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 */ |
36 | enum ads7828_chips { ads7828, ads7830 }; |
37 | |
38 | /* Client specific data */ |
39 | struct 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 */ |
46 | static 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 */ |
52 | static 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(cmd: data->cmd_byte, ch: attr->index); |
58 | unsigned int regval; |
59 | int err; |
60 | |
61 | err = regmap_read(map: data->regmap, reg: cmd, val: ®val); |
62 | if (err < 0) |
63 | return err; |
64 | |
65 | return sprintf(buf, fmt: "%d\n" , |
66 | DIV_ROUND_CLOSEST(regval * data->lsb_resol, 1000)); |
67 | } |
68 | |
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); |
77 | |
78 | static 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 | |
90 | ATTRIBUTE_GROUPS(ads7828); |
91 | |
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 | |
102 | static const struct i2c_device_id ads7828_device_ids[]; |
103 | |
104 | static int ads7828_probe(struct i2c_client *client) |
105 | { |
106 | struct device *dev = &client->dev; |
107 | struct ads7828_platform_data *pdata = dev_get_platdata(dev); |
108 | struct ads7828_data *data; |
109 | struct device *hwmon_dev; |
110 | unsigned int vref_mv = ADS7828_INT_VREF_MV; |
111 | unsigned int vref_uv; |
112 | bool diff_input = false; |
113 | bool ext_vref = false; |
114 | unsigned int regval; |
115 | enum ads7828_chips chip; |
116 | struct regulator *reg; |
117 | |
118 | data = devm_kzalloc(dev, size: sizeof(struct ads7828_data), GFP_KERNEL); |
119 | if (!data) |
120 | return -ENOMEM; |
121 | |
122 | if (pdata) { |
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; |
127 | } else if (dev->of_node) { |
128 | diff_input = of_property_read_bool(np: dev->of_node, |
129 | propname: "ti,differential-input" ); |
130 | reg = devm_regulator_get_optional(dev, id: "vref" ); |
131 | if (!IS_ERR(ptr: reg)) { |
132 | vref_uv = regulator_get_voltage(regulator: 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 | } |
139 | } |
140 | |
141 | if (client->dev.of_node) |
142 | chip = (uintptr_t)of_device_get_match_data(dev: &client->dev); |
143 | else |
144 | chip = i2c_match_id(id: ads7828_device_ids, client)->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(ptr: data->regmap)) |
162 | return PTR_ERR(ptr: 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(map: data->regmap, reg: data->cmd_byte, val: ®val); |
176 | |
177 | hwmon_dev = devm_hwmon_device_register_with_groups(dev, name: client->name, |
178 | drvdata: data, |
179 | groups: ads7828_groups); |
180 | return PTR_ERR_OR_ZERO(ptr: hwmon_dev); |
181 | } |
182 | |
183 | static const struct i2c_device_id ads7828_device_ids[] = { |
184 | { "ads7828" , ads7828 }, |
185 | { "ads7830" , ads7830 }, |
186 | { } |
187 | }; |
188 | MODULE_DEVICE_TABLE(i2c, ads7828_device_ids); |
189 | |
190 | static 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 | }; |
201 | MODULE_DEVICE_TABLE(of, ads7828_of_match); |
202 | |
203 | static 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 | |
213 | module_i2c_driver(ads7828_driver); |
214 | |
215 | MODULE_LICENSE("GPL" ); |
216 | MODULE_AUTHOR("Steve Hardy <shardy@redhat.com>" ); |
217 | MODULE_DESCRIPTION("Driver for TI ADS7828 A/D converter and compatibles" ); |
218 | |