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
39struct adcxx {
40	struct device *hwmon_dev;
41	struct mutex lock;
42	u32 channels;
43	u32 reference; /* in millivolts */
44};
45
46/* sysfs hook function */
47static 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);
79out:
80	mutex_unlock(&adc->lock);
81	return status;
82}
83
84static 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
91static 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
108static 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
129static 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
135static 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
151static 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
189out_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
197static 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
210static const struct spi_device_id adcxx_ids[] = {
211	{ "adcxx1s", 1 },
212	{ "adcxx2s", 2 },
213	{ "adcxx4s", 4 },
214	{ "adcxx8s", 8 },
215	{ },
216};
217MODULE_DEVICE_TABLE(spi, adcxx_ids);
218
219static 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
228module_spi_driver(adcxx_driver);
229
230MODULE_AUTHOR("Marc Pignat");
231MODULE_DESCRIPTION("National Semiconductor adcxx8sxxx Linux driver");
232MODULE_LICENSE("GPL");
233