Re: [PATCH] i2c: document the SDA hold time binding
On 3/18/19 12:35 PM, Andy Shevchenko wrote:
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
---
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...
I guess in our case it's also t(hd:dat).
The DesignWare specification I have mention only tHD;DAT.
--
Jarkko
Re: [PATCH] i2c: document the SDA hold time binding
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
> ---
>
> 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...
I guess in our case it's also t(hd:dat).
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
Re: [PATCH] i2c: document the SDA hold time binding
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
> > ---
> >
> > 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
> >
Re: [PATCH] i2c: document the SDA hold time binding
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
> ---
>
> 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
>
Re: [PATCH] i2c: document the SDA hold time binding
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
> ---
>
> 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
