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 }; 43 44 struct max517_data { 45 struct i2c_client *client; 46 unsigned short vref_mv[2]; 47 }; 48 49 /* 50 * channel: bit 0: channel 1 51 * bit 1: channel 2 52 * (this way, it's possible to set both channels at once) 53 */ 54 static int max517_set_value(struct iio_dev *indio_dev, 55 long val, int channel) 56 { 57 struct max517_data *data = iio_priv(indio_dev); 58 struct i2c_client *client = data->client; 59 u8 outbuf[2]; 60 int res; 61 62 if (val < 0 || val > 255) 63 return -EINVAL; 64 65 outbuf[0] = channel; 66 outbuf[1] = val; 67 68 res = i2c_master_send(client, outbuf, 2); 69 if (res < 0) 70 return res; 71 else if (res != 2) 72 return -EIO; 73 else 74 return 0; 75 } 76 77 static int max517_read_raw(struct iio_dev *indio_dev, 78 struct iio_chan_spec const *chan, 79 int *val, 80 int *val2, 81 long m) 82 { 83 struct max517_data *data = iio_priv(indio_dev); 84 85 switch (m) { 86 case IIO_CHAN_INFO_SCALE: 87 /* Corresponds to Vref / 2^(bits) */ 88 *val = data->vref_mv[chan->channel]; 89 *val2 = 8; 90 return IIO_VAL_FRACTIONAL_LOG2; 91 default: 92 break; 93 } 94 return -EINVAL; 95 } 96 97 static int max517_write_raw(struct iio_dev *indio_dev, 98 struct iio_chan_spec const *chan, int val, int val2, long mask) 99 { 100 int ret; 101 102 switch (mask) { 103 case IIO_CHAN_INFO_RAW: 104 ret = max517_set_value(indio_dev, val, chan->channel); 105 break; 106 default: 107 ret = -EINVAL; 108 break; 109 } 110 111 return ret; 112 } 113 114 #ifdef CONFIG_PM_SLEEP 115 static int max517_suspend(struct device *dev) 116 { 117 u8 outbuf = COMMAND_PD; 118 119 return i2c_master_send(to_i2c_client(dev), &outbuf, 1); 120 } 121 122 static int max517_resume(struct device *dev) 123 { 124 u8 outbuf = 0; 125 126 return i2c_master_send(to_i2c_client(dev), &outbuf, 1); 127 } 128 129 static SIMPLE_DEV_PM_OPS(max517_pm_ops, max517_suspend, max517_resume); 130 #define MAX517_PM_OPS (&max517_pm_ops) 131 #else 132 #define MAX517_PM_OPS NULL 133 #endif 134 135 static const struct iio_info max517_info = { 136 .read_raw = max517_read_raw, 137 .write_raw = max517_write_raw, 138 .driver_module = THIS_MODULE, 139 }; 140 141 #define MAX517_CHANNEL(chan) { \ 142 .type = IIO_VOLTAGE, \ 143 .indexed = 1, \ 144 .output = 1, \ 145 .channel = (chan), \ 146 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | \ 147 BIT(IIO_CHAN_INFO_SCALE), \ 148 } 149 150 static const struct iio_chan_spec max517_channels[] = { 151 MAX517_CHANNEL(0), 152 MAX517_CHANNEL(1) 153 }; 154 155 static int max517_probe(struct i2c_client *client, 156 const struct i2c_device_id *id) 157 { 158 struct max517_data *data; 159 struct iio_dev *indio_dev; 160 struct max517_platform_data *platform_data = client->dev.platform_data; 161 162 indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data)); 163 if (!indio_dev) 164 return -ENOMEM; 165 data = iio_priv(indio_dev); 166 i2c_set_clientdata(client, indio_dev); 167 data->client = client; 168 169 /* establish that the iio_dev is a child of the i2c device */ 170 indio_dev->dev.parent = &client->dev; 171 172 /* reduced channel set for MAX517 */ 173 if (id->driver_data == ID_MAX517) 174 indio_dev->num_channels = 1; 175 else 176 indio_dev->num_channels = 2; 177 indio_dev->channels = max517_channels; 178 indio_dev->modes = INDIO_DIRECT_MODE; 179 indio_dev->info = &max517_info; 180 181 /* 182 * Reference voltage on MAX518 and default is 5V, else take vref_mv 183 * from platform_data 184 */ 185 if (id->driver_data == ID_MAX518 || !platform_data) { 186 data->vref_mv[0] = data->vref_mv[1] = 5000; /* mV */ 187 } else { 188 data->vref_mv[0] = platform_data->vref_mv[0]; 189 data->vref_mv[1] = platform_data->vref_mv[1]; 190 } 191 192 return iio_device_register(indio_dev); 193 } 194 195 static int max517_remove(struct i2c_client *client) 196 { 197 iio_device_unregister(i2c_get_clientdata(client)); 198 return 0; 199 } 200 201 static const struct i2c_device_id max517_id[] = { 202 { "max517", ID_MAX517 }, 203 { "max518", ID_MAX518 }, 204 { "max519", ID_MAX519 }, 205 { } 206 }; 207 MODULE_DEVICE_TABLE(i2c, max517_id); 208 209 static struct i2c_driver max517_driver = { 210 .driver = { 211 .name = MAX517_DRV_NAME, 212 .pm = MAX517_PM_OPS, 213 }, 214 .probe = max517_probe, 215 .remove = max517_remove, 216 .id_table = max517_id, 217 }; 218 module_i2c_driver(max517_driver); 219 220 MODULE_AUTHOR("Roland Stigge <stigge@antcom.de>"); 221 MODULE_DESCRIPTION("MAX517/MAX518/MAX519 8-bit DAC"); 222 MODULE_LICENSE("GPL"); 223