Re: [PATCH v2 1/2] dt-bindings: iio: imu: mpu6050: Add iam20680ht/hp bindings to mpu6050

[Jonathan Cameron]

On Mon, 30 Sep 2024 08:46:05 +0000
Jean-Baptiste Maneyrol <Jean-Baptiste.Maneyrol@xxxxxxx> wrote:

> Hello Jonathan
> 
> for the explanation, the chip variants at reset have a FIFO restricted to 512 bytes like the original one. You have to write specific bits in a register to unlock the FIFO to its full size.
> 
> The driver is writing these bits only when you configure the variant. Otherwise, it will behave really like the original one.
> 
> That's why I call them fully compatible.
Even then I'd go with 'backwards compatible'.

A driver that assumed the new device and tried to use that wouldn't work
with the IAM-20680 so it is one way compatibility.

The binding is fine, just the patch description may imply more than intended.

Jonathan

> 
> Thanks,
> JB
> 
> ________________________________________
> From: Jonathan Cameron <jic23@xxxxxxxxxx>
> Sent: Saturday, September 28, 2024 18:45
> To: Krzysztof Kozlowski <krzk@xxxxxxxxxx>
> Cc: Jean-Baptiste Maneyrol <Jean-Baptiste.Maneyrol@xxxxxxx>; Lars-Peter Clausen <lars@xxxxxxxxxx>; Rob Herring <robh@xxxxxxxxxx>; Krzysztof Kozlowski <krzk+dt@xxxxxxxxxx>; Conor Dooley <conor+dt@xxxxxxxxxx>; Jean-Baptiste Maneyrol <Jean-Baptiste.Maneyrol@xxxxxxx>; linux-iio@xxxxxxxxxxxxxxx <linux-iio@xxxxxxxxxxxxxxx>; devicetree@xxxxxxxxxxxxxxx <devicetree@xxxxxxxxxxxxxxx>; linux-kernel@xxxxxxxxxxxxxxx <linux-kernel@xxxxxxxxxxxxxxx>
> Subject: Re: [PATCH v2 1/2] dt-bindings: iio: imu: mpu6050: Add iam20680ht/hp bindings to mpu6050
>  
> This Message Is From an External Sender
> This message came from outside your organization.
>  
> On Mon, 23 Sep 2024 17:38:44 +0200
> Krzysztof Kozlowski <krzk@xxxxxxxxxx> wrote:
> 
> > On 23/09/2024 16:53, Jean-Baptiste Maneyrol via B4 Relay wrote:  
> > > From: Jean-Baptiste Maneyrol <jean-baptiste.maneyrol@xxxxxxx>
> > > 
> > > IAM-20680HT & HP are 2 variants of IAM-20680 fully compatible.
> > > They just have better specs, temperature range and a bigger FIFO.
> > > 
> > > Signed-off-by: Jean-Baptiste Maneyrol <jean-baptiste.maneyrol@xxxxxxx>
> > > ---    
> > 
> > Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@xxxxxxxxxx>  
> Ah. I missed v2 as checked by email address.
> 
> As per v1 review I've tweaked this patch description to say they are
> backwards compatible rather than fully (as the fifo size is not
> discoverable)
> 
> Jonathan
> 
> > 
> > Best regards,
> > Krzysztof
> >   
>