[PATCH v2 1/3] iio: sps30: separate core and interface specific code
From: Tomasz Duszynski
Date: Sun May 02 2021 - 09:49:08 EST
Move code responsible for handling i2c communication to a separate file.
Rationale for this change is preparation for adding support for serial
communication.
Signed-off-by: Tomasz Duszynski <tomasz.duszynski@xxxxxxxxxxx>
---
MAINTAINERS | 1 +
drivers/iio/chemical/Kconfig | 16 +-
drivers/iio/chemical/Makefile | 1 +
drivers/iio/chemical/sps30.c | 269 ++++++-------------------------
drivers/iio/chemical/sps30.h | 35 ++++
drivers/iio/chemical/sps30_i2c.c | 251 ++++++++++++++++++++++++++++
6 files changed, 347 insertions(+), 226 deletions(-)
create mode 100644 drivers/iio/chemical/sps30.h
create mode 100644 drivers/iio/chemical/sps30_i2c.c
diff --git a/MAINTAINERS b/MAINTAINERS
index ccc59fd7e5c0..4b39a9c48736 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -16137,6 +16137,7 @@ M: Tomasz Duszynski <tduszyns@xxxxxxxxx>
S: Maintained
F: Documentation/devicetree/bindings/iio/chemical/sensirion,sps30.yaml
F: drivers/iio/chemical/sps30.c
+F: drivers/iio/chemical/sps30_i2c.c
SERIAL DEVICE BUS
M: Rob Herring <robh@xxxxxxxxxx>
diff --git a/drivers/iio/chemical/Kconfig b/drivers/iio/chemical/Kconfig
index 10bb431bc3ce..2b45a76ab7bc 100644
--- a/drivers/iio/chemical/Kconfig
+++ b/drivers/iio/chemical/Kconfig
@@ -132,17 +132,21 @@ config SENSIRION_SGP30
module will be called sgp30.
config SPS30
- tristate "SPS30 particulate matter sensor"
- depends on I2C
- select CRC8
+ tristate
select IIO_BUFFER
select IIO_TRIGGERED_BUFFER
+
+config SPS30_I2C
+ tristate "SPS30 particulate matter sensor I2C driver"
+ depends on I2C
+ select SPS30
+ select CRC8
help
- Say Y here to build support for the Sensirion SPS30 particulate
- matter sensor.
+ Say Y here to build support for the Sensirion SPS30 I2C interface
+ driver.
To compile this driver as a module, choose M here: the module will
- be called sps30.
+ be called sps30_i2c.
config VZ89X
tristate "SGX Sensortech MiCS VZ89X VOC sensor"
diff --git a/drivers/iio/chemical/Makefile b/drivers/iio/chemical/Makefile
index fef63dd5bf92..41c264a229c0 100644
--- a/drivers/iio/chemical/Makefile
+++ b/drivers/iio/chemical/Makefile
@@ -17,4 +17,5 @@ obj-$(CONFIG_SCD30_I2C) += scd30_i2c.o
obj-$(CONFIG_SCD30_SERIAL) += scd30_serial.o
obj-$(CONFIG_SENSIRION_SGP30) += sgp30.o
obj-$(CONFIG_SPS30) += sps30.o
+obj-$(CONFIG_SPS30_I2C) += sps30_i2c.o
obj-$(CONFIG_VZ89X) += vz89x.o
diff --git a/drivers/iio/chemical/sps30.c b/drivers/iio/chemical/sps30.c
index 7486591588c3..d51314505115 100644
--- a/drivers/iio/chemical/sps30.c
+++ b/drivers/iio/chemical/sps30.c
@@ -3,11 +3,8 @@
* Sensirion SPS30 particulate matter sensor driver
*
* Copyright (c) Tomasz Duszynski <tduszyns@xxxxxxxxx>
- *
- * I2C slave address: 0x69
*/
-#include <asm/unaligned.h>
