Merge pull request #186 from mkj/rpi-3.6.y

Add bitbanging pullups, use them for w1-gpio

Author: popcornmix

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;
@@ -42,6 +45,16 @@ 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);
+}
+
 static int __init w1_gpio_probe(struct platform_device *pdev)
 {
 	struct w1_bus_master *master;
@@ -70,6 +83,13 @@ 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;
@@ -81,9 +101,9 @@ static int __init w1_gpio_probe(struct platform_device *pdev)
 
 	return 0;
 
- free_gpio:
+free_gpio:
 	gpio_free(pdata->pin);
- free_master:
+free_master:
 	kfree(master);
 
 	return err;
@@ -133,10 +153,10 @@ static int w1_gpio_resume(struct platform_device *pdev)
 
 static struct platform_driver w1_gpio_driver = {
 	.driver = {
-		.name	= "w1-gpio",
-		.owner	= THIS_MODULE,
-	},
-	.remove	= __exit_p(w1_gpio_remove),
+		   .name = "w1-gpio",
+		   .owner = THIS_MODULE,
+		   },
+	.remove = __exit_p(w1_gpio_remove),
 	.suspend = w1_gpio_suspend,
 	.resume = w1_gpio_resume,
 };

drivers/w1/w1.h

@@ -22,16 +22,11 @@
 #ifndef __W1_H
 #define __W1_H
 
-struct w1_reg_num
-{
+struct w1_reg_num {
 #if defined(__LITTLE_ENDIAN_BITFIELD)
-	__u64	family:8,
-		id:48,
-		crc:8;
+	__u64 family:8, id:48, crc:8;
 #elif defined(__BIG_ENDIAN_BITFIELD)
-	__u64	crc:8,
-		id:48,
-		family:8;
+	__u64 crc:8, id:48, family:8;
 #else
 #error "Please fix <asm/byteorder.h>"
 #endif
@@ -59,26 +54,24 @@ struct w1_reg_num
 
 #define W1_SLAVE_ACTIVE		0
 
-struct w1_slave
-{
-	struct module		*owner;
-	unsigned char		name[W1_MAXNAMELEN];
-	struct list_head	w1_slave_entry;
-	struct w1_reg_num	reg_num;
-	atomic_t		refcnt;
-	u8			rom[9];
-	u32			flags;
-	int			ttl;
-
-	struct w1_master	*master;
-	struct w1_family	*family;
-	void			*family_data;
-	struct device		dev;
-	struct completion	released;
+struct w1_slave {
+	struct module *owner;
+	unsigned char name[W1_MAXNAMELEN];
+	struct list_head w1_slave_entry;
+	struct w1_reg_num reg_num;
+	atomic_t refcnt;
+	u8 rom[9];
+	u32 flags;
+	int ttl;
+
+	struct w1_master *master;
+	struct w1_family *family;
+	void *family_data;
+	struct device dev;
+	struct completion released;
 };
 
-typedef void (*w1_slave_found_callback)(struct w1_master *, u64);
-
+typedef void (*w1_slave_found_callback) (struct w1_master *, u64);
 
 /**
  * Note: read_bit and write_bit are very low level functions and should only
@@ -87,19 +80,18 @@ typedef void (*w1_slave_found_callback)(struct w1_master *, u64);
  * Either define read_bit and write_bit OR define, at minimum, touch_bit and
  * reset_bus.
  */
-struct w1_bus_master
-{
+struct w1_bus_master {
 	/** the first parameter in all the functions below */
-	void		*data;
+	void *data;
 
 	/**
 	 * Sample the line level
 	 * @return the level read (0 or 1)
 	 */
-	u8		(*read_bit)(void *);
+	 u8(*read_bit) (void *);
 
 	/** Sets the line level */
-	void		(*write_bit)(void *, u8);
+	void (*write_bit) (void *, u8);
 
 	/**
 	 * touch_bit is the lowest-level function for devices that really
@@ -108,96 +100,103 @@ struct w1_bus_master
 	 * touch_bit(1) = write-1 / read cycle
 	 * @return the bit read (0 or 1)
 	 */
-	u8		(*touch_bit)(void *, u8);
+	 u8(*touch_bit) (void *, u8);
 
 	/**
 	 * Reads a bytes. Same as 8 touch_bit(1) calls.
 	 * @return the byte read
 	 */
-	u8		(*read_byte)(void *);
+	 u8(*read_byte) (void *);
 
 	/**
 	 * Writes a byte. Same as 8 touch_bit(x) calls.
 	 */
-	void		(*write_byte)(void *, u8);
+	void (*write_byte) (void *, u8);
 
