1 /* 2 * max517.c - Support for Maxim MAX517, MAX518 and MAX519 3 * 4 * Copyright (C) 2010, 2011 Roland Stigge <stigge@antcom.de> 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 as published by 8 * the Free Software Foundation; either version 2 of the License, or 9 * (at your option) any later version. 10 * 11 * This program is distributed in the hope that it will be useful, 12 * but WITHOUT ANY WARRANTY; without even the implied warranty of 13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 14 * GNU General Public License for more details. 15 * 16 * You should have received a copy of the GNU General Public License 17 * along with this program; if not, write to the Free Software 18 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. 19 */ 20 21 #include <linux/module.h> 22 #include <linux/slab.h> 23 #include <linux/jiffies.h> 24 #include <linux/i2c.h> 25 #include <linux/err.h> 26 27 #include <linux/iio/iio.h> 28 #include <linux/iio/sysfs.h> 29 #include <linux/iio/dac/max517.h> 30 31 #define MAX517_DRV_NAME "max517" 32 33 /* Commands */ 34 #define COMMAND_CHANNEL0 0x00 35 #define COMMAND_CHANNEL1 0x01 /* for MAX518 and MAX519 */ 36 #define COMMAND_PD 0x08 /* Power Down */ 37 38 enum max517_device_ids { 39 ID_MAX517, 40 ID_MAX518, 41 ID_MAX519, 42 ID_MAX520, 43 ID_MAX521, 44 }; 45 46 struct max517_data { 47 struct i2c_client *client; 48 unsigned short vref_mv[8]; 49 }; 50 51 /* 52 * channel: bit 0: channel 1 53 * bit 1: channel 2 54 * (this way, it's possible to set both channels at once) 55 */ 56 static int max517_set_value(struct iio_dev *indio_dev, 57 long val, int channel) 58 { 59 struct max517_data *data = iio_priv(indio_dev); 60 struct i2c_client *client = data->client; 61 u8 outbuf[2]; 62 int res; 63 64 if (val < 0 || val > 255) 65 return -EINVAL; 66 67 outbuf[0] = channel; 68 outbuf[1] = val; 69 70 res = i2c_master_send(client, outbuf, 2); 71 if (res < 0) 72 return res; 73 else if (res != 2) 74 return -EIO; 75 else 76 return 0; 77 } 78 79 static int max517_read_raw(struct iio_dev *indio_dev, 80 struct iio_chan_spec const *chan, 81 int *val, 82 int *val2, 83 long m) 84 { 85 struct max517_data *data = iio_priv(indio_dev); 86 87 switch (m) { 88 case IIO_CHAN_INFO_SCALE: 89 /* Corresponds to Vref / 2^(bits) */ 90 *val = data->vref_mv[chan->channel]; 91 *val2 = 8; 92 return IIO_VAL_FRACTIONAL_LOG2; 93 default: 94 break; 95 } 96 return -EINVAL; 97 } 98 99 static int max517_write_raw(struct iio_dev *indio_dev, 100 struct iio_chan_spec const *chan, int val, int val2, long mask) 101 { 102 int ret; 103 104 switch (mask) { 105 case IIO_CHAN_INFO_RAW: 106 ret = max517_set_value(indio_dev, val, chan->channel); 107 break; 108 default: 109 ret = -EINVAL; 110 break; 111 } 112 113 return ret; 114 } 115 116 static int __maybe_unused max517_suspend(struct device *dev) 117 { 118 u8 outbuf = COMMAND_PD; 119 120 return i2c_master_send(to_i2c_client(dev), &outbuf, 1); 121 } 122 123 static int __maybe_unused max517_resume(struct device *dev) 124 { 125 u8 outbuf = 0; 126 127 return i2c_master_send(to_i2c_client(dev), &outbuf, 1); 128 } 129 130 static SIMPLE_DEV_PM_OPS(max517_pm_ops, max517_suspend, max517_resume); 131 132 static const struct iio_info max517_info = { 133 .read_raw = max517_read_raw, 134 .write_raw = max517_write_raw, 135 }; 136 137 #define MAX517_CHANNEL(chan) { \ 138 .type = IIO_VOLTAGE, \ 139 .indexed = 1, \ 140 .output = 1, \ 141 .channel = (chan), \ 142 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | \ 143 BIT(IIO_CHAN_INFO_SCALE), \ 144 } 145 146 static const struct iio_chan_spec max517_channels[] = { 147 MAX517_CHANNEL(0), 148 MAX517_CHANNEL(1), 149 MAX517_CHANNEL(2), 150 MAX517_CHANNEL(3), 151 MAX517_CHANNEL(4), 152 MAX517_CHANNEL(5), 153 MAX517_CHANNEL(6), 154 MAX517_CHANNEL(7), 155 }; 156 157 static int max517_probe(struct i2c_client *client, 158 const struct i2c_device_id *id) 159 { 160 struct max517_data *data; 161 struct iio_dev *indio_dev; 162 struct max517_platform_data *platform_data = client->dev.platform_data; 163 int chan; 164 165 indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data)); 166 if (!indio_dev) 167 return -ENOMEM; 168 data = iio_priv(indio_dev); 169 i2c_set_clientdata(client, indio_dev); 170 data->client = client; 171 172 /* establish that the iio_dev is a child of the i2c device */ 173 indio_dev->dev.parent = &client->dev; 174 175 switch (id->driver_data) { 176 case ID_MAX521: 177 indio_dev->num_channels = 8; 178 break; 179 case ID_MAX520: 180 indio_dev->num_channels = 4; 181 break; 182 case ID_MAX519: 183 case ID_MAX518: 184 indio_dev->num_channels = 2; 185 break; 186 default: /* single channel for MAX517 */ 187 indio_dev->num_channels = 1; 188 break; 189 } 190 indio_dev->channels = max517_channels; 191 indio_dev->modes = INDIO_DIRECT_MODE; 192 indio_dev->info = &max517_info; 193 194 /* 195 * Reference voltage on MAX518 and default is 5V, else take vref_mv 196 * from platform_data 197 */ 198 for (chan = 0; chan < indio_dev->num_channels; chan++) { 199 if (id->driver_data == ID_MAX518 || !platform_data) 200 data->vref_mv[chan] = 5000; /* mV */ 201 else 202 data->vref_mv[chan] = platform_data->vref_mv[chan]; 203 } 204 205 return iio_device_register(indio_dev); 206 } 207 208 static int max517_remove(struct i2c_client *client) 209 { 210 iio_device_unregister(i2c_get_clientdata(client)); 211 return 0; 212 } 213 214 static const struct i2c_device_id max517_id[] = { 215 { "max517", ID_MAX517 }, 216 { "max518", ID_MAX518 }, 217 { "max519", ID_MAX519 }, 218 { "max520", ID_MAX520 }, 219 { "max521", ID_MAX521 }, 220 { } 221 }; 222 MODULE_DEVICE_TABLE(i2c, max517_id); 223 224 static struct i2c_driver max517_driver = { 225 .driver = { 226 .name = MAX517_DRV_NAME, 227 .pm = &max517_pm_ops, 228 }, 229 .probe = max517_probe, 230 .remove = max517_remove, 231 .id_table = max517_id, 232 }; 233 module_i2c_driver(max517_driver); 234 235 MODULE_AUTHOR("Roland Stigge <stigge@antcom.de>"); 236 MODULE_DESCRIPTION("MAX517/518/519/520/521 8-bit DAC"); 237 MODULE_LICENSE("GPL"); 238