On 06/03/2010 08:21 AM, Jean Delvare wrote:
On Wed, 02 Jun 2010 13:29:36 +0200, Richard Röjfors wrote:
On 06/02/2010 01:04 PM, Jean Delvare wrote:
Richard, look at drivers/i2c/busses/i2c-i801.c, function i801_probe():
you'll see an example of per-platform I2C device instantiation on x86.
I'm not claiming it is elegant, but it works.
The "problem" I see is that the CPU and the chipset + I2C chip will be populated on several
different boards. It would mean that the I2C bus driver would need knowledge of all the boards where
it is used. And the bus driver itself can not really detect which board it's running on.
That is why I kept the I2C device setup in a separate driver. So each board would have a separate
"setup" driver. Isn't that the most clean solution right now?
I have to admit I don't clearly understand what you are doing. It
should become clearer when I see your code.
The I2C bus driver used is a standard one and the setup of I2C devices depends on the actual board
the chips are deployed on.
I do stuff like this, example of a driver for one specific board (there are more I2C devices to come):
#include <linux/gpio.h>
#include <linux/i2c.h>
#include <linux/i2c/tsc2007.h>
#define DRIVER_NAME "the_module"
static int i2c_bus = 0;
static unsigned tsc2007_irq_pin = 102;
static __devinitdata struct tsc2007_platform_data tsc2007_platform_data = {
.model = 2007,
.x_plate_ohms = 200
};
static __initdata struct i2c_board_info tsc2007_i2c_board_info = {
I2C_BOARD_INFO("tsc2007", 0x48),
.platform_data = &tsc2007_platform_data,
/* irq to be filled in runtime */
};
static struct i2c_client *tsc2007_client;
static __init int the_module_get_irq(unsigned gpio_pin)
{
int err;
err = gpio_request(gpio_pin, DRIVER_NAME);
if (err)
return err;
err = gpio_direction_input(gpio_pin);
if (err)
goto err;
err = gpio_to_irq(gpio_pin);
if (err < 0)
goto err;
return err;
err:
gpio_free(tsc2007_irq_pin);
return err;
}
static __init int the_module_init(void)
{
struct i2c_adapter *adapt;
int err;
adapt = i2c_get_adapter(i2c_bus);
if (!adapt) {
printk(KERN_ERR "%s: Failed to get I2C adapter\n", __func__);
return -ENODEV;
}
err = the_module_get_irq(tsc2007_irq_pin);
if (err < 0)
goto put_adapter;
tsc2007_i2c_board_info.irq = err;
/* add in the devices on the bus */
tsc2007_client = i2c_new_device(adapt, &tsc2007_i2c_board_info);
if (!tsc2007_client)
goto free_tsc2007_pin;
i2c_put_adapter(adapt);
return 0;
free_tsc2007_pin:
gpio_free(tsc2007_irq_pin);
put_adapter:
i2c_put_adapter(adapt);
return err;
}
static void __exit the_module_exit(void)
{
i2c_unregister_device(tsc2007_client);
}
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