i2c-old-porting

I2C总线LINUX驱动程序

I2C Conversion Guide for I2C-old to the current I2C API
July 2002
For Linux Kernel v2.5.x
Frank Davis <[e-mail]>
-------------------------------------------------------

There exists several kernel drivers that are using an old version of the I2C
API. These drivers need to be converted to the current (kernel 2.5.x) version.
The following document provides a guideline to make the appropriate changes to
the affected drivers. There maybe slight modifications to this guide that are 
specific to the driver you are working on. If you see {driver_name}, replace 
that with the respective name of the driver, such as saa7110.c , {driver_name} 
= saa7110.

-------------------------------------------------------

Step 1: Include the right header file
 
Perform the following change within the driver
 
#include <linux/i2c-old.h> --> #include <linux/i2c.h>

Step 2: Add and set the i2c modes

Add the following code near the top of the driver

static unsigned short normal_i2c[] = {34>>1, I2C_CLIENT_END };
static unsigned short normal_i2c_range[] = { I2C_CLIENT_END };
static unsigned short probe[2] = { I2C_CLIENT_END , I2C_CLIENT_END };
static unsigned short probe_range[2] = { I2C_CLIENT_END , I2C_CLIENT_END };	
static unsigned short ignore[2] = { I2C_CLIENT_END , I2C_CLIENT_END };
static unsigned short ignore_range[2] = { I2C_CLIENT_END, I2C_CLIENT_END };
static unsigned short force[2] = { I2C_CLIENT_END , I2C_CLIENT_END };

static struct i2c_client_address_data addr_data  = {
	normal_i2c , normal_i2c_range,
	probe , probe_range,
	ignore , ignore_range,
	force
};

static struct i2c_client client_template;

Step 3: Modify the driver info struct

Within the struct for the driver , such as struct {driver_name}  ,  make the 
following change ,
struct i2c_bus *bus --> struct i2c_client *client

Make changes where this change affects references within the file.

Add a semaphore to the driver struct (as above)

struct semaphore lock 

Step 5: Remove specific read and write functions

Remove the driver specific write and read functions, usually in the form:
{driver_name}_write , {driver_name}_read , {driver_name}_write_block , etc.

Step 6: Update the write and read functions for the current I2C API

Replace all references of {driver_name}_write with i2c_smbus_write_byte_data
Replace all references of {driver_name}_read with i2c_smbus_read_byte_data or
i2c_smbus_read_byte , depending on args passed in.

** Ensure that these functions pass in the i2c_client *client , NOT the
decoder/encoder that was passed in the driver specific write and read
functions. 
 
Step 7: Modify the driver's attach function

Change the driver attach function prototype :
{driver_name}_attach(struct i2c_device *device) --> {driver_name}_attach(struct 
i2c_adapter *adap, int addr , unsigned short flags, int kind)

Create a i2c_client client...
Add the following (where "decoder" is a reference to a struct for the driver
info:

struct i2c_client *client;
client = kmalloc(sizeof(*client), GFP_KERNEL);
if(client == NULL)
	return -ENOMEM;
client_template.adapter = adap;
client_template.addr  = addr;
memcpy(client, &client_template, sizeof(*client));
strcpy(client->name , "{driver_name}");
decoder->client = client;
client->data = decoder;
decoder->addr = addr;

Towards the end of the function, add:

init_MUTEX(&decoder->lock);
i2c_attach_client(client);


Step 8: Modify the driver's detach function

Change the driver detach function prototype :
{driver_name}_detach(struct i2c_device *device) --> {driver_name}_detach(struct 
i2c_client *client)

In the beginning of the detach function, add:
i2c_detach_client(client);

Towards the end of the detach function, add:
kfree(client->data);
kfree(client);

Step 9: Modify the driver's command function

Change the driver command function prototype :

Step 10: Add the probe function after the driver's attach function.

