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 <mach/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 unsigned int system_rev;
48 static inline void netwinder_ds1620_set_clk(int clk)
50 nw_gpio_modify_op(GPIO_DSCLK, clk ? GPIO_DSCLK : 0);
53 static inline void netwinder_ds1620_set_data(int dat)
55 nw_gpio_modify_op(GPIO_DATA, dat ? GPIO_DATA : 0);
58 static inline int netwinder_ds1620_get_data(void)
60 return nw_gpio_read() & GPIO_DATA;
63 static inline void netwinder_ds1620_set_data_dir(int dir)
65 nw_gpio_modify_io(GPIO_DATA, dir ? GPIO_DATA : 0);
68 static inline void netwinder_ds1620_reset(void)
70 nw_cpld_modify(CPLD_DS_ENABLE, 0);
71 nw_cpld_modify(CPLD_DS_ENABLE, CPLD_DS_ENABLE);
74 static inline void netwinder_lock(unsigned long *flags)
76 spin_lock_irqsave(&nw_gpio_lock, *flags);
79 static inline void netwinder_unlock(unsigned long *flags)
81 spin_unlock_irqrestore(&nw_gpio_lock, *flags);
84 static inline void netwinder_set_fan(int i)
88 spin_lock_irqsave(&nw_gpio_lock, flags);
89 nw_gpio_modify_op(GPIO_FAN, i ? GPIO_FAN : 0);
90 spin_unlock_irqrestore(&nw_gpio_lock, flags);
93 static inline int netwinder_get_fan(void)
95 if ((system_rev & 0xf000) == 0x4000)
98 return (nw_gpio_read() & GPIO_FAN) ? FAN_ON : FAN_OFF;
102 * End of NetWinder specifics
105 static void ds1620_send_bits(int nr, int value)
109 for (i = 0; i < nr; i++) {
110 netwinder_ds1620_set_data(value & 1);
111 netwinder_ds1620_set_clk(0);
113 netwinder_ds1620_set_clk(1);
120 static unsigned int ds1620_recv_bits(int nr)
122 unsigned int value = 0, mask = 1;
125 netwinder_ds1620_set_data(0);
127 for (i = 0; i < nr; i++) {
128 netwinder_ds1620_set_clk(0);
131 if (netwinder_ds1620_get_data())
136 netwinder_ds1620_set_clk(1);
143 static void ds1620_out(int cmd, int bits, int value)
147 netwinder_lock(&flags);
148 netwinder_ds1620_set_clk(1);
149 netwinder_ds1620_set_data_dir(0);
150 netwinder_ds1620_reset();
154 ds1620_send_bits(8, cmd);
156 ds1620_send_bits(bits, value);
160 netwinder_ds1620_reset();
161 netwinder_unlock(&flags);
166 static unsigned int ds1620_in(int cmd, int bits)
171 netwinder_lock(&flags);
172 netwinder_ds1620_set_clk(1);
173 netwinder_ds1620_set_data_dir(0);
174 netwinder_ds1620_reset();
178 ds1620_send_bits(8, cmd);
180 netwinder_ds1620_set_data_dir(1);
181 value = ds1620_recv_bits(bits);
183 netwinder_ds1620_reset();
184 netwinder_unlock(&flags);
189 static int cvt_9_to_int(unsigned int val)
197 static void ds1620_write_state(struct therm *therm)
199 ds1620_out(THERM_WRITE_CONFIG, 8, CFG_CPU);
200 ds1620_out(THERM_WRITE_TL, 9, therm->lo);
201 ds1620_out(THERM_WRITE_TH, 9, therm->hi);
202 ds1620_out(THERM_START_CONVERT, 0, 0);
205 static void ds1620_read_state(struct therm *therm)
207 therm->lo = cvt_9_to_int(ds1620_in(THERM_READ_TL, 9));
208 therm->hi = cvt_9_to_int(ds1620_in(THERM_READ_TH, 9));
211 static int ds1620_open(struct inode *inode, struct file *file)
214 return nonseekable_open(inode, file);
218 ds1620_read(struct file *file, char __user *buf, size_t count, loff_t *ptr)
221 signed char cur_temp_degF;
223 cur_temp = cvt_9_to_int(ds1620_in(THERM_READ_TEMP, 9)) >> 1;
