1 | // SPDX-License-Identifier: GPL-2.0-only |
2 | /* |
3 | * linux/drivers/char/ds1620.c: Dallas Semiconductors DS1620 |
4 | * thermometer driver (as used in the Rebel.com NetWinder) |
5 | */ |
6 | #include <linux/module.h> |
7 | #include <linux/miscdevice.h> |
8 | #include <linux/delay.h> |
9 | #include <linux/proc_fs.h> |
10 | #include <linux/seq_file.h> |
11 | #include <linux/capability.h> |
12 | #include <linux/init.h> |
13 | #include <linux/mutex.h> |
14 | |
15 | #include <mach/hardware.h> |
16 | #include <asm/mach-types.h> |
17 | #include <linux/uaccess.h> |
18 | #include <asm/therm.h> |
19 | |
20 | #ifdef CONFIG_PROC_FS |
21 | /* define for /proc interface */ |
22 | #define THERM_USE_PROC |
23 | #endif |
24 | |
25 | /* Definitions for DS1620 chip */ |
26 | #define THERM_START_CONVERT 0xee |
27 | #define THERM_RESET 0xaf |
28 | #define THERM_READ_CONFIG 0xac |
29 | #define THERM_READ_TEMP 0xaa |
30 | #define THERM_READ_TL 0xa2 |
31 | #define THERM_READ_TH 0xa1 |
32 | #define THERM_WRITE_CONFIG 0x0c |
33 | #define THERM_WRITE_TL 0x02 |
34 | #define THERM_WRITE_TH 0x01 |
35 | |
36 | #define CFG_CPU 2 |
37 | #define CFG_1SHOT 1 |
38 | |
39 | static DEFINE_MUTEX(ds1620_mutex); |
40 | static const char *fan_state[] = { "off" , "on" , "on (hardwired)" }; |
41 | |
42 | /* |
43 | * Start of NetWinder specifics |
44 | * Note! We have to hold the gpio lock with IRQs disabled over the |
45 | * whole of our transaction to the Dallas chip, since there is a |
46 | * chance that the WaveArtist driver could touch these bits to |
47 | * enable or disable the speaker. |
48 | */ |
49 | extern unsigned int system_rev; |
50 | |
51 | static inline void netwinder_ds1620_set_clk(int clk) |
52 | { |
53 | nw_gpio_modify_op(GPIO_DSCLK, clk ? GPIO_DSCLK : 0); |
54 | } |
55 | |
56 | static inline void netwinder_ds1620_set_data(int dat) |
57 | { |
58 | nw_gpio_modify_op(GPIO_DATA, dat ? GPIO_DATA : 0); |
59 | } |
60 | |
61 | static inline int netwinder_ds1620_get_data(void) |
62 | { |
63 | return nw_gpio_read() & GPIO_DATA; |
64 | } |
65 | |
66 | static inline void netwinder_ds1620_set_data_dir(int dir) |
67 | { |
68 | nw_gpio_modify_io(GPIO_DATA, dir ? GPIO_DATA : 0); |
69 | } |
70 | |
71 | static inline void netwinder_ds1620_reset(void) |
72 | { |
73 | nw_cpld_modify(CPLD_DS_ENABLE, 0); |
74 | nw_cpld_modify(CPLD_DS_ENABLE, CPLD_DS_ENABLE); |
75 | } |
76 | |
77 | static inline void netwinder_lock(unsigned long *flags) |
78 | { |
79 | raw_spin_lock_irqsave(&nw_gpio_lock, *flags); |
80 | } |
81 | |
82 | static inline void netwinder_unlock(unsigned long *flags) |
83 | { |
84 | raw_spin_unlock_irqrestore(&nw_gpio_lock, *flags); |
85 | } |
86 | |
87 | static inline void netwinder_set_fan(int i) |
88 | { |
89 | unsigned long flags; |
90 | |
91 | raw_spin_lock_irqsave(&nw_gpio_lock, flags); |
92 | nw_gpio_modify_op(GPIO_FAN, i ? GPIO_FAN : 0); |
93 | raw_spin_unlock_irqrestore(&nw_gpio_lock, flags); |
94 | } |
95 | |
