bc0a409c5f
Add support for reading conversion results from the ADC and provide them through a single IIO channel. A proper scaling factor is also exported based on the reference voltage provided by a regulator. Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de> Reviewed-by: Lars-Peter Clausen <lars@metafoo.de> Signed-off-by: Jonathan Cameron <jic23@kernel.org>
161 lines
3.2 KiB
C
161 lines
3.2 KiB
C
/*
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* Copyright (C) 2012 Avionic Design GmbH
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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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#include <linux/err.h>
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#include <linux/i2c.h>
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#include <linux/module.h>
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#include <linux/iio/iio.h>
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#include <linux/regulator/consumer.h>
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struct adc081c {
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struct i2c_client *i2c;
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struct regulator *ref;
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};
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#define REG_CONV_RES 0x00
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static int adc081c_read_raw(struct iio_dev *iio,
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struct iio_chan_spec const *channel, int *value,
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int *shift, long mask)
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{
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struct adc081c *adc = iio_priv(iio);
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int err;
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switch (mask) {
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case IIO_CHAN_INFO_RAW:
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err = i2c_smbus_read_word_swapped(adc->i2c, REG_CONV_RES);
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if (err < 0)
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return err;
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*value = (err >> 4) & 0xff;
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return IIO_VAL_INT;
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case IIO_CHAN_INFO_SCALE:
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err = regulator_get_voltage(adc->ref);
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if (err < 0)
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return err;
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*value = err / 1000;
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*shift = 8;
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return IIO_VAL_FRACTIONAL_LOG2;
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default:
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break;
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}
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return -EINVAL;
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}
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static const struct iio_chan_spec adc081c_channel = {
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.type = IIO_VOLTAGE,
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.info_mask = IIO_CHAN_INFO_SCALE_SHARED_BIT |
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IIO_CHAN_INFO_RAW_SEPARATE_BIT,
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};
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static const struct iio_info adc081c_info = {
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.read_raw = adc081c_read_raw,
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.driver_module = THIS_MODULE,
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};
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static int adc081c_probe(struct i2c_client *client,
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const struct i2c_device_id *id)
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{
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struct iio_dev *iio;
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struct adc081c *adc;
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int err;
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if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_WORD_DATA))
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return -ENODEV;
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iio = iio_device_alloc(sizeof(*adc));
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if (!iio)
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return -ENOMEM;
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adc = iio_priv(iio);
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adc->i2c = client;
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adc->ref = regulator_get(&client->dev, "vref");
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if (IS_ERR(adc->ref)) {
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err = PTR_ERR(adc->ref);
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goto iio_free;
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}
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err = regulator_enable(adc->ref);
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if (err < 0)
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goto regulator_put;
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iio->dev.parent = &client->dev;
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iio->name = dev_name(&client->dev);
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iio->modes = INDIO_DIRECT_MODE;
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iio->info = &adc081c_info;
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iio->channels = &adc081c_channel;
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iio->num_channels = 1;
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err = iio_device_register(iio);
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if (err < 0)
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goto regulator_disable;
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i2c_set_clientdata(client, iio);
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return 0;
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regulator_disable:
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regulator_disable(adc->ref);
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regulator_put:
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regulator_put(adc->ref);
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iio_free:
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iio_device_free(iio);
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return err;
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}
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static int adc081c_remove(struct i2c_client *client)
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{
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struct iio_dev *iio = i2c_get_clientdata(client);
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struct adc081c *adc = iio_priv(iio);
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iio_device_unregister(iio);
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regulator_disable(adc->ref);
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regulator_put(adc->ref);
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iio_device_free(iio);
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return 0;
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}
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static const struct i2c_device_id adc081c_id[] = {
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{ "adc081c", 0 },
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{ }
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};
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MODULE_DEVICE_TABLE(i2c, adc081c_id);
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#ifdef CONFIG_OF
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static const struct of_device_id adc081c_of_match[] = {
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{ .compatible = "ti,adc081c" },
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{ }
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};
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MODULE_DEVICE_TABLE(of, adc081c_of_match);
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#endif
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static struct i2c_driver adc081c_driver = {
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.driver = {
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.name = "adc081c",
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.owner = THIS_MODULE,
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.of_match_table = of_match_ptr(adc081c_of_match),
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},
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.probe = adc081c_probe,
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.remove = adc081c_remove,
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.id_table = adc081c_id,
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};
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module_i2c_driver(adc081c_driver);
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MODULE_AUTHOR("Thierry Reding <thierry.reding@avionic-design.de>");
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MODULE_DESCRIPTION("Texas Instruments ADC081C021/027 driver");
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MODULE_LICENSE("GPL v2");
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