ux500: remove ambiguous irq macros
[linux-2.6/linux-acpi-2.6/ibm-acpi-2.6.git] / drivers / hwmon / ads7828.c
blobaac85f3aed50e6cdd2c08fe065e464643303f4ca
1 /*
2 ads7828.c - lm_sensors driver for ads7828 12-bit 8-channel ADC
3 (C) 2007 EADS Astrium
5 This driver is based on the lm75 and other lm_sensors/hwmon drivers
7 Written by Steve Hardy <steve@linuxrealtime.co.uk>
9 Datasheet available at: http://focus.ti.com/lit/ds/symlink/ads7828.pdf
11 This program is free software; you can redistribute it and/or modify
12 it under the terms of the GNU General Public License as published by
13 the Free Software Foundation; either version 2 of the License, or
14 (at your option) any later version.
16 This program is distributed in the hope that it will be useful,
17 but WITHOUT ANY WARRANTY; without even the implied warranty of
18 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
19 GNU General Public License for more details.
21 You should have received a copy of the GNU General Public License
22 along with this program; if not, write to the Free Software
23 Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
26 #include <linux/module.h>
27 #include <linux/init.h>
28 #include <linux/slab.h>
29 #include <linux/jiffies.h>
30 #include <linux/i2c.h>
31 #include <linux/hwmon.h>
32 #include <linux/hwmon-sysfs.h>
33 #include <linux/err.h>
34 #include <linux/mutex.h>
36 /* The ADS7828 registers */
37 #define ADS7828_NCH 8 /* 8 channels of 12-bit A-D supported */
38 #define ADS7828_CMD_SD_SE 0x80 /* Single ended inputs */
39 #define ADS7828_CMD_SD_DIFF 0x00 /* Differential inputs */
40 #define ADS7828_CMD_PD0 0x0 /* Power Down between A-D conversions */
41 #define ADS7828_CMD_PD1 0x04 /* Internal ref OFF && A-D ON */
42 #define ADS7828_CMD_PD2 0x08 /* Internal ref ON && A-D OFF */
43 #define ADS7828_CMD_PD3 0x0C /* Internal ref ON && A-D ON */
44 #define ADS7828_INT_VREF_MV 2500 /* Internal vref is 2.5V, 2500mV */
46 /* Addresses to scan */
47 static const unsigned short normal_i2c[] = { 0x48, 0x49, 0x4a, 0x4b,
48 I2C_CLIENT_END };
50 /* Module parameters */
51 static int se_input = 1; /* Default is SE, 0 == diff */
52 static int int_vref = 1; /* Default is internal ref ON */
53 static int vref_mv = ADS7828_INT_VREF_MV; /* set if vref != 2.5V */
54 module_param(se_input, bool, S_IRUGO);
55 module_param(int_vref, bool, S_IRUGO);
56 module_param(vref_mv, int, S_IRUGO);
58 /* Global Variables */
59 static u8 ads7828_cmd_byte; /* cmd byte without channel bits */
60 static unsigned int ads7828_lsb_resol; /* resolution of the ADC sample lsb */
62 /* Each client has this additional data */
63 struct ads7828_data {
64 struct device *hwmon_dev;
65 struct mutex update_lock; /* mutex protect updates */
66 char valid; /* !=0 if following fields are valid */
67 unsigned long last_updated; /* In jiffies */
68 u16 adc_input[ADS7828_NCH]; /* ADS7828_NCH 12-bit samples */
71 /* Function declaration - necessary due to function dependencies */
72 static int ads7828_detect(struct i2c_client *client,
73 struct i2c_board_info *info);
74 static int ads7828_probe(struct i2c_client *client,
75 const struct i2c_device_id *id);
77 /* The ADS7828 returns the 12-bit sample in two bytes,
78 these are read as a word then byte-swapped */
79 static u16 ads7828_read_value(struct i2c_client *client, u8 reg)
81 return swab16(i2c_smbus_read_word_data(client, reg));
84 static inline u8 channel_cmd_byte(int ch)
86 /* cmd byte C2,C1,C0 - see datasheet */
87 u8 cmd = (((ch>>1) | (ch&0x01)<<2)<<4);
88 cmd |= ads7828_cmd_byte;
89 return cmd;
92 /* Update data for the device (all 8 channels) */
93 static struct ads7828_data *ads7828_update_device(struct device *dev)
95 struct i2c_client *client = to_i2c_client(dev);
96 struct ads7828_data *data = i2c_get_clientdata(client);
98 mutex_lock(&data->update_lock);
100 if (time_after(jiffies, data->last_updated + HZ + HZ / 2)
101 || !data->valid) {
102 unsigned int ch;
103 dev_dbg(&client->dev, "Starting ads7828 update\n");
105 for (ch = 0; ch < ADS7828_NCH; ch++) {
106 u8 cmd = channel_cmd_byte(ch);
107 data->adc_input[ch] = ads7828_read_value(client, cmd);
109 data->last_updated = jiffies;
110 data->valid = 1;
113 mutex_unlock(&data->update_lock);
115 return data;
118 /* sysfs callback function */
