2010-09-01 07:39:25     I2C help

2010-09-01 07:39:25     I2C help

Martin Jensby (DENMARK)

Message: 93018   

Hi

Hope you can help me out a little bit

I am trying to write a driver that basically is irq driven.

What I am trying to accomplish is when I get the irq I want to read an I2C device

I don't know what I am doing wrong but when I try to modprobe or insmod my module I never get the probe print

and if I trigger and IRQ the driver obviously stack traces.

Futher more I can't seem to find any information as to how I add the I2C address of the device.

I have been looking at the ad7879.c driver for reference.

Thank you

My code is as the following

#include <linux/module.h>

#include <linux/init.h>

#include <linux/i2c.h>

#include <linux/slab.h>

#include <linux/types.h>

#include <linux/interrupt.h>

static struct i2c_device_id capsense_touch_wheel_idtable[] = {

{ "capsense_touch_wheel" },

{ }

};

MODULE_DEVICE_TABLE(i2c, capsense_touch_wheel_idtable);

static irqreturn_t capsense_touch_wheel_handler(int irq, void *dev_id)

{

printk("irq handled dev_id %d\n", dev_id);

struct i2c_client *client = dev_id;

int ret = i2c_smbus_read_byte(client);

printk("read from i2c 0x%x\n", ret);

return IRQ_HANDLED;

}

static int __devinit capsense_touch_wheel_probe(struct i2c_client *client, const struct i2c_device_id *id) {

int err = -ENOMEM;

printk("probing...\n");

/* We want to trigger on the falling egde */

err = set_irq_type(IRQ_PG10, IRQF_TRIGGER_FALLING);

if(err)

return err;

else

printk("irq type set ok\n");

/* Request the IRQ */

err = request_irq(IRQ_PG10, capsense_touch_wheel_handler, 0, "Touch wheel", NULL);

if(err)

return err;

else

printk("request IRQ_PG10 ok\n");

return 0;

}

static int __devexit capsense_touch_wheel_remove(struct i2c_client *client) {

printk("removing...\n");

free_irq(IRQ_PG10, NULL);

return 0;

}

static struct i2c_driver capsense_touch_wheel_driver = {

.driver = {

.name = "capsense_touch_wheel",

},

.probe = capsense_touch_wheel_probe,

.remove = capsense_touch_wheel_remove,

.id_table = capsense_touch_wheel_idtable,

};

static int __init capsense_touch_wheel_init(void)

{

printk("init...\n");

return i2c_add_driver(&capsense_touch_wheel_driver);

};

static void __exit capsense_touch_wheel_exit(void)

{

printk("exit...\n");

i2c_del_driver(&capsense_touch_wheel_driver);

};

module_init(capsense_touch_wheel_init);

module_exit(capsense_touch_wheel_exit);

QuoteReplyEditDelete

2010-09-01 08:32:58     Re: I2C help

Aaron Wu (CHINA)

Message: 93024   

see if file like arch/blackfin/mach-bf518/boards/ezbrd.c will help you

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2010-09-01 10:23:53     Re: I2C help

Martin Jensby (DENMARK)

Message: 93029   

I have added the following lines to my board file

{

I2C_BOARD_INFO("capsense_touch_wheel", 0x19),

.irq = IRQ_PG10,

},

in the I2C section, but I still only see the init line.

I guess the string is what ties the address to the driver I am trying to write.

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2010-09-01 10:50:25     Re: I2C help

Martin Jensby (DENMARK)

Message: 93030   

Apparently very long strings doesn't work, as I should have thought of before.

But now I'm getting my probe

Thank you for your help

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2010-09-02 02:43:58     Re: I2C help

Sonic Zhang (CHINA)

Message: 93045   

You can't do call I2C api from IRQ handler directly. Do it in a workqueue activated in the IRQ handler.

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2010-09-02 08:51:49     Re: I2C help

Martin Jensby (DENMARK)

Message: 93074   

Hi

I changed it to work before reading you post.

And my driver now works as I expect.

Thank you for all your help