]>
Commit | Line | Data |
---|---|---|
5812f928 SH |
1 | /* |
2 | ads7828.c - lm_sensors driver for ads7828 12-bit 8-channel ADC | |
3 | (C) 2007 EADS Astrium | |
4 | ||
5 | This driver is based on the lm75 and other lm_sensors/hwmon drivers | |
6 | ||
5d84291d | 7 | Written by Steve Hardy <shardy@redhat.com> |
5812f928 SH |
8 | |
9 | Datasheet available at: http://focus.ti.com/lit/ds/symlink/ads7828.pdf | |
10 | ||
11 | This program is free software; you can redistribute it and/or modify | |
12 | it under the terms of the GNU General Public License as published by | |
13 | the Free Software Foundation; either version 2 of the License, or | |
14 | (at your option) any later version. | |
15 | ||
16 | This program is distributed in the hope that it will be useful, | |
17 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
18 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
19 | GNU General Public License for more details. | |
20 | ||
21 | You should have received a copy of the GNU General Public License | |
22 | along with this program; if not, write to the Free Software | |
23 | Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. | |
24 | */ | |
25 | ||
26 | #include <linux/module.h> | |
27 | #include <linux/init.h> | |
28 | #include <linux/slab.h> | |
29 | #include <linux/jiffies.h> | |
30 | #include <linux/i2c.h> | |
31 | #include <linux/hwmon.h> | |
32 | #include <linux/hwmon-sysfs.h> | |
33 | #include <linux/err.h> | |
34 | #include <linux/mutex.h> | |
35 | ||
36 | /* The ADS7828 registers */ | |
37 | #define ADS7828_NCH 8 /* 8 channels of 12-bit A-D supported */ | |
38 | #define ADS7828_CMD_SD_SE 0x80 /* Single ended inputs */ | |
39 | #define ADS7828_CMD_SD_DIFF 0x00 /* Differential inputs */ | |
40 | #define ADS7828_CMD_PD0 0x0 /* Power Down between A-D conversions */ | |
41 | #define ADS7828_CMD_PD1 0x04 /* Internal ref OFF && A-D ON */ | |
42 | #define ADS7828_CMD_PD2 0x08 /* Internal ref ON && A-D OFF */ | |
43 | #define ADS7828_CMD_PD3 0x0C /* Internal ref ON && A-D ON */ | |
44 | #define ADS7828_INT_VREF_MV 2500 /* Internal vref is 2.5V, 2500mV */ | |
45 | ||
46 | /* Addresses to scan */ | |
25e9c86d | 47 | static const unsigned short normal_i2c[] = { 0x48, 0x49, 0x4a, 0x4b, |
5812f928 SH |
48 | I2C_CLIENT_END }; |
49 | ||
1f86df49 | 50 | /* Module parameters */ |
5812f928 SH |
51 | static int se_input = 1; /* Default is SE, 0 == diff */ |
52 | static int int_vref = 1; /* Default is internal ref ON */ | |
53 | static int vref_mv = ADS7828_INT_VREF_MV; /* set if vref != 2.5V */ | |
54 | module_param(se_input, bool, S_IRUGO); | |
55 | module_param(int_vref, bool, S_IRUGO); | |
56 | module_param(vref_mv, int, S_IRUGO); | |
57 | ||
58 | /* Global Variables */ | |
59 | static u8 ads7828_cmd_byte; /* cmd byte without channel bits */ | |
60 | static unsigned int ads7828_lsb_resol; /* resolution of the ADC sample lsb */ | |
61 | ||
62 | /* Each client has this additional data */ | |
63 | struct ads7828_data { | |
5812f928 SH |
64 | struct device *hwmon_dev; |
65 | struct mutex update_lock; /* mutex protect updates */ | |
66 | char valid; /* !=0 if following fields are valid */ | |
67 | unsigned long last_updated; /* In jiffies */ | |
68 | u16 adc_input[ADS7828_NCH]; /* ADS7828_NCH 12-bit samples */ | |
69 | }; | |
70 | ||
71 | /* Function declaration - necessary due to function dependencies */ | |
310ec792 | 72 | static int ads7828_detect(struct i2c_client *client, |
7347cb38 JD |
73 | struct i2c_board_info *info); |
74 | static int ads7828_probe(struct i2c_client *client, | |
75 | const struct i2c_device_id *id); | |
5812f928 SH |
76 | |
