From: Jarkko Nikula <jarkko.nikula@linux.intel.com>
To: sergk sergk2mail <sergk.admin@gmail.com>, linux-i2c@vger.kernel.org
Subject: Re: I2c client driver + ACPI on Baytrail & kernel 4.4.2 = ?
Date: Mon, 14 Mar 2016 14:21:16 +0200 [thread overview]
Message-ID: <56E6ACBC.6010508@linux.intel.com> (raw)
In-Reply-To: <CA+V1LzrWqmx2GH6cs65mS=YHkvx+6wnnq7RpeYChH886pn5fog@mail.gmail.com>
Hi
On 03/13/2016 02:43 PM, sergk sergk2mail wrote:
> Hi All,
> Please help to correct create i2c client with ACPI support for device
> (touchscreen) on i2c on vanilla 4.4.2 kernel x86_64 Baytrail,
> disrtibutive = Arch.
> ========================================================
> According kernel Documentation I have created such skeleton:
>
>
> #define DEVICE_NAME "testme"
>
> static const struct acpi_device_id icn_ts_acpi_match[] = {
> { "CHPN0001", 0 },
> { "PNP05C0", 0 },
> { },
> };
Touchscreen and PNPxxxx: can it be i2c-hid compatible touchscreen?
Those typically have vendor specific ACPI _HID but device is matched
using ACPI PNP compatible ID (_CID) "PNP0C50" or "ACPI0C50". See
drivers/hid/i2c-hid/i2c-hid.c.
Just thinking if you have device with _CID "PNP0C50" and either device
is matched before your driver with i2c-hid driver or your driver doesn't
probe because "PNP05C0" != "PNP0C50".
> MAIN QUESTIONS:
>
> 1) What is wrong with i2c client driver code? Why it is NOT obtain
> info from ACPI DSD table?
>
Your example looks ok. Another what comes to my mind is the device
actually present. Sometimes DSDT tables may specify multiple alternative
devices but only one being actually connected. You could check that by
reading the device status which reads 15 if the device is present.
cat /sys/bus/acpi/devices/ACPI01234/status
15
> 2) In which way should be created i2c dev while registering i2c acpi
> driver? Who\where\what and how should create this i2c device?
>
i2c-core registers the i2c devices connected to certain bus when adapter
device for that bus is registered in i2c-core.c: i2c_register_adapter().
--
Jarkko
next prev parent reply other threads:[~2016-03-14 12:21 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-03-13 12:43 I2c client driver + ACPI on Baytrail & kernel 4.4.2 = ? sergk sergk2mail
2016-03-14 12:21 ` Jarkko Nikula [this message]
2016-03-15 22:26 ` sergk sergk2mail
2016-03-15 23:02 ` sergk sergk2mail
2016-03-15 23:12 ` sergk sergk2mail
2016-03-23 9:30 ` Jarkko Nikula
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