1/*
2 * max1111.c - +2.7V, Low-Power, Multichannel, Serial 8-bit ADCs
3 *
4 * Based on arch/arm/mach-pxa/corgi_ssp.c
5 *
6 * Copyright (C) 2004-2005 Richard Purdie
7 *
8 * Copyright (C) 2008 Marvell International Ltd.
9 * Eric Miao <eric.miao@marvell.com>
10 *
11 * This program is free software; you can redistribute it and/or modify
12 * it under the terms of the GNU General Public License version 2 as
13 * publishhed by the Free Software Foundation.
14 */
15
16#include <linux/module.h>
17#include <linux/kernel.h>
18#include <linux/init.h>
19#include <linux/err.h>
20#include <linux/hwmon.h>
21#include <linux/hwmon-sysfs.h>
22#include <linux/spi/spi.h>
23#include <linux/slab.h>
24
25enum chips { max1110, max1111, max1112, max1113 };
26
27#define MAX1111_TX_BUF_SIZE 1
28#define MAX1111_RX_BUF_SIZE 2
29
30/* MAX1111 Commands */
31#define MAX1111_CTRL_PD0 (1u << 0)
32#define MAX1111_CTRL_PD1 (1u << 1)
33#define MAX1111_CTRL_SGL (1u << 2)
34#define MAX1111_CTRL_UNI (1u << 3)
35#define MAX1110_CTRL_SEL_SH (4)
36#define MAX1111_CTRL_SEL_SH (5) /* NOTE: bit 4 is ignored */
37#define MAX1111_CTRL_STR (1u << 7)
38
39struct max1111_data {
40 struct spi_device *spi;
41 struct device *hwmon_dev;
42 struct spi_message msg;
43 struct spi_transfer xfer[2];
44 uint8_t tx_buf[MAX1111_TX_BUF_SIZE];
45 uint8_t rx_buf[MAX1111_RX_BUF_SIZE];
46 struct mutex drvdata_lock;
47 /* protect msg, xfer and buffers from multiple access */
48 int sel_sh;
49 int lsb;
50};
51
52static int max1111_read(struct device *dev, int channel)
53{
54 struct max1111_data *data = dev_get_drvdata(dev);
55 uint8_t v1, v2;
56 int err;
57
58 /* writing to drvdata struct is not thread safe, wait on mutex */
59 mutex_lock(&data->drvdata_lock);
60
61 data->tx_buf[0] = (channel << data->sel_sh) |
62 MAX1111_CTRL_PD0 | MAX1111_CTRL_PD1 |
63 MAX1111_CTRL_SGL | MAX1111_CTRL_UNI | MAX1111_CTRL_STR;
64
65 err = spi_sync(data->spi, &data->msg);
66 if (err < 0) {
67 dev_err(dev, "spi_sync failed with %d\n", err);
68 mutex_unlock(&data->drvdata_lock);
69 return err;
70 }
71
72 v1 = data->rx_buf[0];
73 v2 = data->rx_buf[1];
74
75 mutex_unlock(&data->drvdata_lock);
76
77 if ((v1 & 0xc0) || (v2 & 0x3f))
78 return -EINVAL;
79
80 return (v1 << 2) | (v2 >> 6);
81}
82
83#ifdef CONFIG_SHARPSL_PM
84static struct max1111_data *the_max1111;
85
86int max1111_read_channel(int channel)
87{
88 if (!the_max1111 || !the_max1111->spi)
89 return -ENODEV;
90
91 return max1111_read(&the_max1111->spi->dev, channel);
92}
93EXPORT_SYMBOL(max1111_read_channel);
94#endif
95
96/*
97 * NOTE: SPI devices do not have a default 'name' attribute, which is
98 * likely to be used by hwmon applications to distinguish between
99 * different devices, explicitly add a name attribute here.
100 */
101static ssize_t name_show(struct device *dev,
102 struct device_attribute *attr, char *buf)
103{
104 return sprintf(buf, "%s\n", to_spi_device(dev)->modalias);
105}
106
107static ssize_t show_adc(struct device *dev,
108 struct device_attribute *attr, char *buf)
109{
110 struct max1111_data *data = dev_get_drvdata(dev);
111 int channel = to_sensor_dev_attr(attr)->index;
112 int ret;
113
114 ret = max1111_read(dev, channel);
115 if (ret < 0)
116 return ret;
117
118 /*
119 * Assume the reference voltage to be 2.048V or 4.096V, with an 8-bit
120 * sample. The LSB weight is 8mV or 16mV depending on the chip type.
