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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/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
124 data = devm_kzalloc(dev, sizeof(struct ads7828_data), GFP_KERNEL);
125 if (!data)
126 return -ENOMEM;
127
128 if (pdata) {
129 diff_input = pdata->diff_input;
130 ext_vref = pdata->ext_vref;
131 if (ext_vref && pdata->vref_mv)
132 vref_mv = pdata->vref_mv;
133 }
134
135 /* Bound Vref with min/max values */
136 vref_mv = clamp_val(vref_mv, ADS7828_EXT_VREF_MV_MIN,
137 ADS7828_EXT_VREF_MV_MAX);
138
139 /* ADS7828 uses 12-bit samples, while ADS7830 is 8-bit */
140 if (id->driver_data == ads7828) {
141 data->lsb_resol = DIV_ROUND_CLOSEST(vref_mv * 1000, 4096);
142 data->regmap = devm_regmap_init_i2c(client,
143 &ads2828_regmap_config);
144 } else {
145 data->lsb_resol = DIV_ROUND_CLOSEST(vref_mv * 1000, 256);
146 data->regmap = devm_regmap_init_i2c(client,
147 &ads2830_regmap_config);
148 }
149
150 if (IS_ERR(data->regmap))
151 return PTR_ERR(data->regmap);
152
153 data->cmd_byte = ext_vref ? ADS7828_CMD_PD1 : ADS7828_CMD_PD3;
154 if (!diff_input)
155 data->cmd_byte |= ADS7828_CMD_SD_SE;
156
157 hwmon_dev = devm_hwmon_device_register_with_groups(dev, client->name,
158 data,
159 ads7828_groups);
160 return PTR_ERR_OR_ZERO(hwmon_dev);
161}
162
163static const struct i2c_device_id ads7828_device_ids[] = {
164 { "ads7828", ads7828 },
165 { "ads7830", ads7830 },
166 { }
167};
168MODULE_DEVICE_TABLE(i2c, ads7828_device_ids);
169
170static struct i2c_driver ads7828_driver = {
171 .driver = {
172 .name = "ads7828",
173 },
174
175 .id_table = ads7828_device_ids,
176 .probe = ads7828_probe,
177};
178
179module_i2c_driver(ads7828_driver);
180
181MODULE_LICENSE("GPL");
182MODULE_AUTHOR("Steve Hardy <shardy@redhat.com>");
183MODULE_DESCRIPTION("Driver for TI ADS7828 A/D converter and compatibles");