[PATCH v4 04/14] mfd: Add Samsung PWM/timer master driver

[Tomasz Figa]

Hi Samuel,

On Friday 05 of April 2013 18:39:58 Samuel Ortiz wrote:
> Hi Tomasz,
> 
> On Thu, Apr 04, 2013 at 06:37:01PM +0200, Tomasz Figa wrote:
> > This patch adds master driver for PWM/timer block available on many
> > Samsung SoCs providing clocksource and PWM output capabilities.
> > 
> > Signed-off-by: Tomasz Figa <t.figa at samsung.com>
> > Signed-off-by: Kyungmin Park <kyungmin.park at samsung.com>
> > ---
> > 
> >  .../devicetree/bindings/pwm/pwm-samsung.txt        |  37 ++
> >  drivers/clocksource/Kconfig                        |   1 +
> >  drivers/mfd/Kconfig                                |   3 +
> >  drivers/mfd/Makefile                               |   1 +
> >  drivers/mfd/samsung-pwm.c                          | 439
> >  +++++++++++++++++++++ drivers/pwm/Kconfig                               
> >  |   1 +
> >  include/linux/mfd/samsung-pwm.h                    |  49 +++
> >  include/linux/platform_data/samsung-pwm.h          |  28 ++
> >  8 files changed, 559 insertions(+)
> >  create mode 100644 Documentation/devicetree/bindings/pwm/pwm-samsung.txt
> >  create mode 100644 drivers/mfd/samsung-pwm.c
> >  create mode 100644 include/linux/mfd/samsung-pwm.h
> >  create mode 100644 include/linux/platform_data/samsung-pwm.h
> 
> Why is that an MFD driver, and why aren't you using the PWM APIs for it ?
> Also, you probably want to look at using the regmap APIs for your IO.

The case of Samsung PWM timers is rather complicated. It is a hardware block 
that can be used at the same time to generate PWM signal and as a system 
clocksource.

There was a discussion on how to solve the problem of sharing the hardware:
http://thread.gmane.org/gmane.linux.kernel.samsung-soc/16480/focus=16500
(see the linked post and replies to it).

Best regards,
-- 
Tomasz Figa
Samsung Poland R&D Center
SW Solution Development, Kernel and System Framework