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Message-ID: <9c53981719f8d44c38a5eb32e629dcec4bd2c60a.camel@gmail.com>
Subject: Re: [PATCH 1/2] iio: accel: adxl367: fix DEVID read after reset
From: Nuno =?ISO-8859-1?Q?S=E1?= <noname.nuno@gmail.com>
To: Cosmin Tanislav <demonsingur@gmail.com>
Cc: Lars-Peter Clausen <lars@metafoo.de>, Michael Hennerich
 <Michael.Hennerich@analog.com>, Cosmin Tanislav
 <cosmin.tanislav@analog.com>,  Jonathan Cameron <jic23@kernel.org>,
 linux-iio@vger.kernel.org, linux-kernel@vger.kernel.org
Date: Wed, 07 Feb 2024 10:11:06 +0100
In-Reply-To: <20240207033657.206171-1-demonsingur@gmail.com>
References: <20240207033657.206171-1-demonsingur@gmail.com>
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On Wed, 2024-02-07 at 05:36 +0200, Cosmin Tanislav wrote:
> regmap_read_poll_timeout() will not sleep before reading,
> causing the first read to return -ENXIO on I2C, since the
> chip does not respond to it while it is being reset.
>=20
> The datasheet specifies that a soft reset operation has a
> latency of 7.5ms.
>=20
> Add a 15ms sleep between reset and reading the DEVID register,
> and switch to a simple regmap_read() call.
>=20
> Signed-off-by: Cosmin Tanislav <demonsingur@gmail.com>
> ---

This likely needs a Fixes: tag as well. With that,

Reviewed-by: Nuno Sa <nuno.sa@analog.com>

> =C2=A0drivers/iio/accel/adxl367.c | 8 ++++++--
> =C2=A01 file changed, 6 insertions(+), 2 deletions(-)
>=20
> diff --git a/drivers/iio/accel/adxl367.c b/drivers/iio/accel/adxl367.c
> index 834ee6d63947..210228affb80 100644
> --- a/drivers/iio/accel/adxl367.c
> +++ b/drivers/iio/accel/adxl367.c
> @@ -1368,9 +1368,11 @@ static int adxl367_verify_devid(struct adxl367_sta=
te
> *st)
> =C2=A0	unsigned int val;
> =C2=A0	int ret;
> =C2=A0
> -	ret =3D regmap_read_poll_timeout(st->regmap, ADXL367_REG_DEVID, val,
> -				=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 val =3D=3D ADXL367_DEVID_AD, 10=
00, 10000);
> +	ret =3D regmap_read(st->regmap, ADXL367_REG_DEVID, &val);
> =C2=A0	if (ret)
> +		return dev_err_probe(st->dev, ret, "Failed to read dev
> id\n");
> +
> +	if (val !=3D ADXL367_DEVID_AD)
> =C2=A0		return dev_err_probe(st->dev, -ENODEV,
> =C2=A0				=C2=A0=C2=A0=C2=A0=C2=A0 "Invalid dev id 0x%02X, expected
> 0x%02X\n",
> =C2=A0				=C2=A0=C2=A0=C2=A0=C2=A0 val, ADXL367_DEVID_AD);
> @@ -1449,6 +1451,8 @@ int adxl367_probe(struct device *dev, const struct
> adxl367_ops *ops,
> =C2=A0	if (ret)
> =C2=A0		return ret;
> =C2=A0
> +	fsleep(15000);
> +
> =C2=A0	ret =3D adxl367_verify_devid(st);
> =C2=A0	if (ret)
> =C2=A0		return ret;