From: Andy Shevchenko <andy.shevchenko@gmail.com>
To: Andrea Merello <andrea.merello@gmail.com>
Cc: jdelvare@suse.de, Wolfram Sang <wsa@the-dreams.de>,
linux-i2c@vger.kernel.org,
devicetree <devicetree@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH RFC] I2C: i2c-smbus: add device tree support
Date: Wed, 13 Apr 2016 20:58:49 +0300 [thread overview]
Message-ID: <CAHp75VepT0ztJ3sLoM_Yw+yo9E3QLJaKNae_AQ3TMH=LbNeRfQ@mail.gmail.com> (raw)
In-Reply-To: <1460536591-12573-1-git-send-email-andrea.merello@gmail.com>
On Wed, Apr 13, 2016 at 11:36 AM, Andrea Merello
<andrea.merello@gmail.com> wrote:
> According to Documentation/i2c/smbus-protocol, a smbus controller driver
> that wants to hook-in smbus extensions support, can call
> i2c_setup_smbus_alert(). There are very few drivers that are currently
> doing this.
>
> However the i2c-smbus module can also work with any
> smbus-extensions-unaware I2C controller, as long as we provide an extra
> IRQ line connected to the I2C bus ALARM signal.
>
> This patch makes it possible to go this way via DT. Note that the DT node
> will indeed describe a (little) piece of HW, that is the routing of the
> ALARM signal to an IRQ line (so it seems a fair DT use to me, but RFC).
>
> Note that AFAICT, by design, i2c-smbus module pretends to be an I2C slave
> with address 0x0C (that is the alarm response address), and IMHO this is
> quite consistent with usage in the DT as a I2C child node.
> --- a/drivers/i2c/i2c-smbus.c
> +++ b/drivers/i2c/i2c-smbus.c
> @@ -137,20 +138,29 @@ static int smbalert_probe(struct i2c_client *ara,
> struct i2c_smbus_alert_setup *setup = dev_get_platdata(&ara->dev);
> struct i2c_smbus_alert *alert;
> struct i2c_adapter *adapter = ara->adapter;
> + struct device_node *of_node = ara->dev.of_node;
Perhaps fwnode_handle ?
> int res;
> + int irq_type;
>
> alert = devm_kzalloc(&ara->dev, sizeof(struct i2c_smbus_alert),
> GFP_KERNEL);
> if (!alert)
> return -ENOMEM;
>
> - alert->alert_edge_triggered = setup->alert_edge_triggered;
> - alert->irq = setup->irq;
> + if (setup) {
> + alert->alert_edge_triggered = setup->alert_edge_triggered;
> + alert->irq = setup->irq;
> + } else if (of_node) {
> + alert->irq = irq_of_parse_and_map(of_node, 0);
> + irq_type = irq_get_trigger_type(alert->irq);
> + alert->alert_edge_triggered = (irq_type & IRQ_TYPE_EDGE_BOTH);
> + }
--
With Best Regards,
Andy Shevchenko
next prev parent reply other threads:[~2016-04-13 17:58 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-04-13 8:36 [PATCH RFC] I2C: i2c-smbus: add device tree support Andrea Merello
2016-04-13 17:58 ` Andy Shevchenko [this message]
2016-04-14 9:37 ` Andrea Merello
2016-04-14 16:10 ` Rob Herring
2016-04-18 13:35 ` Andrea Merello
2016-04-18 16:44 ` Rob Herring
2016-04-18 17:13 ` Andrea Merello
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to='CAHp75VepT0ztJ3sLoM_Yw+yo9E3QLJaKNae_AQ3TMH=LbNeRfQ@mail.gmail.com' \
--to=andy.shevchenko@gmail.com \
--cc=andrea.merello@gmail.com \
--cc=devicetree@vger.kernel.org \
--cc=jdelvare@suse.de \
--cc=linux-i2c@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=wsa@the-dreams.de \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).