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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 18:49:45 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 18:49:45 +0000
commit2c3c1048746a4622d8c89a29670120dc8fab93c4 (patch)
tree848558de17fb3008cdf4d861b01ac7781903ce39 /drivers/iio/chemical/scd30_i2c.c
parentInitial commit. (diff)
downloadlinux-2c3c1048746a4622d8c89a29670120dc8fab93c4.tar.xz
linux-2c3c1048746a4622d8c89a29670120dc8fab93c4.zip
Adding upstream version 6.1.76.upstream/6.1.76
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'drivers/iio/chemical/scd30_i2c.c')
-rw-r--r--drivers/iio/chemical/scd30_i2c.c140
1 files changed, 140 insertions, 0 deletions
diff --git a/drivers/iio/chemical/scd30_i2c.c b/drivers/iio/chemical/scd30_i2c.c
new file mode 100644
index 000000000..bae479a47
--- /dev/null
+++ b/drivers/iio/chemical/scd30_i2c.c
@@ -0,0 +1,140 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Sensirion SCD30 carbon dioxide sensor i2c driver
+ *
+ * Copyright (c) 2020 Tomasz Duszynski <tomasz.duszynski@octakon.com>
+ *
+ * I2C slave address: 0x61
+ */
+#include <linux/crc8.h>
+#include <linux/device.h>
+#include <linux/errno.h>
+#include <linux/i2c.h>
+#include <linux/mod_devicetable.h>
+#include <linux/module.h>
+#include <linux/types.h>
+#include <asm/unaligned.h>
+
+#include "scd30.h"
+
+#define SCD30_I2C_MAX_BUF_SIZE 18
+#define SCD30_I2C_CRC8_POLYNOMIAL 0x31
+
+static u16 scd30_i2c_cmd_lookup_tbl[] = {
+ [CMD_START_MEAS] = 0x0010,
+ [CMD_STOP_MEAS] = 0x0104,
+ [CMD_MEAS_INTERVAL] = 0x4600,
+ [CMD_MEAS_READY] = 0x0202,
+ [CMD_READ_MEAS] = 0x0300,
+ [CMD_ASC] = 0x5306,
+ [CMD_FRC] = 0x5204,
+ [CMD_TEMP_OFFSET] = 0x5403,
+ [CMD_FW_VERSION] = 0xd100,
+ [CMD_RESET] = 0xd304,
+};
+
+DECLARE_CRC8_TABLE(scd30_i2c_crc8_tbl);
+
+static int scd30_i2c_xfer(struct scd30_state *state, char *txbuf, int txsize,
+ char *rxbuf, int rxsize)
+{
+ struct i2c_client *client = to_i2c_client(state->dev);
+ int ret;
+
+ /*
+ * repeated start is not supported hence instead of sending two i2c
+ * messages in a row we send one by one
+ */
+ ret = i2c_master_send(client, txbuf, txsize);
+ if (ret < 0)
+ return ret;
+ if (ret != txsize)
+ return -EIO;
+
+ if (!rxbuf)
+ return 0;
+
+ ret = i2c_master_recv(client, rxbuf, rxsize);
+ if (ret < 0)
+ return ret;
+ if (ret != rxsize)
+ return -EIO;
+
+ return 0;
+}
+
+static int scd30_i2c_command(struct scd30_state *state, enum scd30_cmd cmd, u16 arg,
+ void *response, int size)
+{
+ char buf[SCD30_I2C_MAX_BUF_SIZE];
+ char *rsp = response;
+ int i, ret;
+ char crc;
+
+ put_unaligned_be16(scd30_i2c_cmd_lookup_tbl[cmd], buf);
+ i = 2;
+
+ if (rsp) {
+ /* each two bytes are followed by a crc8 */
+ size += size / 2;
+ } else {
+ put_unaligned_be16(arg, buf + i);
+ crc = crc8(scd30_i2c_crc8_tbl, buf + i, 2, CRC8_INIT_VALUE);
+ i += 2;
+ buf[i] = crc;
+ i += 1;
+
+ /* commands below don't take an argument */
+ if ((cmd == CMD_STOP_MEAS) || (cmd == CMD_RESET))
+ i -= 3;
+ }
+
+ ret = scd30_i2c_xfer(state, buf, i, buf, size);
+ if (ret)
+ return ret;
+
+ /* validate received data and strip off crc bytes */
+ for (i = 0; i < size; i += 3) {
+ crc = crc8(scd30_i2c_crc8_tbl, buf + i, 2, CRC8_INIT_VALUE);
+ if (crc != buf[i + 2]) {
+ dev_err(state->dev, "data integrity check failed\n");
+ return -EIO;
+ }
+
+ *rsp++ = buf[i];
+ *rsp++ = buf[i + 1];
+ }
+
+ return 0;
+}
+
+static int scd30_i2c_probe(struct i2c_client *client)
+{
+ if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
+ return -EOPNOTSUPP;
+
+ crc8_populate_msb(scd30_i2c_crc8_tbl, SCD30_I2C_CRC8_POLYNOMIAL);
+
+ return scd30_probe(&client->dev, client->irq, client->name, NULL, scd30_i2c_command);
+}
+
+static const struct of_device_id scd30_i2c_of_match[] = {
+ { .compatible = "sensirion,scd30" },
+ { }
+};
+MODULE_DEVICE_TABLE(of, scd30_i2c_of_match);
+
+static struct i2c_driver scd30_i2c_driver = {
+ .driver = {
+ .name = KBUILD_MODNAME,
+ .of_match_table = scd30_i2c_of_match,
+ .pm = pm_sleep_ptr(&scd30_pm_ops),
+ },
+ .probe_new = scd30_i2c_probe,
+};
+module_i2c_driver(scd30_i2c_driver);
+
+MODULE_AUTHOR("Tomasz Duszynski <tomasz.duszynski@octakon.com>");
+MODULE_DESCRIPTION("Sensirion SCD30 carbon dioxide sensor i2c driver");
+MODULE_LICENSE("GPL v2");
+MODULE_IMPORT_NS(IIO_SCD30);