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* [PATCH] i2c: document the SDA hold time binding
@ 2019-02-11 13:25 Wolfram Sang
  2019-02-11 14:40 ` Andy Shevchenko
  2019-02-13 10:24 ` Ludovic Desroches
  0 siblings, 2 replies; 4+ messages in thread
From: Wolfram Sang @ 2019-02-11 13:25 UTC (permalink / raw)
  To: linux-i2c
  Cc: linux-renesas-soc, Andy Shevchenko, Alexandre Belloni,
	Ludovic Desroches, Wolfram Sang

The documentation was forgotten when the feature was added.

Fixes: 4717be73c284 ("i2c: core: Parse SDA hold time from firmware")
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
---

To everyone on CC: I want to confirm here that you use the value really for
t(hd:sta) and not t(hd:dat). I'd be a little confused otherwise...

 Documentation/devicetree/bindings/i2c/i2c.txt | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/Documentation/devicetree/bindings/i2c/i2c.txt b/Documentation/devicetree/bindings/i2c/i2c.txt
index 44efafdfd7f5..b7bc4c4cc2e6 100644
--- a/Documentation/devicetree/bindings/i2c/i2c.txt
+++ b/Documentation/devicetree/bindings/i2c/i2c.txt
@@ -55,6 +55,10 @@ wants to support one of the below features, it should adapt the bindings below.
 	Number of nanoseconds the SDA signal takes to fall; t(f) in the I2C
 	specification.
 
+- i2c-sda-hold-time-ns
+	Number of nanoseconds the SDA signal needs to be held; t(hd:sta) in
+	the I2C specification.
+
 - interrupts
 	interrupts used by the device.
 
-- 
2.11.0


^ permalink raw reply	[flat|nested] 4+ messages in thread

* Re: [PATCH] i2c: document the SDA hold time binding
  2019-02-11 13:25 [PATCH] i2c: document the SDA hold time binding Wolfram Sang
@ 2019-02-11 14:40 ` Andy Shevchenko
  2019-02-13 10:24 ` Ludovic Desroches
  1 sibling, 0 replies; 4+ messages in thread
From: Andy Shevchenko @ 2019-02-11 14:40 UTC (permalink / raw)
  To: Wolfram Sang
  Cc: linux-i2c, linux-renesas-soc, Alexandre Belloni,
	Ludovic Desroches, Jarkko Nikula

On Mon, Feb 11, 2019 at 02:25:15PM +0100, Wolfram Sang wrote:
> The documentation was forgotten when the feature was added.
> 
> Fixes: 4717be73c284 ("i2c: core: Parse SDA hold time from firmware")
> Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
> ---
> 
> To everyone on CC: I want to confirm here that you use the value really for
> t(hd:sta) and not t(hd:dat). I'd be a little confused otherwise...

+Cc: Jarkko

> 
>  Documentation/devicetree/bindings/i2c/i2c.txt | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/i2c/i2c.txt b/Documentation/devicetree/bindings/i2c/i2c.txt
> index 44efafdfd7f5..b7bc4c4cc2e6 100644
> --- a/Documentation/devicetree/bindings/i2c/i2c.txt
> +++ b/Documentation/devicetree/bindings/i2c/i2c.txt
> @@ -55,6 +55,10 @@ wants to support one of the below features, it should adapt the bindings below.
>  	Number of nanoseconds the SDA signal takes to fall; t(f) in the I2C
>  	specification.
>  
> +- i2c-sda-hold-time-ns
> +	Number of nanoseconds the SDA signal needs to be held; t(hd:sta) in
> +	the I2C specification.
> +
>  - interrupts
>  	interrupts used by the device.
>  
> -- 
> 2.11.0
> 

-- 
With Best Regards,
Andy Shevchenko



^ permalink raw reply	[flat|nested] 4+ messages in thread

* Re: [PATCH] i2c: document the SDA hold time binding
  2019-02-11 13:25 [PATCH] i2c: document the SDA hold time binding Wolfram Sang
  2019-02-11 14:40 ` Andy Shevchenko
@ 2019-02-13 10:24 ` Ludovic Desroches
  2019-02-13 10:27   ` Ludovic Desroches
  1 sibling, 1 reply; 4+ messages in thread
From: Ludovic Desroches @ 2019-02-13 10:24 UTC (permalink / raw)
  To: Wolfram Sang
  Cc: linux-i2c, linux-renesas-soc, Andy Shevchenko, Alexandre Belloni

Hi Wolfram,

On Mon, Feb 11, 2019 at 02:25:15PM +0100, Wolfram Sang wrote:
> The documentation was forgotten when the feature was added.
> 
> Fixes: 4717be73c284 ("i2c: core: Parse SDA hold time from firmware")
> Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
> ---
> 
> To everyone on CC: I want to confirm here that you use the value really for
> t(hd:sta) and not t(hd:dat). I'd be a little confused otherwise...


