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-rw-r--r--drivers/hwmon/aht10.c154
1 files changed, 101 insertions, 53 deletions
diff --git a/drivers/hwmon/aht10.c b/drivers/hwmon/aht10.c
index b8fe3f7248ba..f136bf3ff40a 100644
--- a/drivers/hwmon/aht10.c
+++ b/drivers/hwmon/aht10.c
@@ -1,7 +1,7 @@
// SPDX-License-Identifier: GPL-2.0-only
/*
- * aht10.c - Linux hwmon driver for AHT10 Temperature and Humidity sensor
+ * aht10.c - Linux hwmon driver for AHT10/AHT20 Temperature and Humidity sensors
* Copyright (C) 2020 Johannes Cornelis Draaijer
*/
@@ -10,9 +10,13 @@
#include <linux/i2c.h>
#include <linux/ktime.h>
#include <linux/module.h>
+#include <linux/crc8.h>
#define AHT10_MEAS_SIZE 6
+#define AHT20_MEAS_SIZE 7
+#define AHT20_CRC8_POLY 0x31
+
/*
* Poll intervals (in milliseconds)
*/
@@ -44,9 +48,18 @@
#define AHT10_MAX_POLL_INTERVAL_LEN 30
+enum aht10_variant { aht10, aht20 };
+
+static const struct i2c_device_id aht10_id[] = {
+ { "aht10", aht10 },
+ { "aht20", aht20 },
+ { },
+};
+MODULE_DEVICE_TABLE(i2c, aht10_id);
+
/**
- * struct aht10_data - All the data required to operate an AHT10 chip
- * @client: the i2c client associated with the AHT10
+ * struct aht10_data - All the data required to operate an AHT10/AHT20 chip
+ * @client: the i2c client associated with the AHT10/AHT20
* @lock: a mutex that is used to prevent parallel access to the
* i2c client
* @min_poll_interval: the minimum poll interval
@@ -56,12 +69,14 @@
* the chip from warming up due to the heat it generates.
* If it's unwanted, it can be ignored setting it to
* it to 0. Default value is 2000 ms
- * @previous_poll_time: the previous time that the AHT10
+ * @previous_poll_time: the previous time that the AHT10/AHT20
* was polled
* @temperature: the latest temperature value received from
- * the AHT10
+ * the AHT10/AHT20
* @humidity: the latest humidity value received from the
- * AHT10
+ * AHT10/AHT20
+ * @crc8: crc8 support flag
+ * @meas_size: measurements data size
*/
struct aht10_data {
@@ -75,12 +90,14 @@ struct aht10_data {
ktime_t previous_poll_time;
int temperature;
int humidity;
+ bool crc8;
+ unsigned int meas_size;
};
/**
- * aht10_init() - Initialize an AHT10 chip
- * @data: the data associated with this AHT10 chip
- * Return: 0 if succesfull, 1 if not
+ * aht10_init() - Initialize an AHT10/AHT20 chip
+ * @data: the data associated with this AHT10/AHT20 chip
+ * Return: 0 if successful, 1 if not
*/
static int aht10_init(struct aht10_data *data)
{
@@ -121,54 +138,78 @@ static int aht10_polltime_expired(struct aht10_data *data)
return ktime_after(difference, data->min_poll_interval);
}
+DECLARE_CRC8_TABLE(crc8_table);
+
/**
- * aht10_read_values() - read and parse the raw data from the AHT10
+ * crc8_check() - check crc of the sensor's measurements
+ * @raw_data: data frame received from sensor(including crc as the last byte)
+ * @count: size of the data frame
+ * Return: 0 if successful, 1 if not
+ */
+static int crc8_check(u8 *raw_data, int count)
+{
+ /*
+ * crc calculated on the whole frame(including crc byte) should yield
+ * zero in case of correctly received bytes
+ */
+ return crc8(crc8_table, raw_data, count, CRC8_INIT_VALUE);
+}
+
+/**
+ * aht10_read_values() - read and parse the raw data from the AHT10/AHT20
* @data: the struct aht10_data to use for the lock
- * Return: 0 if succesfull, 1 if not
+ * Return: 0 if successful, 1 if not
*/
static int aht10_read_values(struct aht10_data *data)
{
const u8 cmd_meas[] = {AHT10_CMD_MEAS, 0x33, 0x00};
