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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]; | |
41 | uint8_t *tx_buf; | |
42 | uint8_t *rx_buf; | |
43 | }; | |
44 | ||
45 | static int max1111_read(struct device *dev, int channel) | |
46 | { | |
47 | struct max1111_data *data = dev_get_drvdata(dev); | |
48 | uint8_t v1, v2; | |
49 | int err; | |
50 | ||
51 | data->tx_buf[0] = (channel << MAX1111_CTRL_SEL_SH) | | |
52 | MAX1111_CTRL_PD0 | MAX1111_CTRL_PD1 | | |
53 | MAX1111_CTRL_SGL | MAX1111_CTRL_UNI | MAX1111_CTRL_STR; | |
54 | ||
55 | err = spi_sync(data->spi, &data->msg); | |
56 | if (err < 0) { | |
57 | dev_err(dev, "spi_sync failed with %d\n", err); | |
58 | return err; | |
59 | } | |
60 | ||
61 | v1 = data->rx_buf[0]; | |
62 | v2 = data->rx_buf[1]; | |
63 | ||
64 | if ((v1 & 0xc0) || (v2 & 0x3f)) | |
65 | return -EINVAL; | |
66 | ||
67 | return (v1 << 2) | (v2 >> 6); | |
68 | } | |
69 | ||
f16177c2 EM |
70 | #ifdef CONFIG_SHARPSL_PM |
71 | static struct max1111_data *the_max1111; | |
72 | ||
73 | int max1111_read_channel(int channel) | |
74 | { | |
75 | return max1111_read(&the_max1111->spi->dev, channel); | |
76 | } | |
77 | EXPORT_SYMBOL(max1111_read_channel); | |
78 | #endif | |
79 | ||
55b951e7 EM |
80 | /* |
81 | * NOTE: SPI devices do not have a default 'name' attribute, which is | |
82 | * likely to be used by hwmon applications to distinguish between | |
83 | * different devices, explicitly add a name attribute here. | |
84 | */ | |
85 | static ssize_t show_name(struct device *dev, | |
86 | struct device_attribute *attr, char *buf) | |
87 | { | |
88 | return sprintf(buf, "max1111\n"); | |
89 | } | |
90 | ||
91 | static ssize_t show_adc(struct device *dev, | |
92 | struct device_attribute *attr, char *buf) | |
93 | { | |
94 | int channel = to_sensor_dev_attr(attr)->index; | |
95 | int ret; | |
96 | ||
97 | ret = max1111_read(dev, channel); | |
98 | if (ret < 0) | |
99 | return ret; | |
100 | ||
101 | return sprintf(buf, "%d\n", ret); | |
102 | } | |
103 | ||
104 | #define MAX1111_ADC_ATTR(_id) \ | |
105 | SENSOR_DEVICE_ATTR(adc##_id##_in, S_IRUGO, show_adc, NULL, _id) | |
106 | ||
107 | static DEVICE_ATTR(name, S_IRUGO, show_name, NULL); | |
108 | static MAX1111_ADC_ATTR(0); | |
109 | static MAX1111_ADC_ATTR(1); | |
110 | static MAX1111_ADC_ATTR(2); | |
111 | static MAX1111_ADC_ATTR(3); | |
112 | ||
113 | static struct attribute *max1111_attributes[] = { | |
114 | &dev_attr_name.attr, | |
115 | &sensor_dev_attr_adc0_in.dev_attr.attr, | |
116 | &sensor_dev_attr_adc1_in.dev_attr.attr, | |
117 | &sensor_dev_attr_adc2_in.dev_attr.attr, | |
118 | &sensor_dev_attr_adc3_in.dev_attr.attr, | |
119 | NULL, | |
120 | }; | |
121 | ||
122 | static const struct attribute_group max1111_attr_group = { | |
123 | .attrs = max1111_attributes, | |
124 | }; | |
125 | ||
126 | static int setup_transfer(struct max1111_data *data) | |
