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1// SPDX-License-Identifier: GPL-2.0-only2/*3 * linux/drivers/char/ds1620.c: Dallas Semiconductors DS16204 * 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_FS21/* define for /proc interface */22#define THERM_USE_PROC23#endif24 25/* Definitions for DS1620 chip */26#define THERM_START_CONVERT 0xee27#define THERM_RESET 0xaf28#define THERM_READ_CONFIG 0xac29#define THERM_READ_TEMP 0xaa30#define THERM_READ_TL 0xa231#define THERM_READ_TH 0xa132#define THERM_WRITE_CONFIG 0x0c33#define THERM_WRITE_TL 0x0234#define THERM_WRITE_TH 0x0135 36#define CFG_CPU 237#define CFG_1SHOT 138 39static DEFINE_MUTEX(ds1620_mutex);40static const char *fan_state[] = { "off", "on", "on (hardwired)" };41 42/*43 * Start of NetWinder specifics44 * Note! We have to hold the gpio lock with IRQs disabled over the45 * whole of our transaction to the Dallas chip, since there is a46 * chance that the WaveArtist driver could touch these bits to47 * enable or disable the speaker.48 */49extern unsigned int system_rev;50 51static inline void netwinder_ds1620_set_clk(int clk)52{53 nw_gpio_modify_op(GPIO_DSCLK, clk ? GPIO_DSCLK : 0);54}55 56static inline void netwinder_ds1620_set_data(int dat)57{58 nw_gpio_modify_op(GPIO_DATA, dat ? GPIO_DATA : 0);59}60 61static inline int netwinder_ds1620_get_data(void)62{63 return nw_gpio_read() & GPIO_DATA;64}65 66static inline void netwinder_ds1620_set_data_dir(int dir)67{68 nw_gpio_modify_io(GPIO_DATA, dir ? GPIO_DATA : 0);69}70 71static 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 77static inline void netwinder_lock(unsigned long *flags)78{79 raw_spin_lock_irqsave(&nw_gpio_lock, *flags);80}81 82static inline void netwinder_unlock(unsigned long *flags)83{84 raw_spin_unlock_irqrestore(&nw_gpio_lock, *flags);85}86 87static 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 96static 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 specifics106 */107 108static 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(value & 1);114 netwinder_ds1620_set_clk(0);115 udelay(1);116 netwinder_ds1620_set_clk(1);117 udelay(1);118 119 value >>= 1;120 }121}122 123static unsigned int ds1620_recv_bits(int nr)124{125 unsigned int value = 0, mask = 1;126 int i;127 128 netwinder_ds1620_set_data(0);129 130 for (i = 0; i < nr; i++) {131 netwinder_ds1620_set_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(1);140 udelay(1);141 }142 143 return value;144}145 146static void ds1620_out(int cmd, int bits, int value)147{148 unsigned long flags;149 150 netwinder_lock(&flags);151 netwinder_ds1620_set_clk(1);152 netwinder_ds1620_set_data_dir(0);153 netwinder_ds1620_reset();154 155 udelay(1);156 157 ds1620_send_bits(8, cmd);158 if (bits)159 ds1620_send_bits(bits, value);160 161 udelay(1);162 163 netwinder_ds1620_reset();164 netwinder_unlock(&flags);165 166 msleep(20);167}168 169static unsigned int ds1620_in(int cmd, int bits)170{171 unsigned long flags;172 unsigned int value;173 174 netwinder_lock(&flags);175 netwinder_ds1620_set_clk(1);176 netwinder_ds1620_set_data_dir(0);177 netwinder_ds1620_reset();178 179 udelay(1);180 181 ds1620_send_bits(8, cmd);182 183 netwinder_ds1620_set_data_dir(1);184 value = ds1620_recv_bits(bits);185 186 netwinder_ds1620_reset();187 netwinder_unlock(&flags);188 189 return value;190}191 192static int cvt_9_to_int(unsigned int val)193{194 