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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 | /* ads7828.c - lm_sensors driver for ads7828 12-bit 8-channel ADC (C) 2007 EADS Astrium This driver is based on the lm75 and other lm_sensors/hwmon drivers Written by Steve Hardy <shardy@redhat.com> Datasheet available at: http://focus.ti.com/lit/ds/symlink/ads7828.pdf This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */ #include <linux/module.h> #include <linux/init.h> #include <linux/slab.h> #include <linux/jiffies.h> #include <linux/i2c.h> #include <linux/hwmon.h> #include <linux/hwmon-sysfs.h> #include <linux/err.h> #include <linux/mutex.h> /* The ADS7828 registers */ #define ADS7828_NCH 8 /* 8 channels of 12-bit A-D supported */ #define ADS7828_CMD_SD_SE 0x80 /* Single ended inputs */ #define ADS7828_CMD_SD_DIFF 0x00 /* Differential inputs */ #define ADS7828_CMD_PD0 0x0 /* Power Down between A-D conversions */ #define ADS7828_CMD_PD1 0x04 /* Internal ref OFF && A-D ON */ #define ADS7828_CMD_PD2 0x08 /* Internal ref ON && A-D OFF */ #define ADS7828_CMD_PD3 0x0C /* Internal ref ON && A-D ON */ #define ADS7828_INT_VREF_MV 2500 /* Internal vref is 2.5V, 2500mV */ /* Addresses to scan */ static const unsigned short normal_i2c[] = { 0x48, 0x49, 0x4a, 0x4b, I2C_CLIENT_END }; /* Module parameters */ static bool se_input = 1; /* Default is SE, 0 == diff */ static bool int_vref = 1; /* Default is internal ref ON */ static int vref_mv = ADS7828_INT_VREF_MV; /* set if vref != 2.5V */ module_param(se_input, bool, S_IRUGO); module_param(int_vref, bool, S_IRUGO); module_param(vref_mv, int, S_IRUGO); /* Global Variables */ static u8 ads7828_cmd_byte; /* cmd byte without channel bits */ static unsigned int ads7828_lsb_resol; /* resolution of the ADC sample lsb */ /* Each client has this additional data */ struct ads7828_data { struct device *hwmon_dev; struct mutex update_lock; /* mutex protect updates */ char valid; /* !=0 if following fields are valid */ unsigned long last_updated; /* In jiffies */ u16 adc_input[ADS7828_NCH]; /* ADS7828_NCH 12-bit samples */ }; /* Function declaration - necessary due to function dependencies */ static int ads7828_detect(struct i2c_client *client, struct i2c_board_info *info); static int ads7828_probe(struct i2c_client *client, const struct i2c_device_id *id); static inline u8 channel_cmd_byte(int ch) { /* cmd byte C2,C1,C0 - see datasheet */ u8 cmd = (((ch>>1) | (ch&0x01)<<2)<<4); cmd |= ads7828_cmd_byte; return cmd; } /* Update data for the device (all 8 channels) */ static struct ads7828_data *ads7828_update_device(struct device *dev) { struct i2c_client *client = to_i2c_client(dev); struct ads7828_data *data = i2c_get_clientdata(client); mutex_lock(&data->update_lock); if (time_after(jiffies, data->last_updated + HZ + HZ / 2) || !data->valid) { unsigned int ch; dev_dbg(&client->dev, "Starting ads7828 update\n"); for (ch = 0; ch < ADS7828_NCH; ch++) { u8 cmd = channel_cmd_byte(ch); data->adc_input[ch] = i2c_smbus_read_word_swapped(client, cmd); } data->last_updated = jiffies; data->valid = 1; } mutex_unlock(&data->update_lock); return data; } /* sysfs callback function */ static ssize_t show_in(struct device *dev, struct device_attribute *da, char *buf) { struct sensor_device_attribute *attr = to_sensor_dev_attr(da); struct ads7828_data *data = ads7828_update_device(dev); /* Print value (in mV as specified in sysfs-interface documentation) */ return sprintf(buf, "%d\n", (data->adc_input[attr->index] * ads7828_lsb_resol)/1000); } #define