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-rw-r--r--drivers/w1/w1.c40
-rw-r--r--drivers/w1/w1.h12
-rw-r--r--drivers/w1/w1_int.c16
-rw-r--r--drivers/w1/w1_io.c68
4 files changed, 131 insertions, 5 deletions
diff --git a/drivers/w1/w1.c b/drivers/w1/w1.c
index 9b5c11701c3..32418d4e555 100644
--- a/drivers/w1/w1.c
+++ b/drivers/w1/w1.c
@@ -246,10 +246,14 @@ static ssize_t w1_master_attribute_store_search(struct device * dev,
struct device_attribute *attr,
const char * buf, size_t count)
{
+ long tmp;
struct w1_master *md = dev_to_w1_master(dev);
+ if (strict_strtol(buf, 0, &tmp) == -EINVAL)
+ return -EINVAL;
+
mutex_lock(&md->mutex);
- md->search_count = simple_strtol(buf, NULL, 0);
+ md->search_count = tmp;
mutex_unlock(&md->mutex);
wake_up_process(md->thread);
@@ -270,6 +274,38 @@ static ssize_t w1_master_attribute_show_search(struct device *dev,
return count;
}
+static ssize_t w1_master_attribute_store_pullup(struct device *dev,
+ struct device_attribute *attr,
+ const char *buf, size_t count)
+{
+ long tmp;
+ struct w1_master *md = dev_to_w1_master(dev);
+
+ if (strict_strtol(buf, 0, &tmp) == -EINVAL)
+ return -EINVAL;
+
+ mutex_lock(&md->mutex);
+ md->enable_pullup = tmp;
+ mutex_unlock(&md->mutex);
+ wake_up_process(md->thread);
+
+ return count;
+}
+
+static ssize_t w1_master_attribute_show_pullup(struct device *dev,
+ struct device_attribute *attr,
+ char *buf)
+{
+ struct w1_master *md = dev_to_w1_master(dev);
+ ssize_t count;
+
+ mutex_lock(&md->mutex);
+ count = sprintf(buf, "%d\n", md->enable_pullup);
+ mutex_unlock(&md->mutex);
+
+ return count;
+}
+
static ssize_t w1_master_attribute_show_pointer(struct device *dev, struct device_attribute *attr, char *buf)
{
struct w1_master *md = dev_to_w1_master(dev);
@@ -365,6 +401,7 @@ static W1_MASTER_ATTR_RO(attempts, S_IRUGO);
static W1_MASTER_ATTR_RO(timeout, S_IRUGO);
static W1_MASTER_ATTR_RO(pointer, S_IRUGO);
static W1_MASTER_ATTR_RW(search, S_IRUGO | S_IWUGO);
+static W1_MASTER_ATTR_RW(pullup, S_IRUGO | S_IWUGO);
static struct attribute *w1_master_default_attrs[] = {
&w1_master_attribute_name.attr,
@@ -375,6 +412,7 @@ static struct attribute *w1_master_default_attrs[] = {
&w1_master_attribute_timeout.attr,
&w1_master_attribute_pointer.attr,
&w1_master_attribute_search.attr,
+ &w1_master_attribute_pullup.attr,
NULL
};
diff --git a/drivers/w1/w1.h b/drivers/w1/w1.h
index 34ee01e008a..00b84ab2280 100644
--- a/drivers/w1/w1.h
+++ b/drivers/w1/w1.h
@@ -142,6 +142,12 @@ struct w1_bus_master
*/
u8 (*reset_bus)(void *);
+ /**
+ * Put out a strong pull-up pulse of the specified duration.
+ * @return -1=Error, 0=completed
+ */
+ u8 (*set_pullup)(void *, int);
+
/** Really nice hardware can handles the different types of ROM search
* w1_master* is passed to the slave found callback.
*/
@@ -167,6 +173,11 @@ struct w1_master
void *priv;
int priv_size;
+ /** 5V strong pullup enabled flag, 1 enabled, zero disabled. */
+ int enable_pullup;
+ /** 5V strong pullup duration in milliseconds, zero disabled. */
+ int pullup_duration;
+
struct task_struct *thread;
struct mutex mutex;
@@ -201,6 +212,7 @@ u8 w1_calc_crc8(u8 *, int);
void w1_write_block(struct w1_master *, const u8 *, int);
u8 w1_read_block(struct w1_master *, u8 *, int);
int w1_reset_select_slave(struct w1_slave *sl);
+void w1_next_pullup(struct w1_master *, int);
static inline struct w1_slave* dev_to_w1_slave(struct device *dev)
{
diff --git a/drivers/w1/w1_int.c b/drivers/w1/w1_int.c
index bd877b24ce4..9d723efdf91 100644
--- a/drivers/w1/w1_int.c
+++ b/drivers/w1/w1_int.c
@@ -31,6 +31,9 @@
static u32 w1_ids = 1;
+static int w1_enable_pullup = 1;
+module_param_named(enable_pullup, w1_enable_pullup, int, 0);
+
static struct w1_master * w1_alloc_dev(u32 id, int slave_count, int slave_ttl,
struct device_driver *driver,
struct device *device)
@@ -59,6 +62,7 @@ static struct w1_master * w1_alloc_dev(u32 id, int slave_count, int slave_ttl,
dev->initialized = 0;
dev->id = id;
dev->slave_ttl = slave_ttl;
+ dev->enable_pullup = w1_enable_pullup;
dev->search_count = -1; /* continual scan */
/* 1 for w1_process to decrement
@@ -107,6 +111,18 @@ int w1_add_master_device(struct w1_bus_master *master)
printk(KERN_ERR "w1_add_master_device: invalid function set\n");
return(-EINVAL);
}
+ /* While it would be electrically possible to make a device that
+ * generated a strong pullup in bit bang mode, only hardare that
+ * controls 1-wire time frames are even expected to support a strong
+ * pullup. w1_io.c would need to support calling set_pullup before
+ * the last write_bit operation of a w1_write_8 which it currently
+ * doesn't.
