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55b951e7 EM |
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> | |
5a0e3ad6 | 23 | #include <linux/slab.h> |
55b951e7 EM |
24 | |
25 | #define MAX1111_TX_BUF_SIZE 1 | |
26 | #define MAX1111_RX_BUF_SIZE 2 | |
27 | ||
28 | /* MAX1111 Commands */ | |
29 | #define MAX1111_CTRL_PD0 (1u << 0) | |
30 | #define MAX1111_CTRL_PD1 (1u << 1) | |
31 | #define MAX1111_CTRL_SGL (1u << 2) | |
32 | #define MAX1111_CTRL_UNI (1u << 3) | |
33 | #define MAX1111_CTRL_SEL_SH (5) /* NOTE: bit 4 is ignored */ | |
34 | #define MAX1111_CTRL_STR (1u << 7) | |
35 | ||
36 | struct max1111_data { | |
37 | struct spi_device *spi; | |
38 | struct device *hwmon_dev; | |
39 | struct spi_message msg; | |
40 | struct spi_transfer xfer[2]; | |
d737c09c JD |
41 | uint8_t tx_buf[MAX1111_TX_BUF_SIZE]; |
42 | uint8_t rx_buf[MAX1111_RX_BUF_SIZE]; | |
d3f684f2 PH |
43 | struct mutex drvdata_lock; |
44 | /* protect msg, xfer and buffers from multiple access */ | |
55b951e7 EM |
45 | }; |
46 | ||
47 | static int max1111_read(struct device *dev, int channel) | |
48 | { | |
49 | struct max1111_data *data = dev_get_drvdata(dev); | |
50 | uint8_t v1, v2; | |
51 | int err; | |
52 | ||
d3f684f2 PH |
53 | /* writing to drvdata struct is not thread safe, wait on mutex */ |
54 | mutex_lock(&data->drvdata_lock); | |
55 | ||
55b951e7 EM |
56 | data->tx_buf[0] = (channel << MAX1111_CTRL_SEL_SH) | |
57 | MAX1111_CTRL_PD0 | MAX1111_CTRL_PD1 | | |
58 | MAX1111_CTRL_SGL | MAX1111_CTRL_UNI | MAX1111_CTRL_STR; | |
59 | ||
60 | err = spi_sync(data->spi, &data->msg); | |
61 | if (err < 0) { | |
62 | dev_err(dev, "spi_sync failed with %d\n", err); | |
d3f684f2 | 63 | mutex_unlock(&data->drvdata_lock); |
55b951e7 EM |
64 | return err; |
65 | } | |
66 | ||
67 | v1 = data->rx_buf[0]; | |
68 | v2 = data->rx_buf[1]; | |
69 | ||
d3f684f2 PH |
70 | mutex_unlock(&data->drvdata_lock); |
71 | ||
55b951e7 EM |
72 | if ((v1 & 0xc0) || (v2 & 0x3f)) |
73 | return -EINVAL; | |
74 | ||
75 | return (v1 << 2) | (v2 >> 6); | |
76 | } | |
77 | ||
f16177c2 EM |
78 | #ifdef CONFIG_SHARPSL_PM |
79 | static struct max1111_data *the_max1111; | |
80 | ||
81 | int max1111_read_channel(int channel) | |
82 | { | |
83 | return max1111_read(&the_max1111->spi->dev, channel); | |
84 | } | |
85 | EXPORT_SYMBOL(max1111_read_channel); | |
86 | #endif | |
87 | ||
55b951e7 EM |
88 | /* |
89 | * NOTE: SPI devices do not have a default 'name' attribute, which is | |
90 | * likely to be used by hwmon applications to distinguish between | |
91 | * different devices, explicitly add a name attribute here. | |
92 | */ | |
93 | static ssize_t show_name(struct device *dev, | |
94 | struct device_attribute *attr, char *buf) | |
95 | { | |
96 | return sprintf(buf, "max1111\n"); | |
97 | } | |
98 | ||
99 | static ssize_t show_adc(struct device *dev, | |
100 | struct device_attribute *attr, char *buf) | |
101 | { | |
102 | int channel = to_sensor_dev_attr(attr)->index; | |
103 | int ret; | |
104 | ||
105 | ret = max1111_read(dev, channel); | |
106 | if (ret < 0) | |
107 | return ret; | |
108 | ||
109 | return sprintf(buf, "%d\n", ret); | |
110 | } | |
111 | ||
112 | #define MAX1111_ADC_ATTR(_id) \ | |
113 | SENSOR_DEVICE_ATTR(adc##_id##_in, S_IRUGO, show_adc, NULL, _id) | |
114 | ||
115 | static DEVICE_ATTR(name, S_IRUGO, show_name, NULL); | |
116 | static MAX1111_ADC_ATTR(0); | |
117 | static MAX1111_ADC_ATTR(1); | |
118 | static MAX1111_ADC_ATTR(2); | |
119 | static MAX1111_ADC_ATTR(3); | |
120 | ||
121 | static struct attribute *max1111_attributes[] = { | |
122 | &dev_attr_name.attr, | |
123 | &sensor_dev_attr_adc0_in.dev_attr.attr, | |
124 | &sensor_dev_attr_adc1_in.dev_attr.attr, | |
