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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 */ |
90ab5ee9 RR |
51 | static bool se_input = 1; /* Default is SE, 0 == diff */ |
52 | static bool int_vref = 1; /* Default is internal ref ON */ | |
5812f928 SH |
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 | 76 | |
5812f928 SH |
77 | static inline u8 channel_cmd_byte(int ch) |
78 | { | |
79 | /* cmd byte C2,C1,C0 - see datasheet */ | |
80 | u8 cmd = (((ch>>1) | (ch&0x01)<<2)<<4); | |
81 | cmd |= ads7828_cmd_byte; | |
82 | return cmd; | |
83 | } | |
84 | ||
85 | /* Update data for the device (all 8 channels) */ | |
86 | static struct ads7828_data *ads7828_update_device(struct device *dev) | |
87 | { | |
88 | struct i2c_client *client = to_i2c_client(dev); | |
89 | struct ads7828_data *data = i2c_get_clientdata(client); | |
90 | ||
91 | mutex_lock(&data->update_lock); | |
92 | ||
93 | if (time_after(jiffies, data->last_updated + HZ + HZ / 2) | |
94 | || !data->valid) { | |
95 | unsigned int ch; | |
96 | dev_dbg(&client->dev, "Starting ads7828 update\n"); | |
97 | ||
98 | for (ch = 0; ch < ADS7828_NCH; ch++) { | |
99 | u8 cmd = channel_cmd_byte(ch); | |
90f4102c JD |
100 | data->adc_input[ch] = |
101 | i2c_smbus_read_word_swapped(client, cmd); | |
5812f928 SH |
102 | } |
103 | data->last_updated = jiffies; | |
104 | data->valid = 1; | |
105 | } | |
106 | ||
107 | mutex_unlock(&data->update_lock); | |
108 | ||
109 | return data; | |
110 | } | |
111 | ||
112 | /* sysfs callback function */ | |
113 | static ssize_t show_in(struct device *dev, struct device_attribute *da, | |
114 | char *buf) | |
115 | { | |
116 | struct sensor_device_attribute *attr = to_sensor_dev_attr(da); | |
117 | struct ads7828_data *data = ads7828_update_device(dev); | |
118 | /* Print value (in mV as specified in sysfs-interface documentation) */ | |
119 | return sprintf(buf, "%d\n", (data->adc_input[attr->index] * | |
120 | ads7828_lsb_resol)/1000); | |
121 | } | |
122 | ||
123 | #define in_reg(offset)\ | |
124 | static SENSOR_DEVICE_ATTR(in##offset##_input, S_IRUGO, show_in,\ | |
125 | NULL, offset) | |
126 | ||
127 | in_reg(0); | |
128 | in_reg(1); | |
129 | in_reg(2); | |
130 | in_reg(3); | |
131 | in_reg(4); | |
132 | in_reg(5); | |
133 | in_reg(6); | |
134 | in_reg(7); | |
135 | ||
136 | static struct attribute *ads7828_attributes[] = { | |
137 | &sensor_dev_attr_in0_input.dev_attr.attr, | |
138 | &sensor_dev_attr_in1_input.dev_attr.attr, | |
139 | &sensor_dev_attr_in2_input.dev_attr.attr, | |
140 | &sensor_dev_attr_in3_input.dev_attr.attr, | |
141 | &sensor_dev_attr_in4_input.dev_attr.attr, | |
142 | &sensor_dev_attr_in5_input.dev_attr.attr, | |
143 | &sensor_dev_attr_in6_input.dev_attr.attr, | |
144 | &sensor_dev_attr_in7_input.dev_attr.attr, | |
145 | NULL | |
146 | }; | |
147 | ||
148 | static const struct attribute_group ads7828_group = { | |
149 | .attrs = ads7828_attributes, | |
150 | }; | |
151 | ||
7347cb38 | 152 | static int ads7828_remove(struct i2c_client *client) |
5812f928 SH |
153 | { |
154 | struct ads7828_data *data = i2c_get_clientdata(client); | |
155 | hwmon_device_unregister(data->hwmon_dev); | |
156 | sysfs_remove_group(&client->dev.kobj, &ads7828_group); | |
5812f928 SH |
157 | kfree(i2c_get_clientdata(client)); |
158 | return 0; | |
159 | } | |
160 | ||
7347cb38 | 161 | static const struct i2c_device_id ads7828_id[] = { |
1f86df49 | 162 | { "ads7828", 0 }, |
7347cb38 JD |
163 | { } |
164 | }; | |
165 | MODULE_DEVICE_TABLE(i2c, ads7828_id); | |
166 | ||
5812f928 SH |
167 | /* This is the driver that will be inserted */ |
168 | static struct i2c_driver ads7828_driver = { | |
7347cb38 | 169 | .class = I2C_CLASS_HWMON, |
