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/spi/spi.h>
35
36 #define DRVNAME "adcxx"
37
38 struct adcxx {
39 struct device *hwmon_dev;
40 struct mutex lock;
41 u32 channels;
42 u32 reference; /* in millivolts */
43 };
44
45 /* sysfs hook function */
adcxx_show(struct device * dev,struct device_attribute * devattr,char * buf)46 static ssize_t adcxx_show(struct device *dev,
47 struct device_attribute *devattr, char *buf)
48 {
49 struct spi_device *spi = to_spi_device(dev);
50 struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
51 struct adcxx *adc = spi_get_drvdata(spi);
52 u8 tx_buf[2];
53 u8 rx_buf[2];
54 int status;
55 u32 value;
56
57 if (mutex_lock_interruptible(&adc->lock))
58 return -ERESTARTSYS;
59
60 if (adc->channels == 1) {
61 status = spi_read(spi, rx_buf, sizeof(rx_buf));
62 } else {
63 tx_buf[0] = attr->index << 3; /* other bits are don't care */
64 status = spi_write_then_read(spi, tx_buf, sizeof(tx_buf),
65 rx_buf, sizeof(rx_buf));
66 }
67 if (status < 0) {
68 dev_warn(dev, "SPI synch. transfer failed with status %d\n",
69 status);
70 goto out;
71 }
72
73 value = (rx_buf[0] << 8) + rx_buf[1];
74 dev_dbg(dev, "raw value = 0x%x\n", value);
75
76 value = value * adc->reference >> 12;
77 status = sprintf(buf, "%d\n", value);
78 out:
79 mutex_unlock(&adc->lock);
80 return status;
81 }
82
adcxx_min_show(struct device * dev,struct device_attribute * devattr,char * buf)83 static ssize_t adcxx_min_show(struct device *dev,
84 struct device_attribute *devattr, char *buf)
85 {
86 /* The minimum reference is 0 for this chip family */
87 return sprintf(buf, "0\n");
88 }
89
adcxx_max_show(struct device * dev,struct device_attribute * devattr,char * buf)90 static ssize_t adcxx_max_show(struct device *dev,
91 struct device_attribute *devattr, char *buf)
92 {
93 struct spi_device *spi = to_spi_device(dev);
94 struct adcxx *adc = spi_get_drvdata(spi);
95 u32 reference;
96
97 if (mutex_lock_interruptible(&adc->lock))
98 return -ERESTARTSYS;
99
100 reference = adc->reference;
101
102 mutex_unlock(&adc->lock);
103
104 return sprintf(buf, "%d\n", reference);
105 }
106
adcxx_max_store(struct device * dev,struct device_attribute * devattr,const char * buf,size_t count)107 static ssize_t adcxx_max_store(struct device *dev,
108 struct device_attribute *devattr,
109 const char *buf, size_t count)
110 {
111 struct spi_device *spi = to_spi_device(dev);
112 struct adcxx *adc = spi_get_drvdata(spi);
113 unsigned long value;
114
115 if (kstrtoul(buf, 10, &value))
116 return -EINVAL;
117
118 if (mutex_lock_interruptible(&adc->lock))
119 return -ERESTARTSYS;
120
121 adc->reference = value;
122
123 mutex_unlock(&adc->lock);
124
125 return count;
126 }
127
adcxx_name_show(struct device * dev,struct device_attribute * devattr,char * buf)128 static ssize_t adcxx_name_show(struct device *dev,
129 struct device_attribute *devattr, char *buf)
130 {
131 return sprintf(buf, "%s\n", to_spi_device(dev)->modalias);
132 }
133
134 static struct sensor_device_attribute ad_input[] = {
135 SENSOR_ATTR_RO(name, adcxx_name, 0),
136 SENSOR_ATTR_RO(in_min, adcxx_min, 0),
137 SENSOR_ATTR_RW(in_max, adcxx_max, 0),
138 SENSOR_ATTR_RO(in0_input, adcxx, 0),
139 SENSOR_ATTR_RO(in1_input, adcxx, 1),
140 SENSOR_ATTR_RO(in2_input, adcxx, 2),
141 SENSOR_ATTR_RO(in3_input, adcxx, 3),
142 SENSOR_ATTR_RO(in4_input, adcxx, 4),
143 SENSOR_ATTR_RO(in5_input, adcxx, 5),
144 SENSOR_ATTR_RO(in6_input, adcxx, 6),
145 SENSOR_ATTR_RO(in7_input, adcxx, 7),
146 };
147
148 /*----------------------------------------------------------------------*/
149
adcxx_probe(struct spi_device * spi)150 static int adcxx_probe(struct spi_device *spi)
151 {
152 int channels = spi_get_device_id(spi)->driver_data;
153 struct adcxx *adc;
154 int status;
155 int i;
156
157 adc = devm_kzalloc(&spi->dev, sizeof(*adc), GFP_KERNEL);
158 if (!adc)
159 return -ENOMEM;
160
161 /* set a default value for the reference */
162 adc->reference = 3300;
163 adc->channels = channels;
164 mutex_init(&adc->lock);
165
166 mutex_lock(&adc->lock);
167
168 spi_set_drvdata(spi, adc);
169
170 for (i = 0; i < 3 + adc->channels; i++) {
171 status = device_create_file(&spi->dev, &ad_input[i].dev_attr);
172 if (status) {
173 dev_err(&spi->dev, "device_create_file failed.\n");
174 goto out_err;
175 }
176 }
177
178 adc->hwmon_dev = hwmon_device_register(&spi->dev);
179 if (IS_ERR(adc->hwmon_dev)) {
180 dev_err(&spi->dev, "hwmon_device_register failed.\n");
181 status = PTR_ERR(adc->hwmon_dev);
182 goto out_err;
183 }
184
185 mutex_unlock(&adc->lock);
186 return 0;
187
188 out_err:
189 for (i--; i >= 0; i--)
190 device_remove_file(&spi->dev, &ad_input[i].dev_attr);
191
192 mutex_unlock(&adc->lock);
193 return status;
194 }
195
adcxx_remove(struct spi_device * spi)196 static void adcxx_remove(struct spi_device *spi)
197 {
198 struct adcxx *adc = spi_get_drvdata(spi);
199 int i;
200
201 mutex_lock(&adc->lock);
202 hwmon_device_unregister(adc->hwmon_dev);
203 for (i = 0; i < 3 + adc->channels; i++)
204 device_remove_file(&spi->dev, &ad_input[i].dev_attr);
205
206 mutex_unlock(&adc->lock);
207 }
208
209 static const struct spi_device_id adcxx_ids[] = {
210 { "adcxx1s", 1 },
211 { "adcxx2s", 2 },
212 { "adcxx4s", 4 },
213 { "adcxx8s", 8 },
214 { },
215 };
216 MODULE_DEVICE_TABLE(spi, adcxx_ids);
217
218 static struct spi_driver adcxx_driver = {
219 .driver = {
220 .name = "adcxx",
221 },
222 .id_table = adcxx_ids,
223 .probe = adcxx_probe,
224 .remove = adcxx_remove,
225 };
226
227 module_spi_driver(adcxx_driver);
228
229 MODULE_AUTHOR("Marc Pignat");
230 MODULE_DESCRIPTION("National Semiconductor adcxx8sxxx Linux driver");
231 MODULE_LICENSE("GPL");
232