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SubjectRe: [linux-sunxi] [PATCH v2 2/3] rtc: sun6i: Add support for H6 RTC
Hi,

On Sat, Aug 24, 2019 at 02:32:32PM +0200, Jernej Škrabec wrote:
> Hi!
>
> Dne torek, 20. avgust 2019 ob 17:19:33 CEST je megous@megous.com napisal(a):
> > 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>
> > Reviewed-by: Chen-Yu Tsai <wens@csie.org>
> > ---
> > 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)
> > +#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.

regards,
o.

> Best regards,
> Jernej
>
> > #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 */
> > + 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);
>
>
>
>
>
> _______________________________________________
> linux-arm-kernel mailing list
> linux-arm-kernel@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

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