IIO driver, perhaps a reference driver, since this sensor is already
supported in hwmon/jc42 driver.
Driver supports continuous conversion, resolution changes and
suspend/resume power ops.
Signed-off-by: Alison Schofield <amsfiel...@gmail.com>
Cc: Daniel Baluta <daniel.bal...@gmail.com>
---
drivers/iio/temperature/Kconfig | 10 ++
drivers/iio/temperature/Makefile | 1 +
drivers/iio/temperature/mcp9808.c | 269 ++++++++++++++++++++++++++++++++++++++
3 files changed, 280 insertions(+)
create mode 100644 drivers/iio/temperature/mcp9808.c
diff --git a/drivers/iio/temperature/Kconfig b/drivers/iio/temperature/Kconfig
index c4664e5..25915d2 100644
--- a/drivers/iio/temperature/Kconfig
+++ b/drivers/iio/temperature/Kconfig
@@ -3,6 +3,16 @@
#
menu "Temperature sensors"
+config MCP9808
+ tristate "MCP9808 temperature sensor"
+ depends on I2C
+ help
+ If you say yes here you get support for the Microchip
+ MCP9808 temperature sensor connected with I2C.
+
+ This driver can also be built as a module. If so, the module will
+ be called mcp9808.
+
config MLX90614
tristate "MLX90614 contact-less infrared sensor"
depends on I2C
diff --git a/drivers/iio/temperature/Makefile b/drivers/iio/temperature/Makefile
index 02bc79d..92cd1e6 100644
--- a/drivers/iio/temperature/Makefile
+++ b/drivers/iio/temperature/Makefile
@@ -2,6 +2,7 @@
# Makefile for industrial I/O temperature drivers
#
+obj-$(CONFIG_MCP9808) += mcp9808.o
obj-$(CONFIG_MLX90614) += mlx90614.o
obj-$(CONFIG_TMP006) += tmp006.o
obj-$(CONFIG_TSYS01) += tsys01.o
diff --git a/drivers/iio/temperature/mcp9808.c
b/drivers/iio/temperature/mcp9808.c
new file mode 100644
index 0000000..adab708
--- /dev/null
+++ b/drivers/iio/temperature/mcp9808.c
@@ -0,0 +1,269 @@
+/*
+ * mcp9808.c - Support for Microchip MCP9808 Digital Temperature Sensor
+ *
+ * Copyright (C) 2016 Alison Schofield <amsfiel...@gmail.com>
+ *
+ * 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.
+ *
+ * Datasheet: http://ww1.microchip.com/downloads/en/DeviceDoc/25095A.pdf
+ */
+
+#include <linux/delay.h>
+#include <linux/i2c.h>
+#include <linux/module.h>
+
+#include <linux/iio/iio.h>
+#include <linux/iio/sysfs.h>
+
+#define MCP9808_REG_CONFIG 0x01
+#define MCP9808_REG_TAMBIENT 0x05
+#define MCP9808_REG_MANUF_ID 0x06
+#define MCP9808_REG_DEVICE_ID 0x07
+#define MCP9808_REG_RESOLUTION 0x08
+
+#define MCP9808_CONFIG_DEFAULT 0x00
+#define MCP9808_CONFIG_SHUTDOWN 0x0100
+
+#define MCP9808_RES_DEFAULT 62500
+
+#define MCP9808_MANUF_ID 0x54
+#define MCP9808_DEVICE_ID 0x0400
+#define MCP9808_DEVICE_ID_MASK 0xff00
+
+struct mcp9808_data {
+ struct i2c_client *client;
+ struct mutex lock; /* protect resolution changes */
+ int res_index; /* current resolution index */
+};
+
+/* Resolution, MCP9808_REG_RESOLUTION bits, Conversion Time ms */
+static const int mcp9808_res[][3] = {
+ {500000, 0, 30},
+ {250000, 1, 65},
+ {125000, 2, 130},
+ { 62500, 3, 250},
+};
+
+static IIO_CONST_ATTR(temp_integration_time_available,
+ "0.5 0.25 0.125 0.0625");
+
+static struct attribute *mcp9808_attributes[] = {
+ &iio_const_attr_temp_integration_time_available.dev_attr.attr,
+ NULL
+};
+
+static struct attribute_group mcp9808_attribute_group = {
+ .attrs = mcp9808_attributes,
+};
+
+static int mcp9808_set_resolution(struct mcp9808_data *data, int val2)
+{
+ int i;
+ int ret = -EINVAL;
+ int conv_t = mcp9808_res[data->res_index][2];
+
+ for (i = 0; i < ARRAY_SIZE(mcp9808_res); i++) {
+ if (val2 == mcp9808_res[i][0]) {
+ mutex_lock(&data->lock);
+ ret = i2c_smbus_write_byte_data(data->client,
+ MCP9808_REG_RESOLUTION,
+ mcp9808_res[i][1]);
+ data->res_index = i;
+ mutex_unlock(&data->lock);
+
+ /* delay old + new conversion time */
+ msleep(conv_t + mcp9808_res[i][2]);
+ break;
+ }
+ }
+ return ret;
+}
+
+static int mcp9808_read_raw(struct iio_dev *indio_dev,
+ struct iio_chan_spec const *channel,
+ int *val, int *val2, long mask)
+
+{
+ struct mcp9808_data *data = iio_priv(indio_dev);
+ int ret;
+
+ switch (mask) {
+ case IIO_CHAN_INFO_RAW:
+ ret = i2c_smbus_read_word_swapped(data->client,
+ MCP9808_REG_TAMBIENT);
+ if (ret < 0)
