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

From: Andy Shevchenko
Date: Thu May 15 2014 - 10:53:43 EST


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. 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
> >
>


--
Andy Shevchenko <andriy.shevchenko@xxxxxxxxx>
Intel Finland Oy

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