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5812f928 | 1 | /* |
0962e0f1 | 2 | * ads7828.c - driver for TI ADS7828 8-channel A/D converter and compatibles |
d13d6232 GR |
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 | * | |
0962e0f1 GR |
9 | * ADS7830 support, by Guillaume Roguez <guillaume.roguez@savoirfairelinux.com> |
10 | * | |
46d78462 | 11 | * For further information, see the Documentation/hwmon/ads7828 file. |
d13d6232 GR |
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 | */ | |
5812f928 | 27 | |
46d78462 | 28 | #include <linux/err.h> |
5812f928 SH |
29 | #include <linux/hwmon.h> |
30 | #include <linux/hwmon-sysfs.h> | |
46d78462 VD |
31 | #include <linux/i2c.h> |
32 | #include <linux/init.h> | |
33 | #include <linux/jiffies.h> | |
34 | #include <linux/module.h> | |
5812f928 | 35 | #include <linux/mutex.h> |
46d78462 VD |
36 | #include <linux/platform_data/ads7828.h> |
37 | #include <linux/slab.h> | |
5812f928 SH |
38 | |
39 | /* The ADS7828 registers */ | |
46d78462 VD |
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 | ||
0962e0f1 GR |
48 | /* List of supported devices */ |
49 | enum ads7828_chips { ads7828, ads7830 }; | |
50 | ||
46d78462 | 51 | /* Client specific data */ |
5812f928 | 52 | struct ads7828_data { |
f82b2c34 | 53 | struct i2c_client *client; |
46d78462 VD |
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 */ | |
0962e0f1 | 63 | s32 (*read_channel)(const struct i2c_client *client, u8 command); |
5812f928 SH |
64 | }; |
65 | ||
46d78462 VD |
66 | /* Command byte C2,C1,C0 - see datasheet */ |
67 | static inline u8 ads7828_cmd_byte(u8 cmd, int ch) | |
5812f928 | 68 | { |
46d78462 | 69 | return cmd | (((ch >> 1) | (ch & 0x01) << 2) << 4); |
5812f928 SH |
70 | } |
71 | ||
72 | /* Update data for the device (all 8 channels) */ | |
73 | static struct ads7828_data *ads7828_update_device(struct device *dev) | |
74 | { | |
f82b2c34 AL |
75 | struct ads7828_data *data = dev_get_drvdata(dev); |
76 | struct i2c_client *client = data->client; | |
5812f928 SH |
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++) { | |
46d78462 | 86 | u8 cmd = ads7828_cmd_byte(data->cmd_byte, ch); |
0962e0f1 | 87 | data->adc_input[ch] = data->read_channel(client, cmd); |
5812f928 SH |
88 | } |
89 | data->last_updated = jiffies; | |
46d78462 | 90 | data->valid = true; |
5812f928 SH |
91 | } |
92 | ||
93 | mutex_unlock(&data->update_lock); | |
94 | ||
95 | return data; | |
96 | } | |
97 | ||
98 | /* sysfs callback function */ | |
46d78462 VD |
99 | static ssize_t ads7828_show_in(struct device *dev, struct device_attribute *da, |
100 | char *buf) | |
5812f928 SH |
101 | { |
102 | struct sensor_device_attribute *attr = to_sensor_dev_attr(da); | |
103 | struct ads7828_data *data = ads7828_update_device(dev); | |
46d78462 VD |
104 | unsigned int value = DIV_ROUND_CLOSEST(data->adc_input[attr->index] * |
105 | data->lsb_resol, 1000); | |
5812f928 | 106 | |
46d78462 VD |
107 | return sprintf(buf, "%d\n", value); |
108 | } | |
5812f928 | 109 | |
46d78462 VD |
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); | |