#include <linux/crc8.h>
#include <linux/delay.h>
#include <linux/i2c.h>
@@ -19,27 +16,14 @@
#include <linux/kernel.h>
#include <linux/module.h>
-#define SPS30_CRC8_POLYNOMIAL 0x31
-/* max number of bytes needed to store PM measurements or serial string */
-#define SPS30_MAX_READ_SIZE 48
+#include "sps30.h"
+
/* sensor measures reliably up to 3000 ug / m3 */
#define SPS30_MAX_PM 3000
/* minimum and maximum self cleaning periods in seconds */
#define SPS30_AUTO_CLEANING_PERIOD_MIN 0
#define SPS30_AUTO_CLEANING_PERIOD_MAX 604800
-/* SPS30 commands */
-#define SPS30_START_MEAS 0x0010
-#define SPS30_STOP_MEAS 0x0104
-#define SPS30_RESET 0xd304
-#define SPS30_READ_DATA_READY_FLAG 0x0202
-#define SPS30_READ_DATA 0x0300
-#define SPS30_READ_SERIAL 0xd033
-#define SPS30_START_FAN_CLEANING 0x5607
-#define SPS30_AUTO_CLEANING_PERIOD 0x8004
-/* not a sensor command per se, used only to distinguish write from read */
-#define SPS30_READ_AUTO_CLEANING_PERIOD 0x8005
-
enum {
PM1,
PM2P5,
@@ -52,114 +36,9 @@ enum {
MEASURING,
};
-struct sps30_state {
- struct i2c_client *client;
- /*
- * Guards against concurrent access to sensor registers.
- * Must be held whenever sequence of commands is to be executed.
- */
- struct mutex lock;
- int state;
-};
-
-DECLARE_CRC8_TABLE(sps30_crc8_table);
-
-static int sps30_write_then_read(struct sps30_state *state, u8 *txbuf,
- int txsize, u8 *rxbuf, int rxsize)
-{
- int ret;
-
- /*
- * Sensor does not support repeated start so instead of
- * sending two i2c messages in a row we just send one by one.
- */
- ret = i2c_master_send(state->client, txbuf, txsize);
- if (ret != txsize)
- return ret < 0 ? ret : -EIO;
-
- if (!rxbuf)
- return 0;
-
- ret = i2c_master_recv(state->client, rxbuf, rxsize);
- if (ret != rxsize)
- return ret < 0 ? ret : -EIO;
-
- return 0;
-}
-
-static int sps30_do_cmd(struct sps30_state *state, u16 cmd, u8 *data, int size)
-{
- /*
- * Internally sensor stores measurements in a following manner:
- *
- * PM1: upper two bytes, crc8, lower two bytes, crc8
- * PM2P5: upper two bytes, crc8, lower two bytes, crc8
- * PM4: upper two bytes, crc8, lower two bytes, crc8
- * PM10: upper two bytes, crc8, lower two bytes, crc8
- *
- * What follows next are number concentration measurements and
- * typical particle size measurement which we omit.
- */
- u8 buf[SPS30_MAX_READ_SIZE] = { cmd >> 8, cmd };
- int i, ret = 0;
-
- switch (cmd) {
- case SPS30_START_MEAS:
- buf[2] = 0x03;
- buf[3] = 0x00;
- buf[4] = crc8(sps30_crc8_table, &buf[2], 2, CRC8_INIT_VALUE);
- ret = sps30_write_then_read(state, buf, 5, NULL, 0);
- break;
- case SPS30_STOP_MEAS:
- case SPS30_RESET:
- case SPS30_START_FAN_CLEANING:
- ret = sps30_write_then_read(state, buf, 2, NULL, 0);
- break;
- case SPS30_READ_AUTO_CLEANING_PERIOD:
- buf[0] = SPS30_AUTO_CLEANING_PERIOD >> 8;
