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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
7 Written by Steve Hardy <shardy@redhat.com>
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 */
47static const unsigned short normal_i2c[] = { 0x48, 0x49, 0x4a, 0x4b,
48 I2C_CLIENT_END };
49
50/* Module parameters */
51static int se_input = 1; /* Default is SE, 0 == diff */
52static int int_vref = 1; /* Default is internal ref ON */
53static int vref_mv = ADS7828_INT_VREF_MV; /* set if vref != 2.5V */
54module_param(se_input, bool, S_IRUGO);
55module_param(int_vref, bool, S_IRUGO);
56module_param(vref_mv, int, S_IRUGO);
57
58/* Global Variables */
59static u8 ads7828_cmd_byte; /* cmd byte without channel bits */
60static unsigned int ads7828_lsb_resol; /* resolution of the ADC sample lsb */
61
62/* Each client has this additional data */
63struct ads7828_data {
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 */
72static int ads7828_detect(struct i2c_client *client,
73 struct i2c_board_info *info);
74static int ads7828_probe(struct i2c_client *client,
75 const struct i2c_device_id *id);
76
77/* The ADS7828 returns the 12-bit sample in two bytes,
78 these are read as a word then byte-swapped */
79static u16 ads7828_read_value(struct i2c_client *client, u8 reg)
80{
81 return swab16(i2c_smbus_read_word_data(client, reg));
82}
83
84static 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) */
93static 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 */
119static 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)\
130static SENSOR_DEVICE_ATTR(in##offset##_input, S_IRUGO, show_in,\
131 NULL, offset)
132
133in_reg(0);
134in_reg(1);
135in_reg(2);
136in_reg(3);
137in_reg(4);
138in_reg(5);
139in_reg(6);
140in_reg(7);
141
142static 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
154static const struct attribute_group ads7828_group = {
155 .attrs = ads7828_attributes,
156};
157
158static int ads7828_remove(struct i2c_client *client)
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);
163 kfree(i2c_get_clientdata(client));
164 return 0;
165}
166
167static const struct i2c_device_id ads7828_id[] = {
168 { "ads7828", 0 },
169 { }
170};
171MODULE_DEVICE_TABLE(i2c, ads7828_id);
172
173/* This is the driver that will be inserted */
174static struct i2c_driver ads7828_driver = {
175 .class = I2C_CLASS_HWMON,
176 .driver = {
177 .name = "ads7828",
178 },
179 .probe = ads7828_probe,
180 .remove = ads7828_remove,
181 .id_table = ads7828_id,
182 .detect = ads7828_detect,
183 .address_list = normal_i2c,
184};
185
186/* Return 0 if detection is successful, -ENODEV otherwise */
187static int ads7828_detect(struct i2c_client *client,
188 struct i2c_board_info *info)
189{
190 struct i2c_adapter *adapter = client->adapter;
191 int ch;
192
193 /* Check we have a valid client */
194 if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_READ_WORD_DATA))
195 return -ENODEV;
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 */
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;
211 }
212 }
213
214 strlcpy(info->type, "ads7828", I2C_NAME_SIZE);
215
216 return 0;
217}
218
219static int ads7828_probe(struct i2c_client *client,
220 const struct i2c_device_id *id)
221{
222 struct ads7828_data *data;
223 int err;
224
225 data = kzalloc(sizeof(struct ads7828_data), GFP_KERNEL);
226 if (!data) {
227 err = -ENOMEM;
228 goto exit;
229 }
230
231 i2c_set_clientdata(client, data);
232 mutex_init(&data->update_lock);
233
234 /* Register sysfs hooks */
235 err = sysfs_create_group(&client->dev.kobj, &ads7828_group);
236 if (err)
237 goto exit_free;
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
247exit_remove:
248 sysfs_remove_group(&client->dev.kobj, &ads7828_group);
249exit_free:
250 kfree(data);
251exit:
252 return err;
253}
254
255static 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
269static void __exit sensors_ads7828_exit(void)
270{
271 i2c_del_driver(&ads7828_driver);
272}
273
274MODULE_AUTHOR("Steve Hardy <shardy@redhat.com>");
275MODULE_DESCRIPTION("ADS7828 driver");
276MODULE_LICENSE("GPL");
277
278module_init(sensors_ads7828_init);
279module_exit(sensors_ads7828_exit);
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 *
7 * Written by Steve Hardy <shardy@redhat.com>
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 */
47static const unsigned short normal_i2c[] = { 0x48, 0x49, 0x4a, 0x4b,
48 I2C_CLIENT_END };
49
50/* Module parameters */
51static bool se_input = 1; /* Default is SE, 0 == diff */
52static bool int_vref = 1; /* Default is internal ref ON */
