Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754747AbcDMR6x (ORCPT ); Wed, 13 Apr 2016 13:58:53 -0400 Received: from mail-oi0-f42.google.com ([209.85.218.42]:36551 "EHLO mail-oi0-f42.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752095AbcDMR6v (ORCPT ); Wed, 13 Apr 2016 13:58:51 -0400 MIME-Version: 1.0 In-Reply-To: <1460536591-12573-1-git-send-email-andrea.merello@gmail.com> References: <1460536591-12573-1-git-send-email-andrea.merello@gmail.com> Date: Wed, 13 Apr 2016 20:58:49 +0300 Message-ID: Subject: Re: [PATCH RFC] I2C: i2c-smbus: add device tree support From: Andy Shevchenko To: Andrea Merello Cc: jdelvare@suse.de, Wolfram Sang , linux-i2c@vger.kernel.org, devicetree , "linux-kernel@vger.kernel.org" Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2081 Lines: 52 On Wed, Apr 13, 2016 at 11:36 AM, Andrea Merello 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