[PATCH] ARM: dts: lpc32xx: set pwm1 & pwm2 default clock rate

Sylvain Lemieux slemieux.tyco at gmail.com
Tue Oct 11 08:51:32 PDT 2016


On Wed, 2016-10-05 at 10:11 -0400, Sylvain Lemieux wrote:
> Hi Vladimir,
> 
> On Wed, 2016-10-05 at 05:08 +0300, Vladimir Zapolskiy wrote:
> > Hi Sylvain,
> > 
> > On 26.09.2016 21:54, Sylvain Lemieux wrote:
> > > From: Sylvain Lemieux <slemieux at tycoint.com>
> > > 
> > > Probably most of NXP LPC32xx boards have 13MHz main oscillator
> > > and therefore for HCLK PLL and ARM core clock rate default
> > > hardware setting of 16 * 13MHz = 208MHz and the AHB bus clock
> > > rate of 208MHz / 2 = 104MHz.
> > > 
> > > The change explicitly defines the peripheral PWM1/PWM2 default
> > > clock output rate of 104MHz. If needed it can be redefined
> > > in a board DTS file.
> > > 
> > > Signed-off-by: Sylvain Lemieux <slemieux.tyco at gmail.com>
> > > ---
[...]
> 
> I can submit a version 2 with the proper value and update
> the patch description to list the default peripheral clock
> setup of 13MHz.
> 
> This change is adding a default value for the PWM clock
> (setup to CLK_PERIPH) to the PWM device node, allowing the
> board specific DTS to only enable the PWM to get it work.
> 
> If the PWM clock output is not setup with a default value,
> only enabling the PWM in the board specific DTS file is not
> enough; the PWM divider will keep the default value of zero
> (i.e. PWM clock off).
> 

This patch is no longer needed;
the following patch is handle the issue:
http://www.spinics.net/lists/arm-kernel/msg535313.html

The PWM clock will match the parent clock (i.e. update at
initialization) if the PWM divider value was setup to 0
(i.e. gating functionality).

> > --
> > With best wishes,
> > Vladimir
> 
> Sylvain
> 
> 





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