Add the following code:

static int {driver_name}_probe(struct i2c_adapter *adap)
{
	return i2c_probe(adap, &addr_data, {driver_name}_attach);

}

Step 11: Modify the driver's i2c_driver

Find the i2c_driver , such as
static struct i2c_driver i2c_driver_saa7110
It is usually located towards the end of the driver 
Replace the values from I2C_DRIVERID_{something} to {driver_name}_attach, and 
add the following
I2C_DRIVERID_{driver_name} , // verify by looking in include/linux/i2c-id.h 
I2C_DF_NOTIFY,
{driver_name}_probe, 
....

Step 12: Adding the i2c_client 

Add the i2c_client to the driver. Add the following code:

static struct i2c_client client_template = {
	"{driver_name}_client",
	-1,
	0,
	0,
	NULL,
	{i2c_driver reference}
};

Step 13: Registering and Unregistering

Replace i2c_register_driver with i2c_add_driver
Replace i2c_unregister_driver with i2c_del_driver

-------------------------------------------------------

Example:

The following patch provides the i2c coversion patch for the saa7110 driver
based on the above guide (for clarity).


--- drivers/media/video/saa7110.c.old	Fri Jun 28 10:22:52 2002
+++ drivers/media/video/saa7110.c	Thu Jul  4 16:51:08 2002
@@ -26,7 +26,7 @@
 #include <asm/io.h>
 #include <asm/uaccess.h>
 
-#include <linux/i2c-old.h>
+#include <linux/i2c.h>
 #include <linux/videodev.h>
 #include "linux/video_decoder.h"
 
@@ -37,13 +37,31 @@
 
 #define	I2C_SAA7110		0x9C	/* or 0x9E */
 
+#define IF_NAME	"saa7110"
 #define	I2C_DELAY		10	/* 10 us or 100khz */
 
+static unsigned short normal_i2c[] = {34>>1, I2C_CLIENT_END };
+static unsigned short normal_i2c_range[] = { I2C_CLIENT_END };
+static unsigned short probe[2] = { I2C_CLIENT_END, I2C_CLIENT_END };
+static unsigned short probe_range[2] = { I2C_CLIENT_END, I2C_CLIENT_END };
+static unsigned short ignore[2] = { I2C_CLIENT_END, I2C_CLIENT_END };
+static unsigned short ignore_range[2] = { I2C_CLIENT_END, I2C_CLIENT_END };
+static unsigned short force[2] = { I2C_CLIENT_END, I2C_CLIENT_END };
+
+static struct i2c_client_address_data addr_data = {
+	normal_i2c, normal_i2c_range,
+	probe, probe_range,
+	ignore, ignore_range,
+	force
+};
+
+static struct i2c_client client_template;
+
 struct saa7110 {
-	struct	i2c_bus	*bus;
+	struct i2c_client *client;
 	int		addr;
 	unsigned char	reg[36];
-
+	struct semaphore lock;
 	int		norm;
 	int		input;
 	int		enable;
@@ -54,67 +72,10 @@
 };
 
