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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/of_device.h> | |
35 | #include <linux/platform_data/ads7828.h> | |
36 | #include <linux/regmap.h> | |
37 | #include <linux/slab.h> | |
38 | #include <linux/regulator/consumer.h> | |
39 | ||
40 | /* The ADS7828 registers */ | |
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 */ | |
49 | enum ads7828_chips { ads7828, ads7830 }; | |
50 | ||
51 | /* Client specific data */ | |
52 | struct ads7828_data { | |
53 | struct regmap *regmap; | |
54 | u8 cmd_byte; /* Command byte without channel bits */ | |
55 | unsigned int lsb_resol; /* Resolution of the ADC sample LSB */ | |
56 | }; | |
57 | ||
58 | /* Command byte C2,C1,C0 - see datasheet */ | |
59 | static inline u8 ads7828_cmd_byte(u8 cmd, int ch) | |
60 | { | |
61 | return cmd | (((ch >> 1) | (ch & 0x01) << 2) << 4); | |
62 | } | |
63 | ||
64 | /* sysfs callback function */ | |
65 | static ssize_t ads7828_show_in(struct device *dev, struct device_attribute *da, | |
66 | char *buf) | |
67 | { | |
68 | struct sensor_device_attribute *attr = to_sensor_dev_attr(da); | |
69 | struct ads7828_data *data = dev_get_drvdata(dev); | |
70 | u8 cmd = ads7828_cmd_byte(data->cmd_byte, attr->index); | |
71 | unsigned int regval; | |
72 | int err; | |
73 | ||
74 | err = regmap_read(data->regmap, cmd, ®val); | |
75 | if (err < 0) | |
76 | return err; | |
77 | ||
78 | return sprintf(buf, "%d\n", | |
79 | DIV_ROUND_CLOSEST(regval * data->lsb_resol, 1000)); | |
80 | } | |
81 | ||
82 | static SENSOR_DEVICE_ATTR(in0_input, S_IRUGO, ads7828_show_in, NULL, 0); | |
83 | static SENSOR_DEVICE_ATTR(in1_input, S_IRUGO, ads7828_show_in, NULL, 1); | |
84 | static SENSOR_DEVICE_ATTR(in2_input, S_IRUGO, ads7828_show_in, NULL, 2); | |
85 | static SENSOR_DEVICE_ATTR(in3_input, S_IRUGO, ads7828_show_in, NULL, 3); | |
86 | static SENSOR_DEVICE_ATTR(in4_input, S_IRUGO, ads7828_show_in, NULL, 4); | |
87 | static SENSOR_DEVICE_ATTR(in5_input, S_IRUGO, ads7828_show_in, NULL, 5); | |
88 | static SENSOR_DEVICE_ATTR(in6_input, S_IRUGO, ads7828_show_in, NULL, 6); | |
89 | static SENSOR_DEVICE_ATTR(in7_input, S_IRUGO, ads7828_show_in, NULL, 7); | |
90 | ||
91 | static struct attribute *ads7828_attrs[] = { | |
92 | &sensor_dev_attr_in0_input.dev_attr.attr, | |
93 | &sensor_dev_attr_in1_input.dev_attr.attr, | |
94 | &sensor_dev_attr_in2_input.dev_attr.attr, | |
95 | &sensor_dev_attr_in3_input.dev_attr.attr, | |
96 | &sensor_dev_attr_in4_input.dev_attr.attr, | |
97 | &sensor_dev_attr_in5_input.dev_attr.attr, | |
98 | &sensor_dev_attr_in6_input.dev_attr.attr, | |
99 | &sensor_dev_attr_in7_input.dev_attr.attr, | |
100 | NULL | |
101 | }; | |
102 | ||
103 | ATTRIBUTE_GROUPS(ads7828); | |
104 | ||
105 | static const struct regmap_config ads2828_regmap_config = { | |
106 | .reg_bits = 8, | |
107 | .val_bits = 16, | |
108 | }; | |
109 | ||
110 | static const struct regmap_config ads2830_regmap_config = { | |
111 | .reg_bits = 8, | |
112 | .val_bits = 8, | |
113 | }; | |
114 | ||
115 | static int ads7828_probe(struct i2c_client *client, | |
116 | const struct i2c_device_id *id) | |
117 | { | |
118 | struct device *dev = &client->dev; | |
119 | struct ads7828_platform_data *pdata = dev_get_platdata(dev); | |
120 | struct ads7828_data *data; | |
121 | struct device *hwmon_dev; | |
122 | unsigned int vref_mv = ADS7828_INT_VREF_MV; | |
123 | unsigned int vref_uv; | |
124 | bool diff_input = false; | |
125 | bool ext_vref = false; | |
126 | unsigned int regval; | |
127 | enum ads7828_chips chip; | |
