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 #ifdef CONFIG_PM_SLEEP 117 static int max517_suspend(struct device *dev) 118 { 119 u8 outbuf = COMMAND_PD; 120 121 return i2c_master_send(to_i2c_client(dev), &outbuf, 1); 122 } 123 124 static int max517_resume(struct device *dev) 125 { 126 u8 outbuf = 0; 127 128 return i2c_master_send(to_i2c_client(dev), &outbuf, 1); 129 } 130 131 static SIMPLE_DEV_PM_OPS(max517_pm_ops, max517_suspend, max517_resume); 132 #define MAX517_PM_OPS (&max517_pm_ops) 133 #else 134 #define MAX517_PM_OPS NULL 135 #endif 136 137 static const struct iio_info max517_info = { 138 .read_raw = max517_read_raw, 139 .write_raw = max517_write_raw, 140 }; 141 142 #define MAX517_CHANNEL(chan) { \ 143 .type = IIO_VOLTAGE, \ 144 .indexed = 1, \ 145 .output = 1, \ 146 .channel = (chan), \ 147 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | \ 148 BIT(IIO_CHAN_INFO_SCALE), \ 149 } 150 151 static const struct iio_chan_spec max517_channels[] = { 152 MAX517_CHANNEL(0), 153 MAX517_CHANNEL(1), 154 MAX517_CHANNEL(2), 155 MAX517_CHANNEL(3), 156 MAX517_CHANNEL(4), 157 MAX517_CHANNEL(5), 158 MAX517_CHANNEL(6), 159 MAX517_CHANNEL(7), 160 }; 161 162 static int max517_probe(struct i2c_client *client, 163 const struct i2c_device_id *id) 164 { 165 struct max517_data *data; 166 struct iio_dev *indio_dev; 167 struct max517_platform_data *platform_data = client->dev.platform_data; 168 int chan; 169 170 indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data)); 171 if (!indio_dev) 172 return -ENOMEM; 173 data = iio_priv(indio_dev); 174 i2c_set_clientdata(client, indio_dev); 175 data->client = client; 176 177 /* establish that the iio_dev is a child of the i2c device */ 178 indio_dev->dev.parent = &client->dev; 179 180 switch (id->driver_data) { 181 case ID_MAX521: 182 indio_dev->num_channels = 8; 183 break; 184 case ID_MAX520: 185 indio_dev->num_channels = 4; 186 break; 187 case ID_MAX519: 188 case ID_MAX518: 189 indio_dev->num_channels = 2; 190 break; 191 default: /* single channel for MAX517 */ 192 indio_dev->num_channels = 1; 193 break; 194 } 195 indio_dev->channels = max517_channels; 196 indio_dev->modes = INDIO_DIRECT_MODE; 197 indio_dev->info = &max517_info; 198 199 /* 200 * Reference voltage on MAX518 and default is 5V, else take vref_mv 201 * from platform_data 202 */ 203 for (chan = 0; chan < indio_dev->num_channels; chan++) { 204 if (id->driver_data == ID_MAX518 || !platform_data) 205 data->vref_mv[chan] = 5000; /* mV */ 206 else 207 data->vref_mv[chan] = platform_data->vref_mv[chan]; 208 } 209 210 return iio_device_register(indio_dev); 211 } 212 213 static int max517_remove(struct i2c_client *client) 214 { 215 iio_device_unregister(i2c_get_clientdata(client)); 216 return 0; 217 } 218 219 static const struct i2c_device_id max517_id[] = { 220 { "max517", ID_MAX517 }, 221 { "max518", ID_MAX518 }, 222 { "max519", ID_MAX519 }, 223 { "max520", ID_MAX520 }, 224 { "max521", ID_MAX521 }, 225 { } 226 }; 227 MODULE_DEVICE_TABLE(i2c, max517_id); 228 229 static struct i2c_driver max517_driver = { 230 .driver = { 231 .name = MAX517_DRV_NAME, 232 .pm = MAX517_PM_OPS, 233 }, 234 .probe = max517_probe, 235 .remove = max517_remove, 236 .id_table = max517_id, 237 }; 238 module_i2c_driver(max517_driver); 239 240 MODULE_AUTHOR("Roland Stigge <stigge@antcom.de>"); 241 MODULE_DESCRIPTION("MAX517/518/519/520/521 8-bit DAC"); 242 MODULE_LICENSE("GPL"); 243