iio: sps30: separate core and interface specific code

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@octakon.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

1 files changed, 49 insertions, 220 deletions

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@gmail.com>
- *
- * 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@gmail.com>");
 MODULE_DESCRIPTION("Sensirion SPS30 particulate matter sensor driver");