> --
> 2.11.0
>
diff mbox series

Patch

diff --git a/drivers/i2c/i2c-mux.c b/drivers/i2c/i2c-mux.c
index f330690b4125..603252fa1284 100644
--- a/drivers/i2c/i2c-mux.c
+++ b/drivers/i2c/i2c-mux.c
@@ -310,12 +310,18 @@  int i2c_mux_add_adapter(struct i2c_mux_core *muxc,
 		else
 			priv->algo.master_xfer = __i2c_mux_master_xfer;
 	}
+	if (parent->algo->master_xfer_atomic)
+		priv->algo.master_xfer_atomic = priv->algo.master_xfer;
+
 	if (parent->algo->smbus_xfer) {
 		if (muxc->mux_locked)
 			priv->algo.smbus_xfer = i2c_mux_smbus_xfer;
 		else
 			priv->algo.smbus_xfer = __i2c_mux_smbus_xfer;
 	}
+	if (parent->algo->smbus_xfer_atomic)
+		priv->algo.smbus_xfer_atomic = priv->algo.smbus_xfer;
+
 	priv->algo.functionality = i2c_mux_functionality;
 
 	/* Now fill out new adapter structure */