Root/drivers/char/ds1620.c

1/*
2 * linux/drivers/char/ds1620.c: Dallas Semiconductors DS1620
3 * thermometer driver (as used in the Rebel.com NetWinder)
4 */
5#include <linux/module.h>
6#include <linux/miscdevice.h>
7#include <linux/delay.h>
8#include <linux/proc_fs.h>
9#include <linux/capability.h>
10#include <linux/init.h>
11#include <linux/mutex.h>
12
13#include <mach/hardware.h>
14#include <asm/mach-types.h>
15#include <asm/uaccess.h>
16#include <asm/therm.h>
17
18#ifdef CONFIG_PROC_FS
19/* define for /proc interface */
20#define THERM_USE_PROC
21#endif
22
23/* Definitions for DS1620 chip */
24#define THERM_START_CONVERT 0xee
25#define THERM_RESET 0xaf
26#define THERM_READ_CONFIG 0xac
27#define THERM_READ_TEMP 0xaa
28#define THERM_READ_TL 0xa2
29#define THERM_READ_TH 0xa1
30#define THERM_WRITE_CONFIG 0x0c
31#define THERM_WRITE_TL 0x02
32#define THERM_WRITE_TH 0x01
33
34#define CFG_CPU 2
35#define CFG_1SHOT 1
36
37static DEFINE_MUTEX(ds1620_mutex);
38static const char *fan_state[] = { "off", "on", "on (hardwired)" };
39
40/*
41 * Start of NetWinder specifics
42 * Note! We have to hold the gpio lock with IRQs disabled over the
43 * whole of our transaction to the Dallas chip, since there is a
44 * chance that the WaveArtist driver could touch these bits to
45 * enable or disable the speaker.
46 */
47extern unsigned int system_rev;
48
49static inline void netwinder_ds1620_set_clk(int clk)
50{
51    nw_gpio_modify_op(GPIO_DSCLK, clk ? GPIO_DSCLK : 0);
52}
53
54static inline void netwinder_ds1620_set_data(int dat)
55{
56    nw_gpio_modify_op(GPIO_DATA, dat ? GPIO_DATA : 0);
57}
58
59static inline int netwinder_ds1620_get_data(void)
60{
61    return nw_gpio_read() & GPIO_DATA;
62}
63
64static inline void netwinder_ds1620_set_data_dir(int dir)
65{
66    nw_gpio_modify_io(GPIO_DATA, dir ? GPIO_DATA : 0);
67}
68
69static inline void netwinder_ds1620_reset(void)
70{
71    nw_cpld_modify(CPLD_DS_ENABLE, 0);
72    nw_cpld_modify(CPLD_DS_ENABLE, CPLD_DS_ENABLE);
73}
74
75static inline void netwinder_lock(unsigned long *flags)
76{
77    raw_spin_lock_irqsave(&nw_gpio_lock, *flags);
78}
79
80static inline void netwinder_unlock(unsigned long *flags)
81{
82    raw_spin_unlock_irqrestore(&nw_gpio_lock, *flags);
83}
84
85static inline void netwinder_set_fan(int i)
86{
87    unsigned long flags;
88
89    raw_spin_lock_irqsave(&nw_gpio_lock, flags);
90    nw_gpio_modify_op(GPIO_FAN, i ? GPIO_FAN : 0);
91    raw_spin_unlock_irqrestore(&nw_gpio_lock, flags);
92}
93
94static inline int netwinder_get_fan(void)
95{
96    if ((system_rev & 0xf000) == 0x4000)
97        return FAN_ALWAYS_ON;
98
99    return (nw_gpio_read() & GPIO_FAN) ? FAN_ON : FAN_OFF;
100}
101
102/*
103 * End of NetWinder specifics
104 */
105
106static void ds1620_send_bits(int nr, int value)
107{
108    int i;
109
110    for (i = 0; i < nr; i++) {
111        netwinder_ds1620_set_data(value & 1);
112        netwinder_ds1620_set_clk(0);
113        udelay(1);
114        netwinder_ds1620_set_clk(1);
115        udelay(1);
116
117        value >>= 1;
118    }
119}
120
121static unsigned int ds1620_recv_bits(int nr)
122{
123    unsigned int value = 0, mask = 1;
124    int i;
125
126    netwinder_ds1620_set_data(0);
127
128    for (i = 0; i < nr; i++) {
129        netwinder_ds1620_set_clk(0);
130        udelay(1);
131
132        if (netwinder_ds1620_get_data())
133            value |= mask;
134
135        mask <<= 1;
136
137        netwinder_ds1620_set_clk(1);
138        udelay(1);
139    }
140
141    return value;
142}
143
144static void ds1620_out(int cmd, int bits, int value)
145{
146    unsigned long flags;
