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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// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * ads7828.c - driver for TI ADS7828 8-channel A/D converter and compatibles
4 * (C) 2007 EADS Astrium
5 *
6 * This driver is based on the lm75 and other lm_sensors/hwmon drivers
7 *
8 * Written by Steve Hardy <shardy@redhat.com>
9 *
10 * ADS7830 support, by Guillaume Roguez <guillaume.roguez@savoirfairelinux.com>
11 *
12 * For further information, see the Documentation/hwmon/ads7828.rst file.
13 */
14
15#include <linux/err.h>
16#include <linux/hwmon.h>
17#include <linux/hwmon-sysfs.h>
18#include <linux/i2c.h>
19#include <linux/init.h>
20#include <linux/module.h>
21#include <linux/of.h>
22#include <linux/platform_data/ads7828.h>
23#include <linux/regmap.h>
24#include <linux/slab.h>
25#include <linux/regulator/consumer.h>
26
27/* The ADS7828 registers */
28#define ADS7828_CMD_SD_SE 0x80 /* Single ended inputs */
29#define ADS7828_CMD_PD1 0x04 /* Internal vref OFF && A/D ON */
30#define ADS7828_CMD_PD3 0x0C /* Internal vref ON && A/D ON */
31#define ADS7828_INT_VREF_MV 2500 /* Internal vref is 2.5V, 2500mV */
32#define ADS7828_EXT_VREF_MV_MIN 50 /* External vref min value 0.05V */
33#define ADS7828_EXT_VREF_MV_MAX 5250 /* External vref max value 5.25V */
34
35/* List of supported devices */
36enum ads7828_chips { ads7828, ads7830 };
37
38/* Client specific data */
39struct ads7828_data {
40 struct regmap *regmap;
41 u8 cmd_byte; /* Command byte without channel bits */
42 unsigned int lsb_resol; /* Resolution of the ADC sample LSB */
43};
44
45/* Command byte C2,C1,C0 - see datasheet */
46static inline u8 ads7828_cmd_byte(u8 cmd, int ch)
47{
48 return cmd | (((ch >> 1) | (ch & 0x01) << 2) << 4);
49}
50
51/* sysfs callback function */
52static ssize_t ads7828_in_show(struct device *dev,
53 struct device_attribute *da, char *buf)
54{
55 struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
56 struct ads7828_data *data = dev_get_drvdata(dev);
57 u8 cmd = ads7828_cmd_byte(data->cmd_byte, attr->index);
58 unsigned int regval;
59 int err;
60
61 err = regmap_read(data->regmap, cmd, ®val);
62 if (err < 0)
63 return err;
64
65 return sprintf(buf, "%d\n",
66 DIV_ROUND_CLOSEST(regval * data->lsb_resol, 1000));
67}
68
69static SENSOR_DEVICE_ATTR_RO(in0_input, ads7828_in, 0);
70static SENSOR_DEVICE_ATTR_RO(in1_input, ads7828_in, 1);
71static SENSOR_DEVICE_ATTR_RO(in2_input, ads7828_in, 2);
72static SENSOR_DEVICE_ATTR_RO(in3_input, ads7828_in, 3);
73static SENSOR_DEVICE_ATTR_RO(in4_input, ads7828_in, 4);
74static SENSOR_DEVICE_ATTR_RO(in5_input, ads7828_in, 5);
75static SENSOR_DEVICE_ATTR_RO(in6_input, ads7828_in, 6);
76static SENSOR_DEVICE_ATTR_RO(in7_input, ads7828_in, 7);
77
78static struct attribute *ads7828_attrs[] = {
79 &sensor_dev_attr_in0_input.dev_attr.attr,
80 &sensor_dev_attr_in1_input.dev_attr.attr,
81 &sensor_dev_attr_in2_input.dev_attr.attr,
82 &sensor_dev_attr_in3_input.dev_attr.attr,
83 &sensor_dev_attr_in4_input.dev_attr.attr,
84 &sensor_dev_attr_in5_input.dev_attr.attr,
85 &sensor_dev_attr_in6_input.dev_attr.attr,
86 &sensor_dev_attr_in7_input.dev_attr.attr,
87 NULL
88};
89
90ATTRIBUTE_GROUPS(ads7828);
91
92static const struct regmap_config ads2828_regmap_config = {
93 .reg_bits = 8,
94 .val_bits = 16,
95};
96
97static const struct regmap_config ads2830_regmap_config = {
