1 files changed, 165 insertions, 70 deletions

diff --git a/drivers/iio/chemical/ccs811.c b/drivers/iio/chemical/ccs811.c
index b4a46eb45789..998c9239c4c7 100644
--- a/drivers/iio/chemical/ccs811.c
+++ b/drivers/iio/chemical/ccs811.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  * ccs811.c - Support for AMS CCS811 VOC Sensor
  *
@@ -5,10 +6,6 @@
  *
  * Datasheet: ams.com/content/download/951091/2269479/CCS811_DS000459_3-00.pdf
  *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 as
- * published by the Free Software Foundation.
- *
  * IIO driver for AMS CCS811 (I2C address 0x5A/0x5B set by ADDR Low/High)
  *
  * TODO:
@@ -18,7 +15,9 @@
  * 4. Read error register and put the information in logs
  */
 
+#include <linux/cleanup.h>
 #include <linux/delay.h>
+#include <linux/gpio/consumer.h>
 #include <linux/i2c.h>
 #include <linux/iio/iio.h>
 #include <linux/iio/buffer.h>
@@ -39,6 +38,7 @@
 #define CCS811_ERR		0xE0
 /* Used to transition from boot to application mode */
 #define CCS811_APP_START	0xF4
+#define CCS811_SW_RESET		0xFF
 
 /* Status register flags */
 #define CCS811_STATUS_ERROR		BIT(0)
@@ -77,7 +77,13 @@ struct ccs811_data {
 	struct mutex lock; /* Protect readings */
 	struct ccs811_reading buffer;
 	struct iio_trigger *drdy_trig;
+	struct gpio_desc *wakeup_gpio;
 	bool drdy_trig_on;
+	/* Ensures correct alignment of timestamp if present */
+	struct {
+		s16 channels[2];
+		aligned_s64 ts;
+	} scan;
 };
 
 static const struct iio_chan_spec ccs811_channels[] = {
@@ -169,10 +175,25 @@ static int ccs811_setup(struct i2c_client *client)
 					 CCS811_MODE_IAQ_1SEC);
 }
 
+static void ccs811_set_wakeup(struct ccs811_data *data, bool enable)
+{
+	if (!data->wakeup_gpio)
+		return;
+
+	gpiod_set_value(data->wakeup_gpio, enable);
+
+	if (enable)
+		usleep_range(50, 60);
+	else
+		usleep_range(20, 30);
+}
+
 static int ccs811_get_measurement(struct ccs811_data *data)
 {
 	int ret, tries = 11;
 
+	ccs811_set_wakeup(data, true);
+
 	/* Maximum waiting time: 1s, as measurements are made every second */
 	while (tries-- > 0) {
 		ret = i2c_smbus_read_byte_data(data->client, CCS811_STATUS);
@@ -186,9 +207,46 @@ static int ccs811_get_measurement(struct ccs811_data *data)
 	if (!(ret & CCS811_STATUS_DATA_READY))
 		return -EIO;
 
-	return i2c_smbus_read_i2c_block_data(data->client,
+	ret = i2c_smbus_read_i2c_block_data(data->client,
 					    CCS811_ALG_RESULT_DATA, 8,
 					    (char *)&data->buffer);
+	ccs811_set_wakeup(data, false);
+
+	return ret;
+}
+
+static int ccs811_read_info_raw(struct ccs811_data *data,
+				struct iio_chan_spec const *chan,
+				int *val, int mask)
+{
+	int ret;
+
+	guard(mutex)(&data->lock);
+	ret = ccs811_get_measurement(data);
+	if (ret < 0)
+		return ret;
+
+	switch (chan->type) {
+	case IIO_VOLTAGE:
+		*val = be16_to_cpu(data->buffer.raw_data) & CCS811_VOLTAGE_MASK;
+		return IIO_VAL_INT;
+	case IIO_CURRENT:
+		*val = be16_to_cpu(data->buffer.raw_data) >> 10;
+		return IIO_VAL_INT;
+	case IIO_CONCENTRATION:
+		switch (chan->channel2) {
+		case IIO_MOD_CO2:
+			*val = be16_to_cpu(data->buffer.co2);
+			return IIO_VAL_INT;
+		case IIO_MOD_VOC:
+			*val = be16_to_cpu(data->buffer.voc);
+			return IIO_VAL_INT;
+		default:
+			return -EINVAL;
+		}
+	default:
+		return -EINVAL;
+	}
 }
 
 static int ccs811_read_raw(struct iio_dev *indio_dev,
@@ -200,46 +258,12 @@ static int ccs811_read_raw(struct iio_dev *indio_dev,
 
 	switch (mask) {
 	case IIO_CHAN_INFO_RAW:
-		ret = iio_device_claim_direct_mode(indio_dev);
-		if (ret)
-			return ret;
-		mutex_lock(&data->lock);
-		ret = ccs811_get_measurement(data);
-		if (ret < 0) {
-			mutex_unlock(&data->lock);
-			iio_device_release_direct_mode(indio_dev);
-			return ret;
-		}
+		if (!iio_device_claim_direct(indio_dev))
+			return -EBUSY;
 
