Dne sobota, 24. avgust 2019 ob 15:05:44 CEST je Ondřej Jirman napisal(a):

On Sat, Aug 24, 2019 at 02:51:54PM +0200, Jernej Škrabec wrote:

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Dne sobota, 24. avgust 2019 ob 14:46:54 CEST je Ondřej Jirman napisal(a):

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Hi,

On Sat, Aug 24, 2019 at 02:32:32PM +0200, Jernej Škrabec wrote:

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Hi!

Dne torek, 20. avgust 2019 ob 17:19:33 CEST je megous@megous.com

napisal(a):

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From: Ondrej Jirman <redacted>

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 <redacted>
Reviewed-by: Chen-Yu Tsai <redacted>
---

 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 d50ee023b559..b0c3752bed3f 100644
--- a/drivers/rtc/rtc-sun6i.c
+++ b/drivers/rtc/rtc-sun6i.c

@@ -32,9 +32,11 @@

 /* Control register */
 #define SUN6I_LOSC_CTRL				0x0000
 #define SUN6I_LOSC_CTRL_KEY			(0x16aa 

<< 16)

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+#define SUN6I_LOSC_CTRL_AUTO_SWT_BYPASS		BIT(15)

User manual says that above field is bit 14.

See the previous discussion, this is from BSP.

I have two versions of BSP (don't ask me which) which have this set as bit
14 and changing this to 14 actually solves all my problems with LOSC (no
more issues with setting RTC and HDMI-CEC works now - it uses LOSC as
parent) on Tanix TX6 box.

Interesting. Is LOSC fed externally generated clock, or is it setup as a
crystal oscillator on your board?

I really don't know, but here is DT: http://ix.io/1ThI

Anyway, see here:

https://megous.com/git/linux/tree/drivers/rtc/rtc-sunxi.h?h=h6-4.9-bsp#n649
https://megous.com/git/linux/tree/drivers/rtc/rtc-sunxi.c?h=h6-4.9-bsp#n652

Interesting, 4.9 BSP has additional bit definition, which is not documented in 
manual and 3.10 BSP to which I refer.

I was referring to 3.10 BSP, which uses only bit 14. I thought that you named 
it differently.

It would be nice to know what's really happening.

My output is:

[    0.832252] sun6i-rtc 7000000.rtc: registered as rtc0
[    0.832257] sun6i-rtc 7000000.rtc: RTC enabled
[    1.728968] sun6i-rtc 7000000.rtc: setting system clock to
1970-01-01T00:00:07 UTC (7)

With change, I get same output.

I think, you may have just enabled the auto switch feature, and running the
clock from low precision RC oscillator with your patch.

True, now I think there is no external crystal, but I'm still not sure how to 
confirm that.

The real issue probably is that the mainline driver is missing this:

https://megous.com/git/linux/tree/drivers/rtc/rtc-sunxi.c?h=h6-4.9-bsp#n650

Not sure what you mean by that. ext vs. int source selection?

Best regards,
Jernej

regards,
	o.

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Best regards,
Jernej

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regards,

	o.
	

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Best regards,
Jernej

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 #define SUN6I_LOSC_CTRL_ALM_DHMS_ACC		BIT(9)
 #define SUN6I_LOSC_CTRL_RTC_HMS_ACC		BIT(8)
 #define SUN6I_LOSC_CTRL_RTC_YMD_ACC		BIT(7)

+#define SUN6I_LOSC_CTRL_EXT_LOSC_EN		BIT(4)

 #define SUN6I_LOSC_CTRL_EXT_OSC			BIT(0)
 #define SUN6I_LOSC_CTRL_ACC_MASK		GENMASK(9, 7)

@@ -128,6 +130,8 @@ struct sun6i_rtc_clk_data {

 	unsigned int has_prescaler : 1;
 	unsigned int has_out_clk : 1;
 	unsigned int export_iosc : 1;

+	unsigned int has_losc_en : 1;
+	unsigned int has_auto_swt : 1;

 };
 
 struct sun6i_rtc_dev {

@@ -190,6 +194,10 @@ static int sun6i_rtc_osc_set_parent(struct

clk_hw
*hw,
u8 index) val &= ~SUN6I_LOSC_CTRL_EXT_OSC;

 	val |= SUN6I_LOSC_CTRL_KEY;
 	val |= index ? SUN6I_LOSC_CTRL_EXT_OSC : 0;

+	if (rtc->data->has_losc_en) {
+		val &= ~SUN6I_LOSC_CTRL_EXT_LOSC_EN;
+		val |= index ? SUN6I_LOSC_CTRL_EXT_LOSC_EN : 0;
+	}

 	writel(val, rtc->base + SUN6I_LOSC_CTRL);
 	spin_unlock_irqrestore(&rtc->lock, flags);

@@ -215,6 +223,7 @@ static void __init sun6i_rtc_clk_init(struct

device_node *node, const char *iosc_name = "rtc-int-osc";

 	const char *clkout_name = "osc32k-out";
 	const char *parents[2];

+	u32 reg;

 	rtc = kzalloc(sizeof(*rtc), GFP_KERNEL);
 	if (!rtc)

@@ -235,9 +244,18 @@ static void __init sun6i_rtc_clk_init(struct

device_node *node, goto err;

 	}

+	reg = SUN6I_LOSC_CTRL_KEY;
+	if (rtc->data->has_auto_swt) {
+		/* Bypass auto-switch to int osc, on ext losc failure

*/

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+		reg |= SUN6I_LOSC_CTRL_AUTO_SWT_BYPASS;
+		writel(reg, rtc->base + SUN6I_LOSC_CTRL);
+	}
+

 	/* Switch to the external, more precise, oscillator */

-	writel(SUN6I_LOSC_CTRL_KEY | SUN6I_LOSC_CTRL_EXT_OSC,
-	       rtc->base + SUN6I_LOSC_CTRL);
+	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;

@@ -345,6 +363,23 @@ CLK_OF_DECLARE_DRIVER(sun8i_h3_rtc_clk,

"allwinner,sun8i-h3-rtc", CLK_OF_DECLARE_DRIVER(sun50i_h5_rtc_clk,
"allwinner,sun50i-h5-rtc", sun8i_h3_rtc_clk_init);

+static const struct sun6i_rtc_clk_data sun50i_h6_rtc_data = {
+	.rc_osc_rate = 16000000,
+	.fixed_prescaler = 32,
+	.has_prescaler = 1,
+	.has_out_clk = 1,
+	.export_iosc = 1,
+	.has_losc_en = 1,
+	.has_auto_swt = 1,
+};
+
+static void __init sun50i_h6_rtc_clk_init(struct device_node *node)
+{
+	sun6i_rtc_clk_init(node, &sun50i_h6_rtc_data);
+}
+CLK_OF_DECLARE_DRIVER(sun50i_h6_rtc_clk, "allwinner,sun50i-h6-rtc",
+		      sun50i_h6_rtc_clk_init);
+

 static const struct sun6i_rtc_clk_data sun8i_v3_rtc_data = {
 
 	.rc_osc_rate = 32000,
 	.has_out_clk = 1,

@@ -675,6 +710,7 @@ static const struct of_device_id

sun6i_rtc_dt_ids[]
= {

 	{ .compatible = "allwinner,sun8i-r40-rtc" },
 	{ .compatible = "allwinner,sun8i-v3-rtc" },
 	{ .compatible = "allwinner,sun50i-h5-rtc" },

+	{ .compatible = "allwinner,sun50i-h6-rtc" },

 	{ /* sentinel */ },
 
 };
 MODULE_DEVICE_TABLE(of, sun6i_rtc_dt_ids);

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