2 * linux/drivers/char/ds1620.c: Dallas Semiconductors DS1620
3 * thermometer driver (as used in the Rebel.com NetWinder)
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/smp_lock.h>
13 #include <asm/hardware.h>
14 #include <asm/mach-types.h>
15 #include <asm/uaccess.h>
16 #include <asm/therm.h>
19 /* define for /proc interface */
20 #define THERM_USE_PROC
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
37 static const char *fan_state[] = { "off", "on", "on (hardwired)" };
40 * Start of NetWinder specifics
41 * Note! We have to hold the gpio lock with IRQs disabled over the
42 * whole of our transaction to the Dallas chip, since there is a
43 * chance that the WaveArtist driver could touch these bits to
44 * enable or disable the speaker.
46 extern spinlock_t gpio_lock;
47 extern unsigned int system_rev;
49 static inline void netwinder_ds1620_set_clk(int clk)
51 gpio_modify_op(GPIO_DSCLK, clk ? GPIO_DSCLK : 0);
54 static inline void netwinder_ds1620_set_data(int dat)
56 gpio_modify_op(GPIO_DATA, dat ? GPIO_DATA : 0);
59 static inline int netwinder_ds1620_get_data(void)
61 return gpio_read() & GPIO_DATA;
64 static inline void netwinder_ds1620_set_data_dir(int dir)
66 gpio_modify_io(GPIO_DATA, dir ? GPIO_DATA : 0);
69 static inline void netwinder_ds1620_reset(void)
71 cpld_modify(CPLD_DS_ENABLE, 0);
72 cpld_modify(CPLD_DS_ENABLE, CPLD_DS_ENABLE);
75 static inline void netwinder_lock(unsigned long *flags)
77 spin_lock_irqsave(&gpio_lock, *flags);
80 static inline void netwinder_unlock(unsigned long *flags)
82 spin_unlock_irqrestore(&gpio_lock, *flags);
85 static inline void netwinder_set_fan(int i)
89 spin_lock_irqsave(&gpio_lock, flags);
90 gpio_modify_op(GPIO_FAN, i ? GPIO_FAN : 0);
91 spin_unlock_irqrestore(&gpio_lock, flags);
94 static inline int netwinder_get_fan(void)
96 if ((system_rev & 0xf000) == 0x4000)
99 return (gpio_read() & GPIO_FAN) ? FAN_ON : FAN_OFF;
103 * End of NetWinder specifics
106 static void ds1620_send_bits(int nr, int value)
110 for (i = 0; i < nr; i++) {
111 netwinder_ds1620_set_data(value & 1);
112 netwinder_ds1620_set_clk(0);
114 netwinder_ds1620_set_clk(1);
121 static unsigned int ds1620_recv_bits(int nr)
123 unsigned int value = 0, mask = 1;
126 netwinder_ds1620_set_data(0);
128 for (i = 0; i < nr; i++) {
129 netwinder_ds1620_set_clk(0);
132 if (netwinder_ds1620_get_data())
137 netwinder_ds1620_set_clk(1);
144 static void ds1620_out(int cmd, int bits, int value)
148 netwinder_lock(&flags);
149 netwinder_ds1620_set_clk(1);
150 netwinder_ds1620_set_data_dir(0);
151 netwinder_ds1620_reset();
155 ds1620_send_bits(8, cmd);
157 ds1620_send_bits(bits, value);
161 netwinder_ds1620_reset();
162 netwinder_unlock(&flags);
167 static unsigned int ds1620_in(int cmd, int bits)
172 netwinder_lock(&flags);
173 netwinder_ds1620_set_clk(1);
174 netwinder_ds1620_set_data_dir(0);
175 netwinder_ds1620_reset();
179 ds1620_send_bits(8, cmd);
181 netwinder_ds1620_set_data_dir(1);
182 value = ds1620_recv_bits(bits);
184 netwinder_ds1620_reset();
185 netwinder_unlock(&flags);
190 static int cvt_9_to_int(unsigned int val)
198 static void ds1620_write_state(struct therm *therm)
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);
206 static void ds1620_read_state(struct therm *therm)
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));
212 static int ds1620_open(struct inode *inode, struct file *file)
