linux/drivers/char/ds1620.c

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/*
* linux/drivers/char/ds1620.c: Dallas Semiconductors DS1620
* thermometer driver (as used in the Rebel.com NetWinder)
*/
#include <linux/module.h>
#include <linux/miscdevice.h>
#include <linux/delay.h>
#include <linux/proc_fs.h>
#include <linux/capability.h>
#include <linux/init.h>
#include <linux/mutex.h>
#include <mach/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 DEFINE_MUTEX(ds1620_mutex);
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 unsigned int system_rev;
static inline void netwinder_ds1620_set_clk(int clk)
{
nw_gpio_modify_op(GPIO_DSCLK, clk ? GPIO_DSCLK : 0);
}
static inline void netwinder_ds1620_set_data(int dat)
{
nw_gpio_modify_op(GPIO_DATA, dat ? GPIO_DATA : 0);
}
static inline int netwinder_ds1620_get_data(void)
{
return nw_gpio_read() & GPIO_DATA;
}
static inline void netwinder_ds1620_set_data_dir(int dir)
{
nw_gpio_modify_io(GPIO_DATA, dir ? GPIO_DATA : 0);
}
static inline void netwinder_ds1620_reset(void)
{
nw_cpld_modify(CPLD_DS_ENABLE, 0);
nw_cpld_modify(CPLD_DS_ENABLE, CPLD_DS_ENABLE);
}
static inline void netwinder_lock(unsigned long *flags)
{
raw_spin_lock_irqsave(&nw_gpio_lock, *flags);
}
static inline void netwinder_unlock(unsigned long *flags)
{
raw_spin_unlock_irqrestore(&nw_gpio_lock, *flags);
}
static inline void netwinder_set_fan(int i)
{
unsigned long flags;
raw_spin_lock_irqsave(&nw_gpio_lock, flags);
nw_gpio_modify_op(GPIO_FAN, i ? GPIO_FAN : 0);
raw_spin_unlock_irqrestore(&nw_gpio_lock, flags);
}
static inline int netwinder_get_fan(void)
{
if ((system_rev & 0xf000) == 0x4000)
return FAN_ALWAYS_ON;
return (nw_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);
msleep(20);
}
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 int ds1620_open(struct inode *inode, struct file *file)
{
return nonseekable_open(inode, file);
}
static ssize_t
ds1620_read(struct file *file, char __user *buf, size_t count, loff_t *ptr)
{
signed int cur_temp;
signed char cur_temp_degF;
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 file *file, unsigned int cmd, unsigned long arg)
{
struct therm therm;
union {
struct therm __user *therm;
int __user *i;
} uarg;
int i;
uarg.i = (int __user *)arg;
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, uarg.i))
return -EFAULT;
therm.lo = therm.hi - 3;
} else {
if (copy_from_user(&therm, uarg.therm, 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, uarg.i))
return -EFAULT;
} else {
if (copy_to_user(uarg.therm, &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, uarg.i) ? -EFAULT : 0;
case CMD_GET_STATUS:
i = ds1620_in(THERM_READ_CONFIG, 8) & 0xe3;
return put_user(i, uarg.i) ? -EFAULT : 0;
case CMD_GET_FAN:
i = netwinder_get_fan();
return put_user(i, uarg.i) ? -EFAULT : 0;
case CMD_SET_FAN:
if (!capable(CAP_SYS_ADMIN))
return -EPERM;
if (get_user(i, uarg.i))
return -EFAULT;
netwinder_set_fan(i);
break;
default:
return -ENOIOCTLCMD;
}
return 0;
}
static long
ds1620_unlocked_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
{
int ret;
mutex_lock(&ds1620_mutex);
ret = ds1620_ioctl(file, cmd, arg);
mutex_unlock(&ds1620_mutex);
return ret;
}
#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 const struct file_operations ds1620_fops = {
.owner = THIS_MODULE,
.open = ds1620_open,
.read = ds1620_read,
.unlocked_ioctl = ds1620_unlocked_ioctl,
llseek: automatically add .llseek fop All file_operations should get a .llseek operation so we can make nonseekable_open the default for future file operations without a .llseek pointer. The three cases that we can automatically detect are no_llseek, seq_lseek and default_llseek. For cases where we can we can automatically prove that the file offset is always ignored, we use noop_llseek, which maintains the current behavior of not returning an error from a seek. New drivers should normally not use noop_llseek but instead use no_llseek and call nonseekable_open at open time. Existing drivers can be converted to do the same when the maintainer knows for certain that no user code relies on calling seek on the device file. The generated code is often incorrectly indented and right now contains comments that clarify for each added line why a specific variant was chosen. In the version that gets submitted upstream, the comments will be gone and I will manually fix the indentation, because there does not seem to be a way to do that using coccinelle. Some amount of new code is currently sitting in linux-next that should get the same modifications, which I will do at the end of the merge window. Many thanks to Julia Lawall for helping me learn to write a semantic patch that does all this. ===== begin semantic patch ===== // This adds an llseek= method to all file operations, // as a preparation for making no_llseek the default. // // The rules are // - use no_llseek explicitly if we do nonseekable_open // - use seq_lseek for sequential files // - use default_llseek if we know we access f_pos // - use noop_llseek if we know we don't access f_pos, // but we still want to allow users to call lseek // @ open1 exists @ identifier nested_open; @@ nested_open(...) { <+... nonseekable_open(...) ...+> } @ open exists@ identifier open_f; identifier i, f; identifier open1.nested_open; @@ int open_f(struct inode *i, struct file *f) { <+... ( nonseekable_open(...) | nested_open(...) ) ...