Re: [RFC] sht3x code modifcation
From: JuenKit Yip
Date: Mon Jun 12 2023 - 06:30:09 EST
The original code only support two mode: high-precision mode(high repeatability and
10Hz periodic measurement) and low-power mode(low repeatability and 0.5Hz measurement),
but in fact this sensor support 5 periodic measurement duration(and single shot) and
3 repeatability which are not fully implemented.
High-precision mode was defined manually so that I think that we should reserve the
right to user to choose which one repeatability and periodic measurement is the best.
I just put the patch for reference and hope you could give any comments.
Medium-repeatability was not added into code and I hope put it later.
If you have any other further question, kindly contact to me.
Thanks
Juen Kit Yip
Signed-off-by: JuenKit Yip <JuenKit_Yip@xxxxxxxxxxx>
---
Documentation/hwmon/sht3x.rst | 6 ++----
drivers/hwmon/sht3x.c | 27 +++++++++++++++++----------
include/linux/platform_data/sht3x.h | 1 -
3 files changed, 19 insertions(+), 15 deletions(-)
diff --git a/Documentation/hwmon/sht3x.rst b/Documentation/hwmon/sht3x.rst
index 95a850d5b..c6b7a1aa5 100644
--- a/Documentation/hwmon/sht3x.rst
+++ b/Documentation/hwmon/sht3x.rst
@@ -28,15 +28,13 @@ The device communicates with the I2C protocol. Sensors can have the I2C
addresses 0x44 or 0x45, depending on the wiring. See
Documentation/i2c/instantiating-devices.rst for methods to instantiate the device.
-There are two options configurable by means of sht3x_platform_data:
+There is only one option configurable by means of sht3x_platform_data:
-1. blocking (pull the I2C clock line down while performing the measurement) or
+ blocking (pull the I2C clock line down while performing the measurement) or
non-blocking mode. Blocking mode will guarantee the fastest result but
the I2C bus will be busy during that time. By default, non-blocking mode
is used. Make sure clock-stretching works properly on your device if you
want to use blocking mode.
-2. high or low accuracy. High accuracy is used by default and using it is
- strongly recommended.
The sht3x sensor supports a single shot mode as well as 5 periodic measure
modes, which can be controlled with the update_interval sysfs interface.
diff --git a/drivers/hwmon/sht3x.c b/drivers/hwmon/sht3x.c
index 8305e44d9..6065312ae 100644
--- a/drivers/hwmon/sht3x.c
+++ b/drivers/hwmon/sht3x.c
@@ -22,11 +22,11 @@
#include <linux/jiffies.h>
#include <linux/platform_data/sht3x.h>
-/* commands (high precision mode) */
+/* commands (high repeatability mode) */
static const unsigned char sht3x_cmd_measure_blocking_hpm[] = { 0x2c, 0x06 };
static const unsigned char sht3x_cmd_measure_nonblocking_hpm[] = { 0x24, 0x00 };
-/* commands (low power mode) */
+/* commands (low repeatability mode) */
static const unsigned char sht3x_cmd_measure_blocking_lpm[] = { 0x2c, 0x10 };
static const unsigned char sht3x_cmd_measure_nonblocking_lpm[] = { 0x24, 0x16 };
@@ -69,9 +69,14 @@ enum sht3x_limits {
limit_min_hyst,
};
+enum sht3x_repeatability {
+ high_repeatability,
+ low_repeatability,
+};
+
DECLARE_CRC8_TABLE(sht3x_crc8_table);
-/* periodic measure commands (high precision mode) */
+/* periodic measure commands (high repeatability mode) */
static const char periodic_measure_commands_hpm[][SHT3X_CMD_LENGTH] = {
/* 0.5 measurements per second */
{0x20, 0x32},
@@ -85,7 +90,7 @@ static const char periodic_measure_commands_hpm[][SHT3X_CMD_LENGTH] = {
{0x27, 0x37},
};
-/* periodic measure commands (low power mode) */
+/* periodic measure commands (low repeatability mode) */
static const char periodic_measure_commands_lpm[][SHT3X_CMD_LENGTH] = {
/* 0.5 measurements per second */
{0x20, 0x2f},
@@ -132,6 +137,7 @@ struct sht3x_data {
struct mutex data_lock; /* lock for updating driver data */
u8 mode;
+ enum sht3x_repeatability repeatability;
const unsigned char *command;
u32 wait_time; /* in us*/
unsigned long last_update; /* last update in periodic mode*/
@@ -442,12 +448,13 @@ static void sht3x_select_command(struct sht3x_data *data)
data->command = sht3x_cmd_measure_periodic_mode;
data->wait_time = 0;
} else if (data->setup.blocking_io) {
- data->command = data->setup.high_precision ?
- sht3x_cmd_measure_blocking_hpm :
- sht3x_cmd_measure_blocking_lpm;
+ if(data->repeatability == high_repeatability)
+ data->command = sht3x_cmd_measure_blocking_hpm;
+ else if(data->repeatability == low_repeatability)
+ data->command = sht3x_cmd_measure_blocking_lpm;
data->wait_time = 0;
} else {
- if (data->setup.high_precision) {
+ if (data->repeatability == high_repeatability) {
data->command = sht3x_cmd_measure_nonblocking_hpm;
data->wait_time = SHT3X_NONBLOCKING_WAIT_TIME_HPM;
} else {
@@ -595,7 +602,7 @@ static ssize_t update_interval_store(struct device *dev,
}
if (mode > 0) {
- if (data->setup.high_precision)
+ if (data->repeatability == high_repeatability)
command = periodic_measure_commands_hpm[mode - 1];
else
command = periodic_measure_commands_lpm[mode - 1];
@@ -691,7 +698,7 @@ static int sht3x_probe(struct i2c_client *client)
return -ENOMEM;
data->setup.blocking_io = false;
- data->setup.high_precision = true;
+ data->repeatability = high_repeatability;
data->mode = 0;
data->last_update = jiffies - msecs_to_jiffies(3000);
data->client = client;
diff --git a/include/linux/platform_data/sht3x.h b/include/linux/platform_data/sht3x.h
index 14680d2a9..626c1404a 100644
--- a/include/linux/platform_data/sht3x.h
+++ b/include/linux/platform_data/sht3x.h
@@ -10,6 +10,5 @@
struct sht3x_platform_data {
bool blocking_io;
- bool high_precision;
};
#endif /* __SHT3X_H_ */
--
2.30.2
在 2023/6/12 11:10, Guenter Roeck 写道:
On 6/11/23 19:16, JuenKit Yip wrote:
Hi All,
I was using sht3x driver in my linux device but I saw that it should
be put in IIO module properly.
Why ?
In fact, I am going to add medium-repeatabilty and device-tree
support on it, and planning to add more sysfs interface
"repeatability". The orginal version did not support to modify the
repeatability after device loaded.
I have no idea what you are talking about.
Guenter
If there is any comment or idea, kindly show it.
Thanks
Juen Kit Yip