projects / linux-2.6-block.git / blame
| Commit | Line | Data |
|---|---|---|
| 425c6f10 MK |
1 | // SPDX-License-Identifier: GPL-2.0-or-later |
| 2 | /* | |
| 3 | * Maxim Integrated MAX5432-MAX5435 digital potentiometer driver | |
| 4 | * Copyright (C) 2019 Martin Kaiser <martin@kaiser.cx> | |
| 5 | * | |
| 6 | * Datasheet: | |
| 7 | * https://datasheets.maximintegrated.com/en/ds/MAX5432-MAX5435.pdf | |
| 8 | */ | |
| 9 | ||
| 10 | #include <linux/i2c.h> | |
| 11 | #include <linux/iio/iio.h> | |
| 12 | #include <linux/limits.h> | |
| 13 | #include <linux/module.h> | |
| 14 | #include <linux/of.h> | |
| 15 | #include <linux/of_device.h> | |
| 16 | ||
| 17 | /* All chip variants have 32 wiper positions. */ | |
| 18 | #define MAX5432_MAX_POS 31 | |
| 19 | ||
| 20 | #define MAX5432_OHM_50K (50 * 1000) | |
| 21 | #define MAX5432_OHM_100K (100 * 1000) | |
| 22 | ||
| 23 | /* Update the volatile (currently active) setting. */ | |
| 24 | #define MAX5432_CMD_VREG 0x11 | |
| 25 | ||
| 26 | struct max5432_data { | |
| 27 | struct i2c_client *client; | |
| 28 | unsigned long ohm; | |
| 29 | }; | |
| 30 | ||
| 31 | static const struct iio_chan_spec max5432_channels[] = { | |
| 32 | { | |
| 33 | .type = IIO_RESISTANCE, | |
| 34 | .indexed = 1, | |
| 35 | .output = 1, | |
| 36 | .channel = 0, | |
| 37 | .address = MAX5432_CMD_VREG, | |
| 38 | .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), | |
| 39 | .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), | |
| 40 | } | |
| 41 | }; | |
| 42 | ||
| 43 | static int max5432_read_raw(struct iio_dev *indio_dev, | |
| 44 | struct iio_chan_spec const *chan, | |
| 45 | int *val, int *val2, long mask) | |
| 46 | { | |
| 47 | struct max5432_data *data = iio_priv(indio_dev); | |
| 48 | ||
| 49 | if (mask != IIO_CHAN_INFO_SCALE) | |
| 50 | return -EINVAL; | |
| 51 | ||
| 52 | if (unlikely(data->ohm > INT_MAX)) | |
| 53 | return -ERANGE; | |
| 54 | ||
| 55 | *val = data->ohm; | |
| 56 | *val2 = MAX5432_MAX_POS; | |
| 57 | ||
| 58 | return IIO_VAL_FRACTIONAL; | |
| 59 | } | |
| 60 | ||
| 61 | static int max5432_write_raw(struct iio_dev *indio_dev, | |
| 62 | struct iio_chan_spec const *chan, | |
| 63 | int val, int val2, long mask) | |
| 64 | { | |
| 65 | struct max5432_data *data = iio_priv(indio_dev); | |
| 66 | u8 data_byte; | |
| 67 | ||
| 68 | if (mask != IIO_CHAN_INFO_RAW) | |
| 69 | return -EINVAL; | |
| 70 | ||
| 71 | if (val < 0 || val > MAX5432_MAX_POS) | |
| 72 | return -EINVAL; | |
| 73 | ||
| 74 | if (val2 != 0) | |
| 75 | return -EINVAL; | |
| 76 | ||
| 77 | /* Wiper position is in bits D7-D3. (D2-D0 are don't care bits.) */ | |
| 78 | data_byte = val << 3; | |
| 79 | return i2c_smbus_write_byte_data(data->client, chan->address, | |
| 80 | data_byte); | |
| 81 | } | |
| 82 | ||
| 83 | static const struct iio_info max5432_info = { | |
| 84 | .read_raw = max5432_read_raw, | |
| 85 | .write_raw = max5432_write_raw, | |
| 86 | }; | |
| 87 | ||
| 88 | static int max5432_probe(struct i2c_client *client, | |
| 89 | const struct i2c_device_id *id) | |
| 90 | { | |
| 91 | struct device *dev = &client->dev; | |
| 92 | struct iio_dev *indio_dev; | |
| 93 | struct max5432_data *data; | |
| 94 | ||
| 95 | indio_dev = devm_iio_device_alloc(dev, sizeof(struct max5432_data)); | |
| 96 | if (!indio_dev) | |
| 97 | return -ENOMEM; | |
| 98 | ||
| 99 | i2c_set_clientdata(client, indio_dev); | |
| 100 | ||
| 101 | data = iio_priv(indio_dev); | |
| 102 | data->client = client; | |
| 103 | data->ohm = (unsigned long)of_device_get_match_data(dev); | |
| 104 | ||
| 105 | indio_dev->dev.parent = dev; | |
| 106 | indio_dev->info = &max5432_info; | |
| 107 | indio_dev->channels = max5432_channels; | |
| 108 | indio_dev->num_channels = ARRAY_SIZE(max5432_channels); | |
| 109 | indio_dev->name = client->name; | |
| 110 | ||
| 111 | return devm_iio_device_register(dev, indio_dev); | |
| 112 | } | |
| 113 | ||
| 114 | static const struct of_device_id max5432_dt_ids[] = { | |
| 115 | { .compatible = "maxim,max5432", .data = (void *)MAX5432_OHM_50K }, | |
| 116 | { .compatible = "maxim,max5433", .data = (void *)MAX5432_OHM_100K }, | |
| 117 | { .compatible = "maxim,max5434", .data = (void *)MAX5432_OHM_50K }, | |
| 118 | { .compatible = "maxim,max5435", .data = (void *)MAX5432_OHM_100K }, | |
| 119 | { /* sentinel */ } | |
| 120 | }; | |
| 121 | MODULE_DEVICE_TABLE(of, max5432_dt_ids); | |
| 122 | ||
| 123 | static struct i2c_driver max5432_driver = { | |
| 124 | .driver = { | |
| 125 | .name = "max5432", | |
| 126 | .of_match_table = of_match_ptr(max5432_dt_ids), | |
| 127 | }, | |
| 128 | .probe = max5432_probe, | |
| 129 | }; | |
| 130 | ||
| 131 | module_i2c_driver(max5432_driver); | |
| 132 | ||
| 133 | MODULE_AUTHOR("Martin Kaiser <martin@kaiser.cx>"); | |
| 134 | MODULE_DESCRIPTION("max5432-max5435 digital potentiometers"); | |
| 135 | MODULE_LICENSE("GPL v2"); |