128 | struct regulator *reg; | |
129 | ||
130 | data = devm_kzalloc(dev, sizeof(struct ads7828_data), GFP_KERNEL); | |
131 | if (!data) | |
132 | return -ENOMEM; | |
133 | ||
134 | if (pdata) { | |
135 | diff_input = pdata->diff_input; | |
136 | ext_vref = pdata->ext_vref; | |
137 | if (ext_vref && pdata->vref_mv) | |
138 | vref_mv = pdata->vref_mv; | |
139 | } else if (dev->of_node) { | |
140 | diff_input = of_property_read_bool(dev->of_node, | |
141 | "ti,differential-input"); | |
142 | reg = devm_regulator_get_optional(dev, "vref"); | |
143 | if (!IS_ERR(reg)) { | |
144 | vref_uv = regulator_get_voltage(reg); | |
145 | vref_mv = DIV_ROUND_CLOSEST(vref_uv, 1000); | |
146 | if (vref_mv < ADS7828_EXT_VREF_MV_MIN || | |
147 | vref_mv > ADS7828_EXT_VREF_MV_MAX) | |
148 | return -EINVAL; | |
149 | ext_vref = true; | |
150 | } | |
151 | } | |
152 | ||
153 | if (client->dev.of_node) | |
154 | chip = (enum ads7828_chips) | |
155 | of_device_get_match_data(&client->dev); | |
156 | else | |
157 | chip = id->driver_data; | |
158 | ||
159 | /* Bound Vref with min/max values */ | |
160 | vref_mv = clamp_val(vref_mv, ADS7828_EXT_VREF_MV_MIN, | |
161 | ADS7828_EXT_VREF_MV_MAX); | |
162 | ||
163 | /* ADS7828 uses 12-bit samples, while ADS7830 is 8-bit */ | |
164 | if (chip == ads7828) { | |
165 | data->lsb_resol = DIV_ROUND_CLOSEST(vref_mv * 1000, 4096); | |
166 | data->regmap = devm_regmap_init_i2c(client, | |
167 | &ads2828_regmap_config); | |
168 | } else { | |
169 | data->lsb_resol = DIV_ROUND_CLOSEST(vref_mv * 1000, 256); | |
170 | data->regmap = devm_regmap_init_i2c(client, | |
171 | &ads2830_regmap_config); | |
172 | } | |
173 | ||
174 | if (IS_ERR(data->regmap)) | |
175 | return PTR_ERR(data->regmap); | |
176 | ||
177 | data->cmd_byte = ext_vref ? ADS7828_CMD_PD1 : ADS7828_CMD_PD3; | |
178 | if (!diff_input) | |
179 | data->cmd_byte |= ADS7828_CMD_SD_SE; | |
180 | ||
181 | /* | |
182 | * Datasheet specifies internal reference voltage is disabled by | |
183 | * default. The internal reference voltage needs to be enabled and | |
184 | * voltage needs to settle before getting valid ADC data. So perform a | |
185 | * dummy read to enable the internal reference voltage. | |
186 | */ | |
187 | if (!ext_vref) | |
188 | regmap_read(data->regmap, data->cmd_byte, ®val); | |
189 | ||
190 | hwmon_dev = devm_hwmon_device_register_with_groups(dev, client->name, | |
191 | data, | |
192 | ads7828_groups); | |
193 | return PTR_ERR_OR_ZERO(hwmon_dev); | |
194 | } | |
195 | ||
196 | static const struct i2c_device_id ads7828_device_ids[] = { | |
197 | { "ads7828", ads7828 }, | |
198 | { "ads7830", ads7830 }, | |
199 | { } | |
200 | }; | |
201 | MODULE_DEVICE_TABLE(i2c, ads7828_device_ids); | |
202 | ||
203 | static const struct of_device_id ads7828_of_match[] = { | |
204 | { | |
205 | .compatible = "ti,ads7828", | |
206 | .data = (void *)ads7828 | |
207 | }, | |
208 | { | |
209 | .compatible = "ti,ads7830", | |
210 | .data = (void *)ads7830 | |
211 | }, | |
212 | { }, | |
213 | }; | |
214 | MODULE_DEVICE_TABLE(of, ads7828_of_match); | |
215 | ||
216 | static struct i2c_driver ads7828_driver = { | |
217 | .driver = { | |
218 | .name = "ads7828", | |
219 | .of_match_table = of_match_ptr(ads7828_of_match), | |
220 | }, | |
221 | ||
222 | .id_table = ads7828_device_ids, | |
223 | .probe = ads7828_probe, | |
224 | }; | |
225 | ||
226 | module_i2c_driver(ads7828_driver); | |
227 | ||
228 | MODULE_LICENSE("GPL"); | |
229 | MODULE_AUTHOR("Steve Hardy <shardy@redhat.com>"); | |
230 | MODULE_DESCRIPTION("Driver for TI ADS7828 A/D converter and compatibles"); |