 	/**
 	 * Same as a series of read_byte() calls
 	 * @return the number of bytes read
 	 */
-	u8		(*read_block)(void *, u8 *, int);
+	 u8(*read_block) (void *, u8 *, int);
 
 	/** Same as a series of write_byte() calls */
-	void		(*write_block)(void *, const u8 *, int);
+	void (*write_block) (void *, const u8 *, int);
 
 	/**
 	 * Combines two reads and a smart write for ROM searches
 	 * @return bit0=Id bit1=comp_id bit2=dir_taken
 	 */
-	u8		(*triplet)(void *, u8);
+	 u8(*triplet) (void *, u8);
 
 	/**
 	 * long write-0 with a read for the presence pulse detection
 	 * @return -1=Error, 0=Device present, 1=No device present
 	 */
-	u8		(*reset_bus)(void *);
+	 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);
+	 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.
 	 */
-	void		(*search)(void *, struct w1_master *,
-		u8, w1_slave_found_callback);
+	void (*search) (void *, struct w1_master *,
+			u8, w1_slave_found_callback);
 };
 
-struct w1_master
-{
-	struct list_head	w1_master_entry;
-	struct module		*owner;
-	unsigned char		name[W1_MAXNAMELEN];
-	struct list_head	slist;
-	int			max_slave_count, slave_count;
-	unsigned long		attempts;
-	int			slave_ttl;
-	int			initialized;
-	u32			id;
-	int			search_count;
-
-	atomic_t		refcnt;
-
-	void			*priv;
-	int			priv_size;
+struct w1_master {
+	struct list_head w1_master_entry;
+	struct module *owner;
+	unsigned char name[W1_MAXNAMELEN];
+	struct list_head slist;
+	int max_slave_count, slave_count;
+	unsigned long attempts;
+	int slave_ttl;
+	int initialized;
+	u32 id;
+	int search_count;
+
+	atomic_t refcnt;
+
+	void *priv;
+	int priv_size;
 
 	/** 5V strong pullup enabled flag, 1 enabled, zero disabled. */
-	int			enable_pullup;
+	int enable_pullup;
 	/** 5V strong pullup duration in milliseconds, zero disabled. */
-	int			pullup_duration;
+	int pullup_duration;
 
-	struct task_struct	*thread;
-	struct mutex		mutex;
-	struct mutex		bus_mutex;
+	struct task_struct *thread;
+	struct mutex mutex;
+	struct mutex bus_mutex;
 
-	struct device_driver	*driver;
-	struct device		dev;
+	struct device_driver *driver;
+	struct device dev;
 
-	struct w1_bus_master	*bus_master;
+	struct w1_bus_master *bus_master;
 
-	u32			seq;
+	u32 seq;
 };
 
 int w1_create_master_attributes(struct w1_master *);
 void w1_destroy_master_attributes(struct w1_master *master);
-void w1_search(struct w1_master *dev, u8 search_type, w1_slave_found_callback cb);
-void w1_search_devices(struct w1_master *dev, u8 search_type, w1_slave_found_callback cb);
+void w1_search(struct w1_master *dev, u8 search_type,
+	       w1_slave_found_callback cb);
+void w1_search_devices(struct w1_master *dev, u8 search_type,
+		       w1_slave_found_callback cb);
 struct w1_slave *w1_search_slave(struct w1_reg_num *id);
 void w1_slave_found(struct w1_master *dev, u64 rn);
 void w1_search_process_cb(struct w1_master *dev, u8 search_type,
-	w1_slave_found_callback cb);
+			  w1_slave_found_callback cb);
 struct w1_master *w1_search_master_id(u32 id);
 
 /* Disconnect and reconnect devices in the given family.  Used for finding
@@ -220,17 +219,17 @@ int w1_reset_select_slave(struct w1_slave *sl);
 int w1_reset_resume_command(struct w1_master *);
 void w1_next_pullup(struct w1_master *, int);
 
-static inline struct w1_slave* dev_to_w1_slave(struct device *dev)
+static inline struct w1_slave *dev_to_w1_slave(struct device *dev)
 {
 	return container_of(dev, struct w1_slave, dev);
 }
 
-static inline struct w1_slave* kobj_to_w1_slave(struct kobject *kobj)
+static inline struct w1_slave *kobj_to_w1_slave(struct kobject *kobj)
 {
 	return dev_to_w1_slave(container_of(kobj, struct device, kobj));
 }
 
-static inline struct w1_master* dev_to_w1_master(struct device *dev)
+static inline struct w1_master *dev_to_w1_master(struct device *dev)
 {
 	return container_of(dev, struct w1_master, dev);
 }