-		switch (chan->type) {
-		case IIO_VOLTAGE:
-			*val = be16_to_cpu(data->buffer.raw_data) &
-					   CCS811_VOLTAGE_MASK;
-			ret = IIO_VAL_INT;
-			break;
-		case IIO_CURRENT:
-			*val = be16_to_cpu(data->buffer.raw_data) >> 10;
-			ret = IIO_VAL_INT;
-			break;
-		case IIO_CONCENTRATION:
-			switch (chan->channel2) {
-			case IIO_MOD_CO2:
-				*val = be16_to_cpu(data->buffer.co2);
-				ret =  IIO_VAL_INT;
-				break;
-			case IIO_MOD_VOC:
-				*val = be16_to_cpu(data->buffer.voc);
-				ret = IIO_VAL_INT;
-				break;
-			default:
-				ret = -EINVAL;
-			}
-			break;
-		default:
-			ret = -EINVAL;
-		}
-		mutex_unlock(&data->lock);
-		iio_device_release_direct_mode(indio_dev);
+		ret = ccs811_read_info_raw(data, chan, val, mask);
+
+		iio_device_release_direct(indio_dev);
 
 		return ret;
 
@@ -309,18 +333,18 @@ static irqreturn_t ccs811_trigger_handler(int irq, void *p)
 	struct iio_dev *indio_dev = pf->indio_dev;
 	struct ccs811_data *data = iio_priv(indio_dev);
 	struct i2c_client *client = data->client;
-	s16 buf[8]; /* s16 eCO2 + s16 TVOC + padding + 8 byte timestamp */
 	int ret;
 
-	ret = i2c_smbus_read_i2c_block_data(client, CCS811_ALG_RESULT_DATA, 4,
-					    (u8 *)&buf);
+	ret = i2c_smbus_read_i2c_block_data(client, CCS811_ALG_RESULT_DATA,
+					    sizeof(data->scan.channels),
+					    (u8 *)data->scan.channels);
 	if (ret != 4) {
 		dev_err(&client->dev, "cannot read sensor data\n");
 		goto err;
 	}
 
-	iio_push_to_buffers_with_timestamp(indio_dev, buf,
-					   iio_get_time_ns(indio_dev));
+	iio_push_to_buffers_with_ts(indio_dev, &data->scan, sizeof(data->scan),
+				    iio_get_time_ns(indio_dev));
 
 err:
 	iio_trigger_notify_done(indio_dev->trig);
@@ -339,9 +363,48 @@ static irqreturn_t ccs811_data_rdy_trigger_poll(int irq, void *private)
 	return IRQ_HANDLED;
 }
 
-static int ccs811_probe(struct i2c_client *client,
-			const struct i2c_device_id *id)
+static int ccs811_reset(struct i2c_client *client)
+{
+	struct gpio_desc *reset_gpio;
+	int ret;
+
+	reset_gpio = devm_gpiod_get_optional(&client->dev, "reset",
+					     GPIOD_OUT_LOW);
+	if (IS_ERR(reset_gpio))
+		return PTR_ERR(reset_gpio);
+
+	/* Try to reset using nRESET pin if available else do SW reset */
+	if (reset_gpio) {
+		gpiod_set_value(reset_gpio, 1);
+		usleep_range(20, 30);
+		gpiod_set_value(reset_gpio, 0);
+	} else {
+		/*
+		 * As per the datasheet, this sequence of values needs to be
+		 * written to the SW_RESET register for triggering the soft
+		 * reset in the device and placing it in boot mode.
+		 */
+		static const u8 reset_seq[] = {
+			0x11, 0xE5, 0x72, 0x8A,
+		};
+
+		ret = i2c_smbus_write_i2c_block_data(client, CCS811_SW_RESET,
+					     sizeof(reset_seq), reset_seq);
+		if (ret < 0) {
+			dev_err(&client->dev, "Failed to reset sensor\n");
+			return ret;
+		}
+	}
+
+	/* tSTART delay required after reset */
+	usleep_range(1000, 2000);
+
+	return 0;
+}
+
+static int ccs811_probe(struct i2c_client *client)
 {
+	const struct i2c_device_id *id = i2c_client_get_device_id(client);
 	struct iio_dev *indio_dev;
 	struct ccs811_data *data;
 	int ret;
@@ -351,40 +414,62 @@ static int ccs811_probe(struct i2c_client *client,
 				     | I2C_FUNC_SMBUS_READ_I2C_BLOCK))
 		return -EOPNOTSUPP;
 
