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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 | // SPDX-License-Identifier: GPL-2.0 /* * Industrial I/O driver for Microchip digital potentiometers * * Copyright (c) 2018 Chris Coffey <cmc@babblebit.net> * Based on: Slawomir Stepien's code from mcp4131.c * * Datasheet: http://ww1.microchip.com/downloads/en/devicedoc/11195c.pdf * * DEVID #Wipers #Positions Resistance (kOhm) * mcp41010 1 256 10 * mcp41050 1 256 50 * mcp41100 1 256 100 * mcp42010 2 256 10 * mcp42050 2 256 50 * mcp42100 2 256 100 */ #include <linux/cache.h> #include <linux/err.h> #include <linux/iio/iio.h> #include <linux/iio/types.h> #include <linux/module.h> #include <linux/mutex.h> #include <linux/of.h> #include <linux/of_device.h> #include <linux/spi/spi.h> #define MCP41010_MAX_WIPERS 2 #define MCP41010_WRITE BIT(4) #define MCP41010_WIPER_MAX 255 #define MCP41010_WIPER_CHANNEL BIT(0) struct mcp41010_cfg { char name[16]; int wipers; int kohms; }; enum mcp41010_type { MCP41010, MCP41050, MCP41100, MCP42010, MCP42050, MCP42100, }; static const struct mcp41010_cfg mcp41010_cfg[] = { [MCP41010] = { .name = "mcp41010", .wipers = 1, .kohms = 10, }, [MCP41050] = { .name = "mcp41050", .wipers = 1, .kohms = 50, }, [MCP41100] = { .name = "mcp41100", .wipers = 1, .kohms = 100, }, [MCP42010] = { .name = "mcp42010", .wipers = 2, .kohms = 10, }, [MCP42050] = { .name = "mcp42050", .wipers = 2, .kohms = 50, }, [MCP42100] = { .name = "mcp42100", .wipers = 2, .kohms = 100, }, }; struct mcp41010_data { struct spi_device *spi; const struct mcp41010_cfg *cfg; struct mutex lock; /* Protect write sequences */ unsigned int value[MCP41010_MAX_WIPERS]; /* Cache wiper values */ u8 buf[2] ____cacheline_aligned; }; #define MCP41010_CHANNEL(ch) { \ .type = IIO_RESISTANCE, \ .indexed = 1, \ .output = 1, \ .channel = (ch), \ .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \ .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \ } static const struct iio_chan_spec mcp41010_channels[] = { MCP41010_CHANNEL(0), MCP41010_CHANNEL(1), }; static int mcp41010_read_raw(struct iio_dev *indio_dev, struct iio_chan_spec const *chan, int *val, int *val2, long mask) { struct mcp41010_data *data = iio_priv(indio_dev); int channel = chan->channel; switch (mask) { case IIO_CHAN_INFO_RAW: *val = data->value[channel]; return IIO_VAL_INT; case IIO_CHAN_INFO_SCALE: *val = 1000 * data->cfg->kohms; *val2 = MCP41010_WIPER_MAX; return IIO_VAL_FRACTIONAL; } return -EINVAL; } static int mcp41010_write_raw(struct iio_dev *indio_dev, struct iio_chan_spec const *chan, int val, int val2, long mask) { int err; struct mcp41010_data *data = iio_priv(indio_dev); int channel = chan->channel; if (mask != IIO_CHAN_INFO_RAW) return -EINVAL; if (val > MCP41010_WIPER_MAX || val < 0) return -EINVAL; mutex_lock(&data->lock); data->buf[0] = MCP41010_WIPER_CHANNEL << channel; data->buf[0] |= MCP41010_WRITE; data->buf[1] = val & 0xff; err = spi_write(data->spi, data->buf, sizeof(data->buf)); if (!err) data->value[channel] = val; mutex_unlock(&data->lock); return err; } static const struct iio_info mcp41010_info = { .read_raw = mcp41010_read_raw, .write_raw = mcp41010_write_raw, }; static int mcp41010_probe(struct spi_device *spi) { int err; struct device *dev = &spi->dev; struct mcp41010_data *data; struct iio_dev *indio_dev; indio_dev = devm_iio_device_alloc(dev, sizeof(*data)); if (!indio_dev) return -ENOMEM; data = iio_priv(indio_dev); spi_set_drvdata(spi, indio_dev); data->spi = spi; data->cfg = of_device_get_match_data(&spi->dev); if (!data->cfg) data->cfg = &mcp41010_cfg[spi_get_device_id(spi)->driver_data]; mutex_init(&data->lock); indio_dev->dev.parent = dev; indio_dev->info = &mcp41010_info; indio_dev->channels = mcp41010_channels; indio_dev->num_channels = data->cfg->wipers; indio_dev->name = data->cfg->name; err = devm_iio_device_register(dev, indio_dev); if (err) dev_info(&spi->dev, "Unable to register %s\n", indio_dev->name); return err; } static const struct of_device_id mcp41010_match[] = { { .compatible = "microchip,mcp41010", .data = &mcp41010_cfg[MCP41010] }, { .compatible = "microchip,mcp41050", .data = &mcp41010_cfg[MCP41050] }, { .compatible = "microchip,mcp41100", .data = &mcp41010_cfg[MCP41100] }, { .compatible = "microchip,mcp42010", .data = &mcp41010_cfg[MCP42010] }, { .compatible = "microchip,mcp42050", .data = &mcp41010_cfg[MCP42050] }, { .compatible = "microchip,mcp42100", .data = &mcp41010_cfg[MCP42100] }, {} }; MODULE_DEVICE_TABLE(of, mcp41010_match); static const struct spi_device_id mcp41010_id[] = { { "mcp41010", MCP41010 }, { "mcp41050", MCP41050 }, { "mcp41100", MCP41100 }, { "mcp42010", MCP42010 }, { "mcp42050", MCP42050 }, { "mcp42100", MCP42100 }, {} }; MODULE_DEVICE_TABLE(spi, mcp41010_id); static struct spi_driver mcp41010_driver = { .driver = { .name = "mcp41010", .of_match_table = mcp41010_match, }, .probe = mcp41010_probe, .id_table = mcp41010_id, }; module_spi_driver(mcp41010_driver); MODULE_AUTHOR("Chris Coffey <cmc@babblebit.net>"); MODULE_DESCRIPTION("MCP41010 digital potentiometer"); MODULE_LICENSE("GPL v2"); |