Re: [linux-sunxi] [PATCH 2/3] rtc: sun6i: Add support for H6 RTC

[Chen-Yu Tsai <wens@csie.org>]

On Fri, Apr 12, 2019 at 8:07 PM megous via linux-sunxi
<linux-sunxi@googlegroups.com> wrote:
>
> From: Ondrej Jirman <megous@megous.com>
>
> RTC on H6 is mostly the same as on H5 and H3. It has slight differences
> mostly in features that are not yet supported by this driver.
>
> Some differences are already stated in the comments in existing code.
> One other difference is that H6 has extra bit in LOSC_CTRL_REG, called
> EXT_LOSC_EN to enable/disable external low speed crystal oscillator.
>
> It also has bit EXT_LOSC_STA in LOSC_AUTO_SWT_STA_REG, to check whether
> external low speed oscillator is working correctly.
>
> This patch adds support for enabling LOSC when necessary:
>
> - during reparenting
> - when probing the clock
>
> H6 also has capacbility to automatically reparent RTC clock from
> external crystal oscillator, to internal RC oscillator, if external
> oscillator fails. This is enabled by default. Disable it during
> probe.
>
> Signed-off-by: Ondrej Jirman <megous@megous.com>
> ---
>  drivers/rtc/rtc-sun6i.c | 40 ++++++++++++++++++++++++++++++++++++++--
>  1 file changed, 38 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/rtc/rtc-sun6i.c b/drivers/rtc/rtc-sun6i.c
> index 11f56de52179..7375a530c565 100644
> --- a/drivers/rtc/rtc-sun6i.c
> +++ b/drivers/rtc/rtc-sun6i.c
> @@ -41,9 +41,11 @@
>  /* Control register */
>  #define SUN6I_LOSC_CTRL                                0x0000
>  #define SUN6I_LOSC_CTRL_KEY                    (0x16aa << 16)
> +#define SUN6I_LOSC_CTRL_AUTO_SWT_BYPASS                BIT(15)

Manual says bit 14? Or is this different from LOSC_AUTO_SWT_EN?

The rest looks ok.

ChenYu