- buf[1] = (u8)(SPS30_AUTO_CLEANING_PERIOD & 0xff);
- fallthrough;
- case SPS30_READ_DATA_READY_FLAG:
- case SPS30_READ_DATA:
- case SPS30_READ_SERIAL:
- /* every two data bytes are checksummed */
- size += size / 2;
- ret = sps30_write_then_read(state, buf, 2, buf, size);
- break;
- case SPS30_AUTO_CLEANING_PERIOD:
- buf[2] = data[0];
- buf[3] = data[1];
- buf[4] = crc8(sps30_crc8_table, &buf[2], 2, CRC8_INIT_VALUE);
- buf[5] = data[2];
- buf[6] = data[3];
- buf[7] = crc8(sps30_crc8_table, &buf[5], 2, CRC8_INIT_VALUE);
- ret = sps30_write_then_read(state, buf, 8, NULL, 0);
- break;
- }
-
- if (ret)
- return ret;
-
- /* validate received data and strip off crc bytes */
- for (i = 0; i < size; i += 3) {
- u8 crc = crc8(sps30_crc8_table, &buf[i], 2, CRC8_INIT_VALUE);
-
- if (crc != buf[i + 2]) {
- dev_err(&state->client->dev,
- "data integrity check failed\n");
- return -EIO;
- }
-
- *data++ = buf[i];
- *data++ = buf[i + 1];
- }
-
- return 0;
-}
-
-static s32 sps30_float_to_int_clamped(const u8 *fp)
+static s32 sps30_float_to_int_clamped(__be32 *fp)
{
- int val = get_unaligned_be32(fp);
+ int val = be32_to_cpup(fp);
int mantissa = val & GENMASK(22, 0);
/* this is fine since passed float is always non-negative */
int exp = val >> 23;
@@ -188,38 +67,35 @@ static s32 sps30_float_to_int_clamped(const u8 *fp)
static int sps30_do_meas(struct sps30_state *state, s32 *data, int size)
{
- int i, ret, tries = 5;
- u8 tmp[16];
+ int i, ret;
if (state->state == RESET) {
- ret = sps30_do_cmd(state, SPS30_START_MEAS, NULL, 0);
+ ret = state->ops->start_meas(state);
if (ret)
return ret;
state->state = MEASURING;
}
- while (tries--) {
- ret = sps30_do_cmd(state, SPS30_READ_DATA_READY_FLAG, tmp, 2);
- if (ret)
- return -EIO;
+ ret = state->ops->read_meas(state, (__be32 *)data, size);
+ if (ret)
+ return ret;
- /* new measurements ready to be read */
- if (tmp[1] == 1)
- break;
+ for (i = 0; i < size; i++)
+ data[i] = sps30_float_to_int_clamped((__be32 *)&data[i]);
- msleep_interruptible(300);
- }
+ return 0;
+}
- if (tries == -1)
- return -ETIMEDOUT;
+static int sps30_do_reset(struct sps30_state *state)
+{
+ int ret;
- ret = sps30_do_cmd(state, SPS30_READ_DATA, tmp, sizeof(int) * size);
+ ret = state->ops->reset(state);
if (ret)
return ret;
- for (i = 0; i < size; i++)
- data[i] = sps30_float_to_int_clamped(&tmp[4 * i]);
+ state->state = RESET;
return 0;
}
@@ -310,24 +186,6 @@ static int sps30_read_raw(struct iio_dev *indio_dev,
return -EINVAL;
}
-static int sps30_do_cmd_reset(struct sps30_state *state)
-{
- int ret;
-
- ret = sps30_do_cmd(state, SPS30_RESET, NULL, 0);
- msleep(300);
- /*
- * Power-on-reset causes sensor to produce some glitch on i2c bus and
- * some controllers end up in error state. Recover simply by placing
- * some data on the bus, for example STOP_MEAS command, which
- * is NOP in this case.
