Viewing file:  ds1620.c (8.26 KB) -rw-r--r--
Select action/file-type:
 (+) |  (+) |  (+) | Code (+) | Session (+) |  (+) | SDB (+) |  (+) |  (+) |  (+) |  (+) |  (+) |
/*
* linux/drivers/char/ds1620.c: Dallas Semiconductors DS1620
* thermometer driver (as used in the Rebel.com NetWinder)
*/
#include <linux/config.h>
#include <linux/module.h>
#include <linux/sched.h>
#include <linux/miscdevice.h>
#include <linux/smp_lock.h>
#include <linux/delay.h>
#include <linux/proc_fs.h>
#include <linux/capability.h>
#include <linux/init.h>
#include <asm/hardware.h>
#include <asm/mach-types.h>
#include <asm/uaccess.h>
#include <asm/therm.h>
#ifdef CONFIG_PROC_FS
/* define for /proc interface */
#define THERM_USE_PROC
#endif
/* Definitions for DS1620 chip */
#define THERM_START_CONVERT 0xee
#define THERM_RESET 0xaf
#define THERM_READ_CONFIG 0xac
#define THERM_READ_TEMP 0xaa
#define THERM_READ_TL 0xa2
#define THERM_READ_TH 0xa1
#define THERM_WRITE_CONFIG 0x0c
#define THERM_WRITE_TL 0x02
#define THERM_WRITE_TH 0x01
#define CFG_CPU 2
#define CFG_1SHOT 1
static const char *fan_state[] = { "off", "on", "on (hardwired)" };
/*
* Start of NetWinder specifics
* Note! We have to hold the gpio lock with IRQs disabled over the
* whole of our transaction to the Dallas chip, since there is a
* chance that the WaveArtist driver could touch these bits to
* enable or disable the speaker.
*/
extern spinlock_t gpio_lock;
extern unsigned int system_rev;
static inline void netwinder_ds1620_set_clk(int clk)
{
gpio_modify_op(GPIO_DSCLK, clk ? GPIO_DSCLK : 0);
}
static inline void netwinder_ds1620_set_data(int dat)
{
gpio_modify_op(GPIO_DATA, dat ? GPIO_DATA : 0);
}
static inline int netwinder_ds1620_get_data(void)
{
return gpio_read() & GPIO_DATA;
}
static inline void netwinder_ds1620_set_data_dir(int dir)
{
gpio_modify_io(GPIO_DATA, dir ? GPIO_DATA : 0);
}
static inline void netwinder_ds1620_reset(void)
{
cpld_modify(CPLD_DS_ENABLE, 0);
cpld_modify(CPLD_DS_ENABLE, CPLD_DS_ENABLE);
}
static inline void netwinder_lock(unsigned long *flags)
{
spin_lock_irqsave(&gpio_lock, *flags);
}
static inline void netwinder_unlock(unsigned long *flags)
{
spin_unlock_irqrestore(&gpio_lock, *flags);
}
static inline void netwinder_set_fan(int i)
{
unsigned long flags;
spin_lock_irqsave(&gpio_lock, flags);
gpio_modify_op(GPIO_FAN, i ? GPIO_FAN : 0);
spin_unlock_irqrestore(&gpio_lock, flags);
}
static inline int netwinder_get_fan(void)
{
if ((system_rev & 0xf000) == 0x4000)
return FAN_ALWAYS_ON;
return (gpio_read() & GPIO_FAN) ? FAN_ON : FAN_OFF;
}
/*
* End of NetWinder specifics
*/
static void ds1620_send_bits(int nr, int value)
{
int i;
for (i = 0; i < nr; i++) {
netwinder_ds1620_set_data(value & 1);
netwinder_ds1620_set_clk(0);
