linux-kernel - Re: [PATCH v2 1/1] drivers/rtc: rtc-sun6i: AutoCal Internal OSC Clock

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Message-ID: <6035510.lOV4Wx5bFT@jernej-laptop>
Date: Sun, 21 Apr 2024 21:57:24 +0200
From: Jernej Škrabec <jernej.skrabec@...il.com>
To: a.zummo@...ertech.it, Alois Fertl <a.fertl@...nline.de>
Cc: alexandre.belloni@...tlin.com, wens@...e.org, samuel@...lland.org,
 linux-rtc@...r.kernel.org, linux-sunxi@...ts.linux.dev,
 linux-kernel@...r.kernel.org, a.fertl@...nline.de
Subject: Re: [PATCH v2 1/1] drivers/rtc: rtc-sun6i: AutoCal Internal OSC Clock

Dne nedelja, 21. april 2024 ob 20:36:33 GMT +2 je Alois Fertl napisal(a):
> I have a M98-8K PLUS Magcubic TV-Box based on the Allwinner H618 SOC.
> On board is a Sp6330 wifi/bt module that requires a 32kHz clock to
> operate correctly. Without this change the clock from the SOC is
> ~29kHz and BT module does not start up. The patch enables the Internal
> OSC Clock Auto Calibration of the H616/H618 which than provides the
> necessary 32kHz and the BT module initializes successfully.
> Add a flag and set it for H6 AND H616. The H618 is the same as H616
> regarding rtc.
> 
> v1->v2
> - add flag and activate for H6 AND H616

Please move changelog below --- line.

> 
> Signed-off-by: Alois Fertl <a.fertl@...nline.de>
> ---
>  drivers/rtc/rtc-sun6i.c | 16 +++++++++++++++-
>  1 file changed, 15 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/rtc/rtc-sun6i.c b/drivers/rtc/rtc-sun6i.c
> index e0b85a0d5645..5d0c917b2099 100644
> --- a/drivers/rtc/rtc-sun6i.c
> +++ b/drivers/rtc/rtc-sun6i.c
> @@ -42,6 +42,11 @@
>  
>  #define SUN6I_LOSC_CLK_PRESCAL			0x0008
>  
> +#define SUN6I_LOSC_CLK_AUTO_CAL			0x000c
> +#define SUN6I_LOSC_CLK_AUTO_CAL_16MS		BIT(2)
> +#define SUN6I_LOSC_CLK_AUTO_CAL_EANABLE		BIT(1)

EANABLE -> ENABLE

> +#define SUN6I_LOSC_CLK_AUTO_CAL_SEL_CAL		BIT(0)
> +
>  /* RTC */
>  #define SUN6I_RTC_YMD				0x0010
>  #define SUN6I_RTC_HMS				0x0014
> @@ -126,7 +131,6 @@
>   *     registers (R40, H6)
>   *   - SYS power domain controls (R40)
>   *   - DCXO controls (H6)
> - *   - RC oscillator calibration (H6)
>   *
>   * These functions are not covered by this driver.
>   */
> @@ -138,6 +142,7 @@ struct sun6i_rtc_clk_data {
>  	unsigned int has_losc_en : 1;
>  	unsigned int has_auto_swt : 1;
>  	unsigned int no_ext_losc : 1;
> +	unsigned int has_auto_cal : 1;
>  };
>  
>  #define RTC_LINEAR_DAY	BIT(0)
> @@ -268,6 +273,13 @@ static void __init sun6i_rtc_clk_init(struct device_node *node,
>  	}
>  	writel(reg, rtc->base + SUN6I_LOSC_CTRL);
>  
> +	if (rtc->data->has_auto_cal) {
> +		/* Enable internal OSC clock auto calibration */
> +		reg = (SUN6I_LOSC_CLK_AUTO_CAL_16MS | SUN6I_LOSC_CLK_AUTO_CAL_EANABLE |
> +				SUN6I_LOSC_CLK_AUTO_CAL_SEL_CAL);

Remove parenthesis and fix indentation. Since macro names are pretty long,
maybe put one per line.

Is this safe to be done even on the boards with external 32k crystal?

Best regards,
Jernej

> +		writel(reg, rtc->base + SUN6I_LOSC_CLK_AUTO_CAL);
> +	}
> +
>  	/* Yes, I know, this is ugly. */
>  	sun6i_rtc = rtc;
>  
> @@ -380,6 +392,7 @@ static const struct sun6i_rtc_clk_data sun50i_h6_rtc_data = {
>  	.has_out_clk = 1,
>  	.has_losc_en = 1,
>  	.has_auto_swt = 1,
> +	.has_auto_cal = 1,
>  };
>  
>  static void __init sun50i_h6_rtc_clk_init(struct device_node *node)
> @@ -395,6 +408,7 @@ static const struct sun6i_rtc_clk_data sun50i_h616_rtc_data = {
>  	.has_prescaler = 1,
>  	.has_out_clk = 1,
>  	.no_ext_losc = 1,
> +	.has_auto_cal = 1,
>  };
>  
>  static void __init sun50i_h616_rtc_clk_init(struct device_node *node)
>