if (val & 0x100)195 val |= 0xfffffe00;196 197 return val;198}199 200static void ds1620_write_state(struct therm *therm)201{202 ds1620_out(THERM_WRITE_CONFIG, 8, CFG_CPU);203 ds1620_out(THERM_WRITE_TL, 9, therm->lo);204 ds1620_out(THERM_WRITE_TH, 9, therm->hi);205 ds1620_out(THERM_START_CONVERT, 0, 0);206}207 208static void ds1620_read_state(struct therm *therm)209{210 therm->lo = cvt_9_to_int(ds1620_in(THERM_READ_TL, 9));211 therm->hi = cvt_9_to_int(ds1620_in(THERM_READ_TH, 9));212}213 214static int ds1620_open(struct inode *inode, struct file *file)215{216 return stream_open(inode, file);217}218 219static ssize_t220ds1620_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(ds1620_in(THERM_READ_TEMP, 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(buf, &cur_temp_degF, 1))231 return -EFAULT;232 233 return 1;234}235 236static int237ds1620_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(&therm, uarg.therm, sizeof(therm)))260 return -EFAULT;261 }262 263 therm.lo <<= 1;264 therm.hi <<= 1;265 266 ds1620_write_state(&therm);267 break;268 269 case CMD_GET_THERMOSTATE:270 case CMD_GET_THERMOSTATE2:271 ds1620_read_state(&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(uarg.therm, &therm, 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(ds1620_in(THERM_READ_TEMP, 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, 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 321static long322ds1620_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(&ds1620_mutex);329 330 return ret;331}332 333#ifdef THERM_USE_PROC334static int ds1620_proc_therm_show(struct seq_file *m, void *v)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 seq_printf(m, "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#endif350 351static 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};357 358static struct miscdevice ds1620_miscdev = {359 TEMP_MINOR,360 "temp",361 &ds1620_fops362};363 364static int __init ds1620_init(void)365{366 int ret;367 struct therm th, th_start;368 369 if (!machine_is_netwinder())370 return -ENODEV;371 372 ds1620_out(THERM_RESET, 0, 0);373 ds1620_out(THERM_WRITE_CONFIG, 8, CFG_CPU);374 ds1620_out(THERM_START_CONVERT, 0, 0);375 376 /*377 * Trigger the fan to start by setting378 * temperature high point low. This kicks379 * the fan into action.380 */381 ds1620_read_state(&th);382 th_start.lo = 0;383 th_start.hi = 1;384 ds1620_write_state(&th_start);385 386 msleep(2000);387 388 ds1620_write_state(&th);389 390 ret = misc_register(&ds1620_miscdev);391 if (ret < 0)392 return ret;393 394#ifdef THERM_USE_PROC395 if (!proc_create_single("therm", 0, NULL, ds1620_proc_therm_show))396 printk(KERN_ERR "therm: unable to register /proc/therm\n");397#endif398 399 ds1620_read_state(&th);400 ret = cvt_9_to_int(ds1620_in(THERM_READ_TEMP, 9));401 402 printk(KERN_INFO "Thermostat: high %i.%i, low %i.%i, "403 "current %i.%i C, fan %s.\n",404 th.hi >> 1, th.hi & 1 ? 5 : 0,405 th.lo >> 1, th.lo & 1 ? 5 : 0,406 ret >> 1, ret & 1 ? 5 : 0,407 fan_state[netwinder_get_fan()]);408 409 return 0;410}411 412static void __exit ds1620_exit(void)413{414#ifdef THERM_USE_PROC415 remove_proc_entry("therm", NULL);416#endif417 misc_deregister(&ds1620_miscdev);418}419 420module_init(ds1620_init);421module_exit(ds1620_exit);422 423MODULE_DESCRIPTION("Dallas Semiconductor DS1620 thermometer driver");424MODULE_LICENSE("GPL");425