Root/
1 | /* |
2 | * ads7828.c - driver for TI ADS7828 8-channel A/D converter and compatibles |
3 | * (C) 2007 EADS Astrium |
4 | * |
5 | * This driver is based on the lm75 and other lm_sensors/hwmon drivers |
6 | * |
7 | * Written by Steve Hardy <shardy@redhat.com> |
8 | * |
9 | * ADS7830 support, by Guillaume Roguez <guillaume.roguez@savoirfairelinux.com> |
10 | * |
11 | * For further information, see the Documentation/hwmon/ads7828 file. |
12 | * |
13 | * This program is free software; you can redistribute it and/or modify |
14 | * it under the terms of the GNU General Public License as published by |
15 | * the Free Software Foundation; either version 2 of the License, or |
16 | * (at your option) any later version. |
17 | * |
18 | * This program is distributed in the hope that it will be useful, |
19 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
20 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
21 | * GNU General Public License for more details. |
22 | * |
23 | * You should have received a copy of the GNU General Public License |
24 | * along with this program; if not, write to the Free Software |
25 | * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. |
26 | */ |
27 | |
28 | #include <linux/err.h> |
29 | #include <linux/hwmon.h> |
30 | #include <linux/hwmon-sysfs.h> |
31 | #include <linux/i2c.h> |
32 | #include <linux/init.h> |
33 | #include <linux/jiffies.h> |
34 | #include <linux/module.h> |
35 | #include <linux/mutex.h> |
36 | #include <linux/platform_data/ads7828.h> |
37 | #include <linux/slab.h> |
38 | |
39 | /* The ADS7828 registers */ |
40 | #define ADS7828_NCH 8 /* 8 channels supported */ |
41 | #define ADS7828_CMD_SD_SE 0x80 /* Single ended inputs */ |
42 | #define ADS7828_CMD_PD1 0x04 /* Internal vref OFF && A/D ON */ |
43 | #define ADS7828_CMD_PD3 0x0C /* Internal vref ON && A/D ON */ |
44 | #define ADS7828_INT_VREF_MV 2500 /* Internal vref is 2.5V, 2500mV */ |
45 | #define ADS7828_EXT_VREF_MV_MIN 50 /* External vref min value 0.05V */ |
46 | #define ADS7828_EXT_VREF_MV_MAX 5250 /* External vref max value 5.25V */ |
47 | |
48 | /* List of supported devices */ |
49 | enum ads7828_chips { ads7828, ads7830 }; |
50 | |
51 | /* Client specific data */ |
52 | struct ads7828_data { |
53 | struct device *hwmon_dev; |
54 | struct mutex update_lock; /* Mutex protecting updates */ |
55 | unsigned long last_updated; /* Last updated time (in jiffies) */ |
56 | u16 adc_input[ADS7828_NCH]; /* ADS7828_NCH samples */ |
57 | bool valid; /* Validity flag */ |
58 | bool diff_input; /* Differential input */ |
59 | bool ext_vref; /* External voltage reference */ |
60 | unsigned int vref_mv; /* voltage reference value */ |
61 | u8 cmd_byte; /* Command byte without channel bits */ |
62 | unsigned int lsb_resol; /* Resolution of the ADC sample LSB */ |
63 | s32 (*read_channel)(const struct i2c_client *client, u8 command); |
64 | }; |
65 | |
66 | /* Command byte C2,C1,C0 - see datasheet */ |
67 | static inline u8 ads7828_cmd_byte(u8 cmd, int ch) |
