change system file

hc

2024-10-09 244b2c5ca8b14627e4a17755e5922221e121c771

 kernel/drivers/iio/chemical/ccs811.c
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..
@@ -1,13 +1,10 @@
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+// SPDX-License-Identifier: GPL-2.0-only
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 /*
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  * ccs811.c - Support for AMS CCS811 VOC Sensor
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  *
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  * Copyright (C) 2017 Narcisa Vasile <narcisaanamaria12@gmail.com>
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  *
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  * Datasheet: ams.com/content/download/951091/2269479/CCS811_DS000459_3-00.pdf
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- *
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- * This program is free software; you can redistribute it and/or modify
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- * it under the terms of the GNU General Public License version 2 as
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- * published by the Free Software Foundation.
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  *
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  * IIO driver for AMS CCS811 (I2C address 0x5A/0x5B set by ADDR Low/High)
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  *
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@@ -19,6 +16,7 @@
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  */
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17
 
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 #include <linux/delay.h>
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+#include <linux/gpio/consumer.h>
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 #include <linux/i2c.h>
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 #include <linux/iio/iio.h>
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 #include <linux/iio/buffer.h>
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@@ -39,6 +37,7 @@
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 #define CCS811_ERR		0xE0
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 /* Used to transition from boot to application mode */
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 #define CCS811_APP_START	0xF4
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+#define CCS811_SW_RESET		0xFF
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 /* Status register flags */
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 #define CCS811_STATUS_ERROR		BIT(0)
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@@ -77,6 +76,7 @@
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 	struct mutex lock; /* Protect readings */
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 	struct ccs811_reading buffer;
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 	struct iio_trigger *drdy_trig;
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+	struct gpio_desc *wakeup_gpio;
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 	bool drdy_trig_on;
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 	/* Ensures correct alignment of timestamp if present */
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 	struct {
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@@ -174,9 +174,24 @@
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 					 CCS811_MODE_IAQ_1SEC);
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 }
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+static void ccs811_set_wakeup(struct ccs811_data *data, bool enable)
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+{
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+	if (!data->wakeup_gpio)
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+		return;
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+
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+	gpiod_set_value(data->wakeup_gpio, enable);
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+
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+	if (enable)
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+		usleep_range(50, 60);
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+	else
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+		usleep_range(20, 30);
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+}
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+
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 static int ccs811_get_measurement(struct ccs811_data *data)
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 {
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 	int ret, tries = 11;
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+
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+	ccs811_set_wakeup(data, true);
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 	/* Maximum waiting time: 1s, as measurements are made every second */
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 	while (tries-- > 0) {
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@@ -191,9 +206,12 @@
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 	if (!(ret & CCS811_STATUS_DATA_READY))
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 		return -EIO;
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-	return i2c_smbus_read_i2c_block_data(data->client,
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+	ret = i2c_smbus_read_i2c_block_data(data->client,
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 					    CCS811_ALG_RESULT_DATA, 8,
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 					    (char *)&data->buffer);
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+	ccs811_set_wakeup(data, false);
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+
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+	return ret;
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 }
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 static int ccs811_read_raw(struct iio_dev *indio_dev,
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@@ -344,6 +362,45 @@
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 	return IRQ_HANDLED;
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 }
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364
 