121 */
122 return sprintf(buf, "%d\n", ret * data->lsb);
123}
124
125#define MAX1111_ADC_ATTR(_id) \
126 SENSOR_DEVICE_ATTR(in##_id##_input, S_IRUGO, show_adc, NULL, _id)
127
128static DEVICE_ATTR_RO(name);
129static MAX1111_ADC_ATTR(0);
130static MAX1111_ADC_ATTR(1);
131static MAX1111_ADC_ATTR(2);
132static MAX1111_ADC_ATTR(3);
133static MAX1111_ADC_ATTR(4);
134static MAX1111_ADC_ATTR(5);
135static MAX1111_ADC_ATTR(6);
136static MAX1111_ADC_ATTR(7);
137
138static struct attribute *max1111_attributes[] = {
139 &dev_attr_name.attr,
140 &sensor_dev_attr_in0_input.dev_attr.attr,
141 &sensor_dev_attr_in1_input.dev_attr.attr,
142 &sensor_dev_attr_in2_input.dev_attr.attr,
143 &sensor_dev_attr_in3_input.dev_attr.attr,
144 NULL,
145};
146
147static const struct attribute_group max1111_attr_group = {
148 .attrs = max1111_attributes,
149};
150
151static struct attribute *max1110_attributes[] = {
152 &sensor_dev_attr_in4_input.dev_attr.attr,
153 &sensor_dev_attr_in5_input.dev_attr.attr,
154 &sensor_dev_attr_in6_input.dev_attr.attr,
155 &sensor_dev_attr_in7_input.dev_attr.attr,
156 NULL,
157};
158
159static const struct attribute_group max1110_attr_group = {
160 .attrs = max1110_attributes,
161};
162
163static int setup_transfer(struct max1111_data *data)
164{
165 struct spi_message *m;
166 struct spi_transfer *x;
167
168 m = &data->msg;
169 x = &data->xfer[0];
170
171 spi_message_init(m);
172
173 x->tx_buf = &data->tx_buf[0];
174 x->len = MAX1111_TX_BUF_SIZE;
175 spi_message_add_tail(x, m);
176
177 x++;
178 x->rx_buf = &data->rx_buf[0];
179 x->len = MAX1111_RX_BUF_SIZE;
180 spi_message_add_tail(x, m);
181
182 return 0;
183}
184
185static int max1111_probe(struct spi_device *spi)
186{
187 enum chips chip = spi_get_device_id(spi)->driver_data;
188 struct max1111_data *data;
189 int err;
190
191 spi->bits_per_word = 8;
192 spi->mode = SPI_MODE_0;
193 err = spi_setup(spi);
194 if (err < 0)
195 return err;
196
197 data = devm_kzalloc(&spi->dev, sizeof(struct max1111_data), GFP_KERNEL);
198 if (data == NULL)
199 return -ENOMEM;
200
201 switch (chip) {
202 case max1110:
203 data->lsb = 8;
204 data->sel_sh = MAX1110_CTRL_SEL_SH;
205 break;
206 case max1111:
207 data->lsb = 8;
208 data->sel_sh = MAX1111_CTRL_SEL_SH;
209 break;
210 case max1112:
211 data->lsb = 16;
212 data->sel_sh = MAX1110_CTRL_SEL_SH;
213 break;
214 case max1113:
215 data->lsb = 16;
216 data->sel_sh = MAX1111_CTRL_SEL_SH;
217 break;
218 }
219 err = setup_transfer(data);
220 if (err)
221 return err;
222
223 mutex_init(&data->drvdata_lock);
224
225 data->spi = spi;
226 spi_set_drvdata(spi, data);
227
228 err = sysfs_create_group(&spi->dev.kobj, &max1111_attr_group);
229 if (err) {
230 dev_err(&spi->dev, "failed to create attribute group\n");
231 return err;
232 }
233 if (chip == max1110 || chip == max1112) {
234 err = sysfs_create_group(&spi->dev.kobj, &max1110_attr_group);
235 if (err) {
236 dev_err(&spi->dev,
237 "failed to create extended attribute group\n");
238 goto err_remove;
239 }
240 }
241
242 data->hwmon_dev = hwmon_device_register(&spi->dev);
243 if (IS_ERR(data->hwmon_dev)) {
244 dev_err(&spi->dev, "failed to create hwmon device\n");
245 err = PTR_ERR(data->hwmon_dev);
246 goto err_remove;
247 }
248
249#ifdef CONFIG_SHARPSL_PM
250 the_max1111 = data;
251#endif
252 return 0;
253
254err_remove:
255 sysfs_remove_group(&spi->dev.kobj, &max1110_attr_group);
256 sysfs_remove_group(&spi->dev.kobj, &max1111_attr_group);
257 return err;
258}
259
260static int max1111_remove(struct spi_device *spi)
261{
262 struct max1111_data *data = spi_get_drvdata(spi);
263
264#ifdef CONFIG_SHARPSL_PM
265 the_max1111 = NULL;
266#endif
267 hwmon_device_unregister(data->hwmon_dev);
268 sysfs_remove_group(&spi->dev.kobj, &max1110_attr_group);
269 sysfs_remove_group(&spi->dev.kobj, &max1111_attr_group);
270 mutex_destroy(&data->drvdata_lock);
271 return 0;
272}
273
274static const struct spi_device_id max1111_ids[] = {
275 { "max1110", max1110 },
276 { "max1111", max1111 },
277 { "max1112", max1112 },
278 { "max1113", max1113 },
279 { },
280};
281MODULE_DEVICE_TABLE(spi, max1111_ids);
282
283static struct spi_driver max1111_driver = {
284 .driver = {
285 .name = "max1111",
286 },
287 .id_table = max1111_ids,
288 .probe = max1111_probe,
289 .remove = max1111_remove,
290};
291
292module_spi_driver(max1111_driver);
293
294MODULE_AUTHOR("Eric Miao <eric.miao@marvell.com>");
295MODULE_DESCRIPTION("MAX1110/MAX1111/MAX1112/MAX1113 ADC Driver");
296MODULE_LICENSE("GPL");
297