u32 temp, hum;
int res;
- u8 raw_data[AHT10_MEAS_SIZE];
+ u8 raw_data[AHT20_MEAS_SIZE];
struct i2c_client *client = data->client;
mutex_lock(&data->lock);
- if (aht10_polltime_expired(data)) {
- res = i2c_master_send(client, cmd_meas, sizeof(cmd_meas));
- if (res < 0) {
- mutex_unlock(&data->lock);
- return res;
- }
-
- usleep_range(AHT10_MEAS_DELAY,
- AHT10_MEAS_DELAY + AHT10_DELAY_EXTRA);
-
- res = i2c_master_recv(client, raw_data, AHT10_MEAS_SIZE);
- if (res != AHT10_MEAS_SIZE) {
- mutex_unlock(&data->lock);
- if (res >= 0)
- return -ENODATA;
- else
- return res;
- }
-
- hum = ((u32)raw_data[1] << 12u) |
- ((u32)raw_data[2] << 4u) |
- ((raw_data[3] & 0xF0u) >> 4u);
-
- temp = ((u32)(raw_data[3] & 0x0Fu) << 16u) |
- ((u32)raw_data[4] << 8u) |
- raw_data[5];
-
- temp = ((temp * 625) >> 15u) * 10;
- hum = ((hum * 625) >> 16u) * 10;
-
- data->temperature = (int)temp - 50000;
- data->humidity = hum;
- data->previous_poll_time = ktime_get_boottime();
+ if (!aht10_polltime_expired(data)) {
+ mutex_unlock(&data->lock);
+ return 0;
+ }
+
+ res = i2c_master_send(client, cmd_meas, sizeof(cmd_meas));
+ if (res < 0) {
+ mutex_unlock(&data->lock);
+ return res;
}
+
+ usleep_range(AHT10_MEAS_DELAY, AHT10_MEAS_DELAY + AHT10_DELAY_EXTRA);
+
+ res = i2c_master_recv(client, raw_data, data->meas_size);
+ if (res != data->meas_size) {
+ mutex_unlock(&data->lock);
+ if (res >= 0)
+ return -ENODATA;
+ return res;
+ }
+
+ if (data->crc8 && crc8_check(raw_data, data->meas_size)) {
+ mutex_unlock(&data->lock);
+ return -EIO;
+ }
+
+ hum = ((u32)raw_data[1] << 12u) |
+ ((u32)raw_data[2] << 4u) |
+ ((raw_data[3] & 0xF0u) >> 4u);
+
+ temp = ((u32)(raw_data[3] & 0x0Fu) << 16u) |
+ ((u32)raw_data[4] << 8u) |
+ raw_data[5];
+
+ temp = ((temp * 625) >> 15u) * 10;
+ hum = ((hum * 625) >> 16u) * 10;
+
+ data->temperature = (int)temp - 50000;
+ data->humidity = hum;
+ data->previous_poll_time = ktime_get_boottime();
+
mutex_unlock(&data->lock);
return 0;
}
@@ -290,6 +331,8 @@ static const struct hwmon_chip_info aht10_chip_info = {
static int aht10_probe(struct i2c_client *client)
{
+ const struct i2c_device_id *id = i2c_match_id(aht10_id, client);
+ enum aht10_variant variant = id->driver_data;
struct device *device = &client->dev;
struct device *hwmon_dev;
struct aht10_data *data;
@@ -305,6 +348,17 @@ static int aht10_probe(struct i2c_client *client)
data->min_poll_interval = ms_to_ktime(AHT10_DEFAULT_MIN_POLL_INTERVAL);
data->client = client;
+ switch (variant) {
+ case aht20:
+ data->meas_size = AHT20_MEAS_SIZE;
+ data->crc8 = true;
+ crc8_populate_msb(crc8_table, AHT20_CRC8_POLY);
+ break;
+ default:
+ data->meas_size = AHT10_MEAS_SIZE;
+ break;
+ }
+
mutex_init(&data->lock);
res = aht10_init(data);
@@ -324,23 +378,17 @@ static int aht10_probe(struct i2c_client *client)
return PTR_ERR_OR_ZERO(hwmon_dev);
}
-static const struct i2c_device_id aht10_id[] = {
- { "aht10", 0 },
- { },
-};
-MODULE_DEVICE_TABLE(i2c, aht10_id);
-
static struct i2c_driver aht10_driver = {
.driver = {
.name = "aht10",
},
- .probe_new = aht10_probe,
+ .probe = aht10_probe,
.id_table = aht10_id,
};
module_i2c_driver(aht10_driver);
MODULE_AUTHOR("Johannes Cornelis Draaijer <jcdra1@gmail.com>");
-MODULE_DESCRIPTION("AHT10 Temperature and Humidity sensor driver");
+MODULE_DESCRIPTION("AHT10/AHT20 Temperature and Humidity sensor driver");
MODULE_VERSION("1.0");
MODULE_LICENSE("GPL v2");
generated by cgit v1.2.3 (git 2.39.0) at 2024-07-18 10:13:12 +0300