The patch below does not apply to the 5.15-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.

Possible dependencies:

57572cacd36e ("iio: accel: bma400: Ensure VDDIO is enable defore reading the chip ID.") 12c99f859fd3 ("iio: accel: bma400: conversion to device-managed function") 02e2af20f4f9 ("Merge tag 'char-misc-5.18-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc")

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 57572cacd36e6d4be7722d7770d23f4430219827 Mon Sep 17 00:00:00 2001 From: Jonathan Cameron Jonathan.Cameron@huawei.com Date: Sun, 2 Oct 2022 15:41:33 +0100 Subject: [PATCH] iio: accel: bma400: Ensure VDDIO is enable defore reading the chip ID.

The regulator enables were after the check on the chip variant, which was very unlikely to return a correct value when not powered. Presumably all the device anyone is testing on have a regulator that is already powered up when this code runs for reasons beyond the scope of this driver. Move the read call down a few lines.

Fixes: 3cf7ded15e40 ("iio: accel: bma400: basic regulator support") Signed-off-by: Jonathan Cameron Jonathan.Cameron@huawei.com Reviewed-by: Dan Robertson dan@dlrobertson.com Cc: Stable@vger.kernel.org Link: https://lore.kernel.org/r/20221002144133.3771029-1-jic23@kernel.org

diff --git a/drivers/iio/accel/bma400_core.c b/drivers/iio/accel/bma400_core.c index ad8fce3e08cd..490c342ef72a 100644 --- a/drivers/iio/accel/bma400_core.c +++ b/drivers/iio/accel/bma400_core.c @@ -869,18 +869,6 @@ static int bma400_init(struct bma400_data *data) unsigned int val; int ret;

- /* Try to read chip_id register. It must return 0x90. */ - ret = regmap_read(data->regmap, BMA400_CHIP_ID_REG, &val); - if (ret) { - dev_err(data->dev, "Failed to read chip id register\n"); - return ret; - } - - if (val != BMA400_ID_REG_VAL) { - dev_err(data->dev, "Chip ID mismatch\n"); - return -ENODEV; - } - data->regulators[BMA400_VDD_REGULATOR].supply = "vdd"; data->regulators[BMA400_VDDIO_REGULATOR].supply = "vddio"; ret = devm_regulator_bulk_get(data->dev, @@ -906,6 +894,18 @@ static int bma400_init(struct bma400_data *data) if (ret) return ret;

+ /* Try to read chip_id register. It must return 0x90. */ + ret = regmap_read(data->regmap, BMA400_CHIP_ID_REG, &val); + if (ret) { + dev_err(data->dev, "Failed to read chip id register\n"); + return ret; + } + + if (val != BMA400_ID_REG_VAL) { + dev_err(data->dev, "Chip ID mismatch\n"); + return -ENODEV; + } + ret = bma400_get_power_mode(data); if (ret) { dev_err(data->dev, "Failed to get the initial power-mode\n");