udelay(1);
netwinder_ds1620_set_clk(1);
udelay(1);
value >>= 1;
}
}
static unsigned int ds1620_recv_bits(int nr)
{
unsigned int value = 0, mask = 1;
int i;
netwinder_ds1620_set_data(0);
for (i = 0; i < nr; i++) {
netwinder_ds1620_set_clk(0);
udelay(1);
if (netwinder_ds1620_get_data())
value |= mask;
mask <<= 1;
netwinder_ds1620_set_clk(1);
udelay(1);
}
return value;
}
static void ds1620_out(int cmd, int bits, int value)
{
unsigned long flags;
netwinder_lock(&flags);
netwinder_ds1620_set_clk(1);
netwinder_ds1620_set_data_dir(0);
netwinder_ds1620_reset();
udelay(1);
ds1620_send_bits(8, cmd);
if (bits)
ds1620_send_bits(bits, value);
udelay(1);
netwinder_ds1620_reset();
netwinder_unlock(&flags);
set_current_state(TASK_INTERRUPTIBLE);
schedule_timeout(2);
}
static unsigned int ds1620_in(int cmd, int bits)
{
unsigned long flags;
unsigned int value;
netwinder_lock(&flags);
netwinder_ds1620_set_clk(1);
netwinder_ds1620_set_data_dir(0);
netwinder_ds1620_reset();
udelay(1);
ds1620_send_bits(8, cmd);
netwinder_ds1620_set_data_dir(1);
value = ds1620_recv_bits(bits);
netwinder_ds1620_reset();
netwinder_unlock(&flags);
return value;
}
static int cvt_9_to_int(unsigned int val)
{
if (val & 0x100)
val |= 0xfffffe00;
return val;
}
static void ds1620_write_state(struct therm *therm)
{
ds1620_out(THERM_WRITE_CONFIG, 8, CFG_CPU);
ds1620_out(THERM_WRITE_TL, 9, therm->lo);
ds1620_out(THERM_WRITE_TH, 9, therm->hi);
ds1620_out(THERM_START_CONVERT, 0, 0);
}
static void ds1620_read_state(struct therm *therm)
{
therm->lo = cvt_9_to_int(ds1620_in(THERM_READ_TL, 9));
therm->hi = cvt_9_to_int(ds1620_in(THERM_READ_TH, 9));
}
static ssize_t
ds1620_read(struct file *file, char *buf, size_t count, loff_t *ptr)
{
signed int cur_temp;
signed char cur_temp_degF;
/* Can't seek (pread) on this device */
if (ptr != &file->f_pos)
return -ESPIPE;
cur_temp = cvt_9_to_int(ds1620_in(THERM_READ_TEMP, 9)) >> 1;
/* convert to Fahrenheit, as per wdt.c */
cur_temp_degF = (cur_temp * 9) / 5 + 32;
if (copy_to_user(buf, &cur_temp_degF, 1))
return -EFAULT;
return 1;
}
static int
ds1620_ioctl(struct inode *inode, struct file *file, unsigned int cmd, unsigned long arg)
{
struct therm therm;
int i;
switch(cmd) {
case CMD_SET_THERMOSTATE:
case CMD_SET_THERMOSTATE2:
if (!capable(CAP_SYS_ADMIN))
return -EPERM;
if (cmd == CMD_SET_THERMOSTATE) {
if (get_user(therm.hi, (int *)arg))
return -EFAULT;
therm.lo = therm.hi - 3;
} else {
if (copy_from_user(&therm, (void *)arg, sizeof(therm)))
return -EFAULT;
}
therm.lo <<= 1;
therm.hi <<= 1;
ds1620_write_state(&therm);
break;
case CMD_GET_THERMOSTATE:
case CMD_GET_THERMOSTATE2:
ds1620_read_state(&therm);
therm.lo >>= 1;
therm.hi >>= 1;
if (cmd == CMD_GET_THERMOSTATE) {