5812f928 | 118 | |
f82b2c34 | 119 | static struct attribute *ads7828_attrs[] = { |
5812f928 SH |
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 | ||
f82b2c34 | 131 | ATTRIBUTE_GROUPS(ads7828); |
5812f928 | 132 | |
7347cb38 JD |
133 | static int ads7828_probe(struct i2c_client *client, |
134 | const struct i2c_device_id *id) | |
135 | { | |
f82b2c34 AL |
136 | struct device *dev = &client->dev; |
137 | struct ads7828_platform_data *pdata = dev_get_platdata(dev); | |
7347cb38 | 138 | struct ads7828_data *data; |
f82b2c34 | 139 | struct device *hwmon_dev; |
5812f928 | 140 | |
f82b2c34 | 141 | data = devm_kzalloc(dev, sizeof(struct ads7828_data), GFP_KERNEL); |
34e3f7f5 GR |
142 | if (!data) |
143 | return -ENOMEM; | |
5812f928 | 144 | |
46d78462 VD |
145 | if (pdata) { |
146 | data->diff_input = pdata->diff_input; | |
147 | data->ext_vref = pdata->ext_vref; | |
148 | if (data->ext_vref) | |
149 | data->vref_mv = pdata->vref_mv; | |
150 | } | |
151 | ||
152 | /* Bound Vref with min/max values if it was provided */ | |
153 | if (data->vref_mv) | |
2a844c14 GR |
154 | data->vref_mv = clamp_val(data->vref_mv, |
155 | ADS7828_EXT_VREF_MV_MIN, | |
156 | ADS7828_EXT_VREF_MV_MAX); | |
46d78462 VD |
157 | else |
158 | data->vref_mv = ADS7828_INT_VREF_MV; | |
159 | ||
0962e0f1 GR |
160 | /* ADS7828 uses 12-bit samples, while ADS7830 is 8-bit */ |
161 | if (id->driver_data == ads7828) { | |
162 | data->lsb_resol = DIV_ROUND_CLOSEST(data->vref_mv * 1000, 4096); | |
163 | data->read_channel = i2c_smbus_read_word_swapped; | |
164 | } else { | |
165 | data->lsb_resol = DIV_ROUND_CLOSEST(data->vref_mv * 1000, 256); | |
166 | data->read_channel = i2c_smbus_read_byte_data; | |
167 | } | |
46d78462 VD |
168 | |
169 | data->cmd_byte = data->ext_vref ? ADS7828_CMD_PD1 : ADS7828_CMD_PD3; | |
170 | if (!data->diff_input) | |
171 | data->cmd_byte |= ADS7828_CMD_SD_SE; | |
172 | ||
f82b2c34 | 173 | data->client = client; |
5812f928 SH |
174 | mutex_init(&data->update_lock); |
175 | ||
f82b2c34 AL |
176 | hwmon_dev = devm_hwmon_device_register_with_groups(dev, client->name, |
177 | data, | |
178 | ads7828_groups); | |
179 | return PTR_ERR_OR_ZERO(hwmon_dev); | |
5812f928 SH |
180 | } |
181 | ||
46d78462 | 182 | static const struct i2c_device_id ads7828_device_ids[] = { |
0962e0f1 GR |
183 | { "ads7828", ads7828 }, |
184 | { "ads7830", ads7830 }, | |
46d78462 VD |
185 | { } |
186 | }; | |
187 | MODULE_DEVICE_TABLE(i2c, ads7828_device_ids); | |
5812f928 | 188 | |
46d78462 VD |
189 | static struct i2c_driver ads7828_driver = { |
190 | .driver = { | |
191 | .name = "ads7828", | |
192 | }, | |
5812f928 | 193 | |
46d78462 VD |
194 | .id_table = ads7828_device_ids, |
195 | .probe = ads7828_probe, | |
46d78462 | 196 | }; |
5812f928 | 197 | |
46d78462 | 198 | module_i2c_driver(ads7828_driver); |
5812f928 | 199 | |
5812f928 | 200 | MODULE_LICENSE("GPL"); |
46d78462 | 201 | MODULE_AUTHOR("Steve Hardy <shardy@redhat.com>"); |
0962e0f1 | 202 | MODULE_DESCRIPTION("Driver for TI ADS7828 A/D converter and compatibles"); |