96 | static inline int netwinder_get_fan(void) |
97 | { |
98 | if ((system_rev & 0xf000) == 0x4000) |
99 | return FAN_ALWAYS_ON; |
100 | |
101 | return (nw_gpio_read() & GPIO_FAN) ? FAN_ON : FAN_OFF; |
102 | } |
103 | |
104 | /* |
105 | * End of NetWinder specifics |
106 | */ |
107 | |
108 | static void ds1620_send_bits(int nr, int value) |
109 | { |
110 | int i; |
111 | |
112 | for (i = 0; i < nr; i++) { |
113 | netwinder_ds1620_set_data(dat: value & 1); |
114 | netwinder_ds1620_set_clk(clk: 0); |
115 | udelay(1); |
116 | netwinder_ds1620_set_clk(clk: 1); |
117 | udelay(1); |
118 | |
119 | value >>= 1; |
120 | } |
121 | } |
122 | |
123 | static unsigned int ds1620_recv_bits(int nr) |
124 | { |
125 | unsigned int value = 0, mask = 1; |
126 | int i; |
127 | |
128 | netwinder_ds1620_set_data(dat: 0); |
129 | |
130 | for (i = 0; i < nr; i++) { |
131 | netwinder_ds1620_set_clk(clk: 0); |
132 | udelay(1); |
133 | |
134 | if (netwinder_ds1620_get_data()) |
135 | value |= mask; |
136 | |
137 | mask <<= 1; |
138 | |
139 | netwinder_ds1620_set_clk(clk: 1); |
140 | udelay(1); |
141 | } |
142 | |
143 | return value; |
144 | } |
145 | |
146 | static void ds1620_out(int cmd, int bits, int value) |
147 | { |
148 | unsigned long flags; |
149 | |
150 | netwinder_lock(flags: &flags); |
151 | netwinder_ds1620_set_clk(clk: 1); |
152 | netwinder_ds1620_set_data_dir(dir: 0); |
153 | netwinder_ds1620_reset(); |
154 | |
155 | udelay(1); |
156 | |
157 | ds1620_send_bits(nr: 8, value: cmd); |
158 | if (bits) |
159 | ds1620_send_bits(nr: bits, value); |
160 | |
161 | udelay(1); |
162 | |
163 | netwinder_ds1620_reset(); |
164 | netwinder_unlock(flags: &flags); |
165 | |
166 | msleep(msecs: 20); |
167 | } |
168 | |
169 | static unsigned int ds1620_in(int cmd, int bits) |
170 | { |
171 | unsigned long flags; |
172 | unsigned int value; |
173 | |
174 | netwinder_lock(flags: &flags); |
175 | netwinder_ds1620_set_clk(clk: 1); |
176 | netwinder_ds1620_set_data_dir(dir: 0); |
177 | netwinder_ds1620_reset(); |
178 | |
179 | udelay(1); |
180 | |
181 | ds1620_send_bits(nr: 8, value: cmd); |
182 | |
183 | netwinder_ds1620_set_data_dir(dir: 1); |
184 | value = ds1620_recv_bits(nr: bits); |
185 | |
186 | netwinder_ds1620_reset(); |
187 | netwinder_unlock(flags: &flags); |
188 | |
189 | return value; |
190 | } |
191 | |
192 | static int cvt_9_to_int(unsigned int val) |
193 | { |
194 | if (val & 0x100) |
195 | val |= 0xfffffe00; |
196 | |
197 | return val; |
198 | } |
199 | |
200 | static void ds1620_write_state(struct therm *therm) |
201 | { |
202 | ds1620_out(THERM_WRITE_CONFIG, bits: 8, CFG_CPU); |
203 | ds1620_out(THERM_WRITE_TL, bits: 9, value: therm->lo); |
204 | ds1620_out(THERM_WRITE_TH, bits: 9, value: therm->hi); |
205 | ds1620_out(THERM_START_CONVERT, bits: 0, value: 0); |
206 | } |
207 | |
208 | static void ds1620_read_state(struct therm *therm) |
209 | { |
210 | therm->lo = cvt_9_to_int(val: ds1620_in(THERM_READ_TL, bits: 9)); |