53static int vref_mv = ADS7828_INT_VREF_MV; /* set if vref != 2.5V */
54module_param(se_input, bool, S_IRUGO);
55module_param(int_vref, bool, S_IRUGO);
56module_param(vref_mv, int, S_IRUGO);
57
58/* Global Variables */
59static u8 ads7828_cmd_byte; /* cmd byte without channel bits */
60static unsigned int ads7828_lsb_resol; /* resolution of the ADC sample lsb */
61
62/* Each client has this additional data */
63struct ads7828_data {
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 */
72static int ads7828_detect(struct i2c_client *client,
73 struct i2c_board_info *info);
74static int ads7828_probe(struct i2c_client *client,
75 const struct i2c_device_id *id);
76
77static 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) */
86static 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);
100 data->adc_input[ch] =
101 i2c_smbus_read_word_swapped(client, cmd);
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 */
113static 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)\
124static SENSOR_DEVICE_ATTR(in##offset##_input, S_IRUGO, show_in,\
125 NULL, offset)
126
127in_reg(0);
128in_reg(1);
129in_reg(2);
130in_reg(3);
131in_reg(4);
132in_reg(5);
133in_reg(6);
134in_reg(7);
135
136static 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
148static const struct attribute_group ads7828_group = {
149 .attrs = ads7828_attributes,
150};
151
152static int ads7828_remove(struct i2c_client *client)
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);
157 kfree(i2c_get_clientdata(client));
158 return 0;
159}
160
161static const struct i2c_device_id ads7828_id[] = {
162 { "ads7828", 0 },
163 { }
164};
165MODULE_DEVICE_TABLE(i2c, ads7828_id);
166
167/* This is the driver that will be inserted */
168static struct i2c_driver ads7828_driver = {
169 .class = I2C_CLASS_HWMON,
170 .driver = {
171 .name = "ads7828",
172 },
173 .probe = ads7828_probe,
174 .remove = ads7828_remove,
175 .id_table = ads7828_id,
176 .detect = ads7828_detect,
177 .address_list = normal_i2c,
178};
179
180/* Return 0 if detection is successful, -ENODEV otherwise */
181static int ads7828_detect(struct i2c_client *client,
182 struct i2c_board_info *info)
183{
184 struct i2c_adapter *adapter = client->adapter;
185 int ch;
186
187 /* Check we have a valid client */
188 if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_READ_WORD_DATA))
189 return -ENODEV;
190
191 /*
192 * Now, we do the remaining detection. There is no identification
193 * dedicated register so attempt to sanity check using knowledge of
194 * the chip
195 * - Read from the 8 channel addresses
196 * - Check the top 4 bits of each result are not set (12 data bits)
197 */
198 for (ch = 0; ch < ADS7828_NCH; ch++) {
199 u16 in_data;
200 u8 cmd = channel_cmd_byte(ch);
201 in_data = i2c_smbus_read_word_swapped(client, cmd);
202 if (in_data & 0xF000) {
203 pr_debug("%s : Doesn't look like an ads7828 device\n",
204 __func__);
205 return -ENODEV;
206 }
207 }
208
209 strlcpy(info->type, "ads7828", I2C_NAME_SIZE);
210
211 return 0;
212}
213
214static int ads7828_probe(struct i2c_client *client,
215 const struct i2c_device_id *id)
216{
217 struct ads7828_data *data;
218 int err;
219
220 data = kzalloc(sizeof(struct ads7828_data), GFP_KERNEL);
221 if (!data) {
222 err = -ENOMEM;
223 goto exit;
224 }
225
226 i2c_set_clientdata(client, data);
227 mutex_init(&data->update_lock);
228
229 /* Register sysfs hooks */
230 err = sysfs_create_group(&client->dev.kobj, &ads7828_group);
231 if (err)
232 goto exit_free;
233
234 data->hwmon_dev = hwmon_device_register(&client->dev);
235 if (IS_ERR(data->hwmon_dev)) {
236 err = PTR_ERR(data->hwmon_dev);
237 goto exit_remove;
238 }
239
240 return 0;
241
242exit_remove:
243 sysfs_remove_group(&client->dev.kobj, &ads7828_group);
244exit_free:
245 kfree(data);
246exit:
247 return err;
248}
249
250static int __init sensors_ads7828_init(void)
251{
252 /* Initialize the command byte according to module parameters */
253 ads7828_cmd_byte = se_input ?
254 ADS7828_CMD_SD_SE : ADS7828_CMD_SD_DIFF;
255 ads7828_cmd_byte |= int_vref ?
256 ADS7828_CMD_PD3 : ADS7828_CMD_PD1;
257
258 /* Calculate the LSB resolution */
259 ads7828_lsb_resol = (vref_mv*1000)/4096;
260
261 return i2c_add_driver(&ads7828_driver);
262}
263
264static void __exit sensors_ads7828_exit(void)
265{
266 i2c_del_driver(&ads7828_driver);
267}
268
269MODULE_AUTHOR("Steve Hardy <shardy@redhat.com>");
270MODULE_DESCRIPTION("ADS7828 driver");
271MODULE_LICENSE("GPL");
272
273module_init(sensors_ads7828_init);
274module_exit(sensors_ads7828_exit);