Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932504AbbGGPIW (ORCPT ); Tue, 7 Jul 2015 11:08:22 -0400 Received: from mail-wi0-f176.google.com ([209.85.212.176]:35935 "EHLO mail-wi0-f176.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932424AbbGGPHL (ORCPT ); Tue, 7 Jul 2015 11:07:11 -0400 From: Lee Jones To: linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Cc: kernel@stlinux.com, broonie@kernel.org, lgirdwood@gmail.com, Lee Jones Subject: [PATCH v2 8/9] regulator: pwm-regulator: Simplify voltage to duty-cycle call Date: Tue, 7 Jul 2015 16:06:52 +0100 Message-Id: <1436281613-899-9-git-send-email-lee.jones@linaro.org> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1436281613-899-1-git-send-email-lee.jones@linaro.org> References: <1436281613-899-1-git-send-email-lee.jones@linaro.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2566 Lines: 70 If we reverse some of the logic and change the formula used, we can simplify the function greatly. It is intentional that this function is supplied and then re-worked within the same patch-set. The submission in the previous patch is the tried and tested (i.e. in real releases) method written by ST. This patch contains a simplification provided later. It looks and performs better, but doesn't have the same time-under-test that the original method does. The idea is that we keep some history in order to provide an easy way back i.e. revert. Signed-off-by: Lee Jones --- drivers/regulator/pwm-regulator.c | 27 +++++++-------------------- 1 file changed, 7 insertions(+), 20 deletions(-) diff --git a/drivers/regulator/pwm-regulator.c b/drivers/regulator/pwm-regulator.c index dac145d..d5cb267 100644 --- a/drivers/regulator/pwm-regulator.c +++ b/drivers/regulator/pwm-regulator.c @@ -93,26 +93,13 @@ static int pwm_regulator_list_voltage(struct regulator_dev *rdev, /** * Continuous voltage call-backs */ -static int pwm_voltage_to_duty_cycle(struct regulator_dev *rdev, - int volt_mV) +static int pwm_voltage_to_duty_cycle(struct regulator_dev *rdev, int req_uV) { - struct pwm_regulator_data *drvdata = rdev_get_drvdata(rdev); - int min_mV = rdev->constraints->min_uV / 1000; - int max_mV = rdev->constraints->max_uV / 1000; - int max_duty_cycle = drvdata->max_duty_cycle; - int vdiff = min_mV - max_mV; - int pwm_code; - int tmp; - - tmp = ((max_duty_cycle - min_mV) * max_duty_cycle) / vdiff; - pwm_code = ((tmp + max_duty_cycle) * volt_mV) / vdiff; - - if (pwm_code < 0) - pwm_code = 0; - if (pwm_code > max_duty_cycle) - pwm_code = max_duty_cycle; - - return pwm_code * 100 / max_duty_cycle; + int min_uV = rdev->constraints->min_uV; + int max_uV = rdev->constraints->max_uV; + int diff = max_uV - min_uV; + + return 100 - ((((req_uV * 100) - (min_uV * 100)) / diff)); } static int pwm_regulator_get_voltage(struct regulator_dev *rdev) @@ -131,7 +118,7 @@ static int pwm_regulator_set_voltage(struct regulator_dev *rdev, int duty_cycle; int ret; - duty_cycle = pwm_voltage_to_duty_cycle(rdev, min_uV / 1000); + duty_cycle = pwm_voltage_to_duty_cycle(rdev, min_uV); ret = pwm_config(drvdata->pwm, (drvdata->pwm->period / 100) * duty_cycle, -- 1.9.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/