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From: Cosmin Tanislav <demonsingur@gmail.com>
To: 
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,
	Cosmin Tanislav <demonsingur@gmail.com>
Subject: [PATCH 1/2] iio: accel: adxl367: fix DEVID read after reset
Date: Wed,  7 Feb 2024 05:36:50 +0200
Message-ID: <20240207033657.206171-1-demonsingur@gmail.com>
Precedence: bulk
MIME-Version: 1.0
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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.

The datasheet specifies that a soft reset operation has a
latency of 7.5ms.

Add a 15ms sleep between reset and reading the DEVID register,
and switch to a simple regmap_read() call.

Signed-off-by: Cosmin Tanislav <demonsingur@gmail.com>
---
 drivers/iio/accel/adxl367.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

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_state *st)
 	unsigned int val;
 	int ret;
 
-	ret = regmap_read_poll_timeout(st->regmap, ADXL367_REG_DEVID, val,
-				       val == ADXL367_DEVID_AD, 1000, 10000);
+	ret = regmap_read(st->regmap, ADXL367_REG_DEVID, &val);
 	if (ret)
+		return dev_err_probe(st->dev, ret, "Failed to read dev id\n");
+
+	if (val != ADXL367_DEVID_AD)
 		return dev_err_probe(st->dev, -ENODEV,
 				     "Invalid dev id 0x%02X, expected 0x%02X\n",
 				     val, ADXL367_DEVID_AD);
@@ -1449,6 +1451,8 @@ int adxl367_probe(struct device *dev, const struct adxl367_ops *ops,
 	if (ret)
 		return ret;
 
+	fsleep(15000);
+
 	ret = adxl367_verify_devid(st);
 	if (ret)
 		return ret;
-- 
2.43.0