+ return ret;
+ *val = sign_extend32(ret, 12);
+ return IIO_VAL_INT;
+
+ case IIO_CHAN_INFO_SCALE:
+ *val = 0;
+ *val2 = 62500;
+ return IIO_VAL_INT_PLUS_MICRO;
+
+ case IIO_CHAN_INFO_INT_TIME:
+ *val = 0;
+ *val2 = mcp9808_res[data->res_index][0];
+ return IIO_VAL_INT_PLUS_MICRO;
+
+ default:
+ break;
+ }
+
+ return -EINVAL;
+}
+
+static int mcp9808_write_raw(struct iio_dev *indio_dev,
+ struct iio_chan_spec const *channel,
+ int val, int val2, long mask)
+{
+ struct mcp9808_data *data = iio_priv(indio_dev);
+ int ret = -EINVAL;
+
+ if (mask == IIO_CHAN_INFO_INT_TIME) {
+ if (!val)
+ ret = mcp9808_set_resolution(data, val2);
+ }
+ return ret;
+}
+
+static const struct iio_chan_spec mcp9808_channels[] = {
+ {
+ .type = IIO_TEMP,
+ .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
+ BIT(IIO_CHAN_INFO_SCALE) |
+ BIT(IIO_CHAN_INFO_INT_TIME)
+ }
+};
+
+static const struct iio_info mcp9808_info = {
+ .read_raw = mcp9808_read_raw,
+ .write_raw = mcp9808_write_raw,
+ .attrs = &mcp9808_attribute_group,
+ .driver_module = THIS_MODULE,
+};
+
+static bool mcp9808_check_id(struct i2c_client *client)
+{
+ int mid, did;
+
+ mid = i2c_smbus_read_word_swapped(client, MCP9808_REG_MANUF_ID);
+ if (mid < 0)
+ return false;
+
+ did = i2c_smbus_read_word_swapped(client, MCP9808_REG_DEVICE_ID);
+ if (did < 0)
+ return false;
+
+ return ((mid == MCP9808_MANUF_ID) &&
+ ((did & MCP9808_DEVICE_ID_MASK) == MCP9808_DEVICE_ID));
+}
+
+static int mcp9808_probe(struct i2c_client *client,
+ const struct i2c_device_id *id)
+{
+ struct iio_dev *indio_dev;
+ struct mcp9808_data *data;
+ int ret;
+
+ if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_WORD_DATA
+ | I2C_FUNC_SMBUS_WRITE_BYTE_DATA))
+ return -EOPNOTSUPP;
+
+ if (!mcp9808_check_id(client)) {
+ dev_err(&client->dev, "no MCP9808 sensor\n");
+ return -ENODEV;
+ }
+
+ 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;
+ mutex_init(&data->lock);
+
+ indio_dev->dev.parent = &client->dev;
+ indio_dev->name = id->name;
+ indio_dev->info = &mcp9808_info;
+ indio_dev->modes = INDIO_DIRECT_MODE;
+ indio_dev->channels = mcp9808_channels;
+ indio_dev->num_channels = ARRAY_SIZE(mcp9808_channels);
+
+ /* set config register to power-on default */
+ ret = i2c_smbus_write_word_swapped(data->client, MCP9808_REG_CONFIG,
+ MCP9808_CONFIG_DEFAULT);
+ if (ret < 0)
+ return ret;
+
+ /* set resolution register to power-on default */
+ ret = mcp9808_set_resolution(data, MCP9808_RES_DEFAULT);
+ if (ret < 0)
+ return ret;
+
+ return iio_device_register(indio_dev);
+}
+
+static int mcp9808_shutdown(struct mcp9808_data *data)
+{
+ return i2c_smbus_write_word_swapped(data->client, MCP9808_REG_CONFIG,
+ MCP9808_CONFIG_SHUTDOWN);
+}
+
+static int mcp9808_remove(struct i2c_client *client)
+{
+ struct iio_dev *indio_dev = i2c_get_clientdata(client);
+
+ iio_device_unregister(indio_dev);
+
+ return mcp9808_shutdown(iio_priv(indio_dev));
+}
+
+#ifdef CONFIG_PM_SLEEP
+static int mcp9808_suspend(struct device *dev)
+{
+ struct iio_dev *indio_dev = i2c_get_clientdata(to_i2c_client(dev));
+
+ return mcp9808_shutdown(iio_priv(indio_dev));
+}
+
+static int mcp9808_resume(struct device *dev)
+{
+ struct iio_dev *indio_dev = i2c_get_clientdata(to_i2c_client(dev));
+ struct mcp9808_data *data = iio_priv(indio_dev);
+ int ret;
+
+ ret = mcp9808_set_resolution(data, mcp9808_res[data->res_index][0]);
+ if (ret < 0)
+ return ret;
+
+ return i2c_smbus_write_word_swapped(data->client, MCP9808_REG_CONFIG,
+ MCP9808_CONFIG_DEFAULT);
+}
+#endif
+
+static SIMPLE_DEV_PM_OPS(mcp9808_pm_ops, mcp9808_suspend, mcp9808_resume);
+
+static const struct i2c_device_id mcp9808_id[] = {
+ { "mcp9808", 0 },
+ { }
+};
+MODULE_DEVICE_TABLE(i2c, mcp9808_id);
+
+static struct i2c_driver mcp9808_driver = {
+ .driver = {
+ .name = "mcp9808",
+ .pm = &mcp9808_pm_ops,
+ },
+ .probe = mcp9808_probe,
+ .remove = mcp9808_remove,
+ .id_table = mcp9808_id,
+};
+module_i2c_driver(mcp9808_driver);
+
+MODULE_AUTHOR("Alison Schofield <amsfiel...@gmail.com>");
+MODULE_DESCRIPTION("MCP9808 Temperature Sensor Driver");
+MODULE_LICENSE("GPL v2");
--
2.1.4