211 | therm->hi = cvt_9_to_int(val: ds1620_in(THERM_READ_TH, bits: 9)); |
212 | } |
213 | |
214 | static int ds1620_open(struct inode *inode, struct file *file) |
215 | { |
216 | return stream_open(inode, filp: file); |
217 | } |
218 | |
219 | static ssize_t |
220 | ds1620_read(struct file *file, char __user *buf, size_t count, loff_t *ptr) |
221 | { |
222 | signed int cur_temp; |
223 | signed char cur_temp_degF; |
224 | |
225 | cur_temp = cvt_9_to_int(val: ds1620_in(THERM_READ_TEMP, bits: 9)) >> 1; |
226 | |
227 | /* convert to Fahrenheit, as per wdt.c */ |
228 | cur_temp_degF = (cur_temp * 9) / 5 + 32; |
229 | |
230 | if (copy_to_user(to: buf, from: &cur_temp_degF, n: 1)) |
231 | return -EFAULT; |
232 | |
233 | return 1; |
234 | } |
235 | |
236 | static int |
237 | ds1620_ioctl(struct file *file, unsigned int cmd, unsigned long arg) |
238 | { |
239 | struct therm therm; |
240 | union { |
241 | struct therm __user *therm; |
242 | int __user *i; |
243 | } uarg; |
244 | int i; |
245 | |
246 | uarg.i = (int __user *)arg; |
247 | |
248 | switch(cmd) { |
249 | case CMD_SET_THERMOSTATE: |
250 | case CMD_SET_THERMOSTATE2: |
251 | if (!capable(CAP_SYS_ADMIN)) |
252 | return -EPERM; |
253 | |
254 | if (cmd == CMD_SET_THERMOSTATE) { |
255 | if (get_user(therm.hi, uarg.i)) |
256 | return -EFAULT; |
257 | therm.lo = therm.hi - 3; |
258 | } else { |
259 | if (copy_from_user(to: &therm, from: uarg.therm, n: sizeof(therm))) |
260 | return -EFAULT; |
261 | } |
262 | |
263 | therm.lo <<= 1; |
264 | therm.hi <<= 1; |
265 | |
266 | ds1620_write_state(therm: &therm); |
267 | break; |
268 | |
269 | case CMD_GET_THERMOSTATE: |
270 | case CMD_GET_THERMOSTATE2: |
271 | ds1620_read_state(therm: &therm); |
272 | |
273 | therm.lo >>= 1; |
274 | therm.hi >>= 1; |
275 | |
276 | if (cmd == CMD_GET_THERMOSTATE) { |
277 | if (put_user(therm.hi, uarg.i)) |
278 | return -EFAULT; |
279 | } else { |
280 | if (copy_to_user(to: uarg.therm, from: &therm, n: sizeof(therm))) |
281 | return -EFAULT; |
282 | } |
283 | break; |
284 | |
285 | case CMD_GET_TEMPERATURE: |
286 | case CMD_GET_TEMPERATURE2: |
287 | i = cvt_9_to_int(val: ds1620_in(THERM_READ_TEMP, bits: 9)); |
288 | |
289 | if (cmd == CMD_GET_TEMPERATURE) |
290 | i >>= 1; |
291 | |
292 | return put_user(i, uarg.i) ? -EFAULT : 0; |
293 | |
294 | case CMD_GET_STATUS: |
295 | i = ds1620_in(THERM_READ_CONFIG, bits: 8) & 0xe3; |
296 | |
297 | return put_user(i, uarg.i) ? -EFAULT : 0; |
298 | |
299 | case CMD_GET_FAN: |
300 | i = netwinder_get_fan(); |
301 | |
302 | return put_user(i, uarg.i) ? -EFAULT : 0; |
303 | |
304 | case CMD_SET_FAN: |
305 | if (!capable(CAP_SYS_ADMIN)) |
306 | return -EPERM; |
307 | |
308 | if (get_user(i, uarg.i)) |
309 | return -EFAULT; |
310 | |
311 | netwinder_set_fan(i); |
312 | break; |
313 | |
314 | default: |
315 | return -ENOIOCTLCMD; |
316 | } |
317 | |
318 | return 0; |
319 | } |
320 | |
321 | static long |
322 | ds1620_unlocked_ioctl(struct file *file, unsigned int cmd, unsigned long arg) |
