iio: dac: ds4424: use fsleep() instead of usleep_range()

The DS4422/DS4424 and DS4402/DS4404 datasheets do not specify a minimum
delay between power-up (POR) and the availability of the I2C interface.

The driver previously used `usleep_range(1000, 1200)` to enforce a ~1ms
delay. Replace this with `fsleep(1000)` to allow the kernel to select
the most efficient sleep mechanism while retaining the existing
conservative delay to ensure device readiness.

Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@intel.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

diff --git a/drivers/iio/dac/ds4424.c b/drivers/iio/dac/ds4424.c
index 3e72a40d053cc8199ea0fcbee6c6c4806c9fb3d8..f9cdc695032d7acca4c8cd83eeb3d4b02c46ac78 100644 (file)
--- a/drivers/iio/dac/ds4424.c
+++ b/drivers/iio/dac/ds4424.c
@@ -12,6 +12,7 @@
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/regulator/consumer.h>
+#include <linux/time64.h>
 
 #include <linux/iio/driver.h>
 #include <linux/iio/iio.h>
@@ -244,7 +245,13 @@ static int ds4424_probe(struct i2c_client *client)
                return ret;
        }
 
-       usleep_range(1000, 1200);
+       /*
+        * The datasheet does not specify a power-up to I2C ready time.
+        * Maintain the existing conservative 1ms delay to ensure the
+        * device is ready for communication.
+        */
+       fsleep(1 * USEC_PER_MSEC);
+
        ret = ds4424_verify_chip(indio_dev);
        if (ret < 0)
                goto fail;