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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");
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");