- */
- sps30_do_cmd(state, SPS30_STOP_MEAS, NULL, 0);
- state->state = RESET;
-
- return ret;
-}
-
static ssize_t start_cleaning_store(struct device *dev,
struct device_attribute *attr,
const char *buf, size_t len)
@@ -340,7 +198,7 @@ static ssize_t start_cleaning_store(struct device *dev,
return -EINVAL;
mutex_lock(&state->lock);
- ret = sps30_do_cmd(state, SPS30_START_FAN_CLEANING, NULL, 0);
+ ret = state->ops->clean_fan(state);
mutex_unlock(&state->lock);
if (ret)
return ret;
@@ -349,31 +207,29 @@ static ssize_t start_cleaning_store(struct device *dev,
}
static ssize_t cleaning_period_show(struct device *dev,
- struct device_attribute *attr,
- char *buf)
+ struct device_attribute *attr,
+ char *buf)
{
struct iio_dev *indio_dev = dev_to_iio_dev(dev);
struct sps30_state *state = iio_priv(indio_dev);
- u8 tmp[4];
+ __be32 val;
int ret;
mutex_lock(&state->lock);
- ret = sps30_do_cmd(state, SPS30_READ_AUTO_CLEANING_PERIOD, tmp, 4);
+ ret = state->ops->read_cleaning_period(state, &val);
mutex_unlock(&state->lock);
if (ret)
return ret;
- return sprintf(buf, "%d\n", get_unaligned_be32(tmp));
+ return sprintf(buf, "%d\n", be32_to_cpu(val));
}
-static ssize_t cleaning_period_store(struct device *dev,
- struct device_attribute *attr,
- const char *buf, size_t len)
+static ssize_t cleaning_period_store(struct device *dev, struct device_attribute *attr,
+ const char *buf, size_t len)
{
struct iio_dev *indio_dev = dev_to_iio_dev(dev);
struct sps30_state *state = iio_priv(indio_dev);
int val, ret;
- u8 tmp[4];
if (kstrtoint(buf, 0, &val))
return -EINVAL;
@@ -382,10 +238,8 @@ static ssize_t cleaning_period_store(struct device *dev,
(val > SPS30_AUTO_CLEANING_PERIOD_MAX))
return -EINVAL;
- put_unaligned_be32(val, tmp);
-
mutex_lock(&state->lock);
- ret = sps30_do_cmd(state, SPS30_AUTO_CLEANING_PERIOD, tmp, 0);
+ ret = state->ops->write_cleaning_period(state, cpu_to_be32(val));
if (ret) {
mutex_unlock(&state->lock);
return ret;
@@ -397,7 +251,7 @@ static ssize_t cleaning_period_store(struct device *dev,
* sensor requires reset in order to return up to date self cleaning
* period
*/
- ret = sps30_do_cmd_reset(state);
+ ret = sps30_do_reset(state);
if (ret)
dev_warn(dev,
"period changed but reads will return the old value\n");
@@ -460,90 +314,65 @@ static const struct iio_chan_spec sps30_channels[] = {
IIO_CHAN_SOFT_TIMESTAMP(4),
};
-static void sps30_stop_meas(void *data)
+static void sps30_devm_stop_meas(void *data)
{
struct sps30_state *state = data;
- sps30_do_cmd(state, SPS30_STOP_MEAS, NULL, 0);
+ if (state->state == MEASURING)
+ state->ops->stop_meas(state);
}
static const unsigned long sps30_scan_masks[] = { 0x0f, 0x00 };
-static int sps30_probe(struct i2c_client *client)
+int sps30_probe(struct device *dev, const char *name, void *priv, const struct sps30_ops *ops)
{
struct iio_dev *indio_dev;
struct sps30_state *state;
- u8 buf[32];
int ret;
- if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
- return -EOPNOTSUPP;
-
- indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*state));
+ indio_dev = devm_iio_device_alloc(dev, sizeof(*state));
if (!indio_dev)
return -ENOMEM;
+ dev_set_drvdata(dev, indio_dev);
+
state = iio_priv(indio_dev);
- i2c_set_clientdata(client, indio_dev);
- state->client = client;
- state->state = RESET;
+ state->dev = dev;
+ state->priv = priv;
+ state->ops = ops;
+ mutex_init(&state->lock);
+
indio_dev->info = &sps30_info;
- indio_dev->name = client->name;
+ indio_dev->name = name;
indio_dev->channels = sps30_channels;
indio_dev->num_channels = ARRAY_SIZE(sps30_channels);
indio_dev->modes = INDIO_DIRECT_MODE;
indio_dev->available_scan_masks = sps30_scan_masks;
- mutex_init(&state->lock);
- crc8_populate_msb(sps30_crc8_table, SPS30_CRC8_POLYNOMIAL);
-
- ret = sps30_do_cmd_reset(state);
+ ret = sps30_do_reset(state);
if (ret) {
- dev_err(&client->dev, "failed to reset device\n");
+ dev_err(dev, "failed to reset device\n");
return ret;
}
- ret = sps30_do_cmd(state, SPS30_READ_SERIAL, buf, sizeof(buf));
+ ret = state->ops->show_info(state);
