[v3,5/6] iio: pressure: hsc030pa add mandatory delay
Commit Message
Add a mandatory 2ms delay between consecutive chip reads.
A Technical Note pdf specifies that the measurement cycle in these
chips takes around 1.26ms. By adding this 2ms delay we make sure that
we never get stale measurements.
For more details, please see "Figure 1" in the pdf below:
https://prod-edam.honeywell.com/content/dam/honeywell-edam/sps/siot/en-us/products/sensors/pressure-sensors/common/documents/sps-siot-sleep-mode-technical-note-008286-1-en-ciid-155793.pdf
Signed-off-by: Petre Rodan <petre.rodan@subdimension.ro>
---
v1 -> v3 no changes
drivers/iio/pressure/hsc030pa.h | 1 +
drivers/iio/pressure/hsc030pa_i2c.c | 3 +++
drivers/iio/pressure/hsc030pa_spi.c | 2 ++
3 files changed, 6 insertions(+)
@@ -13,6 +13,7 @@
#include <linux/iio/iio.h>
#define HSC_REG_MEASUREMENT_RD_SIZE 4
+#define HSC_RESP_TIME_MS 2
struct device;
@@ -8,6 +8,7 @@
* Datasheet: https://prod-edam.honeywell.com/content/dam/honeywell-edam/sps/siot/en-us/products/sensors/pressure-sensors/common/documents/sps-siot-sleep-mode-technical-note-008286-1-en-ciid-155793.pdf
*/
+#include <linux/delay.h>
#include <linux/device.h>
#include <linux/errno.h>
#include <linux/i2c.h>
@@ -25,6 +26,8 @@ static int hsc_i2c_recv(struct hsc_data *data)
struct i2c_msg msg;
int ret;
+ msleep_interruptible(HSC_RESP_TIME_MS);
+
msg.addr = client->addr;
msg.flags = client->flags | I2C_M_RD;
msg.len = HSC_REG_MEASUREMENT_RD_SIZE;
@@ -8,6 +8,7 @@
* Datasheet: https://prod-edam.honeywell.com/content/dam/honeywell-edam/sps/siot/en-us/products/sensors/pressure-sensors/common/documents/sps-siot-sleep-mode-technical-note-008286-1-en-ciid-155793.pdf
*/
+#include <linux/delay.h>
#include <linux/device.h>
#include <linux/mod_devicetable.h>
#include <linux/module.h>
@@ -28,6 +29,7 @@ static int hsc_spi_recv(struct hsc_data *data)
.len = HSC_REG_MEASUREMENT_RD_SIZE,
};
+ msleep_interruptible(HSC_RESP_TIME_MS);
return spi_sync_transfer(spi, &xfer, 1);
}