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+static int ccs811_reset(struct i2c_client *client)
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+{
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+	struct gpio_desc *reset_gpio;
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+	int ret;
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+
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+	reset_gpio = devm_gpiod_get_optional(&client->dev, "reset",
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+					     GPIOD_OUT_LOW);
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+	if (IS_ERR(reset_gpio))
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+		return PTR_ERR(reset_gpio);
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+
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+	/* Try to reset using nRESET pin if available else do SW reset */
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+	if (reset_gpio) {
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+		gpiod_set_value(reset_gpio, 1);
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+		usleep_range(20, 30);
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+		gpiod_set_value(reset_gpio, 0);
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+	} else {
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+		/*
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+		 * As per the datasheet, this sequence of values needs to be
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+		 * written to the SW_RESET register for triggering the soft
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+		 * reset in the device and placing it in boot mode.
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+		 */
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+		static const u8 reset_seq[] = {
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+			0x11, 0xE5, 0x72, 0x8A,
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+		};
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+
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+		ret = i2c_smbus_write_i2c_block_data(client, CCS811_SW_RESET,
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+					     sizeof(reset_seq), reset_seq);
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+		if (ret < 0) {
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+			dev_err(&client->dev, "Failed to reset sensor\n");
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+			return ret;
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+		}
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+	}
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+
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+	/* tSTART delay required after reset */
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+	usleep_range(1000, 2000);
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+
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+	return 0;
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+}
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+
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 static int ccs811_probe(struct i2c_client *client,
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 			const struct i2c_device_id *id)
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 {
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@@ -356,40 +413,62 @@
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 				     | I2C_FUNC_SMBUS_READ_I2C_BLOCK))
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 		return -EOPNOTSUPP;
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-	/* Check hardware id (should be 0x81 for this family of devices) */
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-	ret = i2c_smbus_read_byte_data(client, CCS811_HW_ID);
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-	if (ret < 0)
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-		return ret;
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-
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-	if (ret != CCS811_HW_ID_VALUE) {
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-		dev_err(&client->dev, "hardware id doesn't match CCS81x\n");
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-		return -ENODEV;
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-	}
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-
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-	ret = i2c_smbus_read_byte_data(client, CCS811_HW_VERSION);
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-	if (ret < 0)
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-		return ret;
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-
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-	if ((ret & CCS811_HW_VERSION_MASK) != CCS811_HW_VERSION_VALUE) {
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-		dev_err(&client->dev, "no CCS811 sensor\n");
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-		return -ENODEV;
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-	}
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-
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 	indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
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 	if (!indio_dev)
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 		return -ENOMEM;
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-
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-	ret = ccs811_setup(client);
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-	if (ret < 0)
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-		return ret;
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 	data = iio_priv(indio_dev);
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 	i2c_set_clientdata(client, indio_dev);
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 	data->client = client;
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+	data->wakeup_gpio = devm_gpiod_get_optional(&client->dev, "wakeup",
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+						    GPIOD_OUT_HIGH);
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+	if (IS_ERR(data->wakeup_gpio))
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+		return PTR_ERR(data->wakeup_gpio);
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+
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+	ccs811_set_wakeup(data, true);
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+
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+	ret = ccs811_reset(client);
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+	if (ret) {
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+		ccs811_set_wakeup(data, false);
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+		return ret;
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+	}
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+
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+	/* Check hardware id (should be 0x81 for this family of devices) */
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+	ret = i2c_smbus_read_byte_data(client, CCS811_HW_ID);
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+	if (ret < 0) {
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+		ccs811_set_wakeup(data, false);
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+		return ret;
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+	}
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+
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+	if (ret != CCS811_HW_ID_VALUE) {
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+		dev_err(&client->dev, "hardware id doesn't match CCS81x\n");
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+		ccs811_set_wakeup(data, false);
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+		return -ENODEV;
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+	}
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+
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+	ret = i2c_smbus_read_byte_data(client, CCS811_HW_VERSION);
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+	if (ret < 0) {
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+		ccs811_set_wakeup(data, false);
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+		return ret;
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+	}
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+
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+	if ((ret & CCS811_HW_VERSION_MASK) != CCS811_HW_VERSION_VALUE) {
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+		dev_err(&client->dev, "no CCS811 sensor\n");
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+		ccs811_set_wakeup(data, false);
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+		return -ENODEV;
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+	}
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+
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+	ret = ccs811_setup(client);
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+	if (ret < 0) {
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+		ccs811_set_wakeup(data, false);
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+		return ret;
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+	}
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+
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+	ccs811_set_wakeup(data, false);
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+
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 	mutex_init(&data->lock);
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-	indio_dev->dev.parent = &client->dev;
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 	indio_dev->name = id->name;
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 	indio_dev->info = &ccs811_info;
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 	indio_dev->modes = INDIO_DIRECT_MODE;
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@@ -421,11 +500,11 @@
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 		data->drdy_trig->dev.parent = &client->dev;
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 		data->drdy_trig->ops = &ccs811_trigger_ops;
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 		iio_trigger_set_drvdata(data->drdy_trig, indio_dev);
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-		indio_dev->trig = data->drdy_trig;
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-		iio_trigger_get(indio_dev->trig);
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 		ret = iio_trigger_register(data->drdy_trig);
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 		if (ret)
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 			goto err_poweroff;
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+
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+		indio_dev->trig = iio_trigger_get(data->drdy_trig);
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 	}
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 	ret = iio_triggered_buffer_setup(indio_dev, NULL,
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@@ -474,9 +553,16 @@
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 };
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 MODULE_DEVICE_TABLE(i2c, ccs811_id);
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+static const struct of_device_id ccs811_dt_ids[] = {
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+	{ .compatible = "ams,ccs811" },
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+	{ }
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+};
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+MODULE_DEVICE_TABLE(of, ccs811_dt_ids);
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+
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 static struct i2c_driver ccs811_driver = {
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 	.driver = {
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 		.name = "ccs811",
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+		.of_match_table = ccs811_dt_ids,
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 	},
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 	.probe = ccs811_probe,
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 	.remove = ccs811_remove,