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