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iio: pressure: hsc030pa add mandatory delay

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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>
Link: https://lore.kernel.org/r/20240211075645.28777-6-petre.rodan@subdimension.ro
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
This commit is contained in:
Petre Rodan 2024-02-11 09:56:36 +02:00 committed by Jonathan Cameron
parent b0e42c9e93
commit df3186e829
3 changed files with 6 additions and 0 deletions
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1
drivers/iio/pressure/hsc030pa.h
View File

@ -13,6 +13,7 @@
#include <linux/iio/iio.h>
#define HSC_REG_MEASUREMENT_RD_SIZE 4
#define HSC_RESP_TIME_MS 2
struct device;

3
drivers/iio/pressure/hsc030pa_i2c.c
View File

@ -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;

2
drivers/iio/pressure/hsc030pa_spi.c
View File

@ -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);
}