Re: [linux-sunxi] [PATCH 2/3] rtc: sun6i: Add support for H6 RTC
From: Chen-Yu Tsai
Date: Mon Aug 05 2019 - 06:16:36 EST
On Fri, Apr 12, 2019 at 8:07 PM megous via linux-sunxi
> From: Ondrej Jirman <megous@xxxxxxxxxx>
> 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
> Signed-off-by: Ondrej Jirman <megous@xxxxxxxxxx>
> 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.