98 .reg_bits = 8,
99 .val_bits = 8,
100};
101
102static int ads7828_probe(struct i2c_client *client)
103{
104 struct device *dev = &client->dev;
105 struct ads7828_platform_data *pdata = dev_get_platdata(dev);
106 struct ads7828_data *data;
107 struct device *hwmon_dev;
108 unsigned int vref_mv = ADS7828_INT_VREF_MV;
109 unsigned int vref_uv;
110 bool diff_input = false;
111 bool ext_vref = false;
112 unsigned int regval;
113 enum ads7828_chips chip;
114 struct regulator *reg;
115
116 data = devm_kzalloc(dev, sizeof(struct ads7828_data), GFP_KERNEL);
117 if (!data)
118 return -ENOMEM;
119
120 if (pdata) {
121 diff_input = pdata->diff_input;
122 ext_vref = pdata->ext_vref;
123 if (ext_vref && pdata->vref_mv)
124 vref_mv = pdata->vref_mv;
125 } else if (dev->of_node) {
126 diff_input = of_property_read_bool(dev->of_node,
127 "ti,differential-input");
128 reg = devm_regulator_get_optional(dev, "vref");
129 if (!IS_ERR(reg)) {
130 vref_uv = regulator_get_voltage(reg);
131 vref_mv = DIV_ROUND_CLOSEST(vref_uv, 1000);
132 if (vref_mv < ADS7828_EXT_VREF_MV_MIN ||
133 vref_mv > ADS7828_EXT_VREF_MV_MAX)
134 return -EINVAL;
135 ext_vref = true;
136 }
137 }
138
139 chip = (uintptr_t)i2c_get_match_data(client);
140
141 /* Bound Vref with min/max values */
142 vref_mv = clamp_val(vref_mv, ADS7828_EXT_VREF_MV_MIN,
143 ADS7828_EXT_VREF_MV_MAX);
144
145 /* ADS7828 uses 12-bit samples, while ADS7830 is 8-bit */
146 if (chip == ads7828) {
147 data->lsb_resol = DIV_ROUND_CLOSEST(vref_mv * 1000, 4096);
148 data->regmap = devm_regmap_init_i2c(client,
149 &ads2828_regmap_config);
150 } else {
151 data->lsb_resol = DIV_ROUND_CLOSEST(vref_mv * 1000, 256);
152 data->regmap = devm_regmap_init_i2c(client,
153 &ads2830_regmap_config);
154 }
155
156 if (IS_ERR(data->regmap))
157 return PTR_ERR(data->regmap);
158
159 data->cmd_byte = ext_vref ? ADS7828_CMD_PD1 : ADS7828_CMD_PD3;
160 if (!diff_input)
161 data->cmd_byte |= ADS7828_CMD_SD_SE;
162
163 /*
164 * Datasheet specifies internal reference voltage is disabled by
165 * default. The internal reference voltage needs to be enabled and
166 * voltage needs to settle before getting valid ADC data. So perform a
167 * dummy read to enable the internal reference voltage.
168 */
169 if (!ext_vref)
170 regmap_read(data->regmap, data->cmd_byte, ®val);
171
172 hwmon_dev = devm_hwmon_device_register_with_groups(dev, client->name,
173 data,
174 ads7828_groups);
175 return PTR_ERR_OR_ZERO(hwmon_dev);
176}
177
178static const struct i2c_device_id ads7828_device_ids[] = {
179 { "ads7828", ads7828 },
180 { "ads7830", ads7830 },
181 { }
182};
183MODULE_DEVICE_TABLE(i2c, ads7828_device_ids);
184
185static const struct of_device_id __maybe_unused ads7828_of_match[] = {
186 {
187 .compatible = "ti,ads7828",
188 .data = (void *)ads7828
189 },
190 {
191 .compatible = "ti,ads7830",
192 .data = (void *)ads7830
193 },
194 { },
195};
196MODULE_DEVICE_TABLE(of, ads7828_of_match);
197
198static struct i2c_driver ads7828_driver = {
199 .driver = {
200 .name = "ads7828",
201 .of_match_table = of_match_ptr(ads7828_of_match),
202 },
203
204 .id_table = ads7828_device_ids,
205 .probe = ads7828_probe,
206};
207
208module_i2c_driver(ads7828_driver);
209
210MODULE_LICENSE("GPL");
211MODULE_AUTHOR("Steve Hardy <shardy@redhat.com>");
212MODULE_DESCRIPTION("Driver for TI ADS7828 A/D converter and compatibles");