diff options
| -rw-r--r-- | Documentation/ABI/stable/sysfs-driver-w1_ds28ea00 | 6 | ||||
| -rw-r--r-- | Documentation/w1/slaves/w1_therm | 11 | ||||
| -rw-r--r-- | drivers/w1/slaves/w1_therm.c | 102 |
3 files changed, 117 insertions, 2 deletions
diff --git a/Documentation/ABI/stable/sysfs-driver-w1_ds28ea00 b/Documentation/ABI/stable/sysfs-driver-w1_ds28ea00 new file mode 100644 index 0000000..e928def --- /dev/null +++ b/Documentation/ABI/stable/sysfs-driver-w1_ds28ea00 @@ -0,0 +1,6 @@ +What: /sys/bus/w1/devices/.../w1_seq +Date: Apr 2015 +Contact: Matt Campbell <mattrcampbell@gmail.com> +Description: Support for the DS28EA00 chain sequence function + see Documentation/w1/slaves/w1_therm for detailed information +Users: any user space application which wants to communicate with DS28EA00 diff --git a/Documentation/w1/slaves/w1_therm b/Documentation/w1/slaves/w1_therm index cc62a95..13411fe 100644 --- a/Documentation/w1/slaves/w1_therm +++ b/Documentation/w1/slaves/w1_therm @@ -11,12 +11,14 @@ Author: Evgeniy Polyakov <johnpol@2ka.mipt.ru> Description ----------- -w1_therm provides basic temperature conversion for ds18*20 devices. +w1_therm provides basic temperature conversion for ds18*20 devices, and the +ds28ea00 device. supported family codes: W1_THERM_DS18S20 0x10 W1_THERM_DS1822 0x22 W1_THERM_DS18B20 0x28 W1_THERM_DS1825 0x3B +W1_THERM_DS28EA00 0x42 Support is provided through the sysfs w1_slave file. Each open and read sequence will initiate a temperature conversion then provide two @@ -48,3 +50,10 @@ resistor). The DS18b20 temperature sensor specification lists a maximum current draw of 1.5mA and that a 5k pullup resistor is not sufficient. The strong pullup is designed to provide the additional current required. + +The DS28EA00 provides an additional two pins for implementing a sequence +detection algorithm. This feature allows you to determine the physical +location of the chip in the 1-wire bus without needing pre-existing +knowledge of the bus ordering. Support is provided through the sysfs +w1_seq file. The file will contain a single line with an integer value +representing the device index in the bus starting at 0. diff --git a/drivers/w1/slaves/w1_therm.c b/drivers/w1/slaves/w1_therm.c index 55eb86c..d21e686 100644 --- a/drivers/w1/slaves/w1_therm.c +++ b/drivers/w1/slaves/w1_therm.c @@ -92,13 +92,24 @@ static void w1_therm_remove_slave(struct w1_slave *sl) static ssize_t w1_slave_show(struct device *device, struct device_attribute *attr, char *buf); +static ssize_t w1_seq_show(struct device *device, + struct device_attribute *attr, char *buf); + static DEVICE_ATTR_RO(w1_slave); +static DEVICE_ATTR_RO(w1_seq); static struct attribute *w1_therm_attrs[] = { &dev_attr_w1_slave.attr, NULL, }; + +static struct attribute *w1_ds28ea00_attrs[] = { + &dev_attr_w1_slave.attr, + &dev_attr_w1_seq.attr, + NULL, +}; ATTRIBUTE_GROUPS(w1_therm); +ATTRIBUTE_GROUPS(w1_ds28ea00); static struct w1_family_ops w1_therm_fops = { .add_slave = w1_therm_add_slave, @@ -106,6 +117,12 @@ static struct w1_family_ops w1_therm_fops = { .groups = w1_therm_groups, }; +static struct w1_family_ops w1_ds28ea00_fops = { + .add_slave = w1_therm_add_slave, + .remove_slave = w1_therm_remove_slave, + .groups = w1_ds28ea00_groups, +}; + static struct w1_family w1_therm_family_DS18S20 = { .fid = W1_THERM_DS18S20, .fops = &w1_therm_fops, @@ -123,7 +140,7 @@ static struct w1_family w1_therm_family_DS1822 = { static struct w1_family w1_therm_family_DS28EA00 = { .fid = W1_THERM_DS28EA00, - .fops = &w1_therm_fops, + .fops = &w1_ds28ea00_fops, }; static struct w1_family w1_therm_family_DS1825 = { @@ -316,6 +333,89 @@ post_unlock: return ret; } +#define W1_42_CHAIN 0x99 +#define W1_42_CHAIN_OFF 0x3C +#define W1_42_CHAIN_OFF_INV 0xC3 +#define W1_42_CHAIN_ON 0x5A +#define W1_42_CHAIN_ON_INV 0xA5 +#define W1_42_CHAIN_DONE 0x96 +#define W1_42_CHAIN_DONE_INV 0x69 +#define W1_42_COND_READ 0x0F +#define W1_42_SUCCESS_CONFIRM_BYTE 0xAA +#define W1_42_FINISHED_BYTE 0xFF +static ssize_t w1_seq_show(struct device *device, + struct device_attribute *attr, char *buf) +{ + struct w1_slave *sl = dev_to_w1_slave(device); + ssize_t c = PAGE_SIZE; + int rv; + int i; + u8 ack; + u64 rn; + struct w1_reg_num *reg_num; + int seq = 0; + + mutex_lock(&sl->master->mutex); + /* Place all devices in CHAIN state */ + if (w1_reset_bus(sl->master)) + goto error; + w1_write_8(sl->master, W1_SKIP_ROM); + w1_write_8(sl->master, W1_42_CHAIN); + w1_write_8(sl->master, W1_42_CHAIN_ON); + w1_write_8(sl->master, W1_42_CHAIN_ON_INV); + msleep(sl->master->pullup_duration); + + /* check for acknowledgment */ + ack = w1_read_8(sl->master); + if (ack != W1_42_SUCCESS_CONFIRM_BYTE) + goto error; + + /* In case the bus fails to send 0xFF, limit*/ + for (i = 0; i <= 64; i++) { + if (w1_reset_bus(sl->master)) + goto error; + + w1_write_8(sl->master, W1_42_COND_READ); + rv = w1_read_block(sl->master, (u8 *)&rn, 8); + reg_num = (struct w1_reg_num *) &rn; + if ((char)reg_num->family == W1_42_FINISHED_BYTE) + break; + if (sl->reg_num.id == reg_num->id) + seq = i; + + w1_write_8(sl->master, W1_42_CHAIN); + w1_write_8(sl->master, W1_42_CHAIN_DONE); + w1_write_8(sl->master, W1_42_CHAIN_DONE_INV); + w1_read_block(sl->master, &ack, sizeof(ack)); + + /* check for acknowledgment */ + ack = w1_read_8(sl->master); + if (ack != W1_42_SUCCESS_CONFIRM_BYTE) + goto error; + + } + + /* Exit from CHAIN state */ + if (w1_reset_bus(sl->master)) + goto error; + w1_write_8(sl->master, W1_SKIP_ROM); + w1_write_8(sl->master, W1_42_CHAIN); + w1_write_8(sl->master, W1_42_CHAIN_OFF); + w1_write_8(sl->master, W1_42_CHAIN_OFF_INV); + + /* check for acknowledgment */ + ack = w1_read_8(sl->master); + if (ack != W1_42_SUCCESS_CONFIRM_BYTE) + goto error; + mutex_unlock(&sl->master->mutex); + + c -= snprintf(buf + PAGE_SIZE - c, c, "%d\n", seq); + return PAGE_SIZE - c; +error: + mutex_unlock(&sl->master->bus_mutex); + return -EIO; +} + static int __init w1_therm_init(void) { int err, i; |