68 | { |
69 | return cmd | (((ch >> 1) | (ch & 0x01) << 2) << 4); |
70 | } |
71 | |
72 | /* Update data for the device (all 8 channels) */ |
73 | static struct ads7828_data *ads7828_update_device(struct device *dev) |
74 | { |
75 | struct i2c_client *client = to_i2c_client(dev); |
76 | struct ads7828_data *data = i2c_get_clientdata(client); |
77 | |
78 | mutex_lock(&data->update_lock); |
79 | |
80 | if (time_after(jiffies, data->last_updated + HZ + HZ / 2) |
81 | || !data->valid) { |
82 | unsigned int ch; |
83 | dev_dbg(&client->dev, "Starting ads7828 update\n"); |
84 | |
85 | for (ch = 0; ch < ADS7828_NCH; ch++) { |
86 | u8 cmd = ads7828_cmd_byte(data->cmd_byte, ch); |
87 | data->adc_input[ch] = data->read_channel(client, cmd); |
88 | } |
89 | data->last_updated = jiffies; |
90 | data->valid = true; |
91 | } |
92 | |
93 | mutex_unlock(&data->update_lock); |
94 | |
95 | return data; |
96 | } |
97 | |
98 | /* sysfs callback function */ |
99 | static ssize_t ads7828_show_in(struct device *dev, struct device_attribute *da, |
100 | char *buf) |
101 | { |
102 | struct sensor_device_attribute *attr = to_sensor_dev_attr(da); |
103 | struct ads7828_data *data = ads7828_update_device(dev); |
104 | unsigned int value = DIV_ROUND_CLOSEST(data->adc_input[attr->index] * |
105 | data->lsb_resol, 1000); |
106 | |
107 | return sprintf(buf, "%d\n", value); |
108 | } |
109 | |
110 | static SENSOR_DEVICE_ATTR(in0_input, S_IRUGO, ads7828_show_in, NULL, 0); |
111 | static SENSOR_DEVICE_ATTR(in1_input, S_IRUGO, ads7828_show_in, NULL, 1); |
112 | static SENSOR_DEVICE_ATTR(in2_input, S_IRUGO, ads7828_show_in, NULL, 2); |
113 | static SENSOR_DEVICE_ATTR(in3_input, S_IRUGO, ads7828_show_in, NULL, 3); |
114 | static SENSOR_DEVICE_ATTR(in4_input, S_IRUGO, ads7828_show_in, NULL, 4); |
115 | static SENSOR_DEVICE_ATTR(in5_input, S_IRUGO, ads7828_show_in, NULL, 5); |
116 | static SENSOR_DEVICE_ATTR(in6_input, S_IRUGO, ads7828_show_in, NULL, 6); |
117 | static SENSOR_DEVICE_ATTR(in7_input, S_IRUGO, ads7828_show_in, NULL, 7); |
118 | |
119 | static struct attribute *ads7828_attributes[] = { |
120 | &sensor_dev_attr_in0_input.dev_attr.attr, |
121 | &sensor_dev_attr_in1_input.dev_attr.attr, |
122 | &sensor_dev_attr_in2_input.dev_attr.attr, |
123 | &sensor_dev_attr_in3_input.dev_attr.attr, |
124 | &sensor_dev_attr_in4_input.dev_attr.attr, |
125 | &sensor_dev_attr_in5_input.dev_attr.attr, |
126 | &sensor_dev_attr_in6_input.dev_attr.attr, |
127 | &sensor_dev_attr_in7_input.dev_attr.attr, |
128 | NULL |
129 | }; |
130 | |
131 | static const struct attribute_group ads7828_group = { |
132 | .attrs = ads7828_attributes, |
133 | }; |
134 | |
135 | static int ads7828_remove(struct i2c_client *client) |
136 | { |
137 | struct ads7828_data *data = i2c_get_clientdata(client); |
138 | |
139 | hwmon_device_unregister(data->hwmon_dev); |
140 | sysfs_remove_group(&client->dev.kobj, &ads7828_group); |
141 | |
142 | return 0; |
143 | } |
144 | |
145 | static int ads7828_probe(struct i2c_client *client, |
