| Message ID | 20210315131512.133720-3-jacopo+renesas@jmondi.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | media: gmsl: Reliability improvement | expand |
Hi Jacopo, Thank you for the patch. On Mon, Mar 15, 2021 at 02:14:56PM +0100, Jacopo Mondi wrote: > Enable the noise immunity threshold at the end of the rdacm20 > initialization routine. > > The rdacm20 camera module has been so far tested with a startup > delay that allowed the embedded MCU to program the serializer. If > the initialization routine is run before the MCU programs the > serializer and the image sensor and their addresses gets changed > by the rdacm20 driver it is required to manually enable the noise > immunity threshold to make the communication on the control channel > more reliable. I'm still worried by the race with the MCU. Any update on dumping the MCU configuration to check what it initializes ? > Reviewed-by: Kieran Bingham <kieran.bingham+renesas@ideasonboard.com> > Signed-off-by: Jacopo Mondi <jacopo+renesas@jmondi.org> > --- > drivers/media/i2c/rdacm20.c | 8 +++++++- > 1 file changed, 7 insertions(+), 1 deletion(-) > > diff --git a/drivers/media/i2c/rdacm20.c b/drivers/media/i2c/rdacm20.c > index 90eb73f0e6e9..f7fd5ae955d0 100644 > --- a/drivers/media/i2c/rdacm20.c > +++ b/drivers/media/i2c/rdacm20.c > @@ -541,7 +541,13 @@ static int rdacm20_initialize(struct rdacm20_device *dev) > > dev_info(dev->dev, "Identified MAX9271 + OV10635 device\n"); > > - return 0; > + /* > + * Set reverse channel high threshold to increase noise immunity. > + * > + * This should be compensated by increasing the reverse channel > + * amplitude on the remote deserializer side. > + */ > + return max9271_set_high_threshold(&dev->serializer, true); > } > > static int rdacm20_probe(struct i2c_client *client)
Hi Laurent, On Mon, Mar 15, 2021 at 11:37:26PM +0200, Laurent Pinchart wrote: > Hi Jacopo, > > Thank you for the patch. > > On Mon, Mar 15, 2021 at 02:14:56PM +0100, Jacopo Mondi wrote: > > Enable the noise immunity threshold at the end of the rdacm20 > > initialization routine. > > > > The rdacm20 camera module has been so far tested with a startup > > delay that allowed the embedded MCU to program the serializer. If > > the initialization routine is run before the MCU programs the > > serializer and the image sensor and their addresses gets changed > > by the rdacm20 driver it is required to manually enable the noise > > immunity threshold to make the communication on the control channel > > more reliable. > > I'm still worried by the race with the MCU. Any update on dumping the > MCU configuration to check what it initializes ? > Not yet, you're right ... I mainly focused on testing with rdacm21, what if I strip the rdacm20 changes out from this series ? I will have to keep the init() operation introduction to maintain compatibility with max9286 changes, and in case of no regressions, we can keep the 8 seconds delay in the .dtsi. However it will break upstream support on Eagle for rdacm20 as we don't have a regulator where to insert the startup delay there, and a downstream patch that waits for 8 seconds in the deserializer driver should be used instead... > > Reviewed-by: Kieran Bingham <kieran.bingham+renesas@ideasonboard.com> > > Signed-off-by: Jacopo Mondi <jacopo+renesas@jmondi.org> > > --- > > drivers/media/i2c/rdacm20.c | 8 +++++++- > > 1 file changed, 7 insertions(+), 1 deletion(-) > > > > diff --git a/drivers/media/i2c/rdacm20.c b/drivers/media/i2c/rdacm20.c > > index 90eb73f0e6e9..f7fd5ae955d0 100644 > > --- a/drivers/media/i2c/rdacm20.c > > +++ b/drivers/media/i2c/rdacm20.c > > @@ -541,7 +541,13 @@ static int rdacm20_initialize(struct rdacm20_device *dev) > > > > dev_info(dev->dev, "Identified MAX9271 + OV10635 device\n"); > > > > - return 0; > > + /* > > + * Set reverse channel high threshold to increase noise immunity. > > + * > > + * This should be compensated by increasing the reverse channel > > + * amplitude on the remote deserializer side. > > + */ > > + return max9271_set_high_threshold(&dev->serializer, true); > > } > > > > static int rdacm20_probe(struct i2c_client *client) > > -- > Regards, > > Laurent Pinchart
