Re: [PATCHv2 0/4] ACPI / LPSS: Solution for two issues seen on Asus T100

["Li, Aubrey" <aubrey.li@linux.intel.com>]

On 2014/5/15 22:53, Andy Shevchenko wrote:
> On Thu, 2014-05-15 at 22:35 +0800, Li, Aubrey wrote:
>> On 2014/5/15 21:40, Heikki Krogerus wrote:
>>> Changes since v1:
>>> - now using do_div() in clk_fd_recalc_rate() as suggested by Andy
>>> - NULL checks for clk_name allocation in acpi_lpss.c
>>>
>>> This combines two patch sets for LPSS that I had already send for
>>> review separately. They conflicted with each other.
>>>
>>> The first two patches will fix a problem were the context of the
>>> private LPSS registers is lost when entering D3. The last two will add
>>> support for the M/N dividers on LPSS by adding a new basic clock type
>>> for fractional dividers. The UART driver needs support for it in order
>>> to get clock rates that suit the requested baud rates.
>>
>> The major issue in my mind is, this proposal makes a couple between I2C
>> designware, HSUART, or probably DMA driver as well with LPSS driver.
> 
> acpi_lpss driver creates platform devices for each found and enumerated
> device.

> If there no acpi_lpss enabled the drivers work as supposed without it.

This is not true.

Thanks,
-Aubrey


> I didn't see any contradiction here.
> 
>> That is, currently without LPSS driver, I2C/HSUART won't work properly.
>> So we at least need to describe this dependency in Kconfig.
>>
>> Thanks,
>> -Aubrey
>>>
>>>
>>> Heikki Krogerus (4):
>>>   ACPI / PM: Export rest of the subsys functions
>>>   ACPI / LPSS: custom power domain for LPSS
>>>   clk: new basic clk type for fractional divider
>>>   ACPI / LPSS: support for fractional divider clock
>>>
>>>  drivers/acpi/acpi_lpss.c             | 204 ++++++++++++++++++++++++++++++-----
>>>  drivers/acpi/device_pm.c             |   2 +
>>>  drivers/clk/Makefile                 |   1 +
>>>  drivers/clk/clk-fractional-divider.c | 135 +++++++++++++++++++++++
>>>  include/linux/acpi.h                 |   4 +
>>>  include/linux/clk-provider.h         |  31 ++++++
>>>  6 files changed, 349 insertions(+), 28 deletions(-)
>>>  create mode 100644 drivers/clk/clk-fractional-divider.c
>>>
>>
> 
>