146 | const struct i2c_device_id *id) |
147 | { |
148 | struct ads7828_platform_data *pdata = dev_get_platdata(&client->dev); |
149 | struct ads7828_data *data; |
150 | int err; |
151 | |
152 | data = devm_kzalloc(&client->dev, sizeof(struct ads7828_data), |
153 | GFP_KERNEL); |
154 | if (!data) |
155 | return -ENOMEM; |
156 | |
157 | if (pdata) { |
158 | data->diff_input = pdata->diff_input; |
159 | data->ext_vref = pdata->ext_vref; |
160 | if (data->ext_vref) |
161 | data->vref_mv = pdata->vref_mv; |
162 | } |
163 | |
164 | /* Bound Vref with min/max values if it was provided */ |
165 | if (data->vref_mv) |
166 | data->vref_mv = clamp_val(data->vref_mv, |
167 | ADS7828_EXT_VREF_MV_MIN, |
168 | ADS7828_EXT_VREF_MV_MAX); |
169 | else |
170 | data->vref_mv = ADS7828_INT_VREF_MV; |
171 | |
172 | /* ADS7828 uses 12-bit samples, while ADS7830 is 8-bit */ |
173 | if (id->driver_data == ads7828) { |
174 | data->lsb_resol = DIV_ROUND_CLOSEST(data->vref_mv * 1000, 4096); |
175 | data->read_channel = i2c_smbus_read_word_swapped; |
176 | } else { |
177 | data->lsb_resol = DIV_ROUND_CLOSEST(data->vref_mv * 1000, 256); |
178 | data->read_channel = i2c_smbus_read_byte_data; |
179 | } |
180 | |
181 | data->cmd_byte = data->ext_vref ? ADS7828_CMD_PD1 : ADS7828_CMD_PD3; |
182 | if (!data->diff_input) |
183 | data->cmd_byte |= ADS7828_CMD_SD_SE; |
184 | |
185 | i2c_set_clientdata(client, data); |
186 | mutex_init(&data->update_lock); |
187 | |
188 | err = sysfs_create_group(&client->dev.kobj, &ads7828_group); |
189 | if (err) |
190 | return err; |
191 | |
192 | data->hwmon_dev = hwmon_device_register(&client->dev); |
193 | if (IS_ERR(data->hwmon_dev)) { |
194 | err = PTR_ERR(data->hwmon_dev); |
195 | goto error; |
196 | } |
197 | |
198 | return 0; |
199 | |
200 | error: |
201 | sysfs_remove_group(&client->dev.kobj, &ads7828_group); |
202 | return err; |
203 | } |
204 | |
205 | static const struct i2c_device_id ads7828_device_ids[] = { |
206 | { "ads7828", ads7828 }, |
207 | { "ads7830", ads7830 }, |
208 | { } |
209 | }; |
210 | MODULE_DEVICE_TABLE(i2c, ads7828_device_ids); |
211 | |
212 | static struct i2c_driver ads7828_driver = { |
213 | .driver = { |
214 | .name = "ads7828", |
215 | }, |
216 | |
217 | .id_table = ads7828_device_ids, |
218 | .probe = ads7828_probe, |
219 | .remove = ads7828_remove, |
220 | }; |
221 | |
222 | module_i2c_driver(ads7828_driver); |
223 | |
224 | MODULE_LICENSE("GPL"); |
225 | MODULE_AUTHOR("Steve Hardy <shardy@redhat.com>"); |
226 | MODULE_DESCRIPTION("Driver for TI ADS7828 A/D converter and compatibles"); |
227 |
Branches:
ben-wpan
ben-wpan-stefan
javiroman/ks7010
jz-2.6.34
jz-2.6.34-rc5
jz-2.6.34-rc6
jz-2.6.34-rc7
jz-2.6.35
jz-2.6.36
jz-2.6.37
jz-2.6.38
jz-2.6.39
jz-3.0
jz-3.1
jz-3.11
jz-3.12
jz-3.13
jz-3.15
jz-3.16
jz-3.18-dt
jz-3.2
jz-3.3
jz-3.4
jz-3.5
jz-3.6
jz-3.6-rc2-pwm
jz-3.9
jz-3.9-clk
jz-3.9-rc8
jz47xx
jz47xx-2.6.38
master
Tags:
od-2011-09-04
od-2011-09-18
v2.6.34-rc5
v2.6.34-rc6
v2.6.34-rc7
v3.9