Hi Jacopo, On Tue, Mar 16, 2021 at 01:56:07PM +0100, Jacopo Mondi wrote: > On Mon, Mar 15, 2021 at 11:37:26PM +0200, Laurent Pinchart wrote: > > On Mon, Mar 15, 2021 at 02:14:56PM +0100, Jacopo Mondi wrote: > > > Enable the noise immunity threshold at the end of the rdacm20 > > > initialization routine. > > > > > > The rdacm20 camera module has been so far tested with a startup > > > delay that allowed the embedded MCU to program the serializer. If > > > the initialization routine is run before the MCU programs the > > > serializer and the image sensor and their addresses gets changed > > > by the rdacm20 driver it is required to manually enable the noise > > > immunity threshold to make the communication on the control channel > > > more reliable. > > > > I'm still worried by the race with the MCU. Any update on dumping the > > MCU configuration to check what it initializes ? > > Not yet, you're right ... > > I mainly focused on testing with rdacm21, what if I strip the rdacm20 > changes out from this series ? I will have to keep the init() > operation introduction to maintain compatibility with max9286 changes, > and in case of no regressions, we can keep the 8 seconds delay in the > .dtsi. However it will break upstream support on Eagle for rdacm20 as > we don't have a regulator where to insert the startup delay there, and > a downstream patch that waits for 8 seconds in the deserializer driver > should be used instead... I don't think the rdacm20 changes need to wait. Even this one could be merged as-is, as long as we consider it to be a temporary workaround and don't build anything on top that would make it more difficult to address the issue properly (a TODO comment in the code could help). > > > Reviewed-by: Kieran Bingham <kieran.bingham+renesas@ideasonboard.com> > > > Signed-off-by: Jacopo Mondi <jacopo+renesas@jmondi.org> > > > --- > > > drivers/media/i2c/rdacm20.c | 8 +++++++- > > > 1 file changed, 7 insertions(+), 1 deletion(-) > > > > > > diff --git a/drivers/media/i2c/rdacm20.c b/drivers/media/i2c/rdacm20.c > > > index 90eb73f0e6e9..f7fd5ae955d0 100644 > > > --- a/drivers/media/i2c/rdacm20.c > > > +++ b/drivers/media/i2c/rdacm20.c > > > @@ -541,7 +541,13 @@ static int rdacm20_initialize(struct rdacm20_device *dev) > > > > > > dev_info(dev->dev, "Identified MAX9271 + OV10635 device\n"); > > > > > > - return 0; > > > + /* > > > + * Set reverse channel high threshold to increase noise immunity. > > > + * > > > + * This should be compensated by increasing the reverse channel > > > + * amplitude on the remote deserializer side. > > > + */ > > > + return max9271_set_high_threshold(&dev->serializer, true); > > > } > > > > > > static int rdacm20_probe(struct i2c_client *client)
diff --git a/drivers/media/i2c/rdacm20.c b/drivers/media/i2c/rdacm20.c index 90eb73f0e6e9..f7fd5ae955d0 100644 --- a/drivers/media/i2c/rdacm20.c +++ b/drivers/media/i2c/rdacm20.c @@ -541,7 +541,13 @@ static int rdacm20_initialize(struct rdacm20_device *dev) dev_info(dev->dev, "Identified MAX9271 + OV10635 device\n"); - return 0; + /* + * Set reverse channel high threshold to increase noise immunity. + * + * This should be compensated by increasing the reverse channel + * amplitude on the remote deserializer side. + */ + return max9271_set_high_threshold(&dev->serializer, true); } static int rdacm20_probe(struct i2c_client *client)