if (put_user(therm.hi, (int *)arg))
return -EFAULT;
} else {
if (copy_to_user((void *)arg, &therm, sizeof(therm)))
return -EFAULT;
}
break;
case CMD_GET_TEMPERATURE:
case CMD_GET_TEMPERATURE2:
i = cvt_9_to_int(ds1620_in(THERM_READ_TEMP, 9));
if (cmd == CMD_GET_TEMPERATURE)
i >>= 1;
return put_user(i, (int *)arg) ? -EFAULT : 0;
case CMD_GET_STATUS:
i = ds1620_in(THERM_READ_CONFIG, 8) & 0xe3;
return put_user(i, (int *)arg) ? -EFAULT : 0;
case CMD_GET_FAN:
i = netwinder_get_fan();
return put_user(i, (int *)arg) ? -EFAULT : 0;
case CMD_SET_FAN:
if (!capable(CAP_SYS_ADMIN))
return -EPERM;
if (get_user(i, (int *)arg))
return -EFAULT;
netwinder_set_fan(i);
break;
default:
return -ENOIOCTLCMD;
}
return 0;
}
#ifdef THERM_USE_PROC
static int
proc_therm_ds1620_read(char *buf, char **start, off_t offset,
int len, int *eof, void *unused)
{
struct therm th;
int temp;
ds1620_read_state(&th);
temp = cvt_9_to_int(ds1620_in(THERM_READ_TEMP, 9));
len = sprintf(buf, "Thermostat: HI %i.%i, LOW %i.%i; "
"temperature: %i.%i C, fan %s\n",
th.hi >> 1, th.hi & 1 ? 5 : 0,
th.lo >> 1, th.lo & 1 ? 5 : 0,
temp >> 1, temp & 1 ? 5 : 0,
fan_state[netwinder_get_fan()]);
return len;
}
static struct proc_dir_entry *proc_therm_ds1620;
#endif
static struct file_operations ds1620_fops = {
owner: THIS_MODULE,
read: ds1620_read,
ioctl: ds1620_ioctl,
};
static struct miscdevice ds1620_miscdev = {
TEMP_MINOR,
"temp",
&ds1620_fops
};
int __init ds1620_init(void)
{
int ret;
struct therm th, th_start;
if (!machine_is_netwinder())
return -ENODEV;
ds1620_out(THERM_RESET, 0, 0);
ds1620_out(THERM_WRITE_CONFIG, 8, CFG_CPU);
ds1620_out(THERM_START_CONVERT, 0, 0);
/*
* Trigger the fan to start by setting
* temperature high point low. This kicks
* the fan into action.
*/
ds1620_read_state(&th);
th_start.lo = 0;
th_start.hi = 1;
ds1620_write_state(&th_start);
set_current_state(TASK_INTERRUPTIBLE);
schedule_timeout(2*HZ);
ds1620_write_state(&th);
ret = misc_register(&ds1620_miscdev);
if (ret < 0)
return ret;
#ifdef THERM_USE_PROC
proc_therm_ds1620 = create_proc_entry("therm", 0, 0);
if (proc_therm_ds1620)
proc_therm_ds1620->read_proc = proc_therm_ds1620_read;
else
printk(KERN_ERR "therm: unable to register /proc/therm\n");
#endif
ds1620_read_state(&th);
ret = cvt_9_to_int(ds1620_in(THERM_READ_TEMP, 9));
printk(KERN_INFO "Thermostat: high %i.%i, low %i.%i, "
"current %i.%i C, fan %s.\n",
th.hi >> 1, th.hi & 1 ? 5 : 0,
th.lo >> 1, th.lo & 1 ? 5 : 0,
ret >> 1, ret & 1 ? 5 : 0,
fan_state[netwinder_get_fan()]);
return 0;
}
void __exit ds1620_exit(void)
{
#ifdef THERM_USE_PROC
remove_proc_entry("therm", NULL);
#endif
misc_deregister(&ds1620_miscdev);
}
module_init(ds1620_init);
module_exit(ds1620_exit);
MODULE_LICENSE("GPL");
|