119 static ssize_t show_in(struct device *dev, struct device_attribute *da,
120 char *buf)
122 struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
123 struct ads7828_data *data = ads7828_update_device(dev);
124 /* Print value (in mV as specified in sysfs-interface documentation) */
125 return sprintf(buf, "%d\n", (data->adc_input[attr->index] *
126 ads7828_lsb_resol)/1000);
129 #define in_reg(offset)\
130 static SENSOR_DEVICE_ATTR(in##offset##_input, S_IRUGO, show_in,\
131 NULL, offset)
133 in_reg(0);
134 in_reg(1);
135 in_reg(2);
136 in_reg(3);
137 in_reg(4);
138 in_reg(5);
139 in_reg(6);
140 in_reg(7);
142 static struct attribute *ads7828_attributes[] = {
143 &sensor_dev_attr_in0_input.dev_attr.attr,
144 &sensor_dev_attr_in1_input.dev_attr.attr,
145 &sensor_dev_attr_in2_input.dev_attr.attr,
146 &sensor_dev_attr_in3_input.dev_attr.attr,
147 &sensor_dev_attr_in4_input.dev_attr.attr,
148 &sensor_dev_attr_in5_input.dev_attr.attr,
149 &sensor_dev_attr_in6_input.dev_attr.attr,
150 &sensor_dev_attr_in7_input.dev_attr.attr,
151 NULL
154 static const struct attribute_group ads7828_group = {
155 .attrs = ads7828_attributes,
158 static int ads7828_remove(struct i2c_client *client)
160 struct ads7828_data *data = i2c_get_clientdata(client);
161 hwmon_device_unregister(data->hwmon_dev);
162 sysfs_remove_group(&client->dev.kobj, &ads7828_group);
163 kfree(i2c_get_clientdata(client));
164 return 0;
167 static const struct i2c_device_id ads7828_id[] = {
168 { "ads7828", 0 },
171 MODULE_DEVICE_TABLE(i2c, ads7828_id);
173 /* This is the driver that will be inserted */
174 static struct i2c_driver ads7828_driver = {
175 .class = I2C_CLASS_HWMON,
176 .driver = {
177 .name = "ads7828",
179 .probe = ads7828_probe,
180 .remove = ads7828_remove,
181 .id_table = ads7828_id,
182 .detect = ads7828_detect,
183 .address_list = normal_i2c,
186 /* Return 0 if detection is successful, -ENODEV otherwise */
187 static int ads7828_detect(struct i2c_client *client,
188 struct i2c_board_info *info)
190 struct i2c_adapter *adapter = client->adapter;
191 int ch;
193 /* Check we have a valid client */
194 if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_READ_WORD_DATA))
195 return -ENODEV;
197 /* Now, we do the remaining detection. There is no identification
198 dedicated register so attempt to sanity check using knowledge of
199 the chip
200 - Read from the 8 channel addresses
201 - Check the top 4 bits of each result are not set (12 data bits)
203 for (ch = 0; ch < ADS7828_NCH; ch++) {
204 u16 in_data;
205 u8 cmd = channel_cmd_byte(ch);
206 in_data = ads7828_read_value(client, cmd);
207 if (in_data & 0xF000) {
208 pr_debug("%s : Doesn't look like an ads7828 device\n",
209 __func__);
210 return -ENODEV;
214 strlcpy(info->type, "ads7828", I2C_NAME_SIZE);
216 return 0;
219 static int ads7828_probe(struct i2c_client *client,
220 const struct i2c_device_id *id)
222 struct ads7828_data *data;
223 int err;
225 data = kzalloc(sizeof(struct ads7828_data), GFP_KERNEL);
226 if (!data) {
227 err = -ENOMEM;
228 goto exit;
231 i2c_set_clientdata(client, data);
232 mutex_init(&data->update_lock);
234 /* Register sysfs hooks */
235 err = sysfs_create_group(&client->dev.kobj, &ads7828_group);
236 if (err)
237 goto exit_free;
239 data->hwmon_dev = hwmon_device_register(&client->dev);
240 if (IS_ERR(data->hwmon_dev)) {
241 err = PTR_ERR(data->hwmon_dev);
242 goto exit_remove;
245 return 0;
247 exit_remove:
248 sysfs_remove_group(&client->dev.kobj, &ads7828_group);
249 exit_free:
250 kfree(data);
251 exit:
252 return err;
255 static int __init sensors_ads7828_init(void)
257 /* Initialize the command byte according to module parameters */
258 ads7828_cmd_byte = se_input ?
259 ADS7828_CMD_SD_SE : ADS7828_CMD_SD_DIFF;
260 ads7828_cmd_byte |= int_vref ?
261 ADS7828_CMD_PD3 : ADS7828_CMD_PD1;
263 /* Calculate the LSB resolution */
264 ads7828_lsb_resol = (vref_mv*1000)/4096;
266 return i2c_add_driver(&ads7828_driver);
269 static void __exit sensors_ads7828_exit(void)
271 i2c_del_driver(&ads7828_driver);
274 MODULE_AUTHOR("Steve Hardy <steve@linuxrealtime.co.uk>");
275 MODULE_DESCRIPTION("ADS7828 driver");
276 MODULE_LICENSE("GPL");
278 module_init(sensors_ads7828_init);
279 module_exit(sensors_ads7828_exit);