147
148    netwinder_lock(&flags);
149    netwinder_ds1620_set_clk(1);
150    netwinder_ds1620_set_data_dir(0);
151    netwinder_ds1620_reset();
152
153    udelay(1);
154
155    ds1620_send_bits(8, cmd);
156    if (bits)
157        ds1620_send_bits(bits, value);
158
159    udelay(1);
160
161    netwinder_ds1620_reset();
162    netwinder_unlock(&flags);
163
164    msleep(20);
165}
166
167static unsigned int ds1620_in(int cmd, int bits)
168{
169    unsigned long flags;
170    unsigned int value;
171
172    netwinder_lock(&flags);
173    netwinder_ds1620_set_clk(1);
174    netwinder_ds1620_set_data_dir(0);
175    netwinder_ds1620_reset();
176
177    udelay(1);
178
179    ds1620_send_bits(8, cmd);
180
181    netwinder_ds1620_set_data_dir(1);
182    value = ds1620_recv_bits(bits);
183
184    netwinder_ds1620_reset();
185    netwinder_unlock(&flags);
186
187    return value;
188}
189
190static int cvt_9_to_int(unsigned int val)
191{
192    if (val & 0x100)
193        val |= 0xfffffe00;
194
195    return val;
196}
197
198static void ds1620_write_state(struct therm *therm)
199{
200    ds1620_out(THERM_WRITE_CONFIG, 8, CFG_CPU);
201    ds1620_out(THERM_WRITE_TL, 9, therm->lo);
202    ds1620_out(THERM_WRITE_TH, 9, therm->hi);
203    ds1620_out(THERM_START_CONVERT, 0, 0);
204}
205
206static void ds1620_read_state(struct therm *therm)
207{
208    therm->lo = cvt_9_to_int(ds1620_in(THERM_READ_TL, 9));
209    therm->hi = cvt_9_to_int(ds1620_in(THERM_READ_TH, 9));
210}
211
212static int ds1620_open(struct inode *inode, struct file *file)
213{
214    return nonseekable_open(inode, file);
215}
216
217static ssize_t
218ds1620_read(struct file *file, char __user *buf, size_t count, loff_t *ptr)
219{
220    signed int cur_temp;
221    signed char cur_temp_degF;
222
223    cur_temp = cvt_9_to_int(ds1620_in(THERM_READ_TEMP, 9)) >> 1;
224
225    /* convert to Fahrenheit, as per wdt.c */
226    cur_temp_degF = (cur_temp * 9) / 5 + 32;
227
228    if (copy_to_user(buf, &cur_temp_degF, 1))
229        return -EFAULT;
230
231    return 1;
232}
233
234static int
235ds1620_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
236{
237    struct therm therm;
238    union {
239        struct therm __user *therm;
240        int __user *i;
241    } uarg;
242    int i;
243
244    uarg.i = (int __user *)arg;
245
246    switch(cmd) {
247    case CMD_SET_THERMOSTATE:
248    case CMD_SET_THERMOSTATE2:
249        if (!capable(CAP_SYS_ADMIN))
250            return -EPERM;
251
252        if (cmd == CMD_SET_THERMOSTATE) {
253            if (get_user(therm.hi, uarg.i))
254                return -EFAULT;
255            therm.lo = therm.hi - 3;
256        } else {
257            if (copy_from_user(&therm, uarg.therm, sizeof(therm)))
258                return -EFAULT;
259        }
260
261        therm.lo <<= 1;
262        therm.hi <<= 1;
263
264        ds1620_write_state(&therm);
265        break;
266
267    case CMD_GET_THERMOSTATE:
268    case CMD_GET_THERMOSTATE2:
269        ds1620_read_state(&therm);
270
271        therm.lo >>= 1;
272        therm.hi >>= 1;
273
274        if (cmd == CMD_GET_THERMOSTATE) {
275            if (put_user(therm.hi, uarg.i))
276                return -EFAULT;
277        } else {
278            if (copy_to_user(uarg.therm, &therm, sizeof(therm)))
279                return -EFAULT;
280        }
281        break;
282
283    case CMD_GET_TEMPERATURE:
284    case CMD_GET_TEMPERATURE2:
285        i = cvt_9_to_int(ds1620_in(THERM_READ_TEMP, 9));
286
287        if (cmd == CMD_GET_TEMPERATURE)
288            i >>= 1;
289
290        return put_user(i, uarg.i) ? -EFAULT : 0;