if (ret) {
- dev_err(&client->dev, "failed to read serial number\n");
+ dev_err(dev, "failed to read device info\n");
return ret;
}
- /* returned serial number is already NUL terminated */
- dev_info(&client->dev, "serial number: %s\n", buf);
- ret = devm_add_action_or_reset(&client->dev, sps30_stop_meas, state);
+ ret = devm_add_action_or_reset(dev, sps30_devm_stop_meas, state);
if (ret)
return ret;
- ret = devm_iio_triggered_buffer_setup(&client->dev, indio_dev, NULL,
+ ret = devm_iio_triggered_buffer_setup(dev, indio_dev, NULL,
sps30_trigger_handler, NULL);
if (ret)
return ret;
- return devm_iio_device_register(&client->dev, indio_dev);
+ return devm_iio_device_register(dev, indio_dev);
}
-
-static const struct i2c_device_id sps30_id[] = {
- { "sps30" },
- { }
-};
-MODULE_DEVICE_TABLE(i2c, sps30_id);
-
-static const struct of_device_id sps30_of_match[] = {
- { .compatible = "sensirion,sps30" },
- { }
-};
-MODULE_DEVICE_TABLE(of, sps30_of_match);
-
-static struct i2c_driver sps30_driver = {
- .driver = {
- .name = "sps30",
- .of_match_table = sps30_of_match,
- },
- .id_table = sps30_id,
- .probe_new = sps30_probe,
-};
-module_i2c_driver(sps30_driver);
+EXPORT_SYMBOL_GPL(sps30_probe);
MODULE_AUTHOR("Tomasz Duszynski <tduszyns@xxxxxxxxx>");
MODULE_DESCRIPTION("Sensirion SPS30 particulate matter sensor driver");
diff --git a/drivers/iio/chemical/sps30.h b/drivers/iio/chemical/sps30.h
new file mode 100644
index 000000000000..a58ee43cf45d
--- /dev/null
+++ b/drivers/iio/chemical/sps30.h
@@ -0,0 +1,35 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _SPS30_H
+#define _SPS30_H
+
+#include <linux/types.h>
+
+struct sps30_state;
+struct sps30_ops {
+ int (*start_meas)(struct sps30_state *state);
+ int (*stop_meas)(struct sps30_state *state);
+ int (*read_meas)(struct sps30_state *state, __be32 *meas, size_t num);
+ int (*reset)(struct sps30_state *state);
+ int (*clean_fan)(struct sps30_state *state);
+ int (*read_cleaning_period)(struct sps30_state *state, __be32 *period);
+ int (*write_cleaning_period)(struct sps30_state *state, __be32 period);
+ int (*show_info)(struct sps30_state *state);
+};
+
+struct sps30_state {
+ /* serialize access to the device */
+ struct mutex lock;
+ struct device *dev;
+ int state;
+ /*
+ * priv pointer is solely for serdev driver private data. We keep it
+ * here because driver_data inside dev has been already used for iio and
+ * struct serdev_device doesn't have one.
+ */
+ void *priv;
+ const struct sps30_ops *ops;
+};
+
+int sps30_probe(struct device *dev, const char *name, void *priv, const struct sps30_ops *ops);
+
+#endif
diff --git a/drivers/iio/chemical/sps30_i2c.c b/drivers/iio/chemical/sps30_i2c.c
new file mode 100644
index 000000000000..123ef23bf0eb
--- /dev/null
+++ b/drivers/iio/chemical/sps30_i2c.c
@@ -0,0 +1,251 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Sensirion SPS30 particulate matter sensor i2c driver
+ *
+ * Copyright (c) 2020 Tomasz Duszynski <tomasz.duszynski@xxxxxxxxxxx>
+ *
+ * I2C slave address: 0x69
+ */
+#include <asm/unaligned.h>
+#include <linux/crc8.h>
+#include <linux/delay.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 "sps30.h"
+
+#define SPS30_I2C_CRC8_POLYNOMIAL 0x31
+/* max number of bytes needed to store PM measurements or serial string */
+#define SPS30_I2C_MAX_BUF_SIZE 48
+
+DECLARE_CRC8_TABLE(sps30_i2c_crc8_table);
+
+#define SPS30_I2C_START_MEAS 0x0010
+#define SPS30_I2C_STOP_MEAS 0x0104
+#define SPS30_I2C_READ_MEAS 0x0300
+#define SPS30_I2C_MEAS_READY 0x0202
+#define SPS30_I2C_RESET 0xd304
+#define SPS30_I2C_CLEAN_FAN 0x5607
+#define SPS30_I2C_PERIOD 0x8004
+#define SPS30_I2C_READ_SERIAL 0xd033
+#define SPS30_I2C_READ_VERSION 0xd100
+
+static int sps30_i2c_xfer(struct sps30_state *state, unsigned char *txbuf, size_t txsize,
+ unsigned char *rxbuf, size_t rxsize)
+{
+ struct i2c_client *client = to_i2c_client(state->dev);
+ int ret;
+
+ /*
+ * Sensor does not support repeated start so instead of
+ * sending two i2c messages in a row we just send one by one.