125 | &sensor_dev_attr_adc2_in.dev_attr.attr, | |
126 | &sensor_dev_attr_adc3_in.dev_attr.attr, | |
127 | NULL, | |
128 | }; | |
129 | ||
130 | static const struct attribute_group max1111_attr_group = { | |
131 | .attrs = max1111_attributes, | |
132 | }; | |
133 | ||
d737c09c | 134 | static int __devinit setup_transfer(struct max1111_data *data) |
55b951e7 EM |
135 | { |
136 | struct spi_message *m; | |
137 | struct spi_transfer *x; | |
138 | ||
55b951e7 EM |
139 | m = &data->msg; |
140 | x = &data->xfer[0]; | |
141 | ||
142 | spi_message_init(m); | |
143 | ||
144 | x->tx_buf = &data->tx_buf[0]; | |
d737c09c | 145 | x->len = MAX1111_TX_BUF_SIZE; |
55b951e7 EM |
146 | spi_message_add_tail(x, m); |
147 | ||
148 | x++; | |
149 | x->rx_buf = &data->rx_buf[0]; | |
d737c09c | 150 | x->len = MAX1111_RX_BUF_SIZE; |
55b951e7 EM |
151 | spi_message_add_tail(x, m); |
152 | ||
153 | return 0; | |
154 | } | |
155 | ||
156 | static int __devinit max1111_probe(struct spi_device *spi) | |
157 | { | |
158 | struct max1111_data *data; | |
159 | int err; | |
160 | ||
161 | spi->bits_per_word = 8; | |
162 | spi->mode = SPI_MODE_0; | |
163 | err = spi_setup(spi); | |
164 | if (err < 0) | |
165 | return err; | |
166 | ||
167 | data = kzalloc(sizeof(struct max1111_data), GFP_KERNEL); | |
168 | if (data == NULL) { | |
169 | dev_err(&spi->dev, "failed to allocate memory\n"); | |
170 | return -ENOMEM; | |
171 | } | |
172 | ||
173 | err = setup_transfer(data); | |
174 | if (err) | |
175 | goto err_free_data; | |
176 | ||
d3f684f2 PH |
177 | mutex_init(&data->drvdata_lock); |
178 | ||
55b951e7 EM |
179 | data->spi = spi; |
180 | spi_set_drvdata(spi, data); | |
181 | ||
182 | err = sysfs_create_group(&spi->dev.kobj, &max1111_attr_group); | |
183 | if (err) { | |
184 | dev_err(&spi->dev, "failed to create attribute group\n"); | |
d737c09c | 185 | goto err_free_data; |
55b951e7 EM |
186 | } |
187 | ||
188 | data->hwmon_dev = hwmon_device_register(&spi->dev); | |
189 | if (IS_ERR(data->hwmon_dev)) { | |
190 | dev_err(&spi->dev, "failed to create hwmon device\n"); | |
191 | err = PTR_ERR(data->hwmon_dev); | |
192 | goto err_remove; | |
193 | } | |
194 | ||
f16177c2 EM |
195 | #ifdef CONFIG_SHARPSL_PM |
196 | the_max1111 = data; | |
197 | #endif | |
55b951e7 EM |
198 | return 0; |
199 | ||
200 | err_remove: | |
201 | sysfs_remove_group(&spi->dev.kobj, &max1111_attr_group); | |
55b951e7 EM |
202 | err_free_data: |
203 | kfree(data); | |
204 | return err; | |
205 | } | |
206 | ||
207 | static int __devexit max1111_remove(struct spi_device *spi) | |
208 | { | |
209 | struct max1111_data *data = spi_get_drvdata(spi); | |
210 | ||
211 | hwmon_device_unregister(data->hwmon_dev); | |
212 | sysfs_remove_group(&spi->dev.kobj, &max1111_attr_group); | |
d3f684f2 | 213 | mutex_destroy(&data->drvdata_lock); |
55b951e7 EM |
214 | kfree(data); |
215 | return 0; | |
216 | } | |
217 | ||
218 | static struct spi_driver max1111_driver = { | |
219 | .driver = { | |
220 | .name = "max1111", | |
221 | .owner = THIS_MODULE, | |
222 | }, | |
223 | .probe = max1111_probe, | |
224 | .remove = __devexit_p(max1111_remove), | |
225 | }; | |
226 | ||
227 | static int __init max1111_init(void) | |
228 | { | |
229 | return spi_register_driver(&max1111_driver); | |
230 | } | |
231 | module_init(max1111_init); | |
232 | ||
233 | static void __exit max1111_exit(void) | |
234 | { | |
235 | spi_unregister_driver(&max1111_driver); | |
236 | } | |
237 | module_exit(max1111_exit); | |
238 | ||
239 | MODULE_AUTHOR("Eric Miao <eric.miao@marvell.com>"); | |
240 | MODULE_DESCRIPTION("MAX1111 ADC Driver"); | |
241 | MODULE_LICENSE("GPL"); | |
e0626e38 | 242 | MODULE_ALIAS("spi:max1111"); |