77 | /* The ADS7828 returns the 12-bit sample in two bytes, | |
78 | these are read as a word then byte-swapped */ | |
79 | static u16 ads7828_read_value(struct i2c_client *client, u8 reg) | |
80 | { | |
81 | return swab16(i2c_smbus_read_word_data(client, reg)); | |
82 | } | |
83 | ||
84 | static inline u8 channel_cmd_byte(int ch) | |
85 | { | |
86 | /* cmd byte C2,C1,C0 - see datasheet */ | |
87 | u8 cmd = (((ch>>1) | (ch&0x01)<<2)<<4); | |
88 | cmd |= ads7828_cmd_byte; | |
89 | return cmd; | |
90 | } | |
91 | ||
92 | /* Update data for the device (all 8 channels) */ | |
93 | static struct ads7828_data *ads7828_update_device(struct device *dev) | |
94 | { | |
95 | struct i2c_client *client = to_i2c_client(dev); | |
96 | struct ads7828_data *data = i2c_get_clientdata(client); | |
97 | ||
98 | mutex_lock(&data->update_lock); | |
99 | ||
100 | if (time_after(jiffies, data->last_updated + HZ + HZ / 2) | |
101 | || !data->valid) { | |
102 | unsigned int ch; | |
103 | dev_dbg(&client->dev, "Starting ads7828 update\n"); | |
104 | ||
105 | for (ch = 0; ch < ADS7828_NCH; ch++) { | |
106 | u8 cmd = channel_cmd_byte(ch); | |
107 | data->adc_input[ch] = ads7828_read_value(client, cmd); | |
108 | } | |
109 | data->last_updated = jiffies; | |
110 | data->valid = 1; | |
111 | } | |
112 | ||
113 | mutex_unlock(&data->update_lock); | |
114 | ||
115 | return data; | |
116 | } | |
117 | ||
118 | /* sysfs callback function */ | |
119 | static ssize_t show_in(struct device *dev, struct device_attribute *da, | |
120 | char *buf) | |
121 | { | |
122 | struct sensor_device_attribute *attr = to_sensor_dev_attr(da); | |
123 | struct ads7828_data *data = ads7828_update_device(dev); | |
124 | /* Print value (in mV as specified in sysfs-interface documentation) */ | |
125 | return sprintf(buf, "%d\n", (data->adc_input[attr->index] * | |
126 | ads7828_lsb_resol)/1000); | |
127 | } | |
128 | ||
129 | #define in_reg(offset)\ | |
130 | static SENSOR_DEVICE_ATTR(in##offset##_input, S_IRUGO, show_in,\ | |
131 | NULL, offset) | |
132 | ||
133 | in_reg(0); | |
134 | in_reg(1); | |
135 | in_reg(2); | |
136 | in_reg(3); | |
137 | in_reg(4); | |
138 | in_reg(5); | |
139 | in_reg(6); | |
140 | in_reg(7); | |
141 | ||
142 | static struct attribute *ads7828_attributes[] = { | |
143 | &sensor_dev_attr_in0_input.dev_attr.attr, | |
144 | &sensor_dev_attr_in1_input.dev_attr.attr, | |
145 | &sensor_dev_attr_in2_input.dev_attr.attr, | |
146 | &sensor_dev_attr_in3_input.dev_attr.attr, | |
147 | &sensor_dev_attr_in4_input.dev_attr.attr, | |
148 | &sensor_dev_attr_in5_input.dev_attr.attr, | |
149 | &sensor_dev_attr_in6_input.dev_attr.attr, | |
150 | &sensor_dev_attr_in7_input.dev_attr.attr, | |
151 | NULL | |
152 | }; | |
153 | ||
154 | static const struct attribute_group ads7828_group = { | |
155 | .attrs = ads7828_attributes, | |
156 | }; | |
157 | ||
7347cb38 | 158 | static int ads7828_remove(struct i2c_client *client) |
5812f928 SH |
159 | { |
160 | struct ads7828_data *data = i2c_get_clientdata(client); | |
161 | hwmon_device_unregister(data->hwmon_dev); | |
162 | sysfs_remove_group(&client->dev.kobj, &ads7828_group); | |
5812f928 SH |
163 | kfree(i2c_get_clientdata(client)); |
164 | return 0; | |
165 | } | |
166 | ||
7347cb38 | 167 | static const struct i2c_device_id ads7828_id[] = { |
1f86df49 | 168 | { "ads7828", 0 }, |
7347cb38 JD |
169 | { } |
170 | }; | |
171 | MODULE_DEVICE_TABLE(i2c, ads7828_id); | |
172 | ||
5812f928 SH |
173 | /* This is the driver that will be inserted */ |
174 | static struct i2c_driver ads7828_driver = { | |
7347cb38 | 175 | .class = I2C_CLASS_HWMON, |
5812f928 SH |
176 | .driver = { |
