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154 lines
3.7 KiB
154 lines
3.7 KiB
// SPDX-License-Identifier: GPL-2.0-only |
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/* |
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* max5487.c - Support for MAX5487, MAX5488, MAX5489 digital potentiometers |
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* |
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* Copyright (C) 2016 Cristina-Gabriela Moraru <[email protected]> |
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*/ |
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#include <linux/module.h> |
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#include <linux/spi/spi.h> |
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#include <linux/acpi.h> |
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#include <linux/iio/sysfs.h> |
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#include <linux/iio/iio.h> |
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#define MAX5487_WRITE_WIPER_A (0x01 << 8) |
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#define MAX5487_WRITE_WIPER_B (0x02 << 8) |
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/* copy both wiper regs to NV regs */ |
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#define MAX5487_COPY_AB_TO_NV (0x23 << 8) |
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/* copy both NV regs to wiper regs */ |
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#define MAX5487_COPY_NV_TO_AB (0x33 << 8) |
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#define MAX5487_MAX_POS 255 |
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struct max5487_data { |
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struct spi_device *spi; |
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int kohms; |
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}; |
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#define MAX5487_CHANNEL(ch, addr) { \ |
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.type = IIO_RESISTANCE, \ |
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.indexed = 1, \ |
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.output = 1, \ |
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.channel = ch, \ |
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.address = addr, \ |
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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 const struct iio_chan_spec max5487_channels[] = { |
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MAX5487_CHANNEL(0, MAX5487_WRITE_WIPER_A), |
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MAX5487_CHANNEL(1, MAX5487_WRITE_WIPER_B), |
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}; |
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static int max5487_write_cmd(struct spi_device *spi, u16 cmd) |
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{ |
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return spi_write(spi, (const void *) &cmd, sizeof(u16)); |
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} |
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static int max5487_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 max5487_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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*val = 1000 * data->kohms; |
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*val2 = MAX5487_MAX_POS; |
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return IIO_VAL_FRACTIONAL; |
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} |
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static int max5487_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 max5487_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 < 0 || val > MAX5487_MAX_POS) |
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return -EINVAL; |
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return max5487_write_cmd(data->spi, chan->address | val); |
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} |
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static const struct iio_info max5487_info = { |
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.read_raw = max5487_read_raw, |
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.write_raw = max5487_write_raw, |
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}; |
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static int max5487_spi_probe(struct spi_device *spi) |
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{ |
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struct iio_dev *indio_dev; |
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struct max5487_data *data; |
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const struct spi_device_id *id = spi_get_device_id(spi); |
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int ret; |
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indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*data)); |
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if (!indio_dev) |
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return -ENOMEM; |
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spi_set_drvdata(spi, indio_dev); |
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data = iio_priv(indio_dev); |
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data->spi = spi; |
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data->kohms = id->driver_data; |
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indio_dev->info = &max5487_info; |
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indio_dev->name = id->name; |
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indio_dev->modes = INDIO_DIRECT_MODE; |
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indio_dev->channels = max5487_channels; |
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indio_dev->num_channels = ARRAY_SIZE(max5487_channels); |
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/* restore both wiper regs from NV regs */ |
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ret = max5487_write_cmd(data->spi, MAX5487_COPY_NV_TO_AB); |
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if (ret < 0) |
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return ret; |
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return iio_device_register(indio_dev); |
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} |
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static int max5487_spi_remove(struct spi_device *spi) |
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{ |
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struct iio_dev *indio_dev = spi_get_drvdata(spi); |
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iio_device_unregister(indio_dev); |
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/* save both wiper regs to NV regs */ |
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return max5487_write_cmd(spi, MAX5487_COPY_AB_TO_NV); |
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} |
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static const struct spi_device_id max5487_id[] = { |
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{ "MAX5487", 10 }, |
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{ "MAX5488", 50 }, |
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{ "MAX5489", 100 }, |
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{ } |
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}; |
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MODULE_DEVICE_TABLE(spi, max5487_id); |
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static const struct acpi_device_id max5487_acpi_match[] = { |
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{ "MAX5487", 10 }, |
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{ "MAX5488", 50 }, |
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{ "MAX5489", 100 }, |
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{ }, |
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}; |
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MODULE_DEVICE_TABLE(acpi, max5487_acpi_match); |
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static struct spi_driver max5487_driver = { |
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.driver = { |
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.name = "max5487", |
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.acpi_match_table = ACPI_PTR(max5487_acpi_match), |
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}, |
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.id_table = max5487_id, |
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.probe = max5487_spi_probe, |
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.remove = max5487_spi_remove |
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}; |
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module_spi_driver(max5487_driver); |
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MODULE_AUTHOR("Cristina-Gabriela Moraru <[email protected]>"); |
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MODULE_DESCRIPTION("max5487 SPI driver"); |
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MODULE_LICENSE("GPL v2");
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