+	indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
+	if (!indio_dev)
+		return -ENOMEM;
+
+	data = iio_priv(indio_dev);
+	i2c_set_clientdata(client, indio_dev);
+	data->client = client;
+
+	data->wakeup_gpio = devm_gpiod_get_optional(&client->dev, "wakeup",
+						    GPIOD_OUT_HIGH);
+	if (IS_ERR(data->wakeup_gpio))
+		return PTR_ERR(data->wakeup_gpio);
+
+	ccs811_set_wakeup(data, true);
+
+	ret = ccs811_reset(client);
+	if (ret) {
+		ccs811_set_wakeup(data, false);
+		return ret;
+	}
+
 	/* Check hardware id (should be 0x81 for this family of devices) */
 	ret = i2c_smbus_read_byte_data(client, CCS811_HW_ID);
-	if (ret < 0)
+	if (ret < 0) {
+		ccs811_set_wakeup(data, false);
 		return ret;
+	}
 
 	if (ret != CCS811_HW_ID_VALUE) {
 		dev_err(&client->dev, "hardware id doesn't match CCS81x\n");
+		ccs811_set_wakeup(data, false);
 		return -ENODEV;
 	}
 
 	ret = i2c_smbus_read_byte_data(client, CCS811_HW_VERSION);
-	if (ret < 0)
+	if (ret < 0) {
+		ccs811_set_wakeup(data, false);
 		return ret;
+	}
 
 	if ((ret & CCS811_HW_VERSION_MASK) != CCS811_HW_VERSION_VALUE) {
 		dev_err(&client->dev, "no CCS811 sensor\n");
+		ccs811_set_wakeup(data, false);
 		return -ENODEV;
 	}
 
-	indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
-	if (!indio_dev)
-		return -ENOMEM;
-
 	ret = ccs811_setup(client);
-	if (ret < 0)
+	if (ret < 0) {
+		ccs811_set_wakeup(data, false);
 		return ret;
+	}
 
-	data = iio_priv(indio_dev);
-	i2c_set_clientdata(client, indio_dev);
-	data->client = client;
+	ccs811_set_wakeup(data, false);
 
 	mutex_init(&data->lock);
 
-	indio_dev->dev.parent = &client->dev;
 	indio_dev->name = id->name;
 	indio_dev->info = &ccs811_info;
 	indio_dev->modes = INDIO_DIRECT_MODE;
@@ -407,20 +492,19 @@ static int ccs811_probe(struct i2c_client *client,
 		data->drdy_trig = devm_iio_trigger_alloc(&client->dev,
 							 "%s-dev%d",
 							 indio_dev->name,
-							 indio_dev->id);
+							 iio_device_id(indio_dev));
 		if (!data->drdy_trig) {
 			ret = -ENOMEM;
 			goto err_poweroff;
 		}
 
-		data->drdy_trig->dev.parent = &client->dev;
 		data->drdy_trig->ops = &ccs811_trigger_ops;
 		iio_trigger_set_drvdata(data->drdy_trig, indio_dev);
-		indio_dev->trig = data->drdy_trig;
-		iio_trigger_get(indio_dev->trig);
 		ret = iio_trigger_register(data->drdy_trig);
 		if (ret)
 			goto err_poweroff;
+
+		indio_dev->trig = iio_trigger_get(data->drdy_trig);
 	}
 
 	ret = iio_triggered_buffer_setup(indio_dev, NULL,
@@ -449,29 +533,40 @@ err_poweroff:
 	return ret;
 }
 
-static int ccs811_remove(struct i2c_client *client)
+static void ccs811_remove(struct i2c_client *client)
 {
 	struct iio_dev *indio_dev = i2c_get_clientdata(client);
 	struct ccs811_data *data = iio_priv(indio_dev);
+	int ret;
 
 	iio_device_unregister(indio_dev);
 	iio_triggered_buffer_cleanup(indio_dev);
 	if (data->drdy_trig)
 		iio_trigger_unregister(data->drdy_trig);
 
-	return i2c_smbus_write_byte_data(client, CCS811_MEAS_MODE,
-					 CCS811_MODE_IDLE);
+	ret = i2c_smbus_write_byte_data(client, CCS811_MEAS_MODE,
+					CCS811_MODE_IDLE);
+	if (ret)
+		dev_warn(&client->dev, "Failed to power down device (%pe)\n",
+			 ERR_PTR(ret));
 }
 
 static const struct i2c_device_id ccs811_id[] = {
-	{"ccs811", 0},
+	{ "ccs811" },
 	{	}
 };
 MODULE_DEVICE_TABLE(i2c, ccs811_id);
 
+static const struct of_device_id ccs811_dt_ids[] = {
+	{ .compatible = "ams,ccs811" },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, ccs811_dt_ids);
+
 static struct i2c_driver ccs811_driver = {
 	.driver = {
 		.name = "ccs811",
+		.of_match_table = ccs811_dt_ids,
 	},
 	.probe = ccs811_probe,
 	.remove = ccs811_remove,