projects / linux-2.6-block.git / blame
| Commit | Line | Data |
|---|---|---|
| 9a47894f CM |
1 | /* |
| 2 | * max5487.c - Support for MAX5487, MAX5488, MAX5489 digital potentiometers | |
| 3 | * | |
| 4 | * Copyright (C) 2016 Cristina-Gabriela Moraru <cristina.moraru09@gmail.com> | |
| 5 | * | |
| 6 | * This program is free software; you can redistribute it and/or modify | |
| 7 | * it under the terms of the GNU General Public License version 2 as | |
| 8 | * published by the Free Software Foundation. | |
| 9 | * | |
| 10 | */ | |
| 11 | #include <linux/module.h> | |
| 12 | #include <linux/spi/spi.h> | |
| 13 | #include <linux/acpi.h> | |
| 14 | ||
| 15 | #include <linux/iio/sysfs.h> | |
| 16 | #include <linux/iio/iio.h> | |
| 17 | ||
| 18 | #define MAX5487_WRITE_WIPER_A (0x01 << 8) | |
| 19 | #define MAX5487_WRITE_WIPER_B (0x02 << 8) | |
| 20 | ||
| 21 | /* copy both wiper regs to NV regs */ | |
| 22 | #define MAX5487_COPY_AB_TO_NV (0x23 << 8) | |
| 23 | /* copy both NV regs to wiper regs */ | |
| 24 | #define MAX5487_COPY_NV_TO_AB (0x33 << 8) | |
| 25 | ||
| 26 | #define MAX5487_MAX_POS 255 | |
| 27 | ||
| 28 | struct max5487_data { | |
| 29 | struct spi_device *spi; | |
| 30 | int kohms; | |
| 31 | }; | |
| 32 | ||
| 33 | #define MAX5487_CHANNEL(ch, addr) { \ | |
| 34 | .type = IIO_RESISTANCE, \ | |
| 35 | .indexed = 1, \ | |
| 36 | .output = 1, \ | |
| 37 | .channel = ch, \ | |
| 38 | .address = addr, \ | |
| 39 | .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \ | |
| 40 | .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \ | |
| 41 | } | |
| 42 | ||
| 43 | static const struct iio_chan_spec max5487_channels[] = { | |
| 44 | MAX5487_CHANNEL(0, MAX5487_WRITE_WIPER_A), | |
| 45 | MAX5487_CHANNEL(1, MAX5487_WRITE_WIPER_B), | |
| 46 | }; | |
| 47 | ||
| 48 | static int max5487_write_cmd(struct spi_device *spi, u16 cmd) | |
| 49 | { | |
| 50 | return spi_write(spi, (const void *) &cmd, sizeof(u16)); | |
| 51 | } | |
| 52 | ||
| 53 | static int max5487_read_raw(struct iio_dev *indio_dev, | |
| 54 | struct iio_chan_spec const *chan, | |
| 55 | int *val, int *val2, long mask) | |
| 56 | { | |
| 57 | struct max5487_data *data = iio_priv(indio_dev); | |
| 58 | ||
| 59 | if (mask != IIO_CHAN_INFO_SCALE) | |
| 60 | return -EINVAL; | |
| 61 | ||
| 62 | *val = 1000 * data->kohms; | |
| 63 | *val2 = MAX5487_MAX_POS; | |
| 64 | ||
| 65 | return IIO_VAL_FRACTIONAL; | |
| 66 | } | |
| 67 | ||
| 68 | static int max5487_write_raw(struct iio_dev *indio_dev, | |
| 69 | struct iio_chan_spec const *chan, | |
| 70 | int val, int val2, long mask) | |
| 71 | { | |
| 72 | struct max5487_data *data = iio_priv(indio_dev); | |
| 73 | ||
| 74 | if (mask != IIO_CHAN_INFO_RAW) | |
| 75 | return -EINVAL; | |
| 76 | ||
| 77 | if (val < 0 || val > MAX5487_MAX_POS) | |
| 78 | return -EINVAL; | |
| 79 | ||