No in our case, it's t(hd:dat):
TWD is kept unchanged after TWCK falling edge for a
period of (HOLD + 3) × t peripheral clock


Ludovic

> 
>  Documentation/devicetree/bindings/i2c/i2c.txt | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/i2c/i2c.txt b/Documentation/devicetree/bindings/i2c/i2c.txt
> index 44efafdfd7f5..b7bc4c4cc2e6 100644
> --- a/Documentation/devicetree/bindings/i2c/i2c.txt
> +++ b/Documentation/devicetree/bindings/i2c/i2c.txt
> @@ -55,6 +55,10 @@ wants to support one of the below features, it should adapt the bindings below.
>  	Number of nanoseconds the SDA signal takes to fall; t(f) in the I2C
>  	specification.
>  
> +- i2c-sda-hold-time-ns
> +	Number of nanoseconds the SDA signal needs to be held; t(hd:sta) in
> +	the I2C specification.
> +
>  - interrupts
>  	interrupts used by the device.
>  
> -- 
> 2.11.0
> 

^ permalink raw reply	[flat|nested] 4+ messages in thread

* Re: [PATCH] i2c: document the SDA hold time binding
  2019-02-13 10:24 ` Ludovic Desroches
@ 2019-02-13 10:27   ` Ludovic Desroches
  0 siblings, 0 replies; 4+ messages in thread
From: Ludovic Desroches @ 2019-02-13 10:27 UTC (permalink / raw)
  To: Wolfram Sang, linux-i2c, linux-renesas-soc, Andy Shevchenko,
	Alexandre Belloni
  Cc: jarkko.nikula

Sorry I didn't keep the addition of Jarkko to the CC list.

On Wed, Feb 13, 2019 at 11:24:37AM +0100, Ludovic Desroches wrote:
> Hi Wolfram,
> 
> On Mon, Feb 11, 2019 at 02:25:15PM +0100, Wolfram Sang wrote:
> > The documentation was forgotten when the feature was added.
> > 
> > Fixes: 4717be73c284 ("i2c: core: Parse SDA hold time from firmware")
> > Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
> > ---
> > 
> > To everyone on CC: I want to confirm here that you use the value really for
> > t(hd:sta) and not t(hd:dat). I'd be a little confused otherwise...
> 
> 
> No in our case, it's t(hd:dat):
> TWD is kept unchanged after TWCK falling edge for a
> period of (HOLD + 3) × t peripheral clock
> 
> 
> Ludovic
> 
> > 
> >  Documentation/devicetree/bindings/i2c/i2c.txt | 4 ++++
> >  1 file changed, 4 insertions(+)
> > 
> > diff --git a/Documentation/devicetree/bindings/i2c/i2c.txt b/Documentation/devicetree/bindings/i2c/i2c.txt
> > index 44efafdfd7f5..b7bc4c4cc2e6 100644
> > --- a/Documentation/devicetree/bindings/i2c/i2c.txt
> > +++ b/Documentation/devicetree/bindings/i2c/i2c.txt
> > @@ -55,6 +55,10 @@ wants to support one of the below features, it should adapt the bindings below.
> >  	Number of nanoseconds the SDA signal takes to fall; t(f) in the I2C
> >  	specification.
> >  
> > +- i2c-sda-hold-time-ns
> > +	Number of nanoseconds the SDA signal needs to be held; t(hd:sta) in
> > +	the I2C specification.
> > +
> >  - interrupts
> >  	interrupts used by the device.
> >  
> > -- 
> > 2.11.0
> > 

^ permalink raw reply	[flat|nested] 4+ messages in thread

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Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
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2019-02-11 13:25 [PATCH] i2c: document the SDA hold time binding Wolfram Sang
2019-02-11 14:40 ` Andy Shevchenko
2019-02-13 10:24 ` Ludovic Desroches
2019-02-13 10:27   ` Ludovic Desroches

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