From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-it1-f196.google.com ([209.85.166.196]:37743 "EHLO mail-it1-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731285AbeKECqC (ORCPT ); Sun, 4 Nov 2018 21:46:02 -0500 Received: by mail-it1-f196.google.com with SMTP id e74-v6so9504678ita.2 for ; Sun, 04 Nov 2018 09:30:19 -0800 (PST) MIME-Version: 1.0 References: <71f6b6a308a74c863926a9de28cf51d42d26b859.1541341926.git.lorenzo.bianconi@redhat.com> <20181104171250.2279744a@archlinux> In-Reply-To: <20181104171250.2279744a@archlinux> From: Lorenzo Bianconi Date: Sun, 4 Nov 2018 18:30:07 +0100 Message-ID: Subject: Re: [PATCH 2/7] iio: imu: st_lsm6dsx: reboot memory content after reset Content-Type: text/plain; charset="UTF-8" Sender: devicetree-owner@vger.kernel.org To: Jonathan Cameron Cc: linux-iio@vger.kernel.org, devicetree@vger.kernel.org List-ID: > > On Sun, 4 Nov 2018 15:39:01 +0100 > Lorenzo Bianconi wrote: > > > Perform a memory content reboot after device reset > > > > Signed-off-by: Lorenzo Bianconi > > --- > > drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_core.c | 16 +++++++++++++--- > > 1 file changed, 13 insertions(+), 3 deletions(-) > > > > diff --git a/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_core.c b/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_core.c > > index c8b993bea757..e3ebd04d8078 100644 > > --- a/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_core.c > > +++ b/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_core.c > > @@ -56,6 +56,7 @@ > > #define ST_LSM6DSX_REG_WHOAMI_ADDR 0x0f > > #define ST_LSM6DSX_REG_RESET_ADDR 0x12 > > #define ST_LSM6DSX_REG_RESET_MASK BIT(0) > > +#define ST_LSM6DSX_REG_BOOT_MASK BIT(7) > > #define ST_LSM6DSX_REG_BDU_ADDR 0x12 > > #define ST_LSM6DSX_REG_BDU_MASK BIT(6) > > #define ST_LSM6DSX_REG_INT2_ON_INT1_ADDR 0x13 > > @@ -778,12 +779,21 @@ static int st_lsm6dsx_init_device(struct st_lsm6dsx_hw *hw) > > u8 drdy_int_reg; > > int err; > > > > - err = regmap_write(hw->regmap, ST_LSM6DSX_REG_RESET_ADDR, > > - ST_LSM6DSX_REG_RESET_MASK); > > + err = regmap_update_bits(hw->regmap, ST_LSM6DSX_REG_RESET_ADDR, > > + ST_LSM6DSX_REG_RESET_MASK, > > + FIELD_PREP(ST_LSM6DSX_REG_RESET_MASK, 1)); > > if (err < 0) > > return err; > > > > - msleep(200); > > + msleep(50); > > + > > + err = regmap_update_bits(hw->regmap, ST_LSM6DSX_REG_RESET_ADDR, > > + ST_LSM6DSX_REG_BOOT_MASK, > > + FIELD_PREP(ST_LSM6DSX_REG_BOOT_MASK, 1)); > > + if (err < 0) > > + return err; > > + > > + msleep(50); > This change in the timing needs an explanatory comment in the patch > description. > > > > > > /* enable Block Data Update */ > > err = regmap_update_bits(hw->regmap, ST_LSM6DSX_REG_BDU_ADDR, > Hi Jonathan, This patch reloads the trimming parameters to perform a complete reset of the device. Full explanation can be read here: https://www.st.com/resource/en/application_note/dm00517282.pdf, section 5.7. I will add a proper description in v2, thx Regards, Lorenzo