Re: [PATCH 1/2] rtc: sun6i: Make external 32k oscillator optional
From: Maxime Ripard <hidden>
Date: 2020-02-14 08:14:48
Also in:
linux-devicetree, linux-rtc, lkml
Hi Jernej, Thanks for taking care of this On Thu, Feb 13, 2020 at 10:14:26PM +0100, Jernej Skrabec wrote:
quoted hunk ↗ jump to hunk
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 <redacted> --- 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