| 80 | return max5487_write_cmd(data->spi, chan->address | val); | |
| 81 | } | |
| 82 | ||
| 83 | static const struct iio_info max5487_info = { | |
| 84 | .read_raw = max5487_read_raw, | |
| 85 | .write_raw = max5487_write_raw, | |
| 9a47894f CM |
86 | }; |
| 87 | ||
| 88 | static int max5487_spi_probe(struct spi_device *spi) | |
| 89 | { | |
| 90 | struct iio_dev *indio_dev; | |
| 91 | struct max5487_data *data; | |
| 92 | const struct spi_device_id *id = spi_get_device_id(spi); | |
| 93 | int ret; | |
| 94 | ||
| 95 | indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*data)); | |
| 96 | if (!indio_dev) | |
| 97 | return -ENOMEM; | |
| 98 | ||
| 99 | dev_set_drvdata(&spi->dev, indio_dev); | |
| 100 | data = iio_priv(indio_dev); | |
| 101 | ||
| 102 | data->spi = spi; | |
| 103 | data->kohms = id->driver_data; | |
| 104 | ||
| 105 | indio_dev->info = &max5487_info; | |
| 106 | indio_dev->name = id->name; | |
| 107 | indio_dev->dev.parent = &spi->dev; | |
| 108 | indio_dev->modes = INDIO_DIRECT_MODE; | |
| 109 | indio_dev->channels = max5487_channels; | |
| 110 | indio_dev->num_channels = ARRAY_SIZE(max5487_channels); | |
| 111 | ||
| 112 | /* restore both wiper regs from NV regs */ | |
| 113 | ret = max5487_write_cmd(data->spi, MAX5487_COPY_NV_TO_AB); | |
| 114 | if (ret < 0) | |
| 115 | return ret; | |
| 116 | ||
| 117 | return iio_device_register(indio_dev); | |
| 118 | } | |
| 119 | ||
| 120 | static int max5487_spi_remove(struct spi_device *spi) | |
| 121 | { | |
| 122 | struct iio_dev *indio_dev = dev_get_drvdata(&spi->dev); | |
| 123 | ||
| 124 | iio_device_unregister(indio_dev); | |
| 125 | ||
| 126 | /* save both wiper regs to NV regs */ | |
| 127 | return max5487_write_cmd(spi, MAX5487_COPY_AB_TO_NV); | |
| 128 | } | |
| 129 | ||
| 130 | static const struct spi_device_id max5487_id[] = { | |
| 131 | { "MAX5487", 10 }, | |
| 132 | { "MAX5488", 50 }, | |
| 133 | { "MAX5489", 100 }, | |
| 134 | { } | |
| 135 | }; | |
| 136 | MODULE_DEVICE_TABLE(spi, max5487_id); | |
| 137 | ||
| 138 | static const struct acpi_device_id max5487_acpi_match[] = { | |
| 139 | { "MAX5487", 10 }, | |
| 140 | { "MAX5488", 50 }, | |
| 141 | { "MAX5489", 100 }, | |
| 142 | { }, | |
| 143 | }; | |
| 144 | MODULE_DEVICE_TABLE(acpi, max5487_acpi_match); | |
| 145 | ||
| 146 | static struct spi_driver max5487_driver = { | |
| 147 | .driver = { | |
| 148 | .name = "max5487", | |
| 9a47894f CM |
149 | .acpi_match_table = ACPI_PTR(max5487_acpi_match), |
| 150 | }, | |
| 151 | .id_table = max5487_id, | |
| 152 | .probe = max5487_spi_probe, | |
| 153 | .remove = max5487_spi_remove | |
| 154 | }; | |
| 155 | module_spi_driver(max5487_driver); | |
| 156 | ||
| 157 | MODULE_AUTHOR("Cristina-Gabriela Moraru <cristina.moraru09@gmail.com>"); | |
| 158 | MODULE_DESCRIPTION("max5487 SPI driver"); | |
| 159 | MODULE_LICENSE("GPL v2"); |