patch "iio: accel: adxl367: fix DEVID read after reset" added to char-misc-linus

patch "iio: accel: adxl367: fix DEVID read after reset" added to char-misc-linus

[gregkh]

This is a note to let you know that I've just added the patch titled

    iio: accel: adxl367: fix DEVID read after reset

to my char-misc git tree which can be found at
    git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc.git
in the char-misc-linus branch.

The patch will show up in the next release of the linux-next tree
(usually sometime within the next 24 hours during the week.)

The patch will hopefully also be merged in Linus's tree for the
next -rc kernel release.

If you have any questions about this process, please let me know.


From 1b926914bbe4e30cb32f268893ef7d82a85275b8 Mon Sep 17 00:00:00 2001
From: Cosmin Tanislav <demonsingur@gmail.com>
Date: Wed, 7 Feb 2024 05:36:50 +0200
Subject: iio: accel: adxl367: fix DEVID read after reset

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.

Fixes: cbab791c5e2a ("iio: accel: add ADXL367 driver")
Signed-off-by: Cosmin Tanislav <demonsingur@gmail.com>
Reviewed-by: Nuno Sa <nuno.sa@analog.com>
Link: https://lore.kernel.org/r/20240207033657.206171-1-demonsingur@gmail.com
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.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 90b7ae6d42b7..484fe2e9fb17 100644
--- a/drivers/iio/accel/adxl367.c
+++ b/drivers/iio/accel/adxl367.c
@@ -1429,9 +1429,11 @@ 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);
@@ -1510,6 +1512,8 @@ 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;
-- 
2.44.0