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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_device.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 const struct i2c_device_id *id)
104{
105 struct device *dev = &client->dev;
106 struct ads7828_platform_data *pdata = dev_get_platdata(dev);
107 struct ads7828_data *data;
108 struct device *hwmon_dev;
109 unsigned int vref_mv = ADS7828_INT_VREF_MV;
110 unsigned int vref_uv;
111 bool diff_input = false;
112 bool ext_vref = false;
113 unsigned int regval;
114 enum ads7828_chips chip;
115 struct regulator *reg;
116
117 data = devm_kzalloc(dev, sizeof(struct ads7828_data), GFP_KERNEL);
118 if (!data)
119 return -ENOMEM;
120
121 if (pdata) {
122 diff_input = pdata->diff_input;
123 ext_vref = pdata->ext_vref;
124 if (ext_vref && pdata->vref_mv)
125 vref_mv = pdata->vref_mv;
126 } else if (dev->of_node) {
127 diff_input = of_property_read_bool(dev->of_node,
128 "ti,differential-input");
129 reg = devm_regulator_get_optional(dev, "vref");
130 if (!IS_ERR(reg)) {
131 vref_uv = regulator_get_voltage(reg);
132 vref_mv = DIV_ROUND_CLOSEST(vref_uv, 1000);
133 if (vref_mv < ADS7828_EXT_VREF_MV_MIN ||
134 vref_mv > ADS7828_EXT_VREF_MV_MAX)
135 return -EINVAL;
136 ext_vref = true;
137 }
138 }
139
140 if (client->dev.of_node)
141 chip = (enum ads7828_chips)
142 of_device_get_match_data(&client->dev);
143 else
144 chip = id->driver_data;
145
146 /* Bound Vref with min/max values */
147 vref_mv = clamp_val(vref_mv, ADS7828_EXT_VREF_MV_MIN,
148 ADS7828_EXT_VREF_MV_MAX);
149
150 /* ADS7828 uses 12-bit samples, while ADS7830 is 8-bit */
151 if (chip == ads7828) {
152 data->lsb_resol = DIV_ROUND_CLOSEST(vref_mv * 1000, 4096);
153 data->regmap = devm_regmap_init_i2c(client,
154 &ads2828_regmap_config);
155 } else {
156 data->lsb_resol = DIV_ROUND_CLOSEST(vref_mv * 1000, 256);
157 data->regmap = devm_regmap_init_i2c(client,
158 &ads2830_regmap_config);
159 }
160
161 if (IS_ERR(data->regmap))
162 return PTR_ERR(data->regmap);
163
164 data->cmd_byte = ext_vref ? ADS7828_CMD_PD1 : ADS7828_CMD_PD3;
165 if (!diff_input)
166 data->cmd_byte |= ADS7828_CMD_SD_SE;
167
168 /*
169 * Datasheet specifies internal reference voltage is disabled by
170 * default. The internal reference voltage needs to be enabled and
171 * voltage needs to settle before getting valid ADC data. So perform a
172 * dummy read to enable the internal reference voltage.
173 */
174 if (!ext_vref)
175 regmap_read(data->regmap, data->cmd_byte, ®val);
176
177 hwmon_dev = devm_hwmon_device_register_with_groups(dev, client->name,
178 data,
179 ads7828_groups);
180 return PTR_ERR_OR_ZERO(hwmon_dev);
181}
182
183static const struct i2c_device_id ads7828_device_ids[] = {
184 { "ads7828", ads7828 },
185 { "ads7830", ads7830 },
186 { }
187};
188MODULE_DEVICE_TABLE(i2c, ads7828_device_ids);
189
190static const struct of_device_id __maybe_unused ads7828_of_match[] = {
191 {
192 .compatible = "ti,ads7828",
193 .data = (void *)ads7828
194 },
195 {
196 .compatible = "ti,ads7830",
197 .data = (void *)ads7830
198 },
199 { },
200};
201MODULE_DEVICE_TABLE(of, ads7828_of_match);
202
203static struct i2c_driver ads7828_driver = {
204 .driver = {
205 .name = "ads7828",
206 .of_match_table = of_match_ptr(ads7828_of_match),
207 },
208
209 .id_table = ads7828_device_ids,
210 .probe = ads7828_probe,
211};
212
213module_i2c_driver(ads7828_driver);
214
215MODULE_LICENSE("GPL");
216MODULE_AUTHOR("Steve Hardy <shardy@redhat.com>");
217MODULE_DESCRIPTION("Driver for TI ADS7828 A/D converter and compatibles");
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 */
49enum ads7828_chips { ads7828, ads7830 };
50
51/* Client specific data */
52struct 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 */
67static 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) */
73static 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 */
99static 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
110static SENSOR_DEVICE_ATTR(in0_input, S_IRUGO, ads7828_show_in, NULL, 0);
111static SENSOR_DEVICE_ATTR(in1_input, S_IRUGO, ads7828_show_in, NULL, 1);
112static SENSOR_DEVICE_ATTR(in2_input, S_IRUGO, ads7828_show_in, NULL, 2);
113static SENSOR_DEVICE_ATTR(in3_input, S_IRUGO, ads7828_show_in, NULL, 3);
114static SENSOR_DEVICE_ATTR(in4_input, S_IRUGO, ads7828_show_in, NULL, 4);
115static SENSOR_DEVICE_ATTR(in5_input, S_IRUGO, ads7828_show_in, NULL, 5);
116static SENSOR_DEVICE_ATTR(in6_input, S_IRUGO, ads7828_show_in, NULL, 6);
117static SENSOR_DEVICE_ATTR(in7_input, S_IRUGO, ads7828_show_in, NULL, 7);
118
119static 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
131static const struct attribute_group ads7828_group = {
132 .attrs = ads7828_attributes,
133};
134
135static 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
145static 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
200error:
201 sysfs_remove_group(&client->dev.kobj, &ads7828_group);
202 return err;
203}
204
205static const struct i2c_device_id ads7828_device_ids[] = {
206 { "ads7828", ads7828 },
207 { "ads7830", ads7830 },
208 { }
209};
210MODULE_DEVICE_TABLE(i2c, ads7828_device_ids);
211
212static 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
222module_i2c_driver(ads7828_driver);
223
224MODULE_LICENSE("GPL");
225MODULE_AUTHOR("Steve Hardy <shardy@redhat.com>");
226MODULE_DESCRIPTION("Driver for TI ADS7828 A/D converter and compatibles");