225 /* convert to Fahrenheit, as per wdt.c */
226 cur_temp_degF = (cur_temp * 9) / 5 + 32;
228 if (copy_to_user(buf, &cur_temp_degF, 1))
235 ds1620_ioctl(struct inode *inode, struct file *file, unsigned int cmd, unsigned long arg)
239 struct therm __user *therm;
244 uarg.i = (int __user *)arg;
247 case CMD_SET_THERMOSTATE:
248 case CMD_SET_THERMOSTATE2:
249 if (!capable(CAP_SYS_ADMIN))
252 if (cmd == CMD_SET_THERMOSTATE) {
253 if (get_user(therm.hi, uarg.i))
255 therm.lo = therm.hi - 3;
257 if (copy_from_user(&therm, uarg.therm, sizeof(therm)))
264 ds1620_write_state(&therm);
267 case CMD_GET_THERMOSTATE:
268 case CMD_GET_THERMOSTATE2:
269 ds1620_read_state(&therm);
274 if (cmd == CMD_GET_THERMOSTATE) {
275 if (put_user(therm.hi, uarg.i))
278 if (copy_to_user(uarg.therm, &therm, sizeof(therm)))
283 case CMD_GET_TEMPERATURE:
284 case CMD_GET_TEMPERATURE2:
285 i = cvt_9_to_int(ds1620_in(THERM_READ_TEMP, 9));
287 if (cmd == CMD_GET_TEMPERATURE)
290 return put_user(i, uarg.i) ? -EFAULT : 0;
293 i = ds1620_in(THERM_READ_CONFIG, 8) & 0xe3;
295 return put_user(i, uarg.i) ? -EFAULT : 0;
298 i = netwinder_get_fan();
300 return put_user(i, uarg.i) ? -EFAULT : 0;
303 if (!capable(CAP_SYS_ADMIN))
306 if (get_user(i, uarg.i))
309 netwinder_set_fan(i);
319 #ifdef THERM_USE_PROC
321 proc_therm_ds1620_read(char *buf, char **start, off_t offset,
322 int len, int *eof, void *unused)
327 ds1620_read_state(&th);
328 temp = cvt_9_to_int(ds1620_in(THERM_READ_TEMP, 9));
330 len = sprintf(buf, "Thermostat: HI %i.%i, LOW %i.%i; "
331 "temperature: %i.%i C, fan %s\n",
332 th.hi >> 1, th.hi & 1 ? 5 : 0,
333 th.lo >> 1, th.lo & 1 ? 5 : 0,
334 temp >> 1, temp & 1 ? 5 : 0,
335 fan_state[netwinder_get_fan()]);
340 static struct proc_dir_entry *proc_therm_ds1620;
343 static const struct file_operations ds1620_fops = {
344 .owner = THIS_MODULE,
347 .ioctl = ds1620_ioctl,
350 static struct miscdevice ds1620_miscdev = {
356 static int __init ds1620_init(void)
359 struct therm th, th_start;
361 if (!machine_is_netwinder())
364 ds1620_out(THERM_RESET, 0, 0);
365 ds1620_out(THERM_WRITE_CONFIG, 8, CFG_CPU);
366 ds1620_out(THERM_START_CONVERT, 0, 0);
369 * Trigger the fan to start by setting
370 * temperature high point low. This kicks
371 * the fan into action.
373 ds1620_read_state(&th);
376 ds1620_write_state(&th_start);
380 ds1620_write_state(&th);
382 ret = misc_register(&ds1620_miscdev);
386 #ifdef THERM_USE_PROC
387 proc_therm_ds1620 = create_proc_entry("therm", 0, NULL);
388 if (proc_therm_ds1620)
389 proc_therm_ds1620->read_proc = proc_therm_ds1620_read;
391 printk(KERN_ERR "therm: unable to register /proc/therm\n");
394 ds1620_read_state(&th);
395 ret = cvt_9_to_int(ds1620_in(THERM_READ_TEMP, 9));
397 printk(KERN_INFO "Thermostat: high %i.%i, low %i.%i, "
398 "current %i.%i C, fan %s.\n",
399 th.hi >> 1, th.hi & 1 ? 5 : 0,
400 th.lo >> 1, th.lo & 1 ? 5 : 0,
401 ret >> 1, ret & 1 ? 5 : 0,
402 fan_state[netwinder_get_fan()]);
407 static void __exit ds1620_exit(void)
409 #ifdef THERM_USE_PROC
410 remove_proc_entry("therm", NULL);
412 misc_deregister(&ds1620_miscdev);
415 module_init(ds1620_init);
416 module_exit(ds1620_exit);
418 MODULE_LICENSE("GPL");