1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * adcxx.c
4 *
5 * The adcxx4s is an AD converter family from National Semiconductor (NS).
6 *
7 * Copyright (c) 2008 Marc Pignat <marc.pignat@hevs.ch>
8 *
9 * The adcxx4s communicates with a host processor via an SPI/Microwire Bus
10 * interface. This driver supports the whole family of devices with name
11 * ADC<bb><c>S<sss>, where
12 * * bb is the resolution in number of bits (8, 10, 12)
13 * * c is the number of channels (1, 2, 4, 8)
14 * * sss is the maximum conversion speed (021 for 200 kSPS, 051 for 500 kSPS
15 * and 101 for 1 MSPS)
16 *
17 * Complete datasheets are available at National's website here:
18 * http://www.national.com/ds/DC/ADC<bb><c>S<sss>.pdf
19 *
20 * Handling of 8, 10 and 12 bits converters are the same, the
21 * unavailable bits are 0 :)
22 */
23
24 #include <linux/init.h>
25 #include <linux/module.h>
26 #include <linux/kernel.h>
27 #include <linux/slab.h>
28 #include <linux/device.h>
29 #include <linux/err.h>
30 #include <linux/sysfs.h>
31 #include <linux/hwmon.h>
32 #include <linux/hwmon-sysfs.h>
33 #include <linux/mutex.h>
34 #include <linux/mod_devicetable.h>
35 #include <linux/spi/spi.h>
36
37 #define DRVNAME "adcxx"
38
39 struct adcxx {
40 struct device *hwmon_dev;
41 struct mutex lock;
42 u32 channels;
43 u32 reference; /* in millivolts */
44 };
45
46 /* sysfs hook function */
adcxx_show(struct device * dev,struct device_attribute * devattr,char * buf)47 static ssize_t adcxx_show(struct device *dev,
48 struct device_attribute *devattr, char *buf)
49 {
50 struct spi_device *spi = to_spi_device(dev);
51 struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
52 struct adcxx *adc = spi_get_drvdata(spi);
53 u8 tx_buf[2];
54 u8 rx_buf[2];
55 int status;
56 u32 value;
57
58 if (mutex_lock_interruptible(&adc->lock))
59 return -ERESTARTSYS;
60
61 if (adc->channels == 1) {
62 status = spi_read(spi, rx_buf, sizeof(rx_buf));
63 } else {
64 tx_buf[0] = attr->index << 3; /* other bits are don't care */
65 status = spi_write_then_read(spi, tx_buf, sizeof(tx_buf),
66 rx_buf, sizeof(rx_buf));
67 }
68 if (status < 0) {
69 dev_warn(dev, "SPI synch. transfer failed with status %d\n",
70 status);
71 goto out;
72 }
73
74 value = (rx_buf[0] << 8) + rx_buf[1];
75 dev_dbg(dev, "raw value = 0x%x\n", value);
76
77 value = value * adc->reference >> 12;
78 status = sprintf(buf, "%d\n", value);
79 out:
80 mutex_unlock(&adc->lock);
81 return status;
82 }
83
adcxx_min_show(struct device * dev,struct device_attribute * devattr,char * buf)84 static ssize_t adcxx_min_show(struct device *dev,
85 struct device_attribute *devattr, char *buf)
86 {
87 /* The minimum reference is 0 for this chip family */
88 return sprintf(buf, "0\n");
89 }
90
adcxx_max_show(struct device * dev,struct device_attribute * devattr,char * buf)91 static ssize_t adcxx_max_show(struct device *dev,
92 struct device_attribute *devattr, char *buf)
93 {
94 struct spi_device *spi = to_spi_device(dev);
95 struct adcxx *adc = spi_get_drvdata(spi);
96 u32 reference;
97
98 if (mutex_lock_interruptible(&adc->lock))
99 return -ERESTARTSYS;
100
101 reference = adc->reference;
102
103 mutex_unlock(&adc->lock);
104
105 return sprintf(buf, "%d\n", reference);
106 }
107
adcxx_max_store(struct device * dev,struct device_attribute * devattr,const char * buf,size_t count)108 static ssize_t adcxx_max_store(struct device *dev,
