I2c touch screen linux

Static int i2c_ts_probe (struct i2c_client * client,
Const struct i2c_device_id * IDP)
Struct i2c_ts_priv * priv;
Struct input_dev * input;
Int error;
Char Buf [2];

Priv = kzarloc (sizeof (* priv), gfp_kernel );
If (! Priv )Dev_err (& client-> Dev, «failed to allocate driver data \ n «);
Error =-enomem;
Goto err0;
>

Dev_set_drvdata (& client-> Dev, priv );

Input-> evbit [0] = bit_mask (ev_key) | bit_mask (ev_abs );
Input-> keybit [bit_word (btn_touch)] = bit_mask (btn_touch );

Input_set_abs_params (input, abs_x, min_x_coordinate, max_x_coordinate, 0, 0 );
Input_set_abs_params (input, abs_y, min_y_coordinate, max_y_coordinate, 0, 0 );

Input-> name = client-> name;
Input-> ID. bustype = bus_i2c;
Input-> Dev. Parent = & client-> dev;

Input-> open = i2c_ts_open;
Input-> close = i2c_ts_close;

Input_set_drvdata (input, priv );

Priv-> client = client;
Priv-> input = input;
Init_delayed_work (& priv-> Work, i2c_ts_poscheck );
Priv-> IRQ = client-> IRQ;

Error = input_register_device (input );
If (error)
Goto err1;

Error = request_irq (priv-> IRQ, i2c_ts_isr, ir1__trigger_falling,
Client-> name, priv );
If (error )Dev_err (& client-> Dev, «unable to request touchscreen IRQ. \ n «);
Goto err2;
>

Err2:
Input_unregister_device (input );
Input = NULL;/* so we dont try to free it below */
Err1:
Input_free_device (input );
Kfree (priv );
Err0:
Dev_set_drvdata (& client-> Dev, null );
Return Error;
>

Static int i2c_ts_remove (struct i2c_client * client)
Struct i2c_ts_priv * priv = dev_get_drvdata (& client-> Dev );

Free_irq (priv-> IRQ, priv );
Input_unregister_device (priv-> input );
Kfree (priv );

Dev_set_drvdata (& client-> Dev, null );

Static int i2c_ts_suspend (struct i2c_client * client, pm_message_t mesg)
Struct i2c_ts_priv * priv = dev_get_drvdata (& client-> Dev );
If (device_may_wakeup (& client-> Dev ))
Enable_irq_wake (priv-> IRQ );
Return 0;
>

Static int i2c_ts_resume (struct i2c_client * client)
Struct i2c_ts_priv * priv = dev_get_drvdata (& client-> Dev );
If (device_may_wakeup (& client-> Dev ))
Disable_irq_wake (priv-> IRQ );
Return 0;
>

Static const struct i2c_device_id i2c_ts_id [] = ,
<>
>;
Module_device_table (I2C, i2c_ts_id );

Static struct i2c_driver i2c_ts_driver = . Driver = . Name = «i2c-ts «,
>,
. Probe = i2c_ts_probe,
. Remove = i2c_ts_remove,
. Suspend = i2c_ts_suspend,
. Resume = i2c_ts_resume,
. Id_table = i2c_ts_id,
>;

Static int _ init i2c_ts_init (void)
Return i2c_add_driver (& i2c_ts_driver );
>

Static void _ exit i2c_ts_exit (void)
I2c_del_driver (& i2c_ts_driver );
>

Module_description («I2C touchscreen driver «);
Module_author («Allen «);
Module_license («GPL «);

Module_init (i2c_ts_init );
Module_exit (i2c_ts_exit );

4 ). after completing this step, you also need to create and configure the I2C device where the setup file is located in
linux-2.6.32.2/ARCH/ARM/mach-s3c2440/mach-mini2440.c,
Add the following code:
. .
+/* I2C touch screen devices. */
+/* bus configuration */
+ static struct s3c2410_platform_i2c i2c_touchscreen_cfg _ initdata = +. flags = 0,
+. slave_addr = 0x5c,
+. frequency = 100*1000,
+. sda_delay = 2,
+>;

+/* I2C device name is «i2c_ts», address is 0x5c, interrupt is eint20 */
+ Static struct i2c_board_info touchscreen_i2c_devs [] _ initdata = + + I2c_board_info («i2c-ts», 0x5c ),
+. IRQ = irq_eint20,
+ >,
+ >;
. .

Static void _ init mini2440_machine_init (void)
. .
+/* I2C touch screen devices */
+ Maid (& i2c_touchscreen_cfg );
+ I2c_register_board_info (0, touchscreen_i2c_devs, + array_size (touchscreen_i2c_devs ));
. .
>

Here i2c_board_info («i2c-ts», 0x5c), «i2c-ts» should be consistent with i2c_ts_id In the I2C device driver.
In order to ensure that the I2C device driver is loaded successfully.

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Adding touch screen driver to Wandboard, i2c device registration

I compiled the driver into Linux kerenl as a built-in module, tried to run on the board but failed. The driver doesn’t appear in /dev/input . I debuged the kerenl code a bit, and found that the code doesn’t reach to driver’s probe function, instead it fails in device binding (i2c device registration). Just then I come to know about Device tree.

I looked into following dts files (which I believe my Wandboard is using), putting little i2c configuration present in the files here.

i2c1: i2c@021a0000 < #address-cells = ; #size-cells = ; compatible = "fsl,imx6q-i2c", "fsl,imx21-i2c"; reg = ; interrupts = ; clocks = ; status = "disabled"; >; i2c2: i2c@021a4000 < #address-cells = ; #size-cells = ; compatible = "fsl,imx6q-i2c", "fsl,imx21-i2c"; reg = ; interrupts = ; clocks = ; status = "disabled"; >; i2c3: i2c@021a8000 < #address-cells = ; #size-cells = ; compatible = "fsl,imx6q-i2c", "fsl,imx21-i2c"; reg = ; interrupts = ; clocks = ; status = "disabled"; >; 

&hdmi < ddc-i2c-bus = ; status = "okay"; >; &i2c1 < clock-frequency = ; pinctrl-names = "default"; pinctrl-0 = ; status = "okay"; >; &i2c2 < clock-frequency = ; pinctrl-names = "default"; pinctrl-0 = ; status = "okay"; codec: sgtl5000@0a < compatible = "fsl,sgtl5000"; reg = ; clocks = ; VDDA-supply = ; VDDIO-supply = ; >; >; 

I see dts note entry for sgtl5000 which is audio codec which then appears as /dev/input/event0 . But I don’t find any entry for ‘prism’ driver, which actually runs perfectly on the board. Neither dts files nor board-files have entry for ‘prism’ driver. But I am sure it’s using ‘device-tree’ approach.

1. As my Wandboard works fine with ‘prism’ driver and touch device, why I don’t see device node entry for ‘prism’ in dts files ?
2. Is there any other way for ‘i2c device registration’ other than ‘device-tree’ and ‘earlier board-file’ approach ?
3. How could I get past with ilitek touch driver not getting i2c-matched/registered problem ?

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