[i2c-next,v9,1/5] dt-bindings: i2c: Add 'bus-timeout-ms' and '#retries' properties as common optional

This commit adds 'bus-timeout-ms' and '#retries' properties as
common optional properties that can be used for setting 'timeout'
and 'retries' values of 'struct i2c_adapter'. With this patch, the
bus timeout value and the master transfer retries count can be set
through these properties at the registration time of an adapter.
Still the values can be set by I2C_TIMEOUT and I2C_RETRIES ioctls
on cdev at runtime too.

These properties may not be supported by all drivers. However, if
a driver wants to support one of them, it should adapt the
bindings in this document.

Signed-off-by: Jae Hyun Yoo <jae.hyun.yoo@linux.intel.com>
Reviewed-by: Rob Herring <robh@kernel.org>
---
 Documentation/devicetree/bindings/i2c/i2c.txt | 6 ++++++
 1 file changed, 6 insertions(+)

On Tue, Oct 30, 2018 at 02:09:12PM -0700, Jae Hyun Yoo wrote:
> This commit adds 'bus-timeout-ms' and '#retries' properties as
> common optional properties that can be used for setting 'timeout'
> and 'retries' values of 'struct i2c_adapter'. With this patch, the
> bus timeout value and the master transfer retries count can be set
> through these properties at the registration time of an adapter.
> Still the values can be set by I2C_TIMEOUT and I2C_RETRIES ioctls
> on cdev at runtime too.
> 
> These properties may not be supported by all drivers. However, if
> a driver wants to support one of them, it should adapt the
> bindings in this document.
> 
> Signed-off-by: Jae Hyun Yoo <jae.hyun.yoo@linux.intel.com>
> Reviewed-by: Rob Herring <robh@kernel.org>

Definately NACK on the #retries part. This is purely a configuration
thing. Besides that it is kind of ancient cruft, too. I don't recommend
it, at all.

On the timeout thing, I am still not fully convinced that this is a HW
description. I said that before. But maybe I need to understand your
problem case better.

> ---
>  Documentation/devicetree/bindings/i2c/i2c.txt | 6 ++++++
>  1 file changed, 6 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/i2c/i2c.txt b/Documentation/devicetree/bindings/i2c/i2c.txt
> index 11263982470e..bdead91f82a4 100644
> --- a/Documentation/devicetree/bindings/i2c/i2c.txt
> +++ b/Documentation/devicetree/bindings/i2c/i2c.txt
> @@ -80,6 +80,12 @@ wants to support one of the below features, it should adapt the bindings below.
>  	Names of map programmable addresses.
>  	It can contain any map needing another address than default one.
>  
> +- bus-timeout-ms
> +	Bus timeout in milliseconds.
> +
> +- #retries
> +	Number of retries for master transfer.
> +
>  Binding may contain optional "interrupts" property, describing interrupts
>  used by the device. I2C core will assign "irq" interrupt (or the very first
>  interrupt if not using interrupt names) as primary interrupt for the slave.
> -- 
> 2.19.1
>

On 11/28/2018 3:54 PM, Wolfram Sang wrote:
> On Tue, Oct 30, 2018 at 02:09:12PM -0700, Jae Hyun Yoo wrote:
>> This commit adds 'bus-timeout-ms' and '#retries' properties as
>> common optional properties that can be used for setting 'timeout'
>> and 'retries' values of 'struct i2c_adapter'. With this patch, the
>> bus timeout value and the master transfer retries count can be set
>> through these properties at the registration time of an adapter.
>> Still the values can be set by I2C_TIMEOUT and I2C_RETRIES ioctls
>> on cdev at runtime too.
>>
>> These properties may not be supported by all drivers. However, if
>> a driver wants to support one of them, it should adapt the
>> bindings in this document.
>>
>> Signed-off-by: Jae Hyun Yoo <jae.hyun.yoo@linux.intel.com>
>> Reviewed-by: Rob Herring <robh@kernel.org>
> 
> Definately NACK on the #retries part. This is purely a configuration
> thing. Besides that it is kind of ancient cruft, too. I don't recommend
> it, at all.
> 
> On the timeout thing, I am still not fully convinced that this is a HW
> description. I said that before. But maybe I need to understand your
> problem case better.
> 

Okay, I got it. I'll leave those as configuration things. Will remove
this part in the next version.

Thanks for your comment.

Jae