323 | { |
324 | int ret; |
325 | |
326 | mutex_lock(&ds1620_mutex); |
327 | ret = ds1620_ioctl(file, cmd, arg); |
328 | mutex_unlock(lock: &ds1620_mutex); |
329 | |
330 | return ret; |
331 | } |
332 | |
333 | #ifdef THERM_USE_PROC |
334 | static int ds1620_proc_therm_show(struct seq_file *m, void *v) |
335 | { |
336 | struct therm th; |
337 | int temp; |
338 | |
339 | ds1620_read_state(therm: &th); |
340 | temp = cvt_9_to_int(val: ds1620_in(THERM_READ_TEMP, bits: 9)); |
341 | |
342 | seq_printf(m, fmt: "Thermostat: HI %i.%i, LOW %i.%i; temperature: %i.%i C, fan %s\n" , |
343 | th.hi >> 1, th.hi & 1 ? 5 : 0, |
344 | th.lo >> 1, th.lo & 1 ? 5 : 0, |
345 | temp >> 1, temp & 1 ? 5 : 0, |
346 | fan_state[netwinder_get_fan()]); |
347 | return 0; |
348 | } |
349 | #endif |
350 | |
351 | static const struct file_operations ds1620_fops = { |
352 | .owner = THIS_MODULE, |
353 | .open = ds1620_open, |
354 | .read = ds1620_read, |
355 | .unlocked_ioctl = ds1620_unlocked_ioctl, |
356 | .llseek = no_llseek, |
357 | }; |
358 | |
359 | static struct miscdevice ds1620_miscdev = { |
360 | TEMP_MINOR, |
361 | "temp" , |
362 | &ds1620_fops |
363 | }; |
364 | |
365 | static int __init ds1620_init(void) |
366 | { |
367 | int ret; |
368 | struct therm th, th_start; |
369 | |
370 | if (!machine_is_netwinder()) |
371 | return -ENODEV; |
372 | |
373 | ds1620_out(THERM_RESET, bits: 0, value: 0); |
374 | ds1620_out(THERM_WRITE_CONFIG, bits: 8, CFG_CPU); |
375 | ds1620_out(THERM_START_CONVERT, bits: 0, value: 0); |
376 | |
377 | /* |
378 | * Trigger the fan to start by setting |
379 | * temperature high point low. This kicks |
380 | * the fan into action. |
381 | */ |
382 | ds1620_read_state(therm: &th); |
383 | th_start.lo = 0; |
384 | th_start.hi = 1; |
385 | ds1620_write_state(therm: &th_start); |
386 | |
387 | msleep(msecs: 2000); |
388 | |
389 | ds1620_write_state(therm: &th); |
390 | |
391 | ret = misc_register(misc: &ds1620_miscdev); |
392 | if (ret < 0) |
393 | return ret; |
394 | |
395 | #ifdef THERM_USE_PROC |
396 | if (!proc_create_single("therm" , 0, NULL, ds1620_proc_therm_show)) |
397 | printk(KERN_ERR "therm: unable to register /proc/therm\n" ); |
398 | #endif |
399 | |
400 | ds1620_read_state(therm: &th); |
401 | ret = cvt_9_to_int(val: ds1620_in(THERM_READ_TEMP, bits: 9)); |
402 | |
403 | printk(KERN_INFO "Thermostat: high %i.%i, low %i.%i, " |
404 | "current %i.%i C, fan %s.\n" , |
405 | th.hi >> 1, th.hi & 1 ? 5 : 0, |
406 | th.lo >> 1, th.lo & 1 ? 5 : 0, |
407 | ret >> 1, ret & 1 ? 5 : 0, |
408 | fan_state[netwinder_get_fan()]); |
409 | |
410 | return 0; |
411 | } |
412 | |
413 | static void __exit ds1620_exit(void) |
414 | { |
415 | #ifdef THERM_USE_PROC |
416 | remove_proc_entry("therm" , NULL); |
417 | #endif |
418 | misc_deregister(misc: &ds1620_miscdev); |
419 | } |
420 | |
421 | module_init(ds1620_init); |
422 | module_exit(ds1620_exit); |
423 | |
424 | MODULE_LICENSE("GPL" ); |
425 | |