+ */
+ ret = i2c_master_send(client, txbuf, txsize);
+ if (ret < 0)
+ return ret;
+ if (ret != txsize)
+ return -EIO;
+
+ if (!rxsize)
+ return 0;
+
+ ret = i2c_master_recv(client, rxbuf, rxsize);
+ if (ret < 0)
+ return ret;
+ if (ret != rxsize)
+ return -EIO;
+
+ return 0;
+}
+
+static int sps30_i2c_command(struct sps30_state *state, u16 cmd, void *arg, size_t arg_size,
+ void *rsp, size_t rsp_size)
+{
+ /*
+ * Internally sensor stores measurements in a following manner:
+ *
+ * PM1: upper two bytes, crc8, lower two bytes, crc8
+ * PM2P5: upper two bytes, crc8, lower two bytes, crc8
+ * PM4: upper two bytes, crc8, lower two bytes, crc8
+ * PM10: upper two bytes, crc8, lower two bytes, crc8
+ *
+ * What follows next are number concentration measurements and
+ * typical particle size measurement which we omit.
+ */
+ unsigned char buf[SPS30_I2C_MAX_BUF_SIZE];
+ unsigned char *tmp;
+ unsigned char crc;
+ size_t i;
+ int ret;
+
+ put_unaligned_be16(cmd, buf);
+ i = 2;
+
+ if (rsp) {
+ /* each two bytes are followed by a crc8 */
+ rsp_size += rsp_size / 2;
+ } else {
+ tmp = arg;
+
+ while (arg_size) {
+ buf[i] = *tmp++;
+ buf[i + 1] = *tmp++;
+ buf[i + 2] = crc8(sps30_i2c_crc8_table, buf + i, 2, CRC8_INIT_VALUE);
+ arg_size -= 2;
+ i += 3;
+ }
+ }
+
+ ret = sps30_i2c_xfer(state, buf, i, buf, rsp_size);
+ if (ret)
+ return ret;
+
+ /* validate received data and strip off crc bytes */
+ tmp = rsp;
+ for (i = 0; i < rsp_size; i += 3) {
+ crc = crc8(sps30_i2c_crc8_table, buf + i, 2, CRC8_INIT_VALUE);
+ if (crc != buf[i + 2]) {
+ dev_err(state->dev, "data integrity check failed\n");
+ return -EIO;
+ }
+
+ *tmp++ = buf[i];
+ *tmp++ = buf[i + 1];
+ }
+
+ return 0;
+}
+
+static int sps30_i2c_start_meas(struct sps30_state *state)
+{
+ /* request BE IEEE754 formatted data */
+ unsigned char buf[] = { 0x03, 0x00 };
+
+ return sps30_i2c_command(state, SPS30_I2C_START_MEAS, buf, sizeof(buf), NULL, 0);
+}
+
+static int sps30_i2c_stop_meas(struct sps30_state *state)
+{
+ return sps30_i2c_command(state, SPS30_I2C_STOP_MEAS, NULL, 0, NULL, 0);
+}
+
+static int sps30_i2c_reset(struct sps30_state *state)
+{
+ int ret;
+
+ ret = sps30_i2c_command(state, SPS30_I2C_RESET, NULL, 0, NULL, 0);
+ msleep(500);
+ /*
+ * Power-on-reset causes sensor to produce some glitch on i2c bus and
+ * some controllers end up in error state. Recover simply by placing
+ * some data on the bus, for example STOP_MEAS command, which
+ * is NOP in this case.
