Accessing input device TCA6424 from User Space.

hrishikesh choudhary

Other Parts Discussed in Thread: TCA6424, TCA6416

3124.4113.tca6424_matrix.c

Hi,

I am referring the attached Client-driver file for TCA6424. I can see the device register as input in the source code .

        input->id.bustype = BUS_HOST;
        input->id.vendor = 0x0001;
        input->id.product = 0x0001;
        input->id.version = 0x0100;

        /* Enable auto repeat feature of Linux input subsystem */
        if (pdata->rep)
                __set_bit(EV_REP, input->evbit);

        for (i = 0; i < pdata->nbuttons; i++) {
                unsigned int type;

                chip->buttons[i] = pdata->buttons[i];
                type = (pdata->buttons[i].type) ?: EV_KEY;
                input_set_capability(input, type, pdata->buttons[i].code);
        }

        input_set_drvdata(input, chip);

        /*
         * Initialize cached registers from their original values.
         * we can't share this chip with another i2c master.
         */
        error = tca6416_setup_registers(chip);
        if (error)
                goto fail1;

        if (!chip->use_polling) {
                if (pdata->irq_is_gpio)
                        chip->irqnum = gpio_to_irq(client->irq);
                else
                        chip->irqnum = client->irq;

                error = request_threaded_irq(chip->irqnum, NULL,
                                             tca6416_keys_isr,
                                             IRQF_TRIGGER_FALLING,
                                             "tca6416-keypad", chip);
                if (error) {
                        dev_dbg(&client->dev,
                                "Unable to claim irq %d; error %d\n",
                                chip->irqnum, error);
                        goto fail1;
                }
                disable_irq(chip->irqnum);
        }

        error = input_register_device(input);

Can some one guide me how i can see the register input device on target board & access it from user space. I am expecting for every key press to print the value of keys in userspace. Please suggest your views.

Thanks in advance,

Hrishikesh

over 11 years ago

0 Biser Gatchev-XID over 11 years ago

TI__Guru**** 393215 points

Moving this to the Linux forum.

0 Titusrathinaraj Stalin over 11 years ago

TI__Guru** 116100 points

Hi Hrishikesh,

Have you enabled & registered "TCA6424" support in linux ?

Are you added the platform data in board or dts file ?

Please refer to the following links.

https://www.mail-archive.com/linux-omap@vger.kernel.org/msg25655.html

http://markmail.org/message/722qeanq6jshy74b

0 Titusrathinaraj Stalin over 11 years ago in reply to Titusrathinaraj Stalin

TI__Guru** 116100 points

Try to apply the patch for TCA6424 support.

http://www.gossamer-threads.com/lists/linux/kernel/1525215#1525215

https://groups.google.com/forum/#!topic/linux.kernel/DPVO7QKPldg

0 hrishikesh choudhary over 11 years ago in reply to Titusrathinaraj Stalin

Expert 1390 points

Yes .. i have added it in board file . as the linux kernel is 2.6.35.

/* Keypad Initialization */
#define KEYPAD_BUTTON(ev_type, ev_code, act_low) \
{                                                               \
         .type           = ev_type,                              \
         .code           = ev_code,                              \
         .active_low     = act_low,                              \
}

#define KEYPAD_BUTTON_LOW(event_code) KEYPAD_BUTTON(EV_KEY, event_code, 1)

static struct tca6416_button m704_gpio_keys[] = {
         KEYPAD_BUTTON_LOW(KEY_HOME),
         KEYPAD_BUTTON_LOW(KEY_MENU),
         KEYPAD_BUTTON_LOW(KEY_BACK),
         KEYPAD_BUTTON_LOW(KEY_POWER),
         KEYPAD_BUTTON_LOW(KEY_LEFT),
         KEYPAD_BUTTON_LOW(KEY_RIGHT),
         KEYPAD_BUTTON_LOW(KEY_UP),
         KEYPAD_BUTTON_LOW(KEY_DOWN),
};

static struct tca6416_keys_platform_data m704_tca6416_keys_info = {
         .buttons        = m704_gpio_keys,
         .nbuttons       = ARRAY_SIZE(m704_gpio_keys),
         .rep            = 0,
         .use_polling    = 0,
         .pinmask        = 0x00FF,
   .irq_is_gpio    = 1,
};

static struct i2c_board_info __initdata m335x_i2c_device_1[] = {
    {
       I2C_BOARD_INFO("tca6424-keys", 0x22), // Added By Hrishi : I2C IO Expander
       .platform_data = &m704_tca6416_keys_info,
   },
};

should this generate events @ /dev/input/event0 or i have to some additional settings.

0 hrishikesh choudhary over 11 years ago in reply to hrishikesh choudhary

Expert 1390 points

Hi,

After referring the attached file. the input device was registered under /dev/input/event2 for my board.

Thanks TI for the support.

0 Titusrathinaraj Stalin over 11 years ago in reply to hrishikesh choudhary

TI__Guru** 116100 points

Hi Hrishikesh,

Sounds good.

Thanks for your update.

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Accessing input device TCA6424 from User Space.