From patchwork Wed Apr 13 08:36:31 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andrea Merello X-Patchwork-Id: 609901 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 3qlHGg0zDQz9t41 for ; Wed, 13 Apr 2016 18:36:59 +1000 (AEST) Authentication-Results: ozlabs.org; dkim=fail reason="signature verification failed" (2048-bit key; unprotected) header.d=gmail.com header.i=@gmail.com header.b=EArJbd3A; dkim-atps=neutral Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933667AbcDMIgk (ORCPT ); Wed, 13 Apr 2016 04:36:40 -0400 Received: from mail-wm0-f66.google.com ([74.125.82.66]:32996 "EHLO mail-wm0-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754681AbcDMIgi (ORCPT ); Wed, 13 Apr 2016 04:36:38 -0400 Received: by mail-wm0-f66.google.com with SMTP id y144so11774086wmd.0; Wed, 13 Apr 2016 01:36:37 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=from:to:cc:subject:date:message-id; bh=cy/cOHK7HLZCDse//ZEgG7I05hd9YEVsXQ6/qfqGSR8=; b=EArJbd3ApPuzRy7YzJiGP+QjDvj/5zv1wo2DcTTkOZTaMkUGeshxu1vmWFW7vcB72S xoSwNgbbXFEHQwvqgqByvXsvwIzxW0brZ7rOhyctsE4PN/f4lRxX45AJ0eISqI6ZzB8A n/JI0KxY6rkAZO5VY86z2gRo6AAilushPC7GYGwaKlXZ1CQnR7CzwlJM8JoDYVT4zqVB yYrr7e1GiE2XkGrL4hgcl9hsA1Ym7xNusTMK7K9221q6qgpjHb1Jaq0uuR+punEn9QN/ dnctD29D9iFvuwkWFDz0JPtusPRQqvp25cPRUK2NwLQvw5cTCRIsFp+c/NergxMxvKRt F6DQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:from:to:cc:subject:date:message-id; bh=cy/cOHK7HLZCDse//ZEgG7I05hd9YEVsXQ6/qfqGSR8=; b=ZgGQUfZ+hjPR9lPXDyezMXZVrFloEQ68YDymZN7fF6KPG56oZX7uO5tl4wRtBuO0hd Z2k0Ks8FEc3mxI8AutqLXXhvVP/OI3odyy4iOkXJgdPXrKorf5SucdW9dPNf4tyqLkEe 98rToSN3OdEr3ySxEzusapRU2uzT5rU9O5fmjmeF7t0d9DRIkQn/3Lnt3E03vbU+HV0Z D34XhPIqz7yRYGFfd+ZYb9GyssbNckK0sL8Mn5WmHLRvPwLwGiAtQfF6b0YPDTyEsYjN Yw1JlomOp/wYXUi4dV+iL5rflJYKwa/XFZfE3p3DjPDLXnLVto91uL9grlh+CX1ZUm00 BG/w== X-Gm-Message-State: AOPr4FUeKLdtioZJkGe1AtH5VipKvGSwmSXXKZmJB13xd7quSwEtaUtF7/m2ypYvCM8DwA== X-Received: by 10.28.45.136 with SMTP id t130mr8609259wmt.86.1460536596939; Wed, 13 Apr 2016 01:36:36 -0700 (PDT) Received: from NewMoon.humanoids.iit.it (host240.iit.it. [90.147.26.240]) by smtp.gmail.com with ESMTPSA id k125sm26704114wmb.14.2016.04.13.01.36.35 (version=TLS1_2 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Wed, 13 Apr 2016 01:36:36 -0700 (PDT) From: Andrea Merello To: jdelvare@suse.de Cc: wsa@the-dreams.de, linux-i2c@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, Andrea Merello Subject: [PATCH RFC] I2C: i2c-smbus: add device tree support Date: Wed, 13 Apr 2016 10:36:31 +0200 Message-Id: <1460536591-12573-1-git-send-email-andrea.merello@gmail.com> X-Mailer: git-send-email 1.9.1 Sender: linux-i2c-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-i2c@vger.kernel.org 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. Signed-off-by: Andrea Merello --- 1.9.1 -- To unsubscribe from this list: send the line "unsubscribe linux-i2c" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html diff --git a/Documentation/devicetree/bindings/i2c/i2c-smbus.txt b/Documentation/devicetree/bindings/i2c/i2c-smbus.txt new file mode 100644 index 0000000..da83127 --- /dev/null +++ b/Documentation/devicetree/bindings/i2c/i2c-smbus.txt @@ -0,0 +1,20 @@ +* i2c-smbus extensions + +Required Properties: + - compatible: Must contain "smbus_alert" + - interrupts: The irq line for smbus ALERT signal + - reg: I2C slave address. Set to 0x0C (alert response address). + +Note: The i2c-smbus module registers itself as a slave I2C device. Whenever +a smbus controller directly support smbus extensions (and its driver supports +this), there is no need to add anything special to the DT. Otherwise, for using +i2c-smbus with any smbus-extensions-unaware I2C controllers, you need to +route the smbus ALARM signal to an extra IRQ line, thus you need to describe +this in the DT. + +Example: + alert@0x0C { + reg = <0x0C>; + compatible = "smbus_alert"; + interrupts = <0 36 IRQ_TYPE_LEVEL_LOW>; + }; diff --git a/drivers/i2c/i2c-smbus.c b/drivers/i2c/i2c-smbus.c index abb55d3..7f0a566 100644 --- a/drivers/i2c/i2c-smbus.c +++ b/drivers/i2c/i2c-smbus.c @@ -23,6 +23,7 @@ #include #include #include +#include struct i2c_smbus_alert { unsigned int alert_edge_triggered:1; @@ -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; 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); + } + INIT_WORK(&alert->alert, smbus_alert); alert->ara = ara; - if (setup->irq > 0) { - res = devm_request_irq(&ara->dev, setup->irq, smbalert_irq, + if (alert->irq > 0) { + res = devm_request_irq(&ara->dev, alert->irq, smbalert_irq, 0, "smbus_alert", alert); if (res) return res; @@ -158,7 +168,7 @@ static int smbalert_probe(struct i2c_client *ara, i2c_set_clientdata(ara, alert); dev_info(&adapter->dev, "supports SMBALERT#, %s trigger\n", - setup->alert_edge_triggered ? "edge" : "level"); + alert->alert_edge_triggered ? "edge" : "level"); return 0; }