+> } @ read disable optional_qualifier exists @ identifier read_f; identifier f, p, s, off; type ssize_t, size_t, loff_t; expression E; identifier func; @@ ssize_t read_f(struct file *f, char *p, size_t s, loff_t *off) { <+... ( *off = E | *off += E | func(..., off, ...) | E = *off ) ...+> } @ read_no_fpos disable optional_qualifier exists @ identifier read_f; identifier f, p, s, off; type ssize_t, size_t, loff_t; @@ ssize_t read_f(struct file *f, char *p, size_t s, loff_t *off) { ... when != off } @ write @ identifier write_f; identifier f, p, s, off; type ssize_t, size_t, loff_t; expression E; identifier func; @@ ssize_t write_f(struct file *f, const char *p, size_t s, loff_t *off) { <+... ( *off = E | *off += E | func(..., off, ...) | E = *off ) ...+> } @ write_no_fpos @ identifier write_f; identifier f, p, s, off; type ssize_t, size_t, loff_t; @@ ssize_t write_f(struct file *f, const char *p, size_t s, loff_t *off) { ... when != off } @ fops0 @ identifier fops; @@ struct file_operations fops = { ... }; @ has_llseek depends on fops0 @ identifier fops0.fops; identifier llseek_f; @@ struct file_operations fops = { ... .llseek = llseek_f, ... }; @ has_read depends on fops0 @ identifier fops0.fops; identifier read_f; @@ struct file_operations fops = { ... .read = read_f, ... }; @ has_write depends on fops0 @ identifier fops0.fops; identifier write_f; @@ struct file_operations fops = { ... .write = write_f, ... }; @ has_open depends on fops0 @ identifier fops0.fops; identifier open_f; @@ struct file_operations fops = { ... .open = open_f, ... }; // use no_llseek if we call nonseekable_open //////////////////////////////////////////// @ nonseekable1 depends on !has_llseek && has_open @ identifier fops0.fops; identifier nso ~= "nonseekable_open"; @@ struct file_operations fops = { ... .open = nso, ... +.llseek = no_llseek, /* nonseekable */ }; @ nonseekable2 depends on !has_llseek @ identifier fops0.fops; identifier open.open_f; @@ struct file_operations fops = { ... .open = open_f, ... +.llseek = no_llseek, /* open uses nonseekable */ }; // use seq_lseek for sequential files ///////////////////////////////////// @ seq depends on !has_llseek @ identifier fops0.fops; identifier sr ~= "seq_read"; @@ struct file_operations fops = { ... .read = sr, ... +.llseek = seq_lseek, /* we have seq_read */ }; // use default_llseek if there is a readdir /////////////////////////////////////////// @ fops1 depends on !has_llseek && !nonseekable1 && !nonseekable2 && !seq @ identifier fops0.fops; identifier readdir_e; @@ // any other fop is used that changes pos struct file_operations fops = { ... .readdir = readdir_e, ... +.llseek = default_llseek, /* readdir is present */ }; // use default_llseek if at least one of read/write touches f_pos ///////////////////////////////////////////////////////////////// @ fops2 depends on !fops1 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @ identifier fops0.fops; identifier read.read_f; @@ // read fops use offset struct file_operations fops = { ... .read = read_f, ... +.llseek = default_llseek, /* read accesses f_pos */ }; @ fops3 depends on !fops1 && !fops2 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @ identifier fops0.fops; identifier write.write_f; @@ // write fops use offset struct file_operations fops = { ... .write = write_f, ... + .llseek = default_llseek, /* write accesses f_pos */ }; // Use noop_llseek if neither read nor write accesses f_pos /////////////////////////////////////////////////////////// @ fops4 depends on !fops1 && !fops2 && !fops3 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @ identifier fops0.fops; identifier read_no_fpos.read_f; identifier write_no_fpos.write_f; @@ // write fops use offset struct file_operations fops = { ... .write = write_f, .read = read_f, ... +.llseek = noop_llseek, /* read and write both use no f_pos */ }; @ depends on has_write && !has_read && !fops1 && !fops2 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @ identifier fops0.fops; identifier write_no_fpos.write_f; @@ struct file_operations fops = { ... .write = write_f, ... +.llseek = noop_llseek, /* write uses no f_pos */ }; @ depends on has_read && !has_write && !fops1 && !fops2 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @ identifier fops0.fops; identifier read_no_fpos.read_f; @@ struct file_operations fops = { ... .read = read_f, ... +.llseek = noop_llseek, /* read uses no f_pos */ }; @ depends on !has_read && !has_write && !fops1 && !fops2 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @ identifier fops0.fops; @@ struct file_operations fops = { ... +.llseek = noop_llseek, /* no read or write fn */ }; ===== End semantic patch ===== Signed-off-by: Arnd Bergmann <arnd@arndb.de> Cc: Julia Lawall <julia@diku.dk> Cc: Christoph Hellwig <hch@infradead.org>
2010-08-15 16:52:59 +00:00
.llseek = no_llseek,
};
static struct miscdevice ds1620_miscdev = {
TEMP_MINOR,
"temp",
&ds1620_fops
};
static 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);
msleep(2000);
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, NULL);
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;
}
static 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");