sparc64: Fix masking and shifting in VIS fpcmp emulation.
[linux-2.6/linux-acpi-2.6/ibm-acpi-2.6.git] / drivers / hwmon / lm70.c
blobc274ea25d899f5766d06d41283c5ec26876adddd
1 /*
2 * lm70.c
4 * The LM70 is a temperature sensor chip from National Semiconductor (NS).
5 * Copyright (C) 2006 Kaiwan N Billimoria <kaiwan@designergraphix.com>
7 * The LM70 communicates with a host processor via an SPI/Microwire Bus
8 * interface. The complete datasheet is available at National's website
9 * here:
10 * http://www.national.com/pf/LM/LM70.html
12 * This program is free software; you can redistribute it and/or modify
13 * it under the terms of the GNU General Public License as published by
14 * the Free Software Foundation; either version 2 of the License, or
15 * (at your option) any later version.
17 * This program is distributed in the hope that it will be useful,
18 * but WITHOUT ANY WARRANTY; without even the implied warranty of
19 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
20 * GNU General Public License for more details.
22 * You should have received a copy of the GNU General Public License
23 * along with this program; if not, write to the Free Software
24 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
27 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
29 #include <linux/init.h>
30 #include <linux/module.h>
31 #include <linux/kernel.h>
32 #include <linux/device.h>
33 #include <linux/err.h>
34 #include <linux/sysfs.h>
35 #include <linux/hwmon.h>
36 #include <linux/mutex.h>
37 #include <linux/mod_devicetable.h>
38 #include <linux/spi/spi.h>
39 #include <linux/slab.h>
42 #define DRVNAME "lm70"
44 #define LM70_CHIP_LM70 0 /* original NS LM70 */
45 #define LM70_CHIP_TMP121 1 /* TI TMP121/TMP123 */
47 struct lm70 {
48 struct device *hwmon_dev;
49 struct mutex lock;
50 unsigned int chip;
53 /* sysfs hook function */
54 static ssize_t lm70_sense_temp(struct device *dev,
55 struct device_attribute *attr, char *buf)
57 struct spi_device *spi = to_spi_device(dev);
58 int status, val = 0;
59 u8 rxbuf[2];
60 s16 raw=0;
61 struct lm70 *p_lm70 = spi_get_drvdata(spi);
63 if (mutex_lock_interruptible(&p_lm70->lock))
64 return -ERESTARTSYS;
67 * spi_read() requires a DMA-safe buffer; so we use
68 * spi_write_then_read(), transmitting 0 bytes.
70 status = spi_write_then_read(spi, NULL, 0, &rxbuf[0], 2);
71 if (status < 0) {
72 pr_warn("spi_write_then_read failed with status %d\n", status);
73 goto out;
75 raw = (rxbuf[0] << 8) + rxbuf[1];
76 dev_dbg(dev, "rxbuf[0] : 0x%02x rxbuf[1] : 0x%02x raw=0x%04x\n",
77 rxbuf[0], rxbuf[1], raw);
80 * LM70:
81 * The "raw" temperature read into rxbuf[] is a 16-bit signed 2's
82 * complement value. Only the MSB 11 bits (1 sign + 10 temperature
83 * bits) are meaningful; the LSB 5 bits are to be discarded.
84 * See the datasheet.
86 * Further, each bit represents 0.25 degrees Celsius; so, multiply
87 * by 0.25. Also multiply by 1000 to represent in millidegrees
88 * Celsius.
89 * So it's equivalent to multiplying by 0.25 * 1000 = 250.
91 * TMP121/TMP123:
92 * 13 bits of 2's complement data, discard LSB 3 bits,
93 * resolution 0.0625 degrees celsius.
