From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752053Ab2GIDWp (ORCPT ); Sun, 8 Jul 2012 23:22:45 -0400 Received: from mail-pb0-f46.google.com ([209.85.160.46]:50736 "EHLO mail-pb0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751477Ab2GIDWm (ORCPT ); Sun, 8 Jul 2012 23:22:42 -0400 Message-ID: <1341804151.14367.1.camel@phoenix> Subject: [PATCH RFT 1/2] regulator: twl: Fix the formula to calculate vsel and voltage for twl6030ldo From: Axel Lin To: Mark Brown Cc: Rajendra Nayak , Peter Ujfalusi , Liam Girdwood , linux-kernel@vger.kernel.org Date: Mon, 09 Jul 2012 11:22:31 +0800 Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.2.3-0ubuntu6 Content-Transfer-Encoding: 7bit Mime-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org In twl6030ldo_set_voltage, current code use below formula to calculate vsel: vsel = (min_uV/1000 - 1000)/100 + 1; This is worng because when min_uV is 1000000 uV, vsel is 1. It should be 0 in this case. Fix it by change the equation to: (This equation is common for linear mapping) vsel = DIV_ROUND_UP(min_uV - rdev->desc->min_uV, rdev->desc->uV_step); In twl6030ldo_get_voltage, current code use below formula to calculate voltage: mV = 1000mv + 100mv * (vsel - 1) This is worng because when vsel is 0, mV is 900mV. Note the min_uV is 1000mV. Fix it by change the equation to: (This equation is common for linear mapping) return rdev->desc->min_uV + vsel * rdev->desc->uV_step; Signed-off-by: Axel Lin --- drivers/regulator/twl-regulator.c | 17 ++++------------- 1 file changed, 4 insertions(+), 13 deletions(-) diff --git a/drivers/regulator/twl-regulator.c b/drivers/regulator/twl-regulator.c index 8f0bd56..bb51dec 100644 --- a/drivers/regulator/twl-regulator.c +++ b/drivers/regulator/twl-regulator.c @@ -569,30 +569,21 @@ twl6030ldo_set_voltage(struct regulator_dev *rdev, int min_uV, int max_uV, if ((min_uV/1000 < info->min_mV) || (max_uV/1000 > info->max_mV)) return -EDOM; - /* - * Use the below formula to calculate vsel - * mV = 1000mv + 100mv * (vsel - 1) - */ - vsel = (min_uV/1000 - 1000)/100 + 1; + vsel = DIV_ROUND_UP(min_uV - rdev->desc->min_uV, rdev->desc->uV_step); *selector = vsel; - return twlreg_write(info, TWL_MODULE_PM_RECEIVER, VREG_VOLTAGE, vsel); + return twlreg_write(info, TWL_MODULE_PM_RECEIVER, VREG_VOLTAGE, vsel); } static int twl6030ldo_get_voltage(struct regulator_dev *rdev) { struct twlreg_info *info = rdev_get_drvdata(rdev); - int vsel = twlreg_read(info, TWL_MODULE_PM_RECEIVER, - VREG_VOLTAGE); + int vsel = twlreg_read(info, TWL_MODULE_PM_RECEIVER, VREG_VOLTAGE); if (vsel < 0) return vsel; - /* - * Use the below formula to calculate vsel - * mV = 1000mv + 100mv * (vsel - 1) - */ - return (1000 + (100 * (vsel - 1))) * 1000; + return rdev->desc->min_uV + vsel * rdev->desc->uV_step; } static struct regulator_ops twl6030ldo_ops = { -- 1.7.9.5