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229 lines
5.4 KiB
229 lines
5.4 KiB
// SPDX-License-Identifier: GPL-2.0+ |
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/* |
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* Analog Devices AD5272 digital potentiometer driver |
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* Copyright (C) 2018 Phil Reid <[email protected]> |
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* |
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* Datasheet: https://www.analog.com/media/en/technical-documentation/data-sheets/AD5272_5274.pdf |
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* |
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* DEVID #Wipers #Positions Resistor Opts (kOhm) i2c address |
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* ad5272 1 1024 20, 50, 100 01011xx |
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* ad5274 1 256 20, 100 01011xx |
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*/ |
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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/module.h> |
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#include <linux/mod_devicetable.h> |
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#define AD5272_RDAC_WR 1 |
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#define AD5272_RDAC_RD 2 |
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#define AD5272_RESET 4 |
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#define AD5272_CTL 7 |
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#define AD5272_RDAC_WR_EN BIT(1) |
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struct ad5272_cfg { |
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int max_pos; |
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int kohms; |
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int shift; |
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}; |
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enum ad5272_type { |
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AD5272_020, |
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AD5272_050, |
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AD5272_100, |
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AD5274_020, |
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AD5274_100, |
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}; |
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static const struct ad5272_cfg ad5272_cfg[] = { |
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[AD5272_020] = { .max_pos = 1024, .kohms = 20 }, |
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[AD5272_050] = { .max_pos = 1024, .kohms = 50 }, |
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[AD5272_100] = { .max_pos = 1024, .kohms = 100 }, |
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[AD5274_020] = { .max_pos = 256, .kohms = 20, .shift = 2 }, |
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[AD5274_100] = { .max_pos = 256, .kohms = 100, .shift = 2 }, |
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}; |
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struct ad5272_data { |
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struct i2c_client *client; |
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struct mutex lock; |
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const struct ad5272_cfg *cfg; |
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u8 buf[2] ____cacheline_aligned; |
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}; |
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static const struct iio_chan_spec ad5272_channel = { |
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.type = IIO_RESISTANCE, |
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.output = 1, |
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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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static int ad5272_write(struct ad5272_data *data, int reg, int val) |
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{ |
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int ret; |
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data->buf[0] = (reg << 2) | ((val >> 8) & 0x3); |
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data->buf[1] = (u8)val; |
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mutex_lock(&data->lock); |
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ret = i2c_master_send(data->client, data->buf, sizeof(data->buf)); |
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mutex_unlock(&data->lock); |
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return ret < 0 ? ret : 0; |
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} |
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static int ad5272_read(struct ad5272_data *data, int reg, int *val) |
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{ |
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int ret; |
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data->buf[0] = reg << 2; |
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data->buf[1] = 0; |
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mutex_lock(&data->lock); |
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ret = i2c_master_send(data->client, data->buf, sizeof(data->buf)); |
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if (ret < 0) |
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goto error; |
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ret = i2c_master_recv(data->client, data->buf, sizeof(data->buf)); |
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if (ret < 0) |
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goto error; |
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*val = ((data->buf[0] & 0x3) << 8) | data->buf[1]; |
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ret = 0; |
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error: |
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mutex_unlock(&data->lock); |
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return ret; |
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} |
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static int ad5272_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 ad5272_data *data = iio_priv(indio_dev); |
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int ret; |
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switch (mask) { |
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case IIO_CHAN_INFO_RAW: { |
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ret = ad5272_read(data, AD5272_RDAC_RD, val); |
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*val = *val >> data->cfg->shift; |
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return ret ? ret : IIO_VAL_INT; |
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} |
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case IIO_CHAN_INFO_SCALE: |
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*val = 1000 * data->cfg->kohms; |
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*val2 = data->cfg->max_pos; |
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return IIO_VAL_FRACTIONAL; |
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} |
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return -EINVAL; |
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} |
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static int ad5272_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 ad5272_data *data = iio_priv(indio_dev); |
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if (mask != IIO_CHAN_INFO_RAW) |
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return -EINVAL; |
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if (val >= data->cfg->max_pos || val < 0 || val2) |
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return -EINVAL; |
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return ad5272_write(data, AD5272_RDAC_WR, val << data->cfg->shift); |
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} |
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static const struct iio_info ad5272_info = { |
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.read_raw = ad5272_read_raw, |
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.write_raw = ad5272_write_raw, |
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}; |
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static int ad5272_reset(struct ad5272_data *data) |
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{ |
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struct gpio_desc *reset_gpio; |
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reset_gpio = devm_gpiod_get_optional(&data->client->dev, "reset", |
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GPIOD_OUT_HIGH); |
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if (IS_ERR(reset_gpio)) |
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return PTR_ERR(reset_gpio); |
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if (reset_gpio) { |
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udelay(1); |
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gpiod_set_value(reset_gpio, 0); |
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} else { |
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ad5272_write(data, AD5272_RESET, 0); |
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} |
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usleep_range(1000, 2000); |
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return 0; |
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} |
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static int ad5272_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 ad5272_data *data; |
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int ret; |
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indio_dev = devm_iio_device_alloc(dev, sizeof(*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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mutex_init(&data->lock); |
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data->cfg = &ad5272_cfg[id->driver_data]; |
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ret = ad5272_reset(data); |
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if (ret) |
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return ret; |
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ret = ad5272_write(data, AD5272_CTL, AD5272_RDAC_WR_EN); |
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if (ret < 0) |
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return -ENODEV; |
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indio_dev->info = &ad5272_info; |
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indio_dev->channels = &ad5272_channel; |
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indio_dev->num_channels = 1; |
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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 ad5272_dt_ids[] = { |
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{ .compatible = "adi,ad5272-020", .data = (void *)AD5272_020 }, |
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{ .compatible = "adi,ad5272-050", .data = (void *)AD5272_050 }, |
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{ .compatible = "adi,ad5272-100", .data = (void *)AD5272_100 }, |
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{ .compatible = "adi,ad5274-020", .data = (void *)AD5274_020 }, |
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{ .compatible = "adi,ad5274-100", .data = (void *)AD5274_100 }, |
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{} |
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}; |
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MODULE_DEVICE_TABLE(of, ad5272_dt_ids); |
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static const struct i2c_device_id ad5272_id[] = { |
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{ "ad5272-020", AD5272_020 }, |
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{ "ad5272-050", AD5272_050 }, |
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{ "ad5272-100", AD5272_100 }, |
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{ "ad5274-020", AD5274_020 }, |
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{ "ad5274-100", AD5274_100 }, |
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{} |
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}; |
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MODULE_DEVICE_TABLE(i2c, ad5272_id); |
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static struct i2c_driver ad5272_driver = { |
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.driver = { |
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.name = "ad5272", |
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.of_match_table = ad5272_dt_ids, |
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}, |
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.probe = ad5272_probe, |
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.id_table = ad5272_id, |
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}; |
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module_i2c_driver(ad5272_driver); |
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MODULE_AUTHOR("Phil Reid <[email protected]>"); |
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MODULE_DESCRIPTION("AD5272 digital potentiometer"); |
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MODULE_LICENSE("GPL v2");
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