From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:39202 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752391AbdDIT1i (ORCPT ); Sun, 9 Apr 2017 15:27:38 -0400 Subject: Patch "iio: bmg160: reset chip when probing" has been added to the 4.9-stable tree To: quentin.schulz@free-electrons.com, gregkh@linuxfoundation.org, jic23@kernel.org Cc: , From: Date: Sun, 09 Apr 2017 21:26:29 +0200 Message-ID: <1491765989169239@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org List-ID: This is a note to let you know that I've just added the patch titled iio: bmg160: reset chip when probing to the 4.9-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: iio-bmg160-reset-chip-when-probing.patch and it can be found in the queue-4.9 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let know about it. >>From 4bdc9029685ac03be50b320b29691766d2326c2b Mon Sep 17 00:00:00 2001 From: Quentin Schulz Date: Tue, 21 Mar 2017 16:52:14 +0100 Subject: iio: bmg160: reset chip when probing From: Quentin Schulz commit 4bdc9029685ac03be50b320b29691766d2326c2b upstream. The gyroscope chip might need to be reset to be used. Without the chip being reset, the driver stopped at the first regmap_read (to get the CHIP_ID) and failed to probe. The datasheet of the gyroscope says that a minimum wait of 30ms after the reset has to be done. This patch has been checked on a BMX055 and the datasheet of the BMG160 and the BMI055 give the same reset register and bits. Signed-off-by: Quentin Schulz Signed-off-by: Jonathan Cameron Signed-off-by: Greg Kroah-Hartman --- drivers/iio/gyro/bmg160_core.c | 12 ++++++++++++ 1 file changed, 12 insertions(+) --- a/drivers/iio/gyro/bmg160_core.c +++ b/drivers/iio/gyro/bmg160_core.c @@ -27,6 +27,7 @@ #include #include #include +#include #include "bmg160.h" #define BMG160_IRQ_NAME "bmg160_event" @@ -52,6 +53,9 @@ #define BMG160_DEF_BW 100 #define BMG160_REG_PMU_BW_RES BIT(7) +#define BMG160_GYRO_REG_RESET 0x14 +#define BMG160_GYRO_RESET_VAL 0xb6 + #define BMG160_REG_INT_MAP_0 0x17 #define BMG160_INT_MAP_0_BIT_ANY BIT(1) @@ -236,6 +240,14 @@ static int bmg160_chip_init(struct bmg16 int ret; unsigned int val; + /* + * Reset chip to get it in a known good state. A delay of 30ms after + * reset is required according to the datasheet. + */ + regmap_write(data->regmap, BMG160_GYRO_REG_RESET, + BMG160_GYRO_RESET_VAL); + usleep_range(30000, 30700); + ret = regmap_read(data->regmap, BMG160_REG_CHIP_ID, &val); if (ret < 0) { dev_err(dev, "Error reading reg_chip_id\n"); Patches currently in stable-queue which might be from quentin.schulz@free-electrons.com are queue-4.9/iio-bmg160-reset-chip-when-probing.patch