diff options
Diffstat (limited to 'drivers/w1/slaves/w1_therm.c')
| -rw-r--r-- | drivers/w1/slaves/w1_therm.c | 289 |
1 files changed, 289 insertions, 0 deletions
diff --git a/drivers/w1/slaves/w1_therm.c b/drivers/w1/slaves/w1_therm.c new file mode 100644 index 00000000..ff29ae74 --- /dev/null +++ b/drivers/w1/slaves/w1_therm.c @@ -0,0 +1,289 @@ +/* + * w1_therm.c + * + * Copyright (c) 2004 Evgeniy Polyakov <zbr@ioremap.net> + * + * + * 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/sched.h> +#include <linux/device.h> +#include <linux/types.h> +#include <linux/delay.h> + +#include "../w1.h" +#include "../w1_int.h" +#include "../w1_family.h" + +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("Evgeniy Polyakov <zbr@ioremap.net>"); +MODULE_DESCRIPTION("Driver for 1-wire Dallas network protocol, temperature family."); + +/* Allow the strong pullup to be disabled, but default to enabled. + * If it was disabled a parasite powered device might not get the require + * current to do a temperature conversion. If it is enabled parasite powered + * devices have a better chance of getting the current required. + */ +static int w1_strong_pullup = 1; +module_param_named(strong_pullup, w1_strong_pullup, int, 0); + +static u8 bad_roms[][9] = { + {0xaa, 0x00, 0x4b, 0x46, 0xff, 0xff, 0x0c, 0x10, 0x87}, + {} + }; + +static ssize_t w1_therm_read(struct device *device, + struct device_attribute *attr, char *buf); + +static struct device_attribute w1_therm_attr = + __ATTR(w1_slave, S_IRUGO, w1_therm_read, NULL); + +static int w1_therm_add_slave(struct w1_slave *sl) +{ + return device_create_file(&sl->dev, &w1_therm_attr); +} + +static void w1_therm_remove_slave(struct w1_slave *sl) +{ + device_remove_file(&sl->dev, &w1_therm_attr); +} + +static struct w1_family_ops w1_therm_fops = { + .add_slave = w1_therm_add_slave, + .remove_slave = w1_therm_remove_slave, +}; + +static struct w1_family w1_therm_family_DS18S20 = { + .fid = W1_THERM_DS18S20, + .fops = &w1_therm_fops, +}; + +static struct w1_family w1_therm_family_DS18B20 = { + .fid = W1_THERM_DS18B20, + .fops = &w1_therm_fops, +}; + +static struct w1_family w1_therm_family_DS1822 = { + .fid = W1_THERM_DS1822, + .fops = &w1_therm_fops, +}; + +static struct w1_family w1_therm_family_DS28EA00 = { + .fid = W1_THERM_DS28EA00, + .fops = &w1_therm_fops, +}; + +struct w1_therm_family_converter +{ + u8 broken; + u16 reserved; + struct w1_family *f; + int (*convert)(u8 rom[9]); +}; + +/* The return value is millidegrees Centigrade. */ +static inline int w1_DS18B20_convert_temp(u8 rom[9]); +static inline int w1_DS18S20_convert_temp(u8 rom[9]); + +static struct w1_therm_family_converter w1_therm_families[] = { + { + .f = &w1_therm_family_DS18S20, + .convert = w1_DS18S20_convert_temp + }, + { + .f = &w1_therm_family_DS1822, + .convert = w1_DS18B20_convert_temp + }, + { + .f = &w1_therm_family_DS18B20, + .convert = w1_DS18B20_convert_temp + }, + { + .f = &w1_therm_family_DS28EA00, + .convert = w1_DS18B20_convert_temp + }, +}; + +static inline int w1_DS18B20_convert_temp(u8 rom[9]) +{ + s16 t = le16_to_cpup((__le16 *)rom); + return t*1000/16; +} + +static inline int w1_DS18S20_convert_temp(u8 rom[9]) +{ + int t, h; + + if (!rom[7]) + return 0; + + 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 inline int w1_convert_temp(u8 rom[9], u8 fid) +{ + int i; + + for (i = 0; i < ARRAY_SIZE(w1_therm_families); ++i) + if (w1_therm_families[i].f->fid == fid) + return w1_therm_families[i].convert(rom); + + return 0; +} + +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(struct device *device, + struct device_attribute *attr, char *buf) +{ + struct w1_slave *sl = dev_to_w1_slave(device); + struct w1_master *dev = sl->master; + u8 rom[9], crc, verdict, external_power; + int i, max_trying = 10; + ssize_t c = PAGE_SIZE; + + i = mutex_lock_interruptible(&dev->mutex); + if (i != 0) + return i; + + memset(rom, 0, sizeof(rom)); + + verdict = 0; + crc = 0; + + while (max_trying--) { + if (!w1_reset_select_slave(sl)) { + int count = 0; + unsigned int tm = 750; + unsigned long sleep_rem; + + w1_write_8(dev, W1_READ_PSUPPLY); + external_power = w1_read_8(dev); + + if (w1_reset_select_slave(sl)) + continue; + + /* 750ms strong pullup (or delay) after the convert */ + if (!external_power && w1_strong_pullup) + w1_next_pullup(dev, tm); + + w1_write_8(dev, W1_CONVERT_TEMP); + + if (external_power) { + mutex_unlock(&dev->mutex); + + sleep_rem = msleep_interruptible(tm); + if (sleep_rem != 0) + return -EINTR; + + i = mutex_lock_interruptible(&dev->mutex); + if (i != 0) + return i; + } else if (!w1_strong_pullup) { + sleep_rem = msleep_interruptible(tm); + if (sleep_rem != 0) { + mutex_unlock(&dev->mutex); + return -EINTR; + } + } + + if (!w1_reset_select_slave(sl)) { + + w1_write_8(dev, W1_READ_SCRATCHPAD); + if ((count = w1_read_block(dev, rom, 9)) != 9) { + dev_warn(device, "w1_read_block() " + "returned %u instead of 9.\n", + count); + } + + crc = w1_calc_crc8(rom, 8); + + if (rom[8] == crc) + verdict = 1; + } + } + + if (!w1_therm_check_rom(rom)) + break; + } + + for (i = 0; i < 9; ++i) + c -= snprintf(buf + PAGE_SIZE - c, c, "%02x ", rom[i]); + c -= snprintf(buf + PAGE_SIZE - c, c, ": crc=%02x %s\n", + crc, (verdict) ? "YES" : "NO"); + if (verdict) + memcpy(sl->rom, rom, sizeof(sl->rom)); + else + dev_warn(device, "18S20 doesn't respond to CONVERT_TEMP.\n"); + + for (i = 0; i < 9; ++i) + c -= snprintf(buf + PAGE_SIZE - c, c, "%02x ", sl->rom[i]); + + c -= snprintf(buf + PAGE_SIZE - c, c, "t=%d\n", + w1_convert_temp(rom, sl->family->fid)); + mutex_unlock(&dev->mutex); + + return PAGE_SIZE - c; +} + +static int __init w1_therm_init(void) +{ + int err, i; + + for (i = 0; i < ARRAY_SIZE(w1_therm_families); ++i) { + err = w1_register_family(w1_therm_families[i].f); + if (err) + w1_therm_families[i].broken = 1; + } + + return 0; +} + +static void __exit w1_therm_fini(void) +{ + int i; + + for (i = 0; i < ARRAY_SIZE(w1_therm_families); ++i) + if (!w1_therm_families[i].broken) + w1_unregister_family(w1_therm_families[i].f); +} + +module_init(w1_therm_init); +module_exit(w1_therm_fini); |