215 return nonseekable_open(inode, file);
219 ds1620_read(struct file *file, char __user *buf, size_t count, loff_t *ptr)
222 signed char cur_temp_degF;
224 cur_temp = cvt_9_to_int(ds1620_in(THERM_READ_TEMP, 9)) >> 1;
226 /* convert to Fahrenheit, as per wdt.c */
227 cur_temp_degF = (cur_temp * 9) / 5 + 32;
229 if (copy_to_user(buf, &cur_temp_degF, 1))
236 ds1620_ioctl(struct inode *inode, struct file *file, unsigned int cmd, unsigned long arg)
240 struct therm __user *therm;
245 uarg.i = (int __user *)arg;
248 case CMD_SET_THERMOSTATE:
249 case CMD_SET_THERMOSTATE2:
250 if (!capable(CAP_SYS_ADMIN))
253 if (cmd == CMD_SET_THERMOSTATE) {
254 if (get_user(therm.hi, uarg.i))
256 therm.lo = therm.hi - 3;
258 if (copy_from_user(&therm, uarg.therm, sizeof(therm)))
265 ds1620_write_state(&therm);
268 case CMD_GET_THERMOSTATE:
269 case CMD_GET_THERMOSTATE2:
270 ds1620_read_state(&therm);
275 if (cmd == CMD_GET_THERMOSTATE) {
276 if (put_user(therm.hi, uarg.i))
279 if (copy_to_user(uarg.therm, &therm, sizeof(therm)))
284 case CMD_GET_TEMPERATURE:
285 case CMD_GET_TEMPERATURE2:
286 i = cvt_9_to_int(ds1620_in(THERM_READ_TEMP, 9));
288 if (cmd == CMD_GET_TEMPERATURE)
291 return put_user(i, uarg.i) ? -EFAULT : 0;
294 i = ds1620_in(THERM_READ_CONFIG, 8) & 0xe3;
296 return put_user(i, uarg.i) ? -EFAULT : 0;
299 i = netwinder_get_fan();
301 return put_user(i, uarg.i) ? -EFAULT : 0;
304 if (!capable(CAP_SYS_ADMIN))
307 if (get_user(i, uarg.i))
310 netwinder_set_fan(i);
320 #ifdef THERM_USE_PROC
322 proc_therm_ds1620_read(char *buf, char **start, off_t offset,
323 int len, int *eof, void *unused)
328 ds1620_read_state(&th);
329 temp = cvt_9_to_int(ds1620_in(THERM_READ_TEMP, 9));
331 len = sprintf(buf, "Thermostat: HI %i.%i, LOW %i.%i; "
332 "temperature: %i.%i C, fan %s\n",
333 th.hi >> 1, th.hi & 1 ? 5 : 0,
334 th.lo >> 1, th.lo & 1 ? 5 : 0,
335 temp >> 1, temp & 1 ? 5 : 0,
336 fan_state[netwinder_get_fan()]);
341 static struct proc_dir_entry *proc_therm_ds1620;
344 static const struct file_operations ds1620_fops = {
345 .owner = THIS_MODULE,
348 .ioctl = ds1620_ioctl,
351 static struct miscdevice ds1620_miscdev = {
357 static int __init ds1620_init(void)
360 struct therm th, th_start;
362 if (!machine_is_netwinder())
365 ds1620_out(THERM_RESET, 0, 0);
366 ds1620_out(THERM_WRITE_CONFIG, 8, CFG_CPU);
367 ds1620_out(THERM_START_CONVERT, 0, 0);
370 * Trigger the fan to start by setting
371 * temperature high point low. This kicks
372 * the fan into action.
374 ds1620_read_state(&th);
377 ds1620_write_state(&th_start);
381 ds1620_write_state(&th);
383 ret = misc_register(&ds1620_miscdev);
387 #ifdef THERM_USE_PROC
388 proc_therm_ds1620 = create_proc_entry("therm", 0, NULL);
389 if (proc_therm_ds1620)
390 proc_therm_ds1620->read_proc = proc_therm_ds1620_read;
392 printk(KERN_ERR "therm: unable to register /proc/therm\n");
395 ds1620_read_state(&th);
396 ret = cvt_9_to_int(ds1620_in(THERM_READ_TEMP, 9));
398 printk(KERN_INFO "Thermostat: high %i.%i, low %i.%i, "
399 "current %i.%i C, fan %s.\n",
400 th.hi >> 1, th.hi & 1 ? 5 : 0,
401 th.lo >> 1, th.lo & 1 ? 5 : 0,
402 ret >> 1, ret & 1 ? 5 : 0,
403 fan_state[netwinder_get_fan()]);
408 static void __exit ds1620_exit(void)
410 #ifdef THERM_USE_PROC
411 remove_proc_entry("therm", NULL);
413 misc_deregister(&ds1620_miscdev);
416 module_init(ds1620_init);
417 module_exit(ds1620_exit);
419 MODULE_LICENSE("GPL");