291
292    case CMD_GET_STATUS:
293        i = ds1620_in(THERM_READ_CONFIG, 8) & 0xe3;
294
295        return put_user(i, uarg.i) ? -EFAULT : 0;
296
297    case CMD_GET_FAN:
298        i = netwinder_get_fan();
299
300        return put_user(i, uarg.i) ? -EFAULT : 0;
301
302    case CMD_SET_FAN:
303        if (!capable(CAP_SYS_ADMIN))
304            return -EPERM;
305
306        if (get_user(i, uarg.i))
307            return -EFAULT;
308
309        netwinder_set_fan(i);
310        break;
311        
312    default:
313        return -ENOIOCTLCMD;
314    }
315
316    return 0;
317}
318
319static long
320ds1620_unlocked_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
321{
322    int ret;
323
324    mutex_lock(&ds1620_mutex);
325    ret = ds1620_ioctl(file, cmd, arg);
326    mutex_unlock(&ds1620_mutex);
327
328    return ret;
329}
330
331#ifdef THERM_USE_PROC
332static int
333proc_therm_ds1620_read(char *buf, char **start, off_t offset,
334               int len, int *eof, void *unused)
335{
336    struct therm th;
337    int temp;
338
339    ds1620_read_state(&th);
340    temp = cvt_9_to_int(ds1620_in(THERM_READ_TEMP, 9));
341
342    len = sprintf(buf, "Thermostat: HI %i.%i, LOW %i.%i; "
343              "temperature: %i.%i C, fan %s\n",
344              th.hi >> 1, th.hi & 1 ? 5 : 0,
345              th.lo >> 1, th.lo & 1 ? 5 : 0,
346              temp >> 1, temp & 1 ? 5 : 0,
347              fan_state[netwinder_get_fan()]);
348
349    return len;
350}
351
352static struct proc_dir_entry *proc_therm_ds1620;
353#endif
354
355static const struct file_operations ds1620_fops = {
356    .owner = THIS_MODULE,
357    .open = ds1620_open,
358    .read = ds1620_read,
359    .unlocked_ioctl = ds1620_unlocked_ioctl,
360    .llseek = no_llseek,
361};
362
363static struct miscdevice ds1620_miscdev = {
364    TEMP_MINOR,
365    "temp",
366    &ds1620_fops
367};
368
369static int __init ds1620_init(void)
370{
371    int ret;
372    struct therm th, th_start;
373
374    if (!machine_is_netwinder())
375        return -ENODEV;
376
377    ds1620_out(THERM_RESET, 0, 0);
378    ds1620_out(THERM_WRITE_CONFIG, 8, CFG_CPU);
379    ds1620_out(THERM_START_CONVERT, 0, 0);
380
381    /*
382     * Trigger the fan to start by setting
383     * temperature high point low. This kicks
384     * the fan into action.
385     */
386    ds1620_read_state(&th);
387    th_start.lo = 0;
388    th_start.hi = 1;
389    ds1620_write_state(&th_start);
390
391    msleep(2000);
392
393    ds1620_write_state(&th);
394
395    ret = misc_register(&ds1620_miscdev);
396    if (ret < 0)
397        return ret;
398
399#ifdef THERM_USE_PROC
400    proc_therm_ds1620 = create_proc_entry("therm", 0, NULL);
401    if (proc_therm_ds1620)
402        proc_therm_ds1620->read_proc = proc_therm_ds1620_read;
403    else
404        printk(KERN_ERR "therm: unable to register /proc/therm\n");
405#endif
406
407    ds1620_read_state(&th);
408    ret = cvt_9_to_int(ds1620_in(THERM_READ_TEMP, 9));
409
410    printk(KERN_INFO "Thermostat: high %i.%i, low %i.%i, "
411           "current %i.%i C, fan %s.\n",
412           th.hi >> 1, th.hi & 1 ? 5 : 0,
413           th.lo >> 1, th.lo & 1 ? 5 : 0,
414           ret >> 1, ret & 1 ? 5 : 0,
415           fan_state[netwinder_get_fan()]);
416
417    return 0;
418}
419
420static void __exit ds1620_exit(void)
421{
422#ifdef THERM_USE_PROC
423    remove_proc_entry("therm", NULL);
424#endif
425    misc_deregister(&ds1620_miscdev);
426}
427
428module_init(ds1620_init);
429module_exit(ds1620_exit);
430
431MODULE_LICENSE("GPL");
432

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