[PATCH v3 06/10] pwm: Add NVIDIA Tegra SoC support
Thierry Reding
thierry.reding at avionic-design.de
Sun Mar 4 09:42:12 EST 2012
* Stephen Warren wrote:
> Thierry Reding wrote at Wednesday, February 22, 2012 8:17 AM:
> > This commit adds a generic PWM framework driver for the PWFM controller
> > found on NVIDIA Tegra SoCs. The driver is based on code from the
> > Chromium kernel tree and was originally written by Gary King (NVIDIA)
> > and later modified by Simon Que (Chromium).
>
> > diff --git a/drivers/pwm/pwm-tegra.c b/drivers/pwm/pwm-tegra.c
>
> > +static int tegra_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
>
> > + /*
> > + * Convert from duty_ns / period_ns to a fixed number of duty
> > + * ticks per (1 << PWM_DUTY_WIDTH) cycles.
> > + */
> > + c = duty_ns * ((1 << PWM_DUTY_WIDTH) - 1);
>
> The driver in ChromeOS has the following extra line here:
>
> c += (period_ns / 2);
>
> and the following extra line in the comment above:
>
> Also, make sure to round to the nearest integer during division.
>
> I don't know the HW well enough to know if that line should be present?
>
> Otherwise, this looks similar enough to the ChromeOS driver, so:
>
> Acked-by: Stephen Warren <swarren at nvidia.com>
Those probably weren't there yet when I prepared the first series. I'll have
another look will sync up with it after testing that it still works.
Thierry
-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: application/pgp-signature
Size: 198 bytes
Desc: not available
URL: <http://lists.ozlabs.org/pipermail/devicetree-discuss/attachments/20120303/ab9fcace/attachment.pgp>
More information about the devicetree-discuss
mailing list