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74ba9207 | 1 | // SPDX-License-Identifier: GPL-2.0-or-later |
5812f928 | 2 | /* |
0962e0f1 | 3 | * ads7828.c - driver for TI ADS7828 8-channel A/D converter and compatibles |
d13d6232 GR |
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 | * | |
0962e0f1 GR |
10 | * ADS7830 support, by Guillaume Roguez <guillaume.roguez@savoirfairelinux.com> |
11 | * | |
7ebd8b66 | 12 | * For further information, see the Documentation/hwmon/ads7828.rst file. |
d13d6232 | 13 | */ |
5812f928 | 14 | |
46d78462 | 15 | #include <linux/err.h> |
5812f928 SH |
16 | #include <linux/hwmon.h> |
17 | #include <linux/hwmon-sysfs.h> | |
46d78462 VD |
18 | #include <linux/i2c.h> |
19 | #include <linux/init.h> | |
46d78462 | 20 | #include <linux/module.h> |
2d688f14 | 21 | #include <linux/of_device.h> |
46d78462 | 22 | #include <linux/platform_data/ads7828.h> |
bea0bab0 | 23 | #include <linux/regmap.h> |
46d78462 | 24 | #include <linux/slab.h> |
a8ddfea0 | 25 | #include <linux/regulator/consumer.h> |
5812f928 SH |
26 | |
27 | /* The ADS7828 registers */ | |
46d78462 VD |
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 | ||
0962e0f1 GR |
35 | /* List of supported devices */ |
36 | enum ads7828_chips { ads7828, ads7830 }; | |
37 | ||
46d78462 | 38 | /* Client specific data */ |
5812f928 | 39 | struct ads7828_data { |
bea0bab0 | 40 | struct regmap *regmap; |
46d78462 VD |
41 | u8 cmd_byte; /* Command byte without channel bits */ |
42 | unsigned int lsb_resol; /* Resolution of the ADC sample LSB */ | |
5812f928 SH |
43 | }; |
44 | ||
46d78462 VD |
45 | /* Command byte C2,C1,C0 - see datasheet */ |
46 | static inline u8 ads7828_cmd_byte(u8 cmd, int ch) | |
5812f928 | 47 | { |
46d78462 | 48 | return cmd | (((ch >> 1) | (ch & 0x01) << 2) << 4); |
5812f928 SH |
49 | } |
50 | ||
5812f928 | 51 | /* sysfs callback function */ |
3ecd2783 GR |
52 | static ssize_t ads7828_in_show(struct device *dev, |
53 | struct device_attribute *da, char *buf) | |
5812f928 SH |
54 | { |
55 | struct sensor_device_attribute *attr = to_sensor_dev_attr(da); | |
bea0bab0 GR |
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; | |
5812f928 | 60 | |
bea0bab0 GR |
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)); | |
46d78462 | 67 | } |
5812f928 | 68 | |
3ecd2783 GR |
69 | static SENSOR_DEVICE_ATTR_RO(in0_input, ads7828_in, 0); |
70 | static SENSOR_DEVICE_ATTR_RO(in1_input, ads7828_in, 1); | |
71 | static SENSOR_DEVICE_ATTR_RO(in2_input, ads7828_in, 2); | |
72 | static SENSOR_DEVICE_ATTR_RO(in3_input, ads7828_in, 3); | |
73 | static SENSOR_DEVICE_ATTR_RO(in4_input, ads7828_in, 4); | |
74 | static SENSOR_DEVICE_ATTR_RO(in5_input, ads7828_in, 5); | |
75 | static SENSOR_DEVICE_ATTR_RO(in6_input, ads7828_in, 6); | |
76 | static SENSOR_DEVICE_ATTR_RO(in7_input, ads7828_in, 7); | |
5812f928 | 77 | |
f82b2c34 | 78 | static struct attribute *ads7828_attrs[] = { |
5812f928 SH |
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 | ||
f82b2c34 | 90 | ATTRIBUTE_GROUPS(ads7828); |
5812f928 | 91 | |
bea0bab0 GR |
92 | static const struct regmap_config ads2828_regmap_config = { |
93 | .reg_bits = 8, | |
94 | .val_bits = 16, | |
95 | }; | |
96 | ||
97 | static const struct regmap_config ads2830_regmap_config = { | |
98 | .reg_bits = 8, | |
99 | .val_bits = 8, | |
100 | }; | |
101 | ||
673afe46 SK |
102 | static const struct i2c_device_id ads7828_device_ids[]; |
103 | ||
104 | static int ads7828_probe(struct i2c_client *client) | |
7347cb38 | 105 | { |
f82b2c34 AL |
106 | struct device *dev = &client->dev; |
107 | struct ads7828_platform_data *pdata = dev_get_platdata(dev); | |
7347cb38 | 108 | struct ads7828_data *data; |
f82b2c34 | 109 | struct device *hwmon_dev; |
7f444bf0 | 110 | unsigned int vref_mv = ADS7828_INT_VREF_MV; |
a8ddfea0 | 111 | unsigned int vref_uv; |
7f444bf0 GR |
112 | bool diff_input = false; |
113 | bool ext_vref = false; | |
7a18afe8 | 114 | unsigned int regval; |
2d688f14 | 115 | enum ads7828_chips chip; |
a8ddfea0 | 116 | struct regulator *reg; |
5812f928 | 117 | |
