From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 52101C4360F for ; Wed, 3 Apr 2019 15:14:34 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 26F412075E for ; Wed, 3 Apr 2019 15:14:34 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726833AbfDCPOd convert rfc822-to-8bit (ORCPT ); Wed, 3 Apr 2019 11:14:33 -0400 Received: from smtp.asem.it ([151.1.184.197]:56847 "EHLO smtp.asem.it" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726099AbfDCPOc (ORCPT ); Wed, 3 Apr 2019 11:14:32 -0400 Received: from webmail.asem.it by asem.it (smtp.asem.it) (SecurityGateway 5.5.0) with ESMTP id SG003789590.MSG for ; Wed, 03 Apr 2019 17:14:24 +0200S Received: from ASAS044.asem.intra (172.16.16.44) by ASAS044.asem.intra (172.16.16.44) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P256) id 15.1.1261.35; Wed, 3 Apr 2019 17:14:24 +0200 Received: from ASAS044.asem.intra ([::1]) by ASAS044.asem.intra ([::1]) with mapi id 15.01.1261.035; Wed, 3 Apr 2019 17:14:24 +0200 From: Flavio Suligoi To: Alexandre Belloni CC: Alessandro Zummo , Rob Herring , Mark Rutland , "linux-rtc@vger.kernel.org" , "devicetree@vger.kernel.org" , "linux-kernel@vger.kernel.org" Subject: RE: [PATCH 2/2] rtc: pcf2127: add battery-low INTn generation Thread-Topic: [PATCH 2/2] rtc: pcf2127: add battery-low INTn generation Thread-Index: AQHU6izzDrhx33Rd2E28nY3Qp112E6YqaEkAgAAhzmA= Date: Wed, 3 Apr 2019 15:14:24 +0000 Message-ID: <452a4cf1410a41c8b6f767ac6258482e@asem.it> References: <1554303165-24813-1-git-send-email-f.suligoi@asem.it> <1554303165-24813-2-git-send-email-f.suligoi@asem.it> <20190403150824.GO22216@piout.net> In-Reply-To: <20190403150824.GO22216@piout.net> Accept-Language: it-IT, en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-originating-ip: [172.16.17.208] Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 8BIT MIME-Version: 1.0 X-SGHeloLookup-Result: pass smtp.helo=webmail.asem.it (ip=172.16.16.44) X-SGSPF-Result: none (smtp.asem.it) X-SGOP-RefID: str=0001.0A0B020F.5CA4CDD1.001E,ss=1,re=0.000,recu=0.000,reip=0.000,cl=1,cld=1,fgs=0 (_st=1 _vt=0 _iwf=0) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Alexandre, > On 03/04/2019 16:52:45+0200, Flavio Suligoi wrote: > > The pcf2127 has an automatic battery-low detection function. > > > > In case of battery-low event, an interrupt generation through > > the pin INTn (active low) can be enabled, setting the flag BLIE > > in the register Control_3. > > > > This function is activated by the "battery-low-hw-alarm" DT property. > > > > Example of use for an NXP i.MX7D board: > > > > &i2c3 { > > clock-frequency = <100000>; > > pinctrl-names = "default"; > > pinctrl-0 = <&pinctrl_i2c3>; > > status = "okay"; > > > > pcf2127@51 { > > compatible = "nxp,pcf2127"; > > reg = <0x51>; > > battery-low-hw-alarm; > > status = "okay"; > > }; > > }; > > > > So I'm curious, how do you then use that signal? I have a (not yet sent) > series adding alarm support for the pcf2127. The issue having BLIE is > that then this will prevent the alarm to work properly. > > So my guess is that you have nINT connected to an LED or something that > the user can see? > I'm working on our custom embedded board with an NXP i.MX7D, developed here, in Asem (www.asem.it). The nINT pin is connected to a GPIO of the MX7 and then used by an applicative sw, to generate an alarm for the user. > > Signed-off-by: Flavio Suligoi > > --- > > drivers/rtc/rtc-pcf2127.c | 33 +++++++++++++++++++++++++++++++++ > > 1 file changed, 33 insertions(+) > > > > diff --git a/drivers/rtc/rtc-pcf2127.c b/drivers/rtc/rtc-pcf2127.c > > index 7cb786d..e3805c8 100644 > > --- a/drivers/rtc/rtc-pcf2127.c > > +++ b/drivers/rtc/rtc-pcf2127.c > > @@ -228,6 +228,10 @@ static int pcf2127_probe(struct device *dev, struct > regmap *regmap, > > const char *name, bool has_nvmem) > > { > > struct pcf2127 *pcf2127; > > + struct device_node *np; > > + struct i2c_client *client = to_i2c_client(dev); > > + unsigned char buf[2]; > > + int err; > > int ret = 0; > > > > dev_dbg(dev, "%s\n", __func__); > > @@ -245,6 +249,35 @@ static int pcf2127_probe(struct device *dev, struct > regmap *regmap, > > if (IS_ERR(pcf2127->rtc)) > > return PTR_ERR(pcf2127->rtc); > > > > + /* > > + * The pcf2127 has an automatic battery-low detection function. > > + * > > + * In case of battery-low event, an interrupt generation through > > + * the pin INTn (active low) can be enabled, setting the flag BLIE > > + * in the register Control_3. > > + */ > > + np = of_node_get(dev->of_node); > > + if (!np) { > > + dev_err(dev, "failed to find the RTC pcf2127 node\n"); > > + return -ENOENT; > > + } > > + if (of_get_property(np, "battery-low-hw-alarm", NULL)) { > > + dev_info(dev, "enable battery-low hw alarm on INTn pin\n"); > > + > > + /* > > + * Set BLIE bit in register Control_3 (override is possible > > + * because this register is fully zero after reset) > > + */ > > + buf[0] = PCF2127_REG_CTRL3; > > + buf[1] = 0x01; > > + /* write register's data */ > > + err = i2c_master_send(client, buf, 2); > > This has to use regmap_update_bits because this also has to work on spi. > (I don't know where you get the client pointer from anyway). > > > + if (err != 2) { > > + dev_err(dev, "%s: err=%d", __func__, err); > > + return -EIO; > > + } > > + } > > + > > if (has_nvmem) { > > struct nvmem_config nvmem_cfg = { > > .priv = pcf2127, > > -- > > 2.7.4 > > > > -- > Alexandre Belloni, Bootlin > Embedded Linux and Kernel engineering > https://bootlin.com Flavio Suligoi