in_reg(offset)\ static SENSOR_DEVICE_ATTR(in##offset##_input, S_IRUGO, show_in,\ NULL, offset) in_reg(0); in_reg(1); in_reg(2); in_reg(3); in_reg(4); in_reg(5); in_reg(6); in_reg(7); static struct attribute *ads7828_attributes[] = { &sensor_dev_attr_in0_input.dev_attr.attr, &sensor_dev_attr_in1_input.dev_attr.attr, &sensor_dev_attr_in2_input.dev_attr.attr, &sensor_dev_attr_in3_input.dev_attr.attr, &sensor_dev_attr_in4_input.dev_attr.attr, &sensor_dev_attr_in5_input.dev_attr.attr, &sensor_dev_attr_in6_input.dev_attr.attr, &sensor_dev_attr_in7_input.dev_attr.attr, NULL }; static const struct attribute_group ads7828_group = { .attrs = ads7828_attributes, }; static int ads7828_remove(struct i2c_client *client) { struct ads7828_data *data = i2c_get_clientdata(client); hwmon_device_unregister(data->hwmon_dev); sysfs_remove_group(&client->dev.kobj, &ads7828_group); kfree(i2c_get_clientdata(client)); return 0; } static const struct i2c_device_id ads7828_id[] = { { "ads7828", 0 }, { } }; MODULE_DEVICE_TABLE(i2c, ads7828_id); /* This is the driver that will be inserted */ static struct i2c_driver ads7828_driver = { .class = I2C_CLASS_HWMON, .driver = { .name = "ads7828", }, .probe = ads7828_probe, .remove = ads7828_remove, .id_table = ads7828_id, .detect = ads7828_detect, .address_list = normal_i2c, }; /* Return 0 if detection is successful, -ENODEV otherwise */ static int ads7828_detect(struct i2c_client *client, struct i2c_board_info *info) { struct i2c_adapter *adapter = client->adapter; int ch; /* Check we have a valid client */ if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_READ_WORD_DATA)) return -ENODEV; /* Now, we do the remaining detection. There is no identification dedicated register so attempt to sanity check using knowledge of the chip - Read from the 8 channel addresses - Check the top 4 bits of each result are not set (12 data bits) */ for (ch = 0; ch < ADS7828_NCH; ch++) { u16 in_data; u8 cmd = channel_cmd_byte(ch); in_data = i2c_smbus_read_word_swapped(client, cmd); if (in_data & 0xF000) { pr_debug("%s : Doesn't look like an ads7828 device\n", __func__); return -ENODEV; } } strlcpy(info->type, "ads7828", I2C_NAME_SIZE); return 0; } static int ads7828_probe(struct i2c_client *client, const struct i2c_device_id *id) { struct ads7828_data *data; int err; data = kzalloc(sizeof(struct ads7828_data), GFP_KERNEL); if (!data) { err = -ENOMEM; goto exit; } i2c_set_clientdata(client, data); mutex_init(&data->update_lock); /* Register sysfs hooks */ err = sysfs_create_group(&client->dev.kobj, &ads7828_group); if (err) goto exit_free; data->hwmon_dev = hwmon_device_register(&client->dev); if (IS_ERR(data->hwmon_dev)) { err = PTR_ERR(data->hwmon_dev); goto exit_remove; } return 0; exit_remove: sysfs_remove_group(&client->dev.kobj, &ads7828_group); exit_free: kfree(data); exit: return err; } static int __init sensors_ads7828_init(void) { /* Initialize the command byte according to module parameters */ ads7828_cmd_byte = se_input ? ADS7828_CMD_SD_SE : ADS7828_CMD_SD_DIFF; ads7828_cmd_byte |= int_vref ? ADS7828_CMD_PD3 : ADS7828_CMD_PD1; /* Calculate the LSB resolution */ ads7828_lsb_resol = (vref_mv*1000)/4096; return i2c_add_driver(&ads7828_driver); } static void __exit sensors_ads7828_exit(void) { i2c_del_driver(&ads7828_driver); } MODULE_AUTHOR("Steve Hardy <shardy@redhat.com>"); MODULE_DESCRIPTION("ADS7828 driver"); MODULE_LICENSE("GPL"); module_init(sensors_ads7828_init); module_exit(sensors_ads7828_exit); |