109 struct device_attribute *devattr,
110 const char *buf, size_t count)
111 {
112 struct spi_device *spi = to_spi_device(dev);
113 struct adcxx *adc = spi_get_drvdata(spi);
114 unsigned long value;
115
116 if (kstrtoul(buf, 10, &value))
117 return -EINVAL;
118
119 if (mutex_lock_interruptible(&adc->lock))
120 return -ERESTARTSYS;
121
122 adc->reference = value;
123
124 mutex_unlock(&adc->lock);
125
126 return count;
127 }
128
adcxx_name_show(struct device * dev,struct device_attribute * devattr,char * buf)129 static ssize_t adcxx_name_show(struct device *dev,
130 struct device_attribute *devattr, char *buf)
131 {
132 return sprintf(buf, "%s\n", to_spi_device(dev)->modalias);
133 }
134
135 static struct sensor_device_attribute ad_input[] = {
136 SENSOR_ATTR_RO(name, adcxx_name, 0),
137 SENSOR_ATTR_RO(in_min, adcxx_min, 0),
138 SENSOR_ATTR_RW(in_max, adcxx_max, 0),
139 SENSOR_ATTR_RO(in0_input, adcxx, 0),
140 SENSOR_ATTR_RO(in1_input, adcxx, 1),
141 SENSOR_ATTR_RO(in2_input, adcxx, 2),
142 SENSOR_ATTR_RO(in3_input, adcxx, 3),
143 SENSOR_ATTR_RO(in4_input, adcxx, 4),
144 SENSOR_ATTR_RO(in5_input, adcxx, 5),
145 SENSOR_ATTR_RO(in6_input, adcxx, 6),
146 SENSOR_ATTR_RO(in7_input, adcxx, 7),
147 };
148
149 /*----------------------------------------------------------------------*/
150
adcxx_probe(struct spi_device * spi)151 static int adcxx_probe(struct spi_device *spi)
152 {
153 int channels = spi_get_device_id(spi)->driver_data;
154 struct adcxx *adc;
155 int status;
156 int i;
157
158 adc = devm_kzalloc(&spi->dev, sizeof(*adc), GFP_KERNEL);
159 if (!adc)
160 return -ENOMEM;
161
162 /* set a default value for the reference */
163 adc->reference = 3300;
164 adc->channels = channels;
165 mutex_init(&adc->lock);
166
167 mutex_lock(&adc->lock);
168
169 spi_set_drvdata(spi, adc);
170
171 for (i = 0; i < 3 + adc->channels; i++) {
172 status = device_create_file(&spi->dev, &ad_input[i].dev_attr);
173 if (status) {
174 dev_err(&spi->dev, "device_create_file failed.\n");
175 goto out_err;
176 }
177 }
178
179 adc->hwmon_dev = hwmon_device_register(&spi->dev);
180 if (IS_ERR(adc->hwmon_dev)) {
181 dev_err(&spi->dev, "hwmon_device_register failed.\n");
182 status = PTR_ERR(adc->hwmon_dev);
183 goto out_err;
184 }
185
186 mutex_unlock(&adc->lock);
187 return 0;
188
189 out_err:
190 for (i--; i >= 0; i--)
191 device_remove_file(&spi->dev, &ad_input[i].dev_attr);
192
193 mutex_unlock(&adc->lock);
194 return status;
195 }
196
adcxx_remove(struct spi_device * spi)197 static void adcxx_remove(struct spi_device *spi)
198 {
199 struct adcxx *adc = spi_get_drvdata(spi);
200 int i;
201
202 mutex_lock(&adc->lock);
203 hwmon_device_unregister(adc->hwmon_dev);
204 for (i = 0; i < 3 + adc->channels; i++)
205 device_remove_file(&spi->dev, &ad_input[i].dev_attr);
206
207 mutex_unlock(&adc->lock);
208 }
209
210 static const struct spi_device_id adcxx_ids[] = {
211 { "adcxx1s", 1 },
212 { "adcxx2s", 2 },
213 { "adcxx4s", 4 },
214 { "adcxx8s", 8 },
215 { },
216 };
217 MODULE_DEVICE_TABLE(spi, adcxx_ids);
218
219 static struct spi_driver adcxx_driver = {
220 .driver = {
221 .name = "adcxx",
222 },
223 .id_table = adcxx_ids,
224 .probe = adcxx_probe,
225 .remove = adcxx_remove,
226 };
227
228 module_spi_driver(adcxx_driver);
229
230 MODULE_AUTHOR("Marc Pignat");
231 MODULE_DESCRIPTION("National Semiconductor adcxx8sxxx Linux driver");
232 MODULE_LICENSE("GPL");
233