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Message-ID: <9e49fc42-75be-3bd5-dfa4-9cc61348d501@redhat.com>
Date: Fri, 18 May 2018 15:09:29 +0200
From: Hans de Goede <hdegoede@...hat.com>
To: Jarkko Nikula <jarkko.nikula@...ux.intel.com>,
Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
Chris Chiu <chiu@...lessm.com>
Cc: Daniel Drake <drake@...lessm.com>,
Jian-Hong Pan <jian-hong@...lessm.com>,
Jiri Kosina <jikos@...nel.org>,
Benjamin Tissoires <benjamin.tissoires@...hat.com>,
Jani Nikula <jani.nikula@...el.com>,
Dmitry Torokhov <dmitry.torokhov@...il.com>,
Adrian Salido <salidoa@...gle.com>,
Jason Gerecke <killertofu@...il.com>,
linux-input <linux-input@...r.kernel.org>,
Mika Westerberg <mika.westerberg@...ux.intel.com>,
Wolfram Sang <wsa@...-dreams.de>, linux-i2c@...r.kernel.org,
Linux Kernel <linux-kernel@...r.kernel.org>,
Linux Upstreaming Team <linux@...lessm.com>
Subject: Re: [BUG] i2c-hid: ELAN Touchpad does not work on ASUS X580GD
Hi,
On 18-05-18 12:58, Jarkko Nikula wrote:
> On 05/18/2018 01:20 PM, Andy Shevchenko wrote:
>> On Fri, 2018-05-18 at 11:37 +0300, Andy Shevchenko wrote:
>>> On Fri, 2018-05-18 at 09:48 +0200, Hans de Goede wrote:
>>>
>>>
>>>> Could it be the i2c input clock definition in drivers/mfd/intel-
>>>> lpss-
>>>> pci.c
>>>> is also wrong for Apollo Lake (N3450) ? There are lots of people
>>>> having
>>>> various issues with i2c attached touchpads on Apollo Lake devices,
>>>> this bug:
>>>> https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1728244
>>>>
>>>> Is sort of a collection bug for these. Various models laptops, lots
>>>> of
>>>> reporters. Note not sure thie is an i2c-designware issue, but it
>>>> would
>>>> be good to double check the input clock on Apollo Lake.
>>>>
>>>> I've checked the datasheet and the datasheet mentions 133MHz as
>>>> "serial input clk" in the lpio_bxt_regs Registers Summary, which is
>>>> also part of the LPSS, no clk is mentioned in the "Summary of
>>>> DW_apb_i2c_mem_map_DW_apb_i2c_addr_block1 Registers".
>>>
>>> The internal datasheet we have access to mentioned in this case for
>>> Broxton and Cannonlake together. So, your assumption might be quite
>>> close to the truth and the issue is inherited from Broxton.
>>>
>>
> Nope. The specification I have mention the I2C input clock in Broxton is fixed 133 MHz but in Cannon Lake it is derived through non-SW visible divider.
>
>> Hans, can your reporters try the following patch? Depending on the
>> result I may send it out ASAP.
>>
>> --- a/drivers/mfd/intel-lpss-pci.c
>> +++ b/drivers/mfd/intel-lpss-pci.c
>> @@ -120,7 +120,7 @@ static struct property_entry apl_i2c_properties[] =
>> {
>> };
>> static const struct intel_lpss_platform_info apl_i2c_info = {
>> - .clk_rate = 133000000,
>> + .clk_rate = 216000000,
>> .properties = apl_i2c_properties,
>> };
>>
> Nack. The Apollo Lake HW here shows expected I2C bus clock on oscilloscope so it is indeed clocked at 133 MHz.
Ok, thank you for checking this.
Regards,
Hans
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