MOD_INC_USE_COUNT placement

["Perry Gilfillan" <perrye@linuxmail.org>]

Question: Where to put MOD_INC_USE_COUNT and MOD_DEC_USE_COUNT, and appropriate statements for linux-2.6.0 kernel?

I posted an earlier question asking for help with updating the v3tv drivers for the Voodoo3 TV 3500 video capture card.  Here is a specific question.

I succeded in getting the driver to compile, install and run on linux-2.4.22 with I2C-2.8.1 patch applied.  In the process, refrence to the functions voodoo3_inc and voodoo3_dec in voodoo.c were removed from the struct i2c_adapter.  Now the module v3tv.o which links both voodoo.c and voodoo-i2c.c, does not have its usage updated.  I want to find the appropriate place to update module use count, and do it for pre and post 2.5.0 kernels.

voodoo.c does not define struct i2c_adapter.  voodoo-i2c.c defines two:

struct i2c_adapter voodoo3_i2c_adapter = {
	name:			"I2C Voodoo3/Banshee adapter",
	id:			I2C_HW_SMBUS_VOODOO3,
	algo_data:		&voo_i2c_bit_data,
	client_register:	voodoo3_i2c_client_register,
	client_unregister:	voodoo3_i2c_client_deregister
};

struct i2c_adapter voodoo3_ddc_adapter = {
	name:		"DDC Voodoo3/Banshee adapter",
	id:		I2C_HW_SMBUS_VOODOO3,
	algo_data:	&voo_ddc_bit_data
};

I went back and looked at the i2c implementation of i2c-voodoo3 from lm_sensors, and see that there is not a register or unregister function.  A more basic question might be, do I need to do usage count?

i2c-voodoo3 from lm_sensors also uses module_init() and module_exit().  The v3tv module does mot use these, but other modules in the v3tv package do.  Should these functions be added to the v3tv module rather than usage count?

voodoo3_i2c_adapter is the more important one at this time, but I think usage should be incremented for voodoo3_ddc_adapter as well.  We can just concentrate on the i2c adapter.  voodoo.c does include functions voodoo3_inc and voodoo3_dec, but I think I'll omit them now, and eventually remove them all together later.

Now I need to consider where to update usgae count in the register functions.  voodoo-i2c.c has this function:

static int voodoo3_i2c_client_register(struct i2c_client *client)
{
	short i;

	for (i = 0; i < V3_MAX_I2C_CLIENTS; i++) {
		if (voodoo->i2c_clients[i] == NULL || 
			voodoo->i2c_clients[i]->driver->id == client->driver->id) 
		{
			voodoo->i2c_clients[i] = client;
			if (debug) {
				printk("voodoo.o: attach client: %s at slot %d\n", 
						client->name, i);
			}
			if (client->driver->id == I2C_DRIVERID_TUNER) {
				int type;
				switch (model) {
				case VOODOO3_MODEL_NTSC:
					type = TUNER_PHILIPS_NTSC;
					break;
				case VOODOO3_MODEL_PAL:
					type = TUNER_SAMSUNG_PAL;
					break;
				case VOODOO3_MODEL_SECAM:
					type = TUNER_PHILIPS_SECAM;
					break;
				default:
					type = TUNER_ABSENT;
					break;
				}
				voodoo_call_i2c_client (I2C_DRIVERID_TUNER, 
						TUNER_SET_TYPE, &type);
			}
			return 0;
		}
	}
	return -ENODEV;
}

Would this be right placed before the return 0;  ?

if LINUX_VERSION_CODE < KERNEL_VERSION(2,5,0)
				MOD_INC_USE_COUNT;
#else
				if (!try_module_get(THIS_MODULE)) {
					dprintk(1,
						KERN_ERR
						"voodoo3: failed to increment usecount\n");
					return NULL;
				}
#endif

If this is good, do I need to assign struct member voodoo3_i2c_adapter.owner = THIS_MODULE first?

Thanks for any input,

Perry Gilfillan

---------------------
Here are a few links to the files I've refered to.

v3tv/voodoo.c http://gilfillan.org:8000/v3tv/voodoo.c
v3tv/voodoo-i2c.c http://gilfillan.org:8000/v3tv/voodoo-i2c.c
linux-2.6.0/drivers/i2c/busses/i2c-voodoo3.c http://gilfillan.org:8000/v3tv/i2c-voodoo3.c

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