From: Ludovic Desroches <ludovic.desroches@microchip.com>
To: Wolfram Sang <wsa+renesas@sang-engineering.com>
Cc: <linux-i2c@vger.kernel.org>, <linux-renesas-soc@vger.kernel.org>,
"Andy Shevchenko" <andriy.shevchenko@linux.intel.com>,
Alexandre Belloni <alexandre.belloni@bootlin.com>
Subject: Re: [PATCH] i2c: document the SDA hold time binding
Date: Wed, 13 Feb 2019 11:24:37 +0100 [thread overview]
Message-ID: <20190213102437.dtemwn4amsosqba7@M43218.corp.atmel.com> (raw)
In-Reply-To: <20190211132515.24163-1-wsa+renesas@sang-engineering.com>
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
>
next prev parent reply other threads:[~2019-02-13 10:24 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
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 [this message]
2019-02-13 10:27 ` Ludovic Desroches
2019-03-18 10:35 ` Andy Shevchenko
2019-03-18 11:22 ` Jarkko Nikula
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