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enable parasite power on one wire (pullup=1) #17

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20 changes: 20 additions & 0 deletions linux-3.4/drivers/w1/masters/w1-gpio.c
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Original file line number Diff line number Diff line change
Expand Up @@ -18,6 +18,9 @@
#include "../w1.h"
#include "../w1_int.h"

static int w1_gpio_pullup = 0;
module_param_named(pullup, w1_gpio_pullup, int, 0);

static void w1_gpio_write_bit_dir(void *data, u8 bit)
{
struct w1_gpio_platform_data *pdata = data;
Expand Down Expand Up @@ -47,6 +50,16 @@ static u8 w1_gpio_read_bit(void *data)
return pin_val;
}

static void w1_gpio_bitbang_pullup(void *data, u8 on)
{
struct w1_gpio_platform_data *pdata = data;

if (on)
gpio_direction_output(pdata->pin, 1);
else
gpio_direction_input(pdata->pin);
}

static int __init w1_gpio_probe(struct platform_device *pdev)
{
struct w1_bus_master *master;
Expand Down Expand Up @@ -83,6 +96,13 @@ static int __init w1_gpio_probe(struct platform_device *pdev)
master->write_bit = w1_gpio_write_bit_dir;
}

if (w1_gpio_pullup)
if (pdata->is_open_drain)
printk(KERN_ERR "w1-gpio 'pullup' option "
"doesn't work with open drain GPIO\n");
else
master->bitbang_pullup = w1_gpio_bitbang_pullup;

err = w1_add_master_device(master);
if (err)
goto free_gpio;
Expand Down
7 changes: 7 additions & 0 deletions linux-3.4/drivers/w1/w1.h
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Original file line number Diff line number Diff line change
Expand Up @@ -148,6 +148,12 @@ struct w1_bus_master
*/
u8 (*set_pullup)(void *, int);

/**
* Turns the pullup on/off in bitbanging mode, takes an on/off argument.
* @return -1=Error, 0=completed
*/
void (*bitbang_pullup)(void *, u8);

/** Really nice hardware can handles the different types of ROM search
* w1_master* is passed to the slave found callback.
*/
Expand Down Expand Up @@ -180,6 +186,7 @@ struct w1_master

struct task_struct *thread;
struct mutex mutex;
struct mutex bus_mutex;

struct device_driver *driver;
struct device dev;
Expand Down
8 changes: 8 additions & 0 deletions linux-3.4/drivers/w1/w1_int.c
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Original file line number Diff line number Diff line change
Expand Up @@ -76,6 +76,7 @@ static struct w1_master * w1_alloc_dev(u32 id, int slave_count, int slave_ttl,

INIT_LIST_HEAD(&dev->slist);
mutex_init(&dev->mutex);
mutex_init(&dev->bus_mutex);

memcpy(&dev->dev, device, sizeof(struct device));
dev_set_name(&dev->dev, "w1_bus_master%u", dev->id);
Expand Down Expand Up @@ -129,6 +130,13 @@ int w1_add_master_device(struct w1_bus_master *master)
master->set_pullup = NULL;
}

if (master->set_pullup && master->bitbang_pullup)
{
printk(KERN_ERR "w1_add_master_device: set_pullup should not "
"be set when bitbang_pullup is used, disabling\n");
master->set_pullup = NULL;
}

/* Lock until the device is added (or not) to w1_masters. */
mutex_lock(&w1_mlock);
/* Search for the first available id (starting at 1). */
Expand Down
36 changes: 29 additions & 7 deletions linux-3.4/drivers/w1/w1_io.c
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Original file line number Diff line number Diff line change
Expand Up @@ -31,6 +31,9 @@
static int w1_delay_parm = 1;
module_param_named(delay_coef, w1_delay_parm, int, 0);

static int w1_disable_irqs = 0;
module_param_named(disable_irqs, w1_disable_irqs, int, 0);

static u8 w1_crc8_table[] = {
0, 94, 188, 226, 97, 63, 221, 131, 194, 156, 126, 32, 163, 253, 31, 65,
157, 195, 33, 127, 252, 162, 64, 30, 95, 1, 227, 189, 62, 96, 130, 220,
Expand Down Expand Up @@ -79,6 +82,10 @@ static u8 w1_touch_bit(struct w1_master *dev, int bit)
*/
static void w1_write_bit(struct w1_master *dev, int bit)
{
unsigned long flags = 0;

if(w1_disable_irqs) local_irq_save(flags);

if (bit) {
dev->bus_master->write_bit(dev->bus_master->data, 0);
w1_delay(6);
Expand All @@ -90,6 +97,8 @@ static void w1_write_bit(struct w1_master *dev, int bit)
dev->bus_master->write_bit(dev->bus_master->data, 1);
w1_delay(10);
}

if(w1_disable_irqs) local_irq_restore(flags);
}

/**
Expand Down Expand Up @@ -118,10 +127,18 @@ static void w1_pre_write(struct w1_master *dev)
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
if (dev->enable_pullup) {
if (dev->bus_master->set_pullup) {
dev->bus_master->set_pullup(dev->bus_master->data, 0);
} else if (dev->bus_master->bitbang_pullup) {
dev->bus_master->bitbang_pullup(dev->bus_master->data, 1);
msleep(dev->pullup_duration);
dev->bus_master->bitbang_pullup(dev->bus_master->data, 0);
}
} else {
msleep(dev->pullup_duration);
}

dev->pullup_duration = 0;
}
}
Expand Down Expand Up @@ -158,7 +175,7 @@ EXPORT_SYMBOL_GPL(w1_write_8);
static u8 w1_read_bit(struct w1_master *dev)
{
int result;
unsigned long flags;
unsigned long flags = 0;

/* sample timing is critical here */
local_irq_save(flags);
Expand Down Expand Up @@ -318,6 +335,9 @@ EXPORT_SYMBOL_GPL(w1_read_block);
int w1_reset_bus(struct w1_master *dev)
{
int result;
unsigned long flags = 0;

if(w1_disable_irqs) local_irq_save(flags);

if (dev->bus_master->reset_bus)
result = dev->bus_master->reset_bus(dev->bus_master->data) & 0x1;
Expand All @@ -330,19 +350,21 @@ int w1_reset_bus(struct w1_master *dev)
* cpu for such a short amount of time AND get it back in
* the maximum amount of time.
*/
w1_delay(480);
w1_delay(500);
dev->bus_master->write_bit(dev->bus_master->data, 1);
w1_delay(70);

result = dev->bus_master->read_bit(dev->bus_master->data) & 0x1;
/* minmum 70 (above) + 410 = 480 us
/* minmum 70 (above) + 430 = 500 us
* There aren't any timing requirements between a reset and
* the following transactions. Sleeping is safe here.
*/
/* w1_delay(410); min required time */
/* w1_delay(430); min required time */
msleep(1);
}

if(w1_disable_irqs) local_irq_restore(flags);

return result;
}
EXPORT_SYMBOL_GPL(w1_reset_bus);
Expand Down