From patchwork Mon May 4 12:55:48 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Hans de Goede X-Patchwork-Id: 11525853 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 1DE1115AB for ; Mon, 4 May 2020 12:56:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 03F6420757 for ; Mon, 4 May 2020 12:56:42 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="hl9aCkDW" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728185AbgEDM4k (ORCPT ); Mon, 4 May 2020 08:56:40 -0400 Received: from us-smtp-delivery-1.mimecast.com ([207.211.31.120]:28782 "EHLO us-smtp-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1728684AbgEDM4f (ORCPT ); Mon, 4 May 2020 08:56:35 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1588596993; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=hAIkL7tTb5SwUjPu6G+afwxtr6wn72tgGZtb1qncHG8=; b=hl9aCkDWfaew7Y+oX8TI50uUSErQLFAmaToWqHeem3P6Pu+jYnpgviV9j6LkNhKrXvGdOC ybklxgMlfOyb90hKFXg7saHiA29PCpqkpMZaARr0OlpGSoZCzO5MJQkrLupakbwQlaBJEE z1K/7imbAY//e+0xehsyU/xOOyofnck= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-289-JaS_CFEdMZqgqdPlj-rSsQ-1; Mon, 04 May 2020 08:56:30 -0400 X-MC-Unique: JaS_CFEdMZqgqdPlj-rSsQ-1 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id D10767BBF; Mon, 4 May 2020 12:56:26 +0000 (UTC) Received: from x1.localdomain.com (ovpn-114-224.ams2.redhat.com [10.36.114.224]) by smtp.corp.redhat.com (Postfix) with ESMTP id D390D5D9D5; Mon, 4 May 2020 12:56:23 +0000 (UTC) From: Hans de Goede To: "Rafael J . Wysocki" , Len Brown , Darren Hart , Andy Shevchenko , Jonathan Cameron Cc: Hans de Goede , linux-acpi@vger.kernel.org, platform-driver-x86@vger.kernel.org, linux-kernel@vger.kernel.org, Hartmut Knaack , Lars-Peter Clausen , Peter Meerwald-Stadler , linux-iio@vger.kernel.org, Andy Shevchenko Subject: [PATCH v4 08/11] iio: light: cm32181: Use units of 1/100000th for calibscale and lux_per_bit Date: Mon, 4 May 2020 14:55:48 +0200 Message-Id: <20200504125551.434647-8-hdegoede@redhat.com> In-Reply-To: <20200504125551.434647-1-hdegoede@redhat.com> References: <20200504125551.434647-1-hdegoede@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 Sender: linux-iio-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-iio@vger.kernel.org Use units of 1/100000th for calibscale and lux_per_bit. The similar cm3232 driver already uses 1/100000th as unit for calibscale. This allows for higher-accuracy and makes it easier to add support for getting device-specific calibscale and lux_per_bit values from a device's ACPI tables, as the values in the ACPI tables also use 1/100000th units. This units change means that our intermediate values in cm32181_get_lux() may get quite big, change the type of the lux variable to a u64 to deal with this. Reviewed-by: Andy Shevchenko Signed-off-by: Hans de Goede --- drivers/iio/light/cm32181.c | 22 +++++++++++----------- 1 file changed, 11 insertions(+), 11 deletions(-) diff --git a/drivers/iio/light/cm32181.c b/drivers/iio/light/cm32181.c index f5af986e1ed4..59c95e22ad00 100644 --- a/drivers/iio/light/cm32181.c +++ b/drivers/iio/light/cm32181.c @@ -45,11 +45,11 @@ #define CM32181_CMD_ALS_SM_MASK (0x03 << CM32181_CMD_ALS_SM_SHIFT) #define CM32181_CMD_ALS_SM_DEFAULT (0x01 << CM32181_CMD_ALS_SM_SHIFT) -#define CM32181_MLUX_PER_BIT 5 /* ALS_SM=01 IT=800ms */ -#define CM32181_MLUX_PER_BIT_BASE_IT 800000 /* Based on IT=800ms */ -#define CM32181_CALIBSCALE_DEFAULT 1000 -#define CM32181_CALIBSCALE_RESOLUTION 1000 -#define MLUX_PER_LUX 1000 +#define CM32181_LUX_PER_BIT 500 /* ALS_SM=01 IT=800ms */ +#define CM32181_LUX_PER_BIT_RESOLUTION 100000 +#define CM32181_LUX_PER_BIT_BASE_IT 800000 /* Based on IT=800ms */ +#define CM32181_CALIBSCALE_DEFAULT 100000 +#define CM32181_CALIBSCALE_RESOLUTION 100000 #define SMBUS_ALERT_RESPONSE_ADDRESS 0x0c @@ -219,15 +219,15 @@ static int cm32181_get_lux(struct cm32181_chip *cm32181) struct i2c_client *client = cm32181->client; int ret; int als_it; - unsigned long lux; + u64 lux; ret = cm32181_read_als_it(cm32181, &als_it); if (ret < 0) return -EINVAL; - lux = CM32181_MLUX_PER_BIT; - lux *= CM32181_MLUX_PER_BIT_BASE_IT; - lux /= als_it; + lux = CM32181_LUX_PER_BIT; + lux *= CM32181_LUX_PER_BIT_BASE_IT; + lux = div_u64(lux, als_it); ret = i2c_smbus_read_word_data(client, CM32181_REG_ADDR_ALS); if (ret < 0) @@ -235,8 +235,8 @@ static int cm32181_get_lux(struct cm32181_chip *cm32181) lux *= ret; lux *= cm32181->calibscale; - lux /= CM32181_CALIBSCALE_RESOLUTION; - lux /= MLUX_PER_LUX; + lux = div_u64(lux, CM32181_CALIBSCALE_RESOLUTION); + lux = div_u64(lux, CM32181_LUX_PER_BIT_RESOLUTION); if (lux > 0xFFFF) lux = 0xFFFF;