127 | { | |
128 | struct spi_message *m; | |
129 | struct spi_transfer *x; | |
130 | ||
131 | data->tx_buf = kmalloc(MAX1111_TX_BUF_SIZE, GFP_KERNEL); | |
132 | if (!data->tx_buf) | |
133 | return -ENOMEM; | |
134 | ||
135 | data->rx_buf = kmalloc(MAX1111_RX_BUF_SIZE, GFP_KERNEL); | |
136 | if (!data->rx_buf) { | |
137 | kfree(data->tx_buf); | |
138 | return -ENOMEM; | |
139 | } | |
140 | ||
141 | m = &data->msg; | |
142 | x = &data->xfer[0]; | |
143 | ||
144 | spi_message_init(m); | |
145 | ||
146 | x->tx_buf = &data->tx_buf[0]; | |
147 | x->len = 1; | |
148 | spi_message_add_tail(x, m); | |
149 | ||
150 | x++; | |
151 | x->rx_buf = &data->rx_buf[0]; | |
152 | x->len = 2; | |
153 | spi_message_add_tail(x, m); | |
154 | ||
155 | return 0; | |
156 | } | |
157 | ||
158 | static int __devinit max1111_probe(struct spi_device *spi) | |
159 | { | |
160 | struct max1111_data *data; | |
161 | int err; | |
162 | ||
163 | spi->bits_per_word = 8; | |
164 | spi->mode = SPI_MODE_0; | |
165 | err = spi_setup(spi); | |
166 | if (err < 0) | |
167 | return err; | |
168 | ||
169 | data = kzalloc(sizeof(struct max1111_data), GFP_KERNEL); | |
170 | if (data == NULL) { | |
171 | dev_err(&spi->dev, "failed to allocate memory\n"); | |
172 | return -ENOMEM; | |
173 | } | |
174 | ||
175 | err = setup_transfer(data); | |
176 | if (err) | |
177 | goto err_free_data; | |
178 | ||
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"); | |
185 | goto err_free_all; | |
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); | |
202 | err_free_all: | |
203 | kfree(data->rx_buf); | |
204 | kfree(data->tx_buf); | |
205 | err_free_data: | |
206 | kfree(data); | |
207 | return err; | |
208 | } | |
209 | ||
210 | static int __devexit max1111_remove(struct spi_device *spi) | |
211 | { | |
212 | struct max1111_data *data = spi_get_drvdata(spi); | |
213 | ||
214 | hwmon_device_unregister(data->hwmon_dev); | |
215 | sysfs_remove_group(&spi->dev.kobj, &max1111_attr_group); | |
216 | kfree(data->rx_buf); | |
217 | kfree(data->tx_buf); | |
218 | kfree(data); | |
219 | return 0; | |
220 | } | |
221 | ||
222 | static struct spi_driver max1111_driver = { | |
223 | .driver = { | |
224 | .name = "max1111", | |
225 | .owner = THIS_MODULE, | |
226 | }, | |
227 | .probe = max1111_probe, | |
228 | .remove = __devexit_p(max1111_remove), | |
229 | }; | |
230 | ||
231 | static int __init max1111_init(void) | |
232 | { | |
233 | return spi_register_driver(&max1111_driver); | |
234 | } | |
235 | module_init(max1111_init); | |
236 | ||
237 | static void __exit max1111_exit(void) | |
238 | { | |
239 | spi_unregister_driver(&max1111_driver); | |
240 | } | |
241 | module_exit(max1111_exit); | |
242 | ||
243 | MODULE_AUTHOR("Eric Miao <eric.miao@marvell.com>"); | |
244 | MODULE_DESCRIPTION("MAX1111 ADC Driver"); | |
245 | MODULE_LICENSE("GPL"); | |
e0626e38 | 246 | MODULE_ALIAS("spi:max1111"); |