+ */
+ sps30_i2c_stop_meas(state);
+
+ return ret;
+}
+
+static bool sps30_i2c_meas_ready(struct sps30_state *state)
+{
+ unsigned char buf[2];
+ int ret;
+
+ ret = sps30_i2c_command(state, SPS30_I2C_MEAS_READY, NULL, 0, buf, sizeof(buf));
+ if (ret)
+ return false;
+
+ return buf[1];
+}
+
+static int sps30_i2c_read_meas(struct sps30_state *state, __be32 *meas, size_t num)
+{
+ /* measurements are ready within a second */
+ if (msleep_interruptible(1000))
+ return -EINTR;
+
+ if (!sps30_i2c_meas_ready(state))
+ return -ETIMEDOUT;
+
+ return sps30_i2c_command(state, SPS30_I2C_READ_MEAS, NULL, 0, meas, sizeof(num) * num);
+}
+
+static int sps30_i2c_clean_fan(struct sps30_state *state)
+{
+ return sps30_i2c_command(state, SPS30_I2C_CLEAN_FAN, NULL, 0, NULL, 0);
+}
+
+static int sps30_i2c_read_cleaning_period(struct sps30_state *state, __be32 *period)
+{
+ return sps30_i2c_command(state, SPS30_I2C_PERIOD, NULL, 0, period, sizeof(*period));
+}
+
+static int sps30_i2c_write_cleaning_period(struct sps30_state *state, __be32 period)
+{
+ return sps30_i2c_command(state, SPS30_I2C_PERIOD, &period, sizeof(period), NULL, 0);
+}
+
+static int sps30_i2c_show_info(struct sps30_state *state)
+{
+ /* extra nul just in case */
+ unsigned char buf[32 + 1] = { 0x00 };
+ int ret;
+
+ ret = sps30_i2c_command(state, SPS30_I2C_READ_SERIAL, NULL, 0, buf, sizeof(buf) - 1);
+ if (ret)
+ return ret;
+
+ dev_info(state->dev, "serial number: %s\n", buf);
+
+ ret = sps30_i2c_command(state, SPS30_I2C_READ_VERSION, NULL, 0, buf, 2);
+ if (ret)
+ return ret;
+
+ dev_info(state->dev, "fw version: %u.%u\n", buf[0], buf[1]);
+
+ return 0;
+}
+
+static const struct sps30_ops sps30_i2c_ops = {
+ .start_meas = sps30_i2c_start_meas,
+ .stop_meas = sps30_i2c_stop_meas,
+ .read_meas = sps30_i2c_read_meas,
+ .reset = sps30_i2c_reset,
+ .clean_fan = sps30_i2c_clean_fan,
+ .read_cleaning_period = sps30_i2c_read_cleaning_period,
+ .write_cleaning_period = sps30_i2c_write_cleaning_period,
+ .show_info = sps30_i2c_show_info,
+};
+
+static int sps30_i2c_probe(struct i2c_client *client)
+{
+ if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
+ return -EOPNOTSUPP;
+
+ crc8_populate_msb(sps30_i2c_crc8_table, SPS30_I2C_CRC8_POLYNOMIAL);
+
+ return sps30_probe(&client->dev, client->name, NULL, &sps30_i2c_ops);
+}
+
+static const struct of_device_id sps30_i2c_of_match[] = {
+ { .compatible = "sensirion,sps30" },
+ { }
+};
+MODULE_DEVICE_TABLE(of, sps30_i2c_of_match);
+
+static struct i2c_driver sps30_i2c_driver = {
+ .driver = {
+ .name = KBUILD_MODNAME,
+ .of_match_table = sps30_i2c_of_match,
+ },
+ .probe_new = sps30_i2c_probe,
+};
+module_i2c_driver(sps30_i2c_driver);
+
+MODULE_AUTHOR("Tomasz Duszynski <tomasz.duszynski@xxxxxxxxxxx>");
+MODULE_DESCRIPTION("Sensirion SPS30 particulate matter sensor i2c driver");
+MODULE_LICENSE("GPL v2");
--
2.31.1