+ */
+ if (!master->write_byte && !master->touch_bit && master->set_pullup) {
+ printk(KERN_ERR "w1_add_master_device: set_pullup requires "
+ "write_byte or touch_bit, disabling\n");
+ master->set_pullup = NULL;
+ }
dev = w1_alloc_dev(w1_ids++, w1_max_slave_count, w1_max_slave_ttl, &w1_master_driver, &w1_master_device);
if (!dev)
diff --git a/drivers/w1/w1_io.c b/drivers/w1/w1_io.c
index 0056ef69009..97b338a16ab 100644
--- a/drivers/w1/w1_io.c
+++ b/drivers/w1/w1_io.c
@@ -93,6 +93,40 @@ static void w1_write_bit(struct w1_master *dev, int bit)
}
/**
+ * Pre-write operation, currently only supporting strong pullups.
+ * Program the hardware for a strong pullup, if one has been requested and
+ * the hardware supports it.
+ *
+ * @param dev the master device
+ */
+static void w1_pre_write(struct w1_master *dev)
+{
+ if (dev->pullup_duration &&
+ dev->enable_pullup && dev->bus_master->set_pullup) {
+ dev->bus_master->set_pullup(dev->bus_master->data,
+ dev->pullup_duration);
+ }
+}
+
+/**
+ * Post-write operation, currently only supporting strong pullups.
+ * If a strong pullup was requested, clear it if the hardware supports
+ * them, or execute the delay otherwise, in either case clear the request.
+ *
+ * @param dev the master device
+ */
+static void w1_post_write(struct w1_master *dev)
+{
+ if (dev->pullup_duration) {
+ if (dev->enable_pullup && dev->bus_master->set_pullup)
+ dev->bus_master->set_pullup(dev->bus_master->data, 0);
+ else
+ msleep(dev->pullup_duration);
+ dev->pullup_duration = 0;
+ }
+}
+
+/**
* Writes 8 bits.
*
* @param dev the master device
@@ -102,11 +136,17 @@ void w1_write_8(struct w1_master *dev, u8 byte)
{
int i;
- if (dev->bus_master->write_byte)
+ if (dev->bus_master->write_byte) {
+ w1_pre_write(dev);
dev->bus_master->write_byte(dev->bus_master->data, byte);
+ }
else
- for (i = 0; i < 8; ++i)
+ for (i = 0; i < 8; ++i) {
+ if (i == 7)
+ w1_pre_write(dev);
w1_touch_bit(dev, (byte >> i) & 0x1);
+ }
+ w1_post_write(dev);
}
EXPORT_SYMBOL_GPL(w1_write_8);
@@ -203,11 +243,14 @@ void w1_write_block(struct w1_master *dev, const u8 *buf, int len)
{
int i;
- if (dev->bus_master->write_block)
+ if (dev->bus_master->write_block) {
+ w1_pre_write(dev);
dev->bus_master->write_block(dev->bus_master->data, buf, len);
+ }
else
for (i = 0; i < len; ++i)
- w1_write_8(dev, buf[i]);
+ w1_write_8(dev, buf[i]); /* calls w1_pre_write */
+ w1_post_write(dev);
}
EXPORT_SYMBOL_GPL(w1_write_block);
@@ -306,3 +349,20 @@ int w1_reset_select_slave(struct w1_slave *sl)
return 0;
}
EXPORT_SYMBOL_GPL(w1_reset_select_slave);
+
+/**
+ * Put out a strong pull-up of the specified duration after the next write
+ * operation. Not all hardware supports strong pullups. Hardware that
+ * doesn't support strong pullups will sleep for the given time after the
+ * write operation without a strong pullup. This is a one shot request for
+ * the next write, specifying zero will clear a previous request.
+ * The w1 master lock must be held.
+ *
+ * @param delay time in milliseconds
+ * @return 0=success, anything else=error
+ */
+void w1_next_pullup(struct w1_master *dev, int delay)
+{
+ dev->pullup_duration = delay;
+}
+EXPORT_SYMBOL_GPL(w1_next_pullup);
generated by cgit v1.2.3-70-g09d2 (git 2.46.0) at 2024-12-24 05:35:30 +0000