iio/dac/max517.c

0001 // SPDX-License-Identifier: GPL-2.0-or-later
0002 /*
0003  *  max517.c - Support for Maxim MAX517, MAX518 and MAX519
0004  *
0005  *  Copyright (C) 2010, 2011 Roland Stigge <stigge@antcom.de>
0006  */
0007
0008 #include <linux/module.h>
0009 #include <linux/slab.h>
0010 #include <linux/jiffies.h>
0011 #include <linux/i2c.h>
0012 #include <linux/err.h>
0013
0014 #include <linux/iio/iio.h>
0015 #include <linux/iio/sysfs.h>
0016 #include <linux/iio/dac/max517.h>
0017
0018 #define MAX517_DRV_NAME "max517"
0019
0020 /* Commands */
0021 #define COMMAND_CHANNEL0    0x00
0022 #define COMMAND_CHANNEL1    0x01 /* for MAX518 and MAX519 */
0023 #define COMMAND_PD      0x08 /* Power Down */
0024
0025 enum max517_device_ids {
0026     ID_MAX517,
0027     ID_MAX518,
0028     ID_MAX519,
0029     ID_MAX520,
0030     ID_MAX521,
0031 };
0032
0033 struct max517_data {
0034     struct i2c_client   *client;
0035     unsigned short      vref_mv[8];
0036 };
0037
0038 /*
0039  * channel: bit 0: channel 1
0040  *          bit 1: channel 2
0041  * (this way, it's possible to set both channels at once)
0042  */
0043 static int max517_set_value(struct iio_dev *indio_dev,
0044     long val, int channel)
0045 {
0046     struct max517_data *data = iio_priv(indio_dev);
0047     struct i2c_client *client = data->client;
0048     u8 outbuf[2];
0049     int res;
0050
0051     if (val < 0 || val > 255)
0052         return -EINVAL;
0053
0054     outbuf[0] = channel;
0055     outbuf[1] = val;
0056
0057     res = i2c_master_send(client, outbuf, 2);
0058     if (res < 0)
0059         return res;
0060     else if (res != 2)
0061         return -EIO;
0062     else
0063         return 0;
0064 }
0065
0066 static int max517_read_raw(struct iio_dev *indio_dev,
0067                struct iio_chan_spec const *chan,
0068                int *val,
0069                int *val2,
0070                long m)
0071 {
0072     struct max517_data *data = iio_priv(indio_dev);
0073
0074     switch (m) {
0075     case IIO_CHAN_INFO_SCALE:
0076         /* Corresponds to Vref / 2^(bits) */
0077         *val = data->vref_mv[chan->channel];
0078         *val2 = 8;
0079         return IIO_VAL_FRACTIONAL_LOG2;
0080     default:
0081         break;
0082     }
0083     return -EINVAL;
0084 }
0085
0086 static int max517_write_raw(struct iio_dev *indio_dev,
0087     struct iio_chan_spec const *chan, int val, int val2, long mask)
0088 {
0089     int ret;
0090
0091     switch (mask) {
0092     case IIO_CHAN_INFO_RAW:
0093         ret = max517_set_value(indio_dev, val, chan->channel);
0094         break;
0095     default:
0096         ret = -EINVAL;
0097         break;
0098     }
0099
0100     return ret;
0101 }
0102
0103 static int max517_suspend(struct device *dev)
0104 {
0105     u8 outbuf = COMMAND_PD;
0106
0107     return i2c_master_send(to_i2c_client(dev), &outbuf, 1);
0108 }
0109
0110 static int max517_resume(struct device *dev)
0111 {
0112     u8 outbuf = 0;
0113
0114     return i2c_master_send(to_i2c_client(dev), &outbuf, 1);
0115 }
0116
0117 static DEFINE_SIMPLE_DEV_PM_OPS(max517_pm_ops, max517_suspend, max517_resume);
0118
0119 static const struct iio_info max517_info = {
0120     .read_raw = max517_read_raw,
0121     .write_raw = max517_write_raw,
0122 };
0123
0124 #define MAX517_CHANNEL(chan) {              \
0125     .type = IIO_VOLTAGE,                \
0126     .indexed = 1,                   \
0127     .output = 1,                    \
0128     .channel = (chan),              \
0129     .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |  \
0130     BIT(IIO_CHAN_INFO_SCALE),           \
0131 }
0132
0133 static const struct iio_chan_spec max517_channels[] = {
0134     MAX517_CHANNEL(0),
0135     MAX517_CHANNEL(1),
0136     MAX517_CHANNEL(2),
0137     MAX517_CHANNEL(3),
0138     MAX517_CHANNEL(4),
0139     MAX517_CHANNEL(5),
0140     MAX517_CHANNEL(6),
0141     MAX517_CHANNEL(7),
0142 };
0143
0144 static int max517_probe(struct i2c_client *client,
0145             const struct i2c_device_id *id)
0146 {
0147     struct max517_data *data;
0148     struct iio_dev *indio_dev;
0149     struct max517_platform_data *platform_data = client->dev.platform_data;
0150     int chan;
0151
0152     indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
0153     if (!indio_dev)
0154         return -ENOMEM;
0155     data = iio_priv(indio_dev);
0156     data->client = client;
0157
0158     switch (id->driver_data) {
0159     case ID_MAX521:
0160         indio_dev->num_channels = 8;
0161         break;
0162     case ID_MAX520:
0163         indio_dev->num_channels = 4;
0164         break;
0165     case ID_MAX519:
0166     case ID_MAX518:
0167         indio_dev->num_channels = 2;
0168         break;
0169     default:  /* single channel for MAX517 */
0170         indio_dev->num_channels = 1;
0171         break;
0172     }
0173     indio_dev->channels = max517_channels;
0174     indio_dev->modes = INDIO_DIRECT_MODE;
0175     indio_dev->info = &max517_info;
0176
0177     /*
0178      * Reference voltage on MAX518 and default is 5V, else take vref_mv
0179      * from platform_data
0180      */
0181     for (chan = 0; chan < indio_dev->num_channels; chan++) {
0182         if (id->driver_data == ID_MAX518 || !platform_data)
0183             data->vref_mv[chan] = 5000; /* mV */
0184         else
0185             data->vref_mv[chan] = platform_data->vref_mv[chan];
0186     }
0187
0188     return devm_iio_device_register(&client->dev, indio_dev);
0189 }
0190
0191 static const struct i2c_device_id max517_id[] = {
0192     { "max517", ID_MAX517 },
0193     { "max518", ID_MAX518 },
0194     { "max519", ID_MAX519 },
0195     { "max520", ID_MAX520 },
0196     { "max521", ID_MAX521 },
0197     { }
0198 };
0199 MODULE_DEVICE_TABLE(i2c, max517_id);
0200
0201 static struct i2c_driver max517_driver = {
0202     .driver = {
0203         .name   = MAX517_DRV_NAME,
0204         .pm = pm_sleep_ptr(&max517_pm_ops),
0205     },
0206     .probe      = max517_probe,
0207     .id_table   = max517_id,
0208 };
0209 module_i2c_driver(max517_driver);
0210
0211 MODULE_AUTHOR("Roland Stigge <stigge@antcom.de>");
0212 MODULE_DESCRIPTION("MAX517/518/519/520/521 8-bit DAC");
0213 MODULE_LICENSE("GPL");