177 | .name = "ads7828", | |
178 | }, | |
7347cb38 JD |
179 | .probe = ads7828_probe, |
180 | .remove = ads7828_remove, | |
181 | .id_table = ads7828_id, | |
182 | .detect = ads7828_detect, | |
c3813d6a | 183 | .address_list = normal_i2c, |
5812f928 SH |
184 | }; |
185 | ||
7347cb38 | 186 | /* Return 0 if detection is successful, -ENODEV otherwise */ |
310ec792 | 187 | static int ads7828_detect(struct i2c_client *client, |
7347cb38 | 188 | struct i2c_board_info *info) |
5812f928 | 189 | { |
7347cb38 | 190 | struct i2c_adapter *adapter = client->adapter; |
52df6440 | 191 | int ch; |
5812f928 SH |
192 | |
193 | /* Check we have a valid client */ | |
194 | if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_READ_WORD_DATA)) | |
7347cb38 | 195 | return -ENODEV; |
5812f928 SH |
196 | |
197 | /* Now, we do the remaining detection. There is no identification | |
198 | dedicated register so attempt to sanity check using knowledge of | |
199 | the chip | |
200 | - Read from the 8 channel addresses | |
201 | - Check the top 4 bits of each result are not set (12 data bits) | |
202 | */ | |
52df6440 JD |
203 | for (ch = 0; ch < ADS7828_NCH; ch++) { |
204 | u16 in_data; | |
205 | u8 cmd = channel_cmd_byte(ch); | |
206 | in_data = ads7828_read_value(client, cmd); | |
207 | if (in_data & 0xF000) { | |
208 | pr_debug("%s : Doesn't look like an ads7828 device\n", | |
209 | __func__); | |
210 | return -ENODEV; | |
5812f928 SH |
211 | } |
212 | } | |
52df6440 | 213 | |
7347cb38 | 214 | strlcpy(info->type, "ads7828", I2C_NAME_SIZE); |
5812f928 | 215 | |
7347cb38 JD |
216 | return 0; |
217 | } | |
5812f928 | 218 | |
7347cb38 JD |
219 | static int ads7828_probe(struct i2c_client *client, |
220 | const struct i2c_device_id *id) | |
221 | { | |
222 | struct ads7828_data *data; | |
223 | int err; | |
5812f928 | 224 | |
7347cb38 JD |
225 | data = kzalloc(sizeof(struct ads7828_data), GFP_KERNEL); |
226 | if (!data) { | |
227 | err = -ENOMEM; | |
228 | goto exit; | |
229 | } | |
5812f928 | 230 | |
7347cb38 | 231 | i2c_set_clientdata(client, data); |
5812f928 SH |
232 | mutex_init(&data->update_lock); |
233 | ||
5812f928 SH |
234 | /* Register sysfs hooks */ |
235 | err = sysfs_create_group(&client->dev.kobj, &ads7828_group); | |
236 | if (err) | |
7347cb38 | 237 | goto exit_free; |
5812f928 SH |
238 | |
239 | data->hwmon_dev = hwmon_device_register(&client->dev); | |
240 | if (IS_ERR(data->hwmon_dev)) { | |
241 | err = PTR_ERR(data->hwmon_dev); | |
242 | goto exit_remove; | |
243 | } | |
244 | ||
245 | return 0; | |
246 | ||
247 | exit_remove: | |
248 | sysfs_remove_group(&client->dev.kobj, &ads7828_group); | |
5812f928 SH |
249 | exit_free: |
250 | kfree(data); | |
251 | exit: | |
252 | return err; | |
253 | } | |
254 | ||
255 | static int __init sensors_ads7828_init(void) | |
256 | { | |
257 | /* Initialize the command byte according to module parameters */ | |
258 | ads7828_cmd_byte = se_input ? | |
259 | ADS7828_CMD_SD_SE : ADS7828_CMD_SD_DIFF; | |
260 | ads7828_cmd_byte |= int_vref ? | |
261 | ADS7828_CMD_PD3 : ADS7828_CMD_PD1; | |
262 | ||
263 | /* Calculate the LSB resolution */ | |
264 | ads7828_lsb_resol = (vref_mv*1000)/4096; | |
265 | ||
266 | return i2c_add_driver(&ads7828_driver); | |
267 | } | |
268 | ||
269 | static void __exit sensors_ads7828_exit(void) | |
270 | { | |
271 | i2c_del_driver(&ads7828_driver); | |
272 | } | |
273 | ||
5d84291d | 274 | MODULE_AUTHOR("Steve Hardy <shardy@redhat.com>"); |
5812f928 SH |
275 | MODULE_DESCRIPTION("ADS7828 driver"); |
276 | MODULE_LICENSE("GPL"); | |
277 | ||
278 | module_init(sensors_ads7828_init); | |
279 | module_exit(sensors_ads7828_exit); |