f82b2c34 | 118 | data = devm_kzalloc(dev, sizeof(struct ads7828_data), GFP_KERNEL); |
34e3f7f5 GR |
119 | if (!data) |
120 | return -ENOMEM; | |
5812f928 | 121 | |
46d78462 | 122 | if (pdata) { |
7f444bf0 GR |
123 | diff_input = pdata->diff_input; |
124 | ext_vref = pdata->ext_vref; | |
125 | if (ext_vref && pdata->vref_mv) | |
126 | vref_mv = pdata->vref_mv; | |
a8ddfea0 SP |
127 | } else if (dev->of_node) { |
128 | diff_input = of_property_read_bool(dev->of_node, | |
129 | "ti,differential-input"); | |
130 | reg = devm_regulator_get_optional(dev, "vref"); | |
131 | if (!IS_ERR(reg)) { | |
132 | vref_uv = regulator_get_voltage(reg); | |
133 | vref_mv = DIV_ROUND_CLOSEST(vref_uv, 1000); | |
134 | if (vref_mv < ADS7828_EXT_VREF_MV_MIN || | |
135 | vref_mv > ADS7828_EXT_VREF_MV_MAX) | |
136 | return -EINVAL; | |
137 | ext_vref = true; | |
138 | } | |
46d78462 VD |
139 | } |
140 | ||
2d688f14 JMC |
141 | if (client->dev.of_node) |
142 | chip = (enum ads7828_chips) | |
143 | of_device_get_match_data(&client->dev); | |
144 | else | |
673afe46 | 145 | chip = i2c_match_id(ads7828_device_ids, client)->driver_data; |
2d688f14 | 146 | |
7f444bf0 GR |
147 | /* Bound Vref with min/max values */ |
148 | vref_mv = clamp_val(vref_mv, ADS7828_EXT_VREF_MV_MIN, | |
149 | ADS7828_EXT_VREF_MV_MAX); | |
46d78462 | 150 | |
0962e0f1 | 151 | /* ADS7828 uses 12-bit samples, while ADS7830 is 8-bit */ |
2d688f14 | 152 | if (chip == ads7828) { |
7f444bf0 | 153 | data->lsb_resol = DIV_ROUND_CLOSEST(vref_mv * 1000, 4096); |
bea0bab0 GR |
154 | data->regmap = devm_regmap_init_i2c(client, |
155 | &ads2828_regmap_config); | |
0962e0f1 | 156 | } else { |
7f444bf0 | 157 | data->lsb_resol = DIV_ROUND_CLOSEST(vref_mv * 1000, 256); |
bea0bab0 GR |
158 | data->regmap = devm_regmap_init_i2c(client, |
159 | &ads2830_regmap_config); | |
0962e0f1 | 160 | } |
46d78462 | 161 | |
d9ef72cd AL |
162 | if (IS_ERR(data->regmap)) |
163 | return PTR_ERR(data->regmap); | |
164 | ||
7f444bf0 GR |
165 | data->cmd_byte = ext_vref ? ADS7828_CMD_PD1 : ADS7828_CMD_PD3; |
166 | if (!diff_input) | |
46d78462 VD |
167 | data->cmd_byte |= ADS7828_CMD_SD_SE; |
168 | ||
7a18afe8 AB |
169 | /* |
170 | * Datasheet specifies internal reference voltage is disabled by | |
171 | * default. The internal reference voltage needs to be enabled and | |
172 | * voltage needs to settle before getting valid ADC data. So perform a | |
173 | * dummy read to enable the internal reference voltage. | |
174 | */ | |
175 | if (!ext_vref) | |
176 | regmap_read(data->regmap, data->cmd_byte, ®val); | |
177 | ||
f82b2c34 AL |
178 | hwmon_dev = devm_hwmon_device_register_with_groups(dev, client->name, |
179 | data, | |
180 | ads7828_groups); | |
181 | return PTR_ERR_OR_ZERO(hwmon_dev); | |
5812f928 SH |
182 | } |
183 | ||
46d78462 | 184 | static const struct i2c_device_id ads7828_device_ids[] = { |
0962e0f1 GR |
185 | { "ads7828", ads7828 }, |
186 | { "ads7830", ads7830 }, | |
46d78462 VD |
187 | { } |
188 | }; | |
189 | MODULE_DEVICE_TABLE(i2c, ads7828_device_ids); | |
5812f928 | 190 | |
0337dd9b | 191 | static const struct of_device_id __maybe_unused ads7828_of_match[] = { |
2d688f14 JMC |
192 | { |
193 | .compatible = "ti,ads7828", | |
194 | .data = (void *)ads7828 | |
195 | }, | |
196 | { | |
197 | .compatible = "ti,ads7830", | |
198 | .data = (void *)ads7830 | |
199 | }, | |
200 | { }, | |
201 | }; | |
202 | MODULE_DEVICE_TABLE(of, ads7828_of_match); | |
203 | ||
46d78462 VD |
204 | static struct i2c_driver ads7828_driver = { |
205 | .driver = { | |
206 | .name = "ads7828", | |
2d688f14 | 207 | .of_match_table = of_match_ptr(ads7828_of_match), |
46d78462 | 208 | }, |
5812f928 | 209 | |
46d78462 | 210 | .id_table = ads7828_device_ids, |
673afe46 | 211 | .probe_new = ads7828_probe, |
46d78462 | 212 | }; |
5812f928 | 213 | |
46d78462 | 214 | module_i2c_driver(ads7828_driver); |
5812f928 | 215 | |
5812f928 | 216 | MODULE_LICENSE("GPL"); |
46d78462 | 217 | MODULE_AUTHOR("Steve Hardy <shardy@redhat.com>"); |
0962e0f1 | 218 | MODULE_DESCRIPTION("Driver for TI ADS7828 A/D converter and compatibles"); |