1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * max517.c - Support for Maxim MAX517, MAX518 and MAX519 4 * 5 * Copyright (C) 2010, 2011 Roland Stigge <stigge@antcom.de> 6 */ 7 8 #include <linux/module.h> 9 #include <linux/slab.h> 10 #include <linux/jiffies.h> 11 #include <linux/i2c.h> 12 #include <linux/err.h> 13 14 #include <linux/iio/iio.h> 15 #include <linux/iio/sysfs.h> 16 #include <linux/iio/dac/max517.h> 17 18 #define MAX517_DRV_NAME "max517" 19 20 /* Commands */ 21 #define COMMAND_CHANNEL0 0x00 22 #define COMMAND_CHANNEL1 0x01 /* for MAX518 and MAX519 */ 23 #define COMMAND_PD 0x08 /* Power Down */ 24 25 enum max517_device_ids { 26 ID_MAX517, 27 ID_MAX518, 28 ID_MAX519, 29 ID_MAX520, 30 ID_MAX521, 31 }; 32 33 struct max517_data { 34 struct i2c_client *client; 35 unsigned short vref_mv[8]; 36 }; 37 38 /* 39 * channel: bit 0: channel 1 40 * bit 1: channel 2 41 * (this way, it's possible to set both channels at once) 42 */ 43 static int max517_set_value(struct iio_dev *indio_dev, 44 long val, int channel) 45 { 46 struct max517_data *data = iio_priv(indio_dev); 47 struct i2c_client *client = data->client; 48 u8 outbuf[2]; 49 int res; 50 51 if (val < 0 || val > 255) 52 return -EINVAL; 53 54 outbuf[0] = channel; 55 outbuf[1] = val; 56 57 res = i2c_master_send(client, outbuf, 2); 58 if (res < 0) 59 return res; 60 else if (res != 2) 61 return -EIO; 62 else 63 return 0; 64 } 65 66 static int max517_read_raw(struct iio_dev *indio_dev, 67 struct iio_chan_spec const *chan, 68 int *val, 69 int *val2, 70 long m) 71 { 72 struct max517_data *data = iio_priv(indio_dev); 73 74 switch (m) { 75 case IIO_CHAN_INFO_SCALE: 76 /* Corresponds to Vref / 2^(bits) */ 77 *val = data->vref_mv[chan->channel]; 78 *val2 = 8; 79 return IIO_VAL_FRACTIONAL_LOG2; 80 default: 81 break; 82 } 83 return -EINVAL; 84 } 85 86 static int max517_write_raw(struct iio_dev *indio_dev, 87 struct iio_chan_spec const *chan, int val, int val2, long mask) 88 { 89 int ret; 90 91 switch (mask) { 92 case IIO_CHAN_INFO_RAW: 93 ret = max517_set_value(indio_dev, val, chan->channel); 94 break; 95 default: 96 ret = -EINVAL; 97 break; 98 } 99 100 return ret; 101 } 102 103 static int __maybe_unused max517_suspend(struct device *dev) 104 { 105 u8 outbuf = COMMAND_PD; 106 107 return i2c_master_send(to_i2c_client(dev), &outbuf, 1); 108 } 109 110 static int __maybe_unused max517_resume(struct device *dev) 111 { 112 u8 outbuf = 0; 113 114 return i2c_master_send(to_i2c_client(dev), &outbuf, 1); 115 } 116 117 static SIMPLE_DEV_PM_OPS(max517_pm_ops, max517_suspend, max517_resume); 118 119 static const struct iio_info max517_info = { 120 .read_raw = max517_read_raw, 121 .write_raw = max517_write_raw, 122 }; 123 124 #define MAX517_CHANNEL(chan) { \ 125 .type = IIO_VOLTAGE, \ 126 .indexed = 1, \ 127 .output = 1, \ 128 .channel = (chan), \ 129 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | \ 130 BIT(IIO_CHAN_INFO_SCALE), \ 131 } 132 133 static const struct iio_chan_spec max517_channels[] = { 134 MAX517_CHANNEL(0), 135 MAX517_CHANNEL(1), 136 MAX517_CHANNEL(2), 137 MAX517_CHANNEL(3), 138 MAX517_CHANNEL(4), 139 MAX517_CHANNEL(5), 140 MAX517_CHANNEL(6), 141 MAX517_CHANNEL(7), 142 }; 143 144 static int max517_probe(struct i2c_client *client, 145 const struct i2c_device_id *id) 146 { 147 struct max517_data *data; 148 struct iio_dev *indio_dev; 149 struct max517_platform_data *platform_data = client->dev.platform_data; 150 int chan; 151 152 indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data)); 153 if (!indio_dev) 154 return -ENOMEM; 155 data = iio_priv(indio_dev); 156 data->client = client; 157 158 switch (id->driver_data) { 159 case ID_MAX521: 160 indio_dev->num_channels = 8; 161 break; 162 case ID_MAX520: 163 indio_dev->num_channels = 4; 164 break; 165 case ID_MAX519: 166 case ID_MAX518: 167 indio_dev->num_channels = 2; 168 break; 169 default: /* single channel for MAX517 */ 170 indio_dev->num_channels = 1; 171 break; 172 } 173 indio_dev->channels = max517_channels; 174 indio_dev->modes = INDIO_DIRECT_MODE; 175 indio_dev->info = &max517_info; 176 177 /* 178 * Reference voltage on MAX518 and default is 5V, else take vref_mv 179 * from platform_data 180 */ 181 for (chan = 0; chan < indio_dev->num_channels; chan++) { 182 if (id->driver_data == ID_MAX518 || !platform_data) 183 data->vref_mv[chan] = 5000; /* mV */ 184 else 185 data->vref_mv[chan] = platform_data->vref_mv[chan]; 186 } 187 188 return devm_iio_device_register(&client->dev, indio_dev); 189 } 190 191 static const struct i2c_device_id max517_id[] = { 192 { "max517", ID_MAX517 }, 193 { "max518", ID_MAX518 }, 194 { "max519", ID_MAX519 }, 195 { "max520", ID_MAX520 }, 196 { "max521", ID_MAX521 }, 197 { } 198 }; 199 MODULE_DEVICE_TABLE(i2c, max517_id); 200 201 static struct i2c_driver max517_driver = { 202 .driver = { 203 .name = MAX517_DRV_NAME, 204 .pm = &max517_pm_ops, 205 }, 206 .probe = max517_probe, 207 .id_table = max517_id, 208 }; 209 module_i2c_driver(max517_driver); 210 211 MODULE_AUTHOR("Roland Stigge <stigge@antcom.de>"); 212 MODULE_DESCRIPTION("MAX517/518/519/520/521 8-bit DAC"); 213 MODULE_LICENSE("GPL"); 214