From d3f94435245f6d1bcfdf0cb9cbf796dc5218802f Mon Sep 17 00:00:00 2001
From: blm <blm@poczta.fm>
Date: Tue, 16 Feb 2016 10:50:51 +0100
Subject: [PATCH] merge bassed on https://github.com/raspberrypi/linux/pull/186
 to enable pullup=1 option

---
 linux-3.4/drivers/w1/masters/w1-gpio.c | 20 ++++++++++++++
 linux-3.4/drivers/w1/w1.h              |  7 +++++
 linux-3.4/drivers/w1/w1_int.c          |  8 ++++++
 linux-3.4/drivers/w1/w1_io.c           | 36 +++++++++++++++++++++-----
 4 files changed, 64 insertions(+), 7 deletions(-)

diff --git a/linux-3.4/drivers/w1/masters/w1-gpio.c b/linux-3.4/drivers/w1/masters/w1-gpio.c
index ca31e5b0..694728a8 100644
--- a/linux-3.4/drivers/w1/masters/w1-gpio.c
+++ b/linux-3.4/drivers/w1/masters/w1-gpio.c
@@ -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;
@@ -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;
@@ -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;
diff --git a/linux-3.4/drivers/w1/w1.h b/linux-3.4/drivers/w1/w1.h
index 4d012ca3..463d019d 100644
--- a/linux-3.4/drivers/w1/w1.h
+++ b/linux-3.4/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.
 	 */
@@ -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;
diff --git a/linux-3.4/drivers/w1/w1_int.c b/linux-3.4/drivers/w1/w1_int.c
index 68288355..34e97bc6 100644
--- a/linux-3.4/drivers/w1/w1_int.c
+++ b/linux-3.4/drivers/w1/w1_int.c
@@ -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);
@@ -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). */
diff --git a/linux-3.4/drivers/w1/w1_io.c b/linux-3.4/drivers/w1/w1_io.c
index 3135b2c6..e546fdcb 100644
--- a/linux-3.4/drivers/w1/w1_io.c
+++ b/linux-3.4/drivers/w1/w1_io.c
@@ -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,
@@ -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);
@@ -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);
 }
 
 /**
@@ -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;
 	}
 }
@@ -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);
@@ -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;
@@ -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);