Re: [PATCH 1/2] rtc: sun6i: Make external 32k oscillator optional

Maxime Ripard
2020-02-14T08:14:51Z

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Hi Jernej,

Thanks for taking care of this

On Thu, Feb 13, 2020 at 10:14:26PM +0100, Jernej Skrabec wrote:
> Some boards, like OrangePi PC2 (H5), OrangePi Plus 2E (H3) and Tanix TX6
> (H6) don't have external 32kHz oscillator. Till H6, it didn't really
> matter if external oscillator was enabled because HW detected error and
> fall back to internal one. H6 has same functionality but it's the first
> SoC which have "auto switch bypass" bit documented and always enabled in
> driver. This prevents RTC to work correctly if external crystal is not
> present on board. There are other side effects - all peripherals which
> depends on this clock also don't work (HDMI CEC for example).
>
> Make clocks property optional. If it is present, select external
> oscillator. If not, stay on internal.
>
> Signed-off-by: Jernej Skrabec <jernej.skrabec@siol.net>
> ---
> drivers/rtc/rtc-sun6i.c | 14 ++++++--------
> 1 file changed, 6 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/rtc/rtc-sun6i.c b/drivers/rtc/rtc-sun6i.c
> index 852f5f3b3592..538cf7e19034 100644
> --- a/drivers/rtc/rtc-sun6i.c
> +++ b/drivers/rtc/rtc-sun6i.c
> @@ -250,19 +250,17 @@ static void __init sun6i_rtc_clk_init(struct device_node *node,
> writel(reg, rtc->base + SUN6I_LOSC_CTRL);
> }
>
> - /* Switch to the external, more precise, oscillator */
> - reg |= SUN6I_LOSC_CTRL_EXT_OSC;
> - if (rtc->data->has_losc_en)
> - reg |= SUN6I_LOSC_CTRL_EXT_LOSC_EN;
> + /* Switch to the external, more precise, oscillator, if present */
> + if (of_get_property(node, "clocks", NULL)) {
> + reg |= SUN6I_LOSC_CTRL_EXT_OSC;
> + if (rtc->data->has_losc_en)
> + reg |= SUN6I_LOSC_CTRL_EXT_LOSC_EN;
> + }
> writel(reg, rtc->base + SUN6I_LOSC_CTRL);
>
> /* Yes, I know, this is ugly. */
> sun6i_rtc = rtc;
>
> - /* Deal with old DTs */
> - if (!of_get_property(node, "clocks", NULL))
> - goto err;
> -

Doesn't that prevent the parents to be properly set if there's an
external crystal?

Maxime

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