diff options
Diffstat (limited to 'drivers/w1/w1_therm.c')
| -rw-r--r-- | drivers/w1/w1_therm.c | 205 |
1 files changed, 205 insertions, 0 deletions
diff --git a/drivers/w1/w1_therm.c b/drivers/w1/w1_therm.c new file mode 100644 index 0000000..0b18178 --- /dev/null +++ b/drivers/w1/w1_therm.c @@ -0,0 +1,205 @@ +/* + * w1_therm.c + * + * Copyright (c) 2004 Evgeniy Polyakov <johnpol@2ka.mipt.ru> + * + * + * This program is free software; you can redistribute it and/or modify + * it under the therms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA + */ + +#include <asm/types.h> + +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/moduleparam.h> +#include <linux/device.h> +#include <linux/types.h> +#include <linux/delay.h> + +#include "w1.h" +#include "w1_io.h" +#include "w1_int.h" +#include "w1_family.h" + +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("Evgeniy Polyakov <johnpol@2ka.mipt.ru>"); +MODULE_DESCRIPTION("Driver for 1-wire Dallas network protocol, temperature family."); + +static u8 bad_roms[][9] = { + {0xaa, 0x00, 0x4b, 0x46, 0xff, 0xff, 0x0c, 0x10, 0x87}, + {} + }; + +static ssize_t w1_therm_read_name(struct device *, char *); +static ssize_t w1_therm_read_temp(struct device *, char *); +static ssize_t w1_therm_read_bin(struct kobject *, char *, loff_t, size_t); + +static struct w1_family_ops w1_therm_fops = { + .rname = &w1_therm_read_name, + .rbin = &w1_therm_read_bin, + .rval = &w1_therm_read_temp, + .rvalname = "temp1_input", +}; + +static ssize_t w1_therm_read_name(struct device *dev, char *buf) +{ + struct w1_slave *sl = container_of(dev, struct w1_slave, dev); + + return sprintf(buf, "%s\n", sl->name); +} + +static inline int w1_convert_temp(u8 rom[9]) +{ + int t, h; + + if (rom[1] == 0) + t = ((s32)rom[0] >> 1)*1000; + else + t = 1000*(-1*(s32)(0x100-rom[0]) >> 1); + + t -= 250; + h = 1000*((s32)rom[7] - (s32)rom[6]); + h /= (s32)rom[7]; + t += h; + + return t; +} + +static ssize_t w1_therm_read_temp(struct device *dev, char *buf) +{ + struct w1_slave *sl = container_of(dev, struct w1_slave, dev); + + return sprintf(buf, "%d\n", w1_convert_temp(sl->rom)); +} + +static int w1_therm_check_rom(u8 rom[9]) +{ + int i; + + for (i=0; i<sizeof(bad_roms)/9; ++i) + if (!memcmp(bad_roms[i], rom, 9)) + return 1; + + return 0; +} + +static ssize_t w1_therm_read_bin(struct kobject *kobj, char *buf, loff_t off, size_t count) +{ + struct w1_slave *sl = container_of(container_of(kobj, struct device, kobj), + struct w1_slave, dev); + struct w1_master *dev = sl->master; + u8 rom[9], crc, verdict; + int i, max_trying = 10; + + atomic_inc(&sl->refcnt); + smp_mb__after_atomic_inc(); + if (down_interruptible(&sl->master->mutex)) { + count = 0; + goto out_dec; + } + + if (off > W1_SLAVE_DATA_SIZE) { + count = 0; + goto out; + } + if (off + count > W1_SLAVE_DATA_SIZE) { + count = 0; + goto out; + } + + memset(buf, 0, count); + memset(rom, 0, sizeof(rom)); + + count = 0; + verdict = 0; + crc = 0; + + while (max_trying--) { + if (!w1_reset_bus (dev)) { + int count = 0; + u8 match[9] = {W1_MATCH_ROM, }; + unsigned int tm = 750; + + memcpy(&match[1], (u64 *) & sl->reg_num, 8); + + w1_write_block(dev, match, 9); + + w1_write_8(dev, W1_CONVERT_TEMP); + + while (tm) { + tm = msleep_interruptible(tm); + if (signal_pending(current)) + flush_signals(current); + } + + if (!w1_reset_bus (dev)) { + w1_write_block(dev, match, 9); + + w1_write_8(dev, W1_READ_SCRATCHPAD); + if ((count = w1_read_block(dev, rom, 9)) != 9) { + dev_warn(&dev->dev, "w1_read_block() returned %d instead of 9.\n", count); + } + + crc = w1_calc_crc8(rom, 8); + + if (rom[8] == crc && rom[0]) + verdict = 1; + + } + } + + if (!w1_therm_check_rom(rom)) + break; + } + + for (i = 0; i < 9; ++i) + count += sprintf(buf + count, "%02x ", rom[i]); + count += sprintf(buf + count, ": crc=%02x %s\n", + crc, (verdict) ? "YES" : "NO"); + if (verdict) + memcpy(sl->rom, rom, sizeof(sl->rom)); + else + dev_warn(&dev->dev, "18S20 doesn't respond to CONVERT_TEMP.\n"); + + for (i = 0; i < 9; ++i) + count += sprintf(buf + count, "%02x ", sl->rom[i]); + + count += sprintf(buf + count, "t=%d\n", w1_convert_temp(rom)); +out: + up(&dev->mutex); +out_dec: + smp_mb__before_atomic_inc(); + atomic_dec(&sl->refcnt); + + return count; +} + +static struct w1_family w1_therm_family = { + .fid = W1_FAMILY_THERM, + .fops = &w1_therm_fops, +}; + +static int __init w1_therm_init(void) +{ + return w1_register_family(&w1_therm_family); +} + +static void __exit w1_therm_fini(void) +{ + w1_unregister_family(&w1_therm_family); +} + +module_init(w1_therm_init); +module_exit(w1_therm_fini); |