 /* ----------------------------------------------------------------------- */
-/* I2C support functions						   */
-/* ----------------------------------------------------------------------- */
-static
-int saa7110_write(struct saa7110 *decoder, unsigned char subaddr, unsigned char data)
-{
-	int ack;
-
-	LOCK_I2C_BUS(decoder->bus);
-	i2c_start(decoder->bus);
-	i2c_sendbyte(decoder->bus, decoder->addr, I2C_DELAY);
-	i2c_sendbyte(decoder->bus, subaddr, I2C_DELAY);
-	ack = i2c_sendbyte(decoder->bus, data, I2C_DELAY);
-	i2c_stop(decoder->bus);
-	decoder->reg[subaddr] = data;
-	UNLOCK_I2C_BUS(decoder->bus);
-	return ack;
-}
-
-static
-int saa7110_write_block(struct saa7110* decoder, unsigned const char *data, unsigned int len)
-{
-	unsigned subaddr = *data;
-
-	LOCK_I2C_BUS(decoder->bus);
-        i2c_start(decoder->bus);
-        i2c_sendbyte(decoder->bus,decoder->addr,I2C_DELAY);
-	while (len-- > 0) {
-                if (i2c_sendbyte(decoder->bus,*data,0)) {
-                        i2c_stop(decoder->bus);
-                        UNLOCK_I2C_BUS(decoder->bus);
-                        return -EAGAIN;
-                }
-		decoder->reg[subaddr++] = *data++;
-        }
-	i2c_stop(decoder->bus);
-	UNLOCK_I2C_BUS(decoder->bus);
-
-	return 0;
-}
-
-static
-int saa7110_read(struct saa7110* decoder)
-{
-	int data;
-
-	LOCK_I2C_BUS(decoder->bus);
-	i2c_start(decoder->bus);
-	i2c_sendbyte(decoder->bus, decoder->addr, I2C_DELAY);
-	i2c_start(decoder->bus);
-	i2c_sendbyte(decoder->bus, decoder->addr | 1, I2C_DELAY);
-	data = i2c_readbyte(decoder->bus, 1);
-	i2c_stop(decoder->bus);
-	UNLOCK_I2C_BUS(decoder->bus);
-	return data;
-}
-
-/* ----------------------------------------------------------------------- */
 /* SAA7110 functions							   */
 /* ----------------------------------------------------------------------- */
 static
-int saa7110_selmux(struct i2c_device *device, int chan)
+int saa7110_selmux(struct i2c_client *client, int chan)
 {
 static	const unsigned char modes[9][8] = {
 /* mode 0 */	{ 0x00, 0xD9, 0x17, 0x40, 0x03, 0x44, 0x75, 0x16 },
@@ -126,61 +87,59 @@
 /* mode 6 */	{ 0x80, 0x59, 0x17, 0x42, 0xA3, 0x44, 0x75, 0x12 },
 /* mode 7 */	{ 0x80, 0x9A, 0x17, 0xB1, 0x13, 0x60, 0xB5, 0x14 },
 /* mode 8 */	{ 0x80, 0x3C, 0x27, 0xC1, 0x23, 0x44, 0x75, 0x21 } };
-	struct saa7110* decoder = device->data;
 	const unsigned char* ptr = modes[chan];
 
-	saa7110_write(decoder,0x06,ptr[0]);	/* Luminance control	*/
-	saa7110_write(decoder,0x20,ptr[1]);	/* Analog Control #1	*/
-	saa7110_write(decoder,0x21,ptr[2]);	/* Analog Control #2	*/
-	saa7110_write(decoder,0x22,ptr[3]);	/* Mixer Control #1	*/
-	saa7110_write(decoder,0x2C,ptr[4]);	/* Mixer Control #2	*/
-	saa7110_write(decoder,0x30,ptr[5]);	/* ADCs gain control	*/
-	saa7110_write(decoder,0x31,ptr[6]);	/* Mixer Control #3	*/
-	saa7110_write(decoder,0x21,ptr[7]);	/* Analog Control #2	*/
+	i2c_smbus_write_byte_data(client,0x06,ptr[0]);	/* Luminance control	*/
+	i2c_smbus_write_byte_data(client,0x20,ptr[1]);	/* Analog Control #1	*/
+	i2c_smbus_write_byte_data(client,0x21,ptr[2]);	/* Analog Control #2	*/
+	i2c_smbus_write_byte_data(client,0x22,ptr[3]);	/* Mixer Control #1	*/
+	i2c_smbus_write_byte_data(client,0x2C,ptr[4]);	/* Mixer Control #2	*/
+	i2c_smbus_write_byte_data(client,0x30,ptr[5]);	/* ADCs gain control	*/
+	i2c_smbus_write_byte_data(client,0x31,ptr[6]);	/* Mixer Control #3	*/
+	i2c_smbus_write_byte_data(client,0x21,ptr[7]);	/* Analog Control #2	*/
 
 	return 0;
 }
 
 static
-int determine_norm(struct i2c_device* dev)
+int determine_norm(struct i2c_client* client)
 {
-	struct	saa7110* decoder = dev->data;
 	int	status;
 
 	/* mode changed, start automatic detection */
-	status = saa7110_read(decoder);
+	status = i2c_smbus_read_byte(client);