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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 - 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/module.h>
34#include <linux/platform_data/ads7828.h>
35#include <linux/regmap.h>
36#include <linux/slab.h>
37
38/* The ADS7828 registers */
39#define ADS7828_CMD_SD_SE 0x80 /* Single ended inputs */
40#define ADS7828_CMD_PD1 0x04 /* Internal vref OFF && A/D ON */
41#define ADS7828_CMD_PD3 0x0C /* Internal vref ON && A/D ON */
42#define ADS7828_INT_VREF_MV 2500 /* Internal vref is 2.5V, 2500mV */
43#define ADS7828_EXT_VREF_MV_MIN 50 /* External vref min value 0.05V */
44#define ADS7828_EXT_VREF_MV_MAX 5250 /* External vref max value 5.25V */
45
46/* List of supported devices */
47enum ads7828_chips { ads7828, ads7830 };
48
49/* Client specific data */
50struct ads7828_data {
51 struct regmap *regmap;
52 u8 cmd_byte; /* Command byte without channel bits */
53 unsigned int lsb_resol; /* Resolution of the ADC sample LSB */
54};
55
56/* Command byte C2,C1,C0 - see datasheet */
57static inline u8 ads7828_cmd_byte(u8 cmd, int ch)
58{
59 return cmd | (((ch >> 1) | (ch & 0x01) << 2) << 4);
60}
61
62/* sysfs callback function */
63static ssize_t ads7828_show_in(struct device *dev, struct device_attribute *da,
64 char *buf)
65{
66 struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
67 struct ads7828_data *data = dev_get_drvdata(dev);
68 u8 cmd = ads7828_cmd_byte(data->cmd_byte, attr->index);
69 unsigned int regval;
70 int err;
71
72 err = regmap_read(data->regmap, cmd, ®val);
73 if (err < 0)
74 return err;
75
76 return sprintf(buf, "%d\n",
77 DIV_ROUND_CLOSEST(regval * data->lsb_resol, 1000));
78}
79
80static SENSOR_DEVICE_ATTR(in0_input, S_IRUGO, ads7828_show_in, NULL, 0);
81static SENSOR_DEVICE_ATTR(in1_input, S_IRUGO, ads7828_show_in, NULL, 1);
82static SENSOR_DEVICE_ATTR(in2_input, S_IRUGO, ads7828_show_in, NULL, 2);
83static SENSOR_DEVICE_ATTR(in3_input, S_IRUGO, ads7828_show_in, NULL, 3);
84static SENSOR_DEVICE_ATTR(in4_input, S_IRUGO, ads7828_show_in, NULL, 4);
85static SENSOR_DEVICE_ATTR(in5_input, S_IRUGO, ads7828_show_in, NULL, 5);
86static SENSOR_DEVICE_ATTR(in6_input, S_IRUGO, ads7828_show_in, NULL, 6);
87static SENSOR_DEVICE_ATTR(in7_input, S_IRUGO, ads7828_show_in, NULL, 7);
88
89static struct attribute *ads7828_attrs[] = {
90 &sensor_dev_attr_in0_input.dev_attr.attr,
91 &sensor_dev_attr_in1_input.dev_attr.attr,
92 &sensor_dev_attr_in2_input.dev_attr.attr,
93 &sensor_dev_attr_in3_input.dev_attr.attr,
94 &sensor_dev_attr_in4_input.dev_attr.attr,
95 &sensor_dev_attr_in5_input.dev_attr.attr,
96 &sensor_dev_attr_in6_input.dev_attr.attr,
97 &sensor_dev_attr_in7_input.dev_attr.attr,
98 NULL
99};
100
101ATTRIBUTE_GROUPS(ads7828);
102
103static const struct regmap_config ads2828_regmap_config = {
104 .reg_bits = 8,
105 .val_bits = 16,
106};
107
108static const struct regmap_config ads2830_regmap_config = {
109 .reg_bits = 8,
110 .val_bits = 8,
111};
112
113static int ads7828_probe(struct i2c_client *client,
114 const struct i2c_device_id *id)
115{
116 struct device *dev = &client->dev;
117 struct ads7828_platform_data *pdata = dev_get_platdata(dev);
118 struct ads7828_data *data;
119 struct device *hwmon_dev;
120 unsigned int vref_mv = ADS7828_INT_VREF_MV;
121 bool diff_input = false;
122 bool ext_vref = false;
123 unsigned int regval;
124
125 data = devm_kzalloc(dev, sizeof(struct ads7828_data), GFP_KERNEL);
126 if (!data)
127 return -ENOMEM;
128
129 if (pdata) {
130 diff_input = pdata->diff_input;
131 ext_vref = pdata->ext_vref;
132 if (ext_vref && pdata->vref_mv)
133 vref_mv = pdata->vref_mv;
134 }
135
136 /* Bound Vref with min/max values */
137 vref_mv = clamp_val(vref_mv, ADS7828_EXT_VREF_MV_MIN,
138 ADS7828_EXT_VREF_MV_MAX);
139
140 /* ADS7828 uses 12-bit samples, while ADS7830 is 8-bit */
141 if (id->driver_data == ads7828) {
142 data->lsb_resol = DIV_ROUND_CLOSEST(vref_mv * 1000, 4096);
143 data->regmap = devm_regmap_init_i2c(client,
144 &ads2828_regmap_config);
145 } else {
146 data->lsb_resol = DIV_ROUND_CLOSEST(vref_mv * 1000, 256);
147 data->regmap = devm_regmap_init_i2c(client,
148 &ads2830_regmap_config);
149 }
150
151 if (IS_ERR(data->regmap))
152 return PTR_ERR(data->regmap);
153
154 data->cmd_byte = ext_vref ? ADS7828_CMD_PD1 : ADS7828_CMD_PD3;
155 if (!diff_input)
156 data->cmd_byte |= ADS7828_CMD_SD_SE;
157
158 /*
159 * Datasheet specifies internal reference voltage is disabled by
160 * default. The internal reference voltage needs to be enabled and
161 * voltage needs to settle before getting valid ADC data. So perform a
162 * dummy read to enable the internal reference voltage.
163 */
164 if (!ext_vref)
165 regmap_read(data->regmap, data->cmd_byte, ®val);
166
167 hwmon_dev = devm_hwmon_device_register_with_groups(dev, client->name,
168 data,
169 ads7828_groups);
170 return PTR_ERR_OR_ZERO(hwmon_dev);
171}
172
173static const struct i2c_device_id ads7828_device_ids[] = {
174 { "ads7828", ads7828 },
175 { "ads7830", ads7830 },
176 { }
177};
178MODULE_DEVICE_TABLE(i2c, ads7828_device_ids);
179
180static struct i2c_driver ads7828_driver = {
181 .driver = {
182 .name = "ads7828",
183 },
184
185 .id_table = ads7828_device_ids,
186 .probe = ads7828_probe,
187};
188
189module_i2c_driver(ads7828_driver);
190
191MODULE_LICENSE("GPL");
192MODULE_AUTHOR("Steve Hardy <shardy@redhat.com>");
193MODULE_DESCRIPTION("Driver for TI ADS7828 A/D converter and compatibles");