From patchwork Sat May 30 12:32:22 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Kevin P. Fleming" X-Patchwork-Id: 1301209 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=vger.kernel.org (client-ip=23.128.96.18; helo=vger.kernel.org; envelope-from=linux-rtc-owner@vger.kernel.org; receiver=) Authentication-Results: ozlabs.org; dmarc=none (p=none dis=none) header.from=km6g.us Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by ozlabs.org (Postfix) with ESMTP id 49Z16x2g9sz9sRN for ; Sat, 30 May 2020 22:32:57 +1000 (AEST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728875AbgE3Mc4 (ORCPT ); Sat, 30 May 2020 08:32:56 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48910 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726860AbgE3Mcy (ORCPT ); Sat, 30 May 2020 08:32:54 -0400 Received: from mail.net18.km6g.us (mail.net18.km6g.us [IPv6:2607:5300:203:24b0:3::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E10F5C03E969 for ; Sat, 30 May 2020 05:32:52 -0700 (PDT) Received: from [2001:470:8afe:60:716b:c9b9:d55a:f6f1] (helo=balrog20.km6g.us) by mail.net18.km6g.us with esmtp (Exim 4.93.0.4 (FreeBSD)) (envelope-from ) id 1jf0fT-0003hx-NC; Sat, 30 May 2020 08:32:51 -0400 From: "Kevin P. Fleming" To: linux-rtc@vger.kernel.org, devicetree@vger.kernel.org Cc: "Kevin P. Fleming" , Alessandro Zummo , Alexandre Belloni , Rob Herring Subject: [PATCH] rtc: abx80x: Add support for autocalibration filter capacitor Date: Sat, 30 May 2020 08:32:22 -0400 Message-Id: <20200530123222.361104-1-kevin+linux@km6g.us> X-Mailer: git-send-email 2.26.2 MIME-Version: 1.0 Sender: linux-rtc-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-rtc@vger.kernel.org All of the parts supported by this driver can make use of a small capacitor to improve the accuracy of the autocalibration process for their RC oscillators. If a capacitor is connected, a configuration register must be set to enable its use, so a new Device Tree property has been added for that purpose. Signed-off-by: Kevin P. Fleming Cc: Alessandro Zummo Cc: Alexandre Belloni Cc: Rob Herring To: linux-rtc@vger.kernel.org To: devicetree@vger.kernel.org --- .../bindings/rtc/abracon,abx80x.txt | 6 ++++ drivers/rtc/rtc-abx80x.c | 34 +++++++++++++++++++ 2 files changed, 40 insertions(+) diff --git a/Documentation/devicetree/bindings/rtc/abracon,abx80x.txt b/Documentation/devicetree/bindings/rtc/abracon,abx80x.txt index 2405e35a1bc0..ad5d59ed6f24 100644 --- a/Documentation/devicetree/bindings/rtc/abracon,abx80x.txt +++ b/Documentation/devicetree/bindings/rtc/abracon,abx80x.txt @@ -29,3 +29,9 @@ and valid to enable charging: - "abracon,tc-diode": should be "standard" (0.6V) or "schottky" (0.3V) - "abracon,tc-resistor": should be <0>, <3>, <6> or <11>. 0 disables the output resistor, the other values are in kOhm. + +All of the devices can have a 47pf capacitor attached to increase the +autocalibration accuracy of their RC oscillators. To enable usage of the +capacitor the following property has to be defined: + + - "abracon,autocal-filter" diff --git a/drivers/rtc/rtc-abx80x.c b/drivers/rtc/rtc-abx80x.c index 3521d8e8dc38..be5a814e8c0b 100644 --- a/drivers/rtc/rtc-abx80x.c +++ b/drivers/rtc/rtc-abx80x.c @@ -76,6 +76,9 @@ #define ABX8XX_CFG_KEY_OSC 0xa1 #define ABX8XX_CFG_KEY_MISC 0x9d +#define ABX8XX_REG_AFCTRL 0x26 +#define ABX8XX_AUTOCAL_FILTER_ENABLE 0xa0 + #define ABX8XX_REG_ID0 0x28 #define ABX8XX_REG_OUT_CTRL 0x30 @@ -130,6 +133,31 @@ static int abx80x_is_rc_mode(struct i2c_client *client) return (flags & ABX8XX_OSS_OMODE) ? 1 : 0; } +static int abx80x_enable_autocal_filter(struct i2c_client *client) +{ + int err; + + /* + * Write the configuration key register to enable access to the AFCTRL + * register + */ + err = i2c_smbus_write_byte_data(client, ABX8XX_REG_CFG_KEY, + ABX8XX_CFG_KEY_MISC); + if (err < 0) { + dev_err(&client->dev, "Unable to write configuration key\n"); + return -EIO; + } + + err = i2c_smbus_write_byte_data(client, ABX8XX_REG_AFCTRL, + ABX8XX_AUTOCAL_FILTER_ENABLE); + if (err < 0) { + dev_err(&client->dev, "Unable to write autocal filter register\n"); + return -EIO; + } + + return 0; +} + static int abx80x_enable_trickle_charger(struct i2c_client *client, u8 trickle_cfg) { @@ -825,6 +853,12 @@ static int abx80x_probe(struct i2c_client *client, return err; } + if (of_property_read_bool(np, "abracon,autocal_filter")) { + err = abx80x_enable_autocal_filter(client); + if (err) + return err; + } + if (client->irq > 0) { dev_info(&client->dev, "IRQ %d supplied\n", client->irq); err = devm_request_threaded_irq(&client->dev, client->irq, NULL,