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134 lines
3.3 KiB
134 lines
3.3 KiB
// SPDX-License-Identifier: GPL-2.0-or-later |
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/* |
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* Maxim Integrated MAX5432-MAX5435 digital potentiometer driver |
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* Copyright (C) 2019 Martin Kaiser <[email protected]> |
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* |
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* Datasheet: |
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* https://datasheets.maximintegrated.com/en/ds/MAX5432-MAX5435.pdf |
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*/ |
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#include <linux/i2c.h> |
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#include <linux/iio/iio.h> |
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#include <linux/limits.h> |
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#include <linux/module.h> |
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#include <linux/mod_devicetable.h> |
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#include <linux/property.h> |
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/* All chip variants have 32 wiper positions. */ |
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#define MAX5432_MAX_POS 31 |
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#define MAX5432_OHM_50K (50 * 1000) |
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#define MAX5432_OHM_100K (100 * 1000) |
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/* Update the volatile (currently active) setting. */ |
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#define MAX5432_CMD_VREG 0x11 |
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struct max5432_data { |
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struct i2c_client *client; |
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unsigned long ohm; |
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}; |
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static const struct iio_chan_spec max5432_channels[] = { |
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{ |
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.type = IIO_RESISTANCE, |
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.indexed = 1, |
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.output = 1, |
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.channel = 0, |
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.address = MAX5432_CMD_VREG, |
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.info_mask_separate = BIT(IIO_CHAN_INFO_RAW), |
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.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), |
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} |
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}; |
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static int max5432_read_raw(struct iio_dev *indio_dev, |
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struct iio_chan_spec const *chan, |
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int *val, int *val2, long mask) |
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{ |
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struct max5432_data *data = iio_priv(indio_dev); |
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if (mask != IIO_CHAN_INFO_SCALE) |
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return -EINVAL; |
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if (unlikely(data->ohm > INT_MAX)) |
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return -ERANGE; |
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*val = data->ohm; |
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*val2 = MAX5432_MAX_POS; |
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return IIO_VAL_FRACTIONAL; |
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} |
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static int max5432_write_raw(struct iio_dev *indio_dev, |
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struct iio_chan_spec const *chan, |
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int val, int val2, long mask) |
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{ |
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struct max5432_data *data = iio_priv(indio_dev); |
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u8 data_byte; |
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if (mask != IIO_CHAN_INFO_RAW) |
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return -EINVAL; |
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if (val < 0 || val > MAX5432_MAX_POS) |
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return -EINVAL; |
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if (val2 != 0) |
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return -EINVAL; |
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/* Wiper position is in bits D7-D3. (D2-D0 are don't care bits.) */ |
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data_byte = val << 3; |
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return i2c_smbus_write_byte_data(data->client, chan->address, |
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data_byte); |
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} |
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static const struct iio_info max5432_info = { |
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.read_raw = max5432_read_raw, |
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.write_raw = max5432_write_raw, |
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}; |
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static int max5432_probe(struct i2c_client *client, |
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const struct i2c_device_id *id) |
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{ |
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struct device *dev = &client->dev; |
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struct iio_dev *indio_dev; |
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struct max5432_data *data; |
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indio_dev = devm_iio_device_alloc(dev, sizeof(struct max5432_data)); |
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if (!indio_dev) |
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return -ENOMEM; |
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i2c_set_clientdata(client, indio_dev); |
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data = iio_priv(indio_dev); |
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data->client = client; |
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data->ohm = (unsigned long)device_get_match_data(dev); |
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indio_dev->info = &max5432_info; |
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indio_dev->channels = max5432_channels; |
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indio_dev->num_channels = ARRAY_SIZE(max5432_channels); |
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indio_dev->name = client->name; |
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return devm_iio_device_register(dev, indio_dev); |
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} |
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static const struct of_device_id max5432_dt_ids[] = { |
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{ .compatible = "maxim,max5432", .data = (void *)MAX5432_OHM_50K }, |
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{ .compatible = "maxim,max5433", .data = (void *)MAX5432_OHM_100K }, |
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{ .compatible = "maxim,max5434", .data = (void *)MAX5432_OHM_50K }, |
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{ .compatible = "maxim,max5435", .data = (void *)MAX5432_OHM_100K }, |
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{ /* sentinel */ } |
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}; |
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MODULE_DEVICE_TABLE(of, max5432_dt_ids); |
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static struct i2c_driver max5432_driver = { |
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.driver = { |
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.name = "max5432", |
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.of_match_table = max5432_dt_ids, |
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}, |
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.probe = max5432_probe, |
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}; |
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module_i2c_driver(max5432_driver); |
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MODULE_AUTHOR("Martin Kaiser <[email protected]>"); |
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MODULE_DESCRIPTION("max5432-max5435 digital potentiometers"); |
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MODULE_LICENSE("GPL v2");
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