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>
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 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 @@
.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_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 @@
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;