From ea390b711a1c1ceaf30d7a44a6b1eb59249456b6 Mon Sep 17 00:00:00 2001
From: Phil Elwell <pelwell@users.noreply.github.com>
Date: Mon, 13 Jul 2015 13:25:31 +0100
Subject: [PATCH 119/171] Merge pull request #1059 from pelwell/rpi-4.0.y
w1_therm: Back-port locking improvements from 4.2-rc1
---
Documentation/ABI/stable/sysfs-driver-w1_ds28ea00 | 6 ++
Documentation/w1/slaves/w1_therm | 11 ++-
drivers/w1/slaves/w1_therm.c | 102 +++++++++++++++++++++-
3 files changed, 117 insertions(+), 2 deletions(-)
create mode 100644 Documentation/ABI/stable/sysfs-driver-w1_ds28ea00
--- /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
--- a/Documentation/w1/slaves/w1_therm
+++ b/Documentation/w1/slaves/w1_therm
@@ -11,12 +11,14 @@ Author: Evgeniy Polyakov <johnpol@2ka.mi
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 sens
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.
--- 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
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_fop
.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_
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->bus_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 (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->bus_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;