From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753300AbeEAJqD (ORCPT ); Tue, 1 May 2018 05:46:03 -0400 Received: from mail-wr0-f193.google.com ([209.85.128.193]:37106 "EHLO mail-wr0-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751071AbeEAJqC (ORCPT ); Tue, 1 May 2018 05:46:02 -0400 X-Google-Smtp-Source: AB8JxZqCJz7JWCjn1o7ubRkB8SwlLt6/6XQPQ7aImY5lcc1Ew4JJo09PgzdQ8ZR0zsys1udxGAvyEQ== From: Lee Jones To: dan.carpenter@oracle.com Cc: linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Lee Jones Subject: [PATCH 1/1] mfd: tps65911-comparator: Fix an off by one bug Date: Tue, 1 May 2018 10:45:53 +0100 Message-Id: <20180501094553.31545-1-lee.jones@linaro.org> X-Mailer: git-send-email 2.17.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The COMP1 and COMP2 elements are in 0 and 1 respectively so this code is accessing the wrong elements and one space beyond the end of the array. The "id" variable is never COMP (0) so that code can be removed. Fixes: 6851ad3ab346 ("TPS65911: Comparator: Add comparator driver") Reported-by: Dan Carpenter Signed-off-by: Lee Jones --- History: Dan was the originator of this patch and the author of the commit log, but produced 2 code solutions which I wasn't happy with. The first submission [0] introduced a COMP device, which after a quick check of the datasheet [1] appeared to be fictitious. A subsequent submission [2] conducted arithmetic in array indexes. It is my belief that the correct solution is to roll which the situation the hardware engineers presented us with and define COMP1 at position 0 and COMP2 at position 1 such that we can use the simplest code possible to select them. Dan wasn't happy to put his name to this, which I completely understand. Calling SOMETHING1 0 (zero) is a little unnatural. However, since I have no shame, I offered to submit it. [0] https://lkml.org/lkml/2018/4/19/449 [1] http://www.ti.com/lit/ds/symlink/tps65911.pdf (page 52) [2] https://lkml.org/lkml/2018/4/20/204 drivers/mfd/tps65911-comparator.c | 11 ++--------- 1 file changed, 2 insertions(+), 9 deletions(-) diff --git a/drivers/mfd/tps65911-comparator.c b/drivers/mfd/tps65911-comparator.c index d223857fb4ad..33591767fb9b 100644 --- a/drivers/mfd/tps65911-comparator.c +++ b/drivers/mfd/tps65911-comparator.c @@ -22,9 +22,8 @@ #include #include -#define COMP 0 -#define COMP1 1 -#define COMP2 2 +#define COMP1 0 +#define COMP2 1 /* Comparator 1 voltage selection table in millivolts */ static const u16 COMP_VSEL_TABLE[] = { @@ -63,9 +62,6 @@ static int comp_threshold_set(struct tps65910 *tps65910, int id, int voltage) int ret; u8 index = 0, val; - if (id == COMP) - return 0; - while (curr_voltage < tps_comp.uV_max) { curr_voltage = tps_comp.vsel_table[index]; if (curr_voltage >= voltage) @@ -89,9 +85,6 @@ static int comp_threshold_get(struct tps65910 *tps65910, int id) unsigned int val; int ret; - if (id == COMP) - return 0; - ret = tps65910_reg_read(tps65910, tps_comp.reg, &val); if (ret < 0) return ret; -- 2.17.0 From mboxrd@z Thu Jan 1 00:00:00 1970 From: lee.jones@linaro.org (Lee Jones) Date: Tue, 1 May 2018 10:45:53 +0100 Subject: [PATCH 1/1] mfd: tps65911-comparator: Fix an off by one bug Message-ID: <20180501094553.31545-1-lee.jones@linaro.org> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org The COMP1 and COMP2 elements are in 0 and 1 respectively so this code is accessing the wrong elements and one space beyond the end of the array. The "id" variable is never COMP (0) so that code can be removed. Fixes: 6851ad3ab346 ("TPS65911: Comparator: Add comparator driver") Reported-by: Dan Carpenter Signed-off-by: Lee Jones --- History: Dan was the originator of this patch and the author of the commit log, but produced 2 code solutions which I wasn't happy with. The first submission [0] introduced a COMP device, which after a quick check of the datasheet [1] appeared to be fictitious. A subsequent submission [2] conducted arithmetic in array indexes. It is my belief that the correct solution is to roll which the situation the hardware engineers presented us with and define COMP1 at position 0 and COMP2 at position 1 such that we can use the simplest code possible to select them. Dan wasn't happy to put his name to this, which I completely understand. Calling SOMETHING1 0 (zero) is a little unnatural. However, since I have no shame, I offered to submit it. [0] https://lkml.org/lkml/2018/4/19/449 [1] http://www.ti.com/lit/ds/symlink/tps65911.pdf (page 52) [2] https://lkml.org/lkml/2018/4/20/204 drivers/mfd/tps65911-comparator.c | 11 ++--------- 1 file changed, 2 insertions(+), 9 deletions(-) diff --git a/drivers/mfd/tps65911-comparator.c b/drivers/mfd/tps65911-comparator.c index d223857fb4ad..33591767fb9b 100644 --- a/drivers/mfd/tps65911-comparator.c +++ b/drivers/mfd/tps65911-comparator.c @@ -22,9 +22,8 @@ #include #include -#define COMP 0 -#define COMP1 1 -#define COMP2 2 +#define COMP1 0 +#define COMP2 1 /* Comparator 1 voltage selection table in millivolts */ static const u16 COMP_VSEL_TABLE[] = { @@ -63,9 +62,6 @@ static int comp_threshold_set(struct tps65910 *tps65910, int id, int voltage) int ret; u8 index = 0, val; - if (id == COMP) - return 0; - while (curr_voltage < tps_comp.uV_max) { curr_voltage = tps_comp.vsel_table[index]; if (curr_voltage >= voltage) @@ -89,9 +85,6 @@ static int comp_threshold_get(struct tps65910 *tps65910, int id) unsigned int val; int ret; - if (id == COMP) - return 0; - ret = tps65910_reg_read(tps65910, tps_comp.reg, &val); if (ret < 0) return ret; -- 2.17.0