142 lines
4.5 KiB
Diff
142 lines
4.5 KiB
Diff
From 0a2fa5a85c2ed9599acb2215f24e06db0379a133 Mon Sep 17 00:00:00 2001
|
|
From: popcornmix <popcornmix@gmail.com>
|
|
Date: Wed, 1 May 2013 21:14:28 +0100
|
|
Subject: [PATCH 055/196] Add bitbanging pullups, use them for w1-gpio
|
|
|
|
Allows parasite power to work, uses module option pullup=1
|
|
---
|
|
drivers/w1/masters/w1-gpio.c | 20 ++++++++++++++++++++
|
|
drivers/w1/w1.h | 6 ++++++
|
|
drivers/w1/w1_int.c | 16 +++++++++-------
|
|
drivers/w1/w1_io.c | 18 +++++++++++++++---
|
|
4 files changed, 50 insertions(+), 10 deletions(-)
|
|
|
|
diff --git a/drivers/w1/masters/w1-gpio.c b/drivers/w1/masters/w1-gpio.c
|
|
index 46d9701..f615f80 100644
|
|
--- a/drivers/w1/masters/w1-gpio.c
|
|
+++ b/drivers/w1/masters/w1-gpio.c
|
|
@@ -23,6 +23,9 @@
|
|
#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;
|
|
@@ -47,6 +50,16 @@ static u8 w1_gpio_read_bit(void *data)
|
|
return gpio_get_value(pdata->pin) ? 1 : 0;
|
|
}
|
|
|
|
+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);
|
|
+}
|
|
+
|
|
#if defined(CONFIG_OF)
|
|
static struct of_device_id w1_gpio_dt_ids[] = {
|
|
{ .compatible = "w1-gpio" },
|
|
@@ -133,6 +146,13 @@ static int 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) {
|
|
dev_err(&pdev->dev, "w1_add_master device failed\n");
|
|
diff --git a/drivers/w1/w1.h b/drivers/w1/w1.h
|
|
index 45908e5..0ba75f6 100644
|
|
--- a/drivers/w1/w1.h
|
|
+++ b/drivers/w1/w1.h
|
|
@@ -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.
|
|
*/
|
|
diff --git a/drivers/w1/w1_int.c b/drivers/w1/w1_int.c
|
|
index 5a98649..a4d69b6 100644
|
|
--- a/drivers/w1/w1_int.c
|
|
+++ b/drivers/w1/w1_int.c
|
|
@@ -117,19 +117,21 @@ 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 hardware 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.
|
|
- */
|
|
+
|
|
+ /* bitbanging hardware uses bitbang_pullup, other hardware uses set_pullup
|
|
+ * and takes care of timing itself */
|
|
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;
|
|
}
|
|
|
|
+ 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). */
|
|
diff --git a/drivers/w1/w1_io.c b/drivers/w1/w1_io.c
|
|
index e10acc2..667fdd5 100644
|
|
--- a/drivers/w1/w1_io.c
|
|
+++ b/drivers/w1/w1_io.c
|
|
@@ -127,10 +127,22 @@ 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;
|
|
}
|
|
}
|
|
--
|
|
1.9.1
|
|
|