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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 8733BC54EE9 for ; Tue, 20 Sep 2022 22:23:43 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230176AbiITWXl (ORCPT ); Tue, 20 Sep 2022 18:23:41 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33820 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230326AbiITWXk (ORCPT ); Tue, 20 Sep 2022 18:23:40 -0400 Received: from aposti.net (aposti.net [89.234.176.197]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 27DE952FFE for ; Tue, 20 Sep 2022 15:23:38 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=crapouillou.net; s=mail; t=1663712616; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=tO+vmLeootHFQmN3/+TkPvD008MTJfgpTAz5k+oP+WY=; b=jwcBlLLeuEX1zfAF1yFSHkkXqCtgZbzVcB7xoH1MKG8AaxzM9v8gCYfCazL4D6Jwk6jPCc BAoJqfRuPKq6QUpMuBOwIrF2jedt1fECqWoWxXWoRsv/fcce7KX5699OW0jR63NXEek9eu Um7JtGjU6ZQ6E4KpZ4gj/H3Xcs98kzk= Date: Tue, 20 Sep 2022 23:23:26 +0100 From: Paul Cercueil Subject: Re: [PATCH 1/3] iio: light: vcnl4000: Preserve conf bits when toggle power To: =?iso-8859-1?q?M=E5rten?= Lindahl Cc: Jonathan Cameron , Lars-Peter Clausen , Uwe =?iso-8859-1?q?Kleine-K=F6nig?= , linux-iio@vger.kernel.org, kernel@axis.com Message-Id: <2V4JIR.7354DS8U39Q53@crapouillou.net> In-Reply-To: <20220920180958.2308229-2-marten.lindahl@axis.com> References: <20220920180958.2308229-1-marten.lindahl@axis.com> <20220920180958.2308229-2-marten.lindahl@axis.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1; format=flowed Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-iio@vger.kernel.org Hi M=E5rten, Le mar., sept. 20 2022 at 20:09:56 +0200, M=E5rten Lindahl=20 a =E9crit : > As the vcnl4040 and vcnl4200 chip uses runtime power management for > turning the ambient light and proximity sensors on/off, it overwrites > the entire register each time. In ALS_CONF register bit fields ALS_IT, > ALS_PERS, ALS_INT_EN are overwritten. In PS_CONF1 register bit fields > PS_DUTY, PS_PERS, PS_IT, PS_HD, and PS_INT are overwritten. >=20 > Add functions for preserving the affected bit fields when changing=20 > power > state. >=20 > Signed-off-by: M=E5rten Lindahl > --- > drivers/iio/light/vcnl4000.c | 53=20 > ++++++++++++++++++++++++++++++++++-- > 1 file changed, 51 insertions(+), 2 deletions(-) >=20 > diff --git a/drivers/iio/light/vcnl4000.c=20 > b/drivers/iio/light/vcnl4000.c > index 3db4e26731bb..0b226c684957 100644 > --- a/drivers/iio/light/vcnl4000.c > +++ b/drivers/iio/light/vcnl4000.c > @@ -74,6 +74,9 @@ > #define VCNL4000_PROX_EN BIT(1) /* start proximity measurement */ > #define VCNL4000_SELF_TIMED_EN BIT(0) /* start self-timed=20 > measurement */ >=20 > +#define VCNL4040_ALS_CONF_ALS_SD BIT(0) /* Enable ambient light=20 > sensor */ > +#define VCNL4040_PS_CONF1_PS_SD BIT(0) /* Enable proximity sensor */ > + > /* Bit masks for interrupt registers. */ > #define VCNL4010_INT_THR_SEL BIT(0) /* Select threshold interrupt=20 > source */ > #define VCNL4010_INT_THR_EN BIT(1) /* Threshold interrupt type */ > @@ -188,16 +191,62 @@ static int vcnl4000_init(struct vcnl4000_data=20 > *data) > return data->chip_spec->set_power_state(data, true); > }; >=20 > +static ssize_t vcnl4000_write_als_enable(struct vcnl4000_data *data,=20 > int val) > +{ > + int ret; > + > + switch (data->id) { > + case VCNL4040: > + case VCNL4200: The switch isn't needed, since vcnl4200_set_power_state() is only=20 called for compatible chips. > + ret =3D i2c_smbus_read_word_data(data->client, VCNL4200_AL_CONF); > + if (ret < 0) > + return ret; > + > + if (val) > + ret &=3D ~VCNL4040_ALS_CONF_ALS_SD; > + else > + ret |=3D VCNL4040_ALS_CONF_ALS_SD; > + > + return i2c_smbus_write_word_data(data->client, VCNL4200_AL_CONF, > + ret); Are you sure a race cannot happen here? I would assume it cannot, but that's still a bit fishy. This driver would benefit from a regmap conversion, but it's probably a=20 bit too much to ask... > + default: > + return -EINVAL; > + } > +} > + > +static ssize_t vcnl4000_write_ps_enable(struct vcnl4000_data *data,=20 > int val) > +{ > + int ret; > + > + switch (data->id) { > + case VCNL4040: > + case VCNL4200: > + ret =3D i2c_smbus_read_word_data(data->client, VCNL4200_PS_CONF1); > + if (ret < 0) > + return ret; > + > + if (val) > + ret &=3D ~VCNL4040_PS_CONF1_PS_SD; > + else > + ret |=3D VCNL4040_PS_CONF1_PS_SD; > + > + return i2c_smbus_write_word_data(data->client, > + VCNL4200_PS_CONF1, ret); > + default: > + return -EINVAL; > + } > +} > + > static int vcnl4200_set_power_state(struct vcnl4000_data *data, bool=20 > on) > { > u16 val =3D on ? 0 /* power on */ : 1 /* shut down */; > int ret; >=20 > - ret =3D i2c_smbus_write_word_data(data->client, VCNL4200_AL_CONF,=20 > val); > + ret =3D vcnl4000_write_als_enable(data, !val); You set "val" to 0 if "on", and to 1 if "!on", then pass "!val", this=20 is very confusing. You could just pass "on" here and below. Cheers, -Paul > if (ret < 0) > return ret; >=20 > - ret =3D i2c_smbus_write_word_data(data->client, VCNL4200_PS_CONF1,=20 > val); > + ret =3D vcnl4000_write_ps_enable(data, !val); > if (ret < 0) > return ret; >=20 > -- > 2.30.2 >=20