95 switch (p_lm70->chip) {
96 case LM70_CHIP_LM70:
97 val = ((int)raw / 32) * 250;
98 break;
100 case LM70_CHIP_TMP121:
101 val = ((int)raw / 8) * 625 / 10;
102 break;
105 status = sprintf(buf, "%d\n", val); /* millidegrees Celsius */
106 out:
107 mutex_unlock(&p_lm70->lock);
108 return status;
111 static DEVICE_ATTR(temp1_input, S_IRUGO, lm70_sense_temp, NULL);
113 static ssize_t lm70_show_name(struct device *dev, struct device_attribute
114 *devattr, char *buf)
116 struct lm70 *p_lm70 = dev_get_drvdata(dev);
117 int ret;
119 switch (p_lm70->chip) {
120 case LM70_CHIP_LM70:
121 ret = sprintf(buf, "lm70\n");
122 break;
123 case LM70_CHIP_TMP121:
124 ret = sprintf(buf, "tmp121\n");
125 break;
126 default:
127 ret = -EINVAL;
129 return ret;
132 static DEVICE_ATTR(name, S_IRUGO, lm70_show_name, NULL);
134 /*----------------------------------------------------------------------*/
136 static int __devinit lm70_probe(struct spi_device *spi)
138 int chip = spi_get_device_id(spi)->driver_data;
139 struct lm70 *p_lm70;
140 int status;
142 /* signaling is SPI_MODE_0 for both LM70 and TMP121 */
143 if (spi->mode & (SPI_CPOL | SPI_CPHA))
144 return -EINVAL;
146 /* 3-wire link (shared SI/SO) for LM70 */
147 if (chip == LM70_CHIP_LM70 && !(spi->mode & SPI_3WIRE))
148 return -EINVAL;
150 /* NOTE: we assume 8-bit words, and convert to 16 bits manually */
152 p_lm70 = kzalloc(sizeof *p_lm70, GFP_KERNEL);
153 if (!p_lm70)
154 return -ENOMEM;
156 mutex_init(&p_lm70->lock);
157 p_lm70->chip = chip;
159 /* sysfs hook */
160 p_lm70->hwmon_dev = hwmon_device_register(&spi->dev);
161 if (IS_ERR(p_lm70->hwmon_dev)) {
162 dev_dbg(&spi->dev, "hwmon_device_register failed.\n");
163 status = PTR_ERR(p_lm70->hwmon_dev);
164 goto out_dev_reg_failed;
166 spi_set_drvdata(spi, p_lm70);
168 if ((status = device_create_file(&spi->dev, &dev_attr_temp1_input))
169 || (status = device_create_file(&spi->dev, &dev_attr_name))) {
170 dev_dbg(&spi->dev, "device_create_file failure.\n");
171 goto out_dev_create_file_failed;
174 return 0;
176 out_dev_create_file_failed:
177 device_remove_file(&spi->dev, &dev_attr_temp1_input);
178 hwmon_device_unregister(p_lm70->hwmon_dev);
179 out_dev_reg_failed:
180 spi_set_drvdata(spi, NULL);
181 kfree(p_lm70);
182 return status;
185 static int __devexit lm70_remove(struct spi_device *spi)
187 struct lm70 *p_lm70 = spi_get_drvdata(spi);
189 device_remove_file(&spi->dev, &dev_attr_temp1_input);
190 device_remove_file(&spi->dev, &dev_attr_name);
191 hwmon_device_unregister(p_lm70->hwmon_dev);
192 spi_set_drvdata(spi, NULL);
193 kfree(p_lm70);
195 return 0;
199 static const struct spi_device_id lm70_ids[] = {
200 { "lm70", LM70_CHIP_LM70 },
201 { "tmp121", LM70_CHIP_TMP121 },
202 { },
204 MODULE_DEVICE_TABLE(spi, lm70_ids);
206 static struct spi_driver lm70_driver = {
207 .driver = {
208 .name = "lm70",
209 .owner = THIS_MODULE,
211 .id_table = lm70_ids,
212 .probe = lm70_probe,
213 .remove = __devexit_p(lm70_remove),
216 static int __init init_lm70(void)
218 return spi_register_driver(&lm70_driver);
221 static void __exit cleanup_lm70(void)
223 spi_unregister_driver(&lm70_driver);
226 module_init(init_lm70);
227 module_exit(cleanup_lm70);
229 MODULE_AUTHOR("Kaiwan N Billimoria");
230 MODULE_DESCRIPTION("NS LM70 / TI TMP121/TMP123 Linux driver");
231 MODULE_LICENSE("GPL");