Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > linux.kernel > #1470307

[PATCHv2 0/2] pwm: sunxi: give the pwm IP block more time

Show all headers | View raw

Hi all,

last year I've sent out this patch series and there was little technical
discussion, so hopefully we can rekindle it.

This patch series fixes 2 issues. For one, we add a delay between disabling
the PWM hardware block and removing the clock, this to yield the PWM hardware
time to actually finish it's PWM and finish in the proper state. If we do not
do this, the output may stay high and may overload speakers for example.

The other issue might need a little more discussion. It also yields the PWM
hardware some extra time. When changing the config, we enable the clock
together with the parameters for the PWM. Sometimes however, the PWM IP core
has not had the time yet to actually set the ready bit. By first enabling
the gate, and then change things, the IP has time to do its thing. The PWM
block has probably done its thing even after the writel has returned. So an
extra delay (of one bus clock cycle?) is overkill.

Changes since v1:
	- Split patch series into several smaller patch series
	- Added driver author

Olliver Schinagl (2):
  pwm: sunxi: allow the pwm to finish its pulse before disable
  pwm: sunxi: Yield some time to the pwm-block to become ready

 drivers/pwm/pwm-sun4i.c | 54 ++++++++++++++++++++++++++++++++-----------------
 1 file changed, 36 insertions(+), 18 deletions(-)

-- 
2.8.1

Back to linux.kernel | Previous | Next — Next in thread | Find similar | Unroll thread

Thread

[PATCHv2 0/2] pwm: sunxi: give the pwm IP block more time Olliver Schinagl <oliver@schinagl.nl> - 2016-08-25 20:00 +0200
  [PATCH 1/2] pwm: sunxi: allow the pwm to finish its pulse before disable Olliver Schinagl <oliver@schinagl.nl> - 2016-08-25 20:00 +0200
    Re: [PATCH 1/2] pwm: sunxi: allow the pwm to finish its pulse before  disable Maxime Ripard <maxime.ripard@free-electrons.com> - 2016-08-27 00:20 +0200
      Re: [PATCH 1/2] pwm: sunxi: allow the pwm to finish its pulse  before disable Olliver Schinagl <oliver@schinagl.nl> - 2016-09-06 09:20 +0200
        Re: [PATCH 1/2] pwm: sunxi: allow the pwm to finish its pulse before  disable Maxime Ripard <maxime.ripard@free-electrons.com> - 2016-09-06 22:00 +0200
          Re: [PATCH 1/2] pwm: sunxi: allow the pwm to finish its pulse  before disable Olliver Schinagl <oliver@schinagl.nl> - 2016-09-09 11:10 +0200
  [PATCH 2/2] pwm: sunxi: Yield some time to the pwm-block to become ready Olliver Schinagl <oliver@schinagl.nl> - 2016-08-25 20:00 +0200
    Re: [PATCH 2/2] pwm: sunxi: Yield some time to the pwm-block to  become ready Maxime Ripard <maxime.ripard@free-electrons.com> - 2016-08-27 00:30 +0200

csiph-web