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 86 switch (m) { 87 case IIO_CHAN_INFO_SCALE: 88 /* Corresponds to Vref / 2^(bits) */ 89 *val = data->vref_mv[chan->channel]; 90 *val2 = 8; 91 return IIO_VAL_FRACTIONAL_LOG2; 92 default: 93 break; 94 } 95 return -EINVAL; 96 } 97 98 static int max517_write_raw(struct iio_dev *indio_dev, 99 struct iio_chan_spec const *chan, int val, int val2, long mask) 100 { 101 int ret; 102 103 switch (mask) { 104 case IIO_CHAN_INFO_RAW: 105 ret = max517_set_value(indio_dev, val, chan->channel); 106 break; 107 default: 108 ret = -EINVAL; 109 break; 110 } 111 112 return ret; 113 } 114 115 #ifdef CONFIG_PM_SLEEP 116 static int 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 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 #define MAX517_PM_OPS (&max517_pm_ops) 132 #else 133 #define MAX517_PM_OPS NULL 134 #endif 135 136 static const struct iio_info max517_info = { 137 .read_raw = max517_read_raw, 138 .write_raw = max517_write_raw, 139 .driver_module = THIS_MODULE, 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 }; 155 156 static int max517_probe(struct i2c_client *client, 157 const struct i2c_device_id *id) 158 { 159 struct max517_data *data; 160 struct iio_dev *indio_dev; 161 struct max517_platform_data *platform_data = client->dev.platform_data; 162 163 indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data)); 164 if (!indio_dev) 165 return -ENOMEM; 166 data = iio_priv(indio_dev); 167 i2c_set_clientdata(client, indio_dev); 168 data->client = client; 169 170 /* establish that the iio_dev is a child of the i2c device */ 171 indio_dev->dev.parent = &client->dev; 172 173 /* reduced channel set for MAX517 */ 174 if (id->driver_data == ID_MAX517) 175 indio_dev->num_channels = 1; 176 else 177 indio_dev->num_channels = 2; 178 indio_dev->channels = max517_channels; 179 indio_dev->modes = INDIO_DIRECT_MODE; 180 indio_dev->info = &max517_info; 181 182 /* 183 * Reference voltage on MAX518 and default is 5V, else take vref_mv 184 * from platform_data 185 */ 186 if (id->driver_data == ID_MAX518 || !platform_data) { 187 data->vref_mv[0] = data->vref_mv[1] = 5000; /* mV */ 188 } else { 189 data->vref_mv[0] = platform_data->vref_mv[0]; 190 data->vref_mv[1] = platform_data->vref_mv[1]; 191 } 192 193 return iio_device_register(indio_dev); 194 } 195 196 static int max517_remove(struct i2c_client *client) 197 { 198 iio_device_unregister(i2c_get_clientdata(client)); 199 return 0; 200 } 201 202 static const struct i2c_device_id max517_id[] = { 203 { "max517", ID_MAX517 }, 204 { "max518", ID_MAX518 }, 205 { "max519", ID_MAX519 }, 206 { } 207 }; 208 MODULE_DEVICE_TABLE(i2c, max517_id); 209 210 static struct i2c_driver max517_driver = { 211 .driver = { 212 .name = MAX517_DRV_NAME, 213 .pm = MAX517_PM_OPS, 214 }, 215 .probe = max517_probe, 216 .remove = max517_remove, 217 .id_table = max517_id, 218 }; 219 module_i2c_driver(max517_driver); 220 221 MODULE_AUTHOR("Roland Stigge <stigge@antcom.de>"); 222 MODULE_DESCRIPTION("MAX517/MAX518/MAX519 8-bit DAC"); 223 MODULE_LICENSE("GPL"); 224