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/init.h> 23 #include <linux/slab.h> 24 #include <linux/jiffies.h> 25 #include <linux/i2c.h> 26 #include <linux/err.h> 27 28 #include <linux/iio/iio.h> 29 #include <linux/iio/sysfs.h> 30 #include <linux/iio/dac/max517.h> 31 32 #define MAX517_DRV_NAME "max517" 33 34 /* Commands */ 35 #define COMMAND_CHANNEL0 0x00 36 #define COMMAND_CHANNEL1 0x01 /* for MAX518 and MAX519 */ 37 #define COMMAND_PD 0x08 /* Power Down */ 38 39 enum max517_device_ids { 40 ID_MAX517, 41 ID_MAX518, 42 ID_MAX519, 43 }; 44 45 struct max517_data { 46 struct i2c_client *client; 47 unsigned short vref_mv[2]; 48 }; 49 50 /* 51 * channel: bit 0: channel 1 52 * bit 1: channel 2 53 * (this way, it's possible to set both channels at once) 54 */ 55 static int max517_set_value(struct iio_dev *indio_dev, 56 long val, int channel) 57 { 58 struct max517_data *data = iio_priv(indio_dev); 59 struct i2c_client *client = data->client; 60 u8 outbuf[2]; 61 int res; 62 63 if (val < 0 || val > 255) 64 return -EINVAL; 65 66 outbuf[0] = channel; 67 outbuf[1] = val; 68 69 res = i2c_master_send(client, outbuf, 2); 70 if (res < 0) 71 return res; 72 else if (res != 2) 73 return -EIO; 74 else 75 return 0; 76 } 77 78 static int max517_read_raw(struct iio_dev *indio_dev, 79 struct iio_chan_spec const *chan, 80 int *val, 81 int *val2, 82 long m) 83 { 84 struct max517_data *data = iio_priv(indio_dev); 85 unsigned int scale_uv; 86 87 switch (m) { 88 case IIO_CHAN_INFO_SCALE: 89 /* Corresponds to Vref / 2^(bits) */ 90 scale_uv = (data->vref_mv[chan->channel] * 1000) >> 8; 91 *val = scale_uv / 1000000; 92 *val2 = scale_uv % 1000000; 93 return IIO_VAL_INT_PLUS_MICRO; 94 default: 95 break; 96 } 97 return -EINVAL; 98 } 99 100 static int max517_write_raw(struct iio_dev *indio_dev, 101 struct iio_chan_spec const *chan, int val, int val2, long mask) 102 { 103 int ret; 104 105 switch (mask) { 106 case IIO_CHAN_INFO_RAW: 107 ret = max517_set_value(indio_dev, val, chan->channel); 108 break; 109 default: 110 ret = -EINVAL; 111 break; 112 } 113 114 return ret; 115 } 116 117 #ifdef CONFIG_PM_SLEEP 118 static int max517_suspend(struct device *dev) 119 { 120 u8 outbuf = COMMAND_PD; 121 122 return i2c_master_send(to_i2c_client(dev), &outbuf, 1); 123 } 124 125 static int max517_resume(struct device *dev) 126 { 127 u8 outbuf = 0; 128 129 return i2c_master_send(to_i2c_client(dev), &outbuf, 1); 130 } 131 132 static SIMPLE_DEV_PM_OPS(max517_pm_ops, max517_suspend, max517_resume); 133 #define MAX517_PM_OPS (&max517_pm_ops) 134 #else 135 #define MAX517_PM_OPS NULL 136 #endif 137 138 static const struct iio_info max517_info = { 139 .read_raw = max517_read_raw, 140 .write_raw = max517_write_raw, 141 .driver_module = THIS_MODULE, 142 }; 143 144 #define MAX517_CHANNEL(chan) { \ 145 .type = IIO_VOLTAGE, \ 146 .indexed = 1, \ 147 .output = 1, \ 148 .channel = (chan), \ 149 .info_mask = IIO_CHAN_INFO_RAW_SEPARATE_BIT | \ 150 IIO_CHAN_INFO_SCALE_SEPARATE_BIT, \ 151 .scan_type = IIO_ST('u', 8, 8, 0), \ 152 } 153 154 static const struct iio_chan_spec max517_channels[] = { 155 MAX517_CHANNEL(0), 156 MAX517_CHANNEL(1) 157 }; 158 159 static int max517_probe(struct i2c_client *client, 160 const struct i2c_device_id *id) 161 { 162 struct max517_data *data; 163 struct iio_dev *indio_dev; 164 struct max517_platform_data *platform_data = client->dev.platform_data; 165 int err; 166 167 indio_dev = iio_device_alloc(sizeof(*data)); 168 if (indio_dev == NULL) { 169 err = -ENOMEM; 170 goto exit; 171 } 172 data = iio_priv(indio_dev); 173 i2c_set_clientdata(client, indio_dev); 174 data->client = client; 175 176 /* establish that the iio_dev is a child of the i2c device */ 177 indio_dev->dev.parent = &client->dev; 178 179 /* reduced channel set for MAX517 */ 180 if (id->driver_data == ID_MAX517) 181 indio_dev->num_channels = 1; 182 else 183 indio_dev->num_channels = 2; 184 indio_dev->channels = max517_channels; 185 indio_dev->modes = INDIO_DIRECT_MODE; 186 indio_dev->info = &max517_info; 187 188 /* 189 * Reference voltage on MAX518 and default is 5V, else take vref_mv 190 * from platform_data 191 */ 192 if (id->driver_data == ID_MAX518 || !platform_data) { 193 data->vref_mv[0] = data->vref_mv[1] = 5000; /* mV */ 194 } else { 195 data->vref_mv[0] = platform_data->vref_mv[0]; 196 data->vref_mv[1] = platform_data->vref_mv[1]; 197 } 198 199 err = iio_device_register(indio_dev); 200 if (err) 201 goto exit_free_device; 202 203 dev_info(&client->dev, "DAC registered\n"); 204 205 return 0; 206 207 exit_free_device: 208 iio_device_free(indio_dev); 209 exit: 210 return err; 211 } 212 213 static int max517_remove(struct i2c_client *client) 214 { 215 iio_device_unregister(i2c_get_clientdata(client)); 216 iio_device_free(i2c_get_clientdata(client)); 217 218 return 0; 219 } 220 221 static const struct i2c_device_id max517_id[] = { 222 { "max517", ID_MAX517 }, 223 { "max518", ID_MAX518 }, 224 { "max519", ID_MAX519 }, 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/MAX518/MAX519 8-bit DAC"); 242 MODULE_LICENSE("GPL"); 243