5812f928 SH |
170 | .driver = { |
171 | .name = "ads7828", | |
172 | }, | |
7347cb38 JD |
173 | .probe = ads7828_probe, |
174 | .remove = ads7828_remove, | |
175 | .id_table = ads7828_id, | |
176 | .detect = ads7828_detect, | |
c3813d6a | 177 | .address_list = normal_i2c, |
5812f928 SH |
178 | }; |
179 | ||
7347cb38 | 180 | /* Return 0 if detection is successful, -ENODEV otherwise */ |
310ec792 | 181 | static int ads7828_detect(struct i2c_client *client, |
7347cb38 | 182 | struct i2c_board_info *info) |
5812f928 | 183 | { |
7347cb38 | 184 | struct i2c_adapter *adapter = client->adapter; |
52df6440 | 185 | int ch; |
5812f928 SH |
186 | |
187 | /* Check we have a valid client */ | |
188 | if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_READ_WORD_DATA)) | |
7347cb38 | 189 | return -ENODEV; |
5812f928 SH |
190 | |
191 | /* Now, we do the remaining detection. There is no identification | |
192 | dedicated register so attempt to sanity check using knowledge of | |
193 | the chip | |
194 | - Read from the 8 channel addresses | |
195 | - Check the top 4 bits of each result are not set (12 data bits) | |
196 | */ | |
52df6440 JD |
197 | for (ch = 0; ch < ADS7828_NCH; ch++) { |
198 | u16 in_data; | |
199 | u8 cmd = channel_cmd_byte(ch); | |
90f4102c | 200 | in_data = i2c_smbus_read_word_swapped(client, cmd); |
52df6440 JD |
201 | if (in_data & 0xF000) { |
202 | pr_debug("%s : Doesn't look like an ads7828 device\n", | |
203 | __func__); | |
204 | return -ENODEV; | |
5812f928 SH |
205 | } |
206 | } | |
52df6440 | 207 | |
7347cb38 | 208 | strlcpy(info->type, "ads7828", I2C_NAME_SIZE); |
5812f928 | 209 | |
7347cb38 JD |
210 | return 0; |
211 | } | |
5812f928 | 212 | |
7347cb38 JD |
213 | static int ads7828_probe(struct i2c_client *client, |
214 | const struct i2c_device_id *id) | |
215 | { | |
216 | struct ads7828_data *data; | |
217 | int err; | |
5812f928 | 218 | |
7347cb38 JD |
219 | data = kzalloc(sizeof(struct ads7828_data), GFP_KERNEL); |
220 | if (!data) { | |
221 | err = -ENOMEM; | |
222 | goto exit; | |
223 | } | |
5812f928 | 224 | |
7347cb38 | 225 | i2c_set_clientdata(client, data); |
5812f928 SH |
226 | mutex_init(&data->update_lock); |
227 | ||
5812f928 SH |
228 | /* Register sysfs hooks */ |
229 | err = sysfs_create_group(&client->dev.kobj, &ads7828_group); | |
230 | if (err) | |
7347cb38 | 231 | goto exit_free; |
5812f928 SH |
232 | |
233 | data->hwmon_dev = hwmon_device_register(&client->dev); | |
234 | if (IS_ERR(data->hwmon_dev)) { | |
235 | err = PTR_ERR(data->hwmon_dev); | |
236 | goto exit_remove; | |
237 | } | |
238 | ||
239 | return 0; | |
240 | ||
241 | exit_remove: | |
242 | sysfs_remove_group(&client->dev.kobj, &ads7828_group); | |
5812f928 SH |
243 | exit_free: |
244 | kfree(data); | |
245 | exit: | |
246 | return err; | |
247 | } | |
248 | ||
249 | static int __init sensors_ads7828_init(void) | |
250 | { | |
251 | /* Initialize the command byte according to module parameters */ | |
252 | ads7828_cmd_byte = se_input ? | |
253 | ADS7828_CMD_SD_SE : ADS7828_CMD_SD_DIFF; | |
254 | ads7828_cmd_byte |= int_vref ? | |
255 | ADS7828_CMD_PD3 : ADS7828_CMD_PD1; | |
256 | ||
257 | /* Calculate the LSB resolution */ | |
258 | ads7828_lsb_resol = (vref_mv*1000)/4096; | |
259 | ||
260 | return i2c_add_driver(&ads7828_driver); | |
261 | } | |
262 | ||
263 | static void __exit sensors_ads7828_exit(void) | |
264 | { | |
265 | i2c_del_driver(&ads7828_driver); | |
266 | } | |
267 | ||
5d84291d | 268 | MODULE_AUTHOR("Steve Hardy <shardy@redhat.com>"); |
5812f928 SH |
269 | MODULE_DESCRIPTION("ADS7828 driver"); |
270 | MODULE_LICENSE("GPL"); | |
271 | ||
272 | module_init(sensors_ads7828_init); | |
273 | module_exit(sensors_ads7828_exit); |