| Message ID | 20210722203407.3588046-4-djrscally@gmail.com |
|---|---|
| State | Superseded |
| Headers | show |
| Series | [01/13] media: i2c: Add ACPI support to ov8865 | expand |
Hi Daniel, On Thu 22 Jul 21, 21:33, Daniel Scally wrote: > The ov8865 driver is one of those that can be connected to a CIO2 > device by the cio2-bridge code. This means that the absence of an > endpoint for this device is not necessarily fatal, as one might be > built by the cio2-bridge when it probes. Return -EPROBE_DEFER if no > endpoint is found rather than a fatal error. Is this an error that you have actually seen in practice? My understanding is that this function should return the handle to the *local* fwnode graph endpoint, which relates to the static device-tree description and should be unrelated to another driver probing. So as far as I can see, this should not be needed (but correct me if I'm wrong). Cheers, Paul > Signed-off-by: Daniel Scally <djrscally@gmail.com> > --- > drivers/media/i2c/ov8865.c | 6 ++---- > 1 file changed, 2 insertions(+), 4 deletions(-) > > diff --git a/drivers/media/i2c/ov8865.c b/drivers/media/i2c/ov8865.c > index 2ef146e7e7ef..66182142c28b 100644 > --- a/drivers/media/i2c/ov8865.c > +++ b/drivers/media/i2c/ov8865.c > @@ -2796,10 +2796,8 @@ static int ov8865_probe(struct i2c_client *client) > /* Graph Endpoint */ > > handle = fwnode_graph_get_next_endpoint(dev_fwnode(dev), NULL); > - if (!handle) { > - dev_err(dev, "unable to find endpoint node\n"); > - return -EINVAL; > - } > + if (!handle) > + return -EPROBE_DEFER; > > sensor->endpoint.bus_type = V4L2_MBUS_CSI2_DPHY; > > -- > 2.25.1 > -- Paul Kocialkowski, Bootlin Embedded Linux and kernel engineering https://bootlin.com
Hi Paul On 23/07/2021 08:49, Paul Kocialkowski wrote: > Hi Daniel, > > On Thu 22 Jul 21, 21:33, Daniel Scally wrote: >> The ov8865 driver is one of those that can be connected to a CIO2 >> device by the cio2-bridge code. This means that the absence of an >> endpoint for this device is not necessarily fatal, as one might be >> built by the cio2-bridge when it probes. Return -EPROBE_DEFER if no >> endpoint is found rather than a fatal error. > Is this an error that you have actually seen in practice? Yes > My understanding is that this function should return the handle to the *local* > fwnode graph endpoint, which relates to the static device-tree description > and should be unrelated to another driver probing. > > So as far as I can see, this should not be needed (but correct me if I'm wrong). It's a newly possible scenario - some laptops with Intel IPU3s have ACPI that is _creative_,. and rather than define the endpoints in an ACPI device's _DSD they're encoded within a buffer that's against the sensor devices instead. We're parsing those out and building the fwnode graph using software nodes in the ipu3-cio2 driver: https://elixir.bootlin.com/linux/v5.14-rc2/source/drivers/media/pci/intel/ipu3/cio2-bridge.c#L166 But that means there's no endpoint for the sensor until ipu3-cio2 has probed. Thanks Dan > > Cheers, > > Paul > >> Signed-off-by: Daniel Scally <djrscally@gmail.com> >> --- >> drivers/media/i2c/ov8865.c | 6 ++---- >> 1 file changed, 2 insertions(+), 4 deletions(-) >> >> diff --git a/drivers/media/i2c/ov8865.c b/drivers/media/i2c/ov8865.c >> index 2ef146e7e7ef..66182142c28b 100644 >> --- a/drivers/media/i2c/ov8865.c >> +++ b/drivers/media/i2c/ov8865.c >> @@ -2796,10 +2796,8 @@ static int ov8865_probe(struct i2c_client *client) >> /* Graph Endpoint */ >> >> handle = fwnode_graph_get_next_endpoint(dev_fwnode(dev), NULL); >> - if (!handle) { >> - dev_err(dev, "unable to find endpoint node\n"); >> - return -EINVAL; >> - } >> + if (!handle) >> + return -EPROBE_DEFER; >> >> sensor->endpoint.bus_type = V4L2_MBUS_CSI2_DPHY; >> >> -- >> 2.25.1 >>
diff --git a/drivers/media/i2c/ov8865.c b/drivers/media/i2c/ov8865.c index 2ef146e7e7ef..66182142c28b 100644 --- a/drivers/media/i2c/ov8865.c +++ b/drivers/media/i2c/ov8865.c @@ -2796,10 +2796,8 @@ static int ov8865_probe(struct i2c_client *client) /* Graph Endpoint */ handle = fwnode_graph_get_next_endpoint(dev_fwnode(dev), NULL); - if (!handle) { - dev_err(dev, "unable to find endpoint node\n"); - return -EINVAL; - } + if (!handle) + return -EPROBE_DEFER; sensor->endpoint.bus_type = V4L2_MBUS_CSI2_DPHY;
The ov8865 driver is one of those that can be connected to a CIO2 device by the cio2-bridge code. This means that the absence of an endpoint for this device is not necessarily fatal, as one might be built by the cio2-bridge when it probes. Return -EPROBE_DEFER if no endpoint is found rather than a fatal error. Signed-off-by: Daniel Scally <djrscally@gmail.com> --- drivers/media/i2c/ov8865.c | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-)