From: Andre Przywara <andre.przywara@arm.com>
To: Ludwig Kormann <ludwig.kormann@ict42.de>,
"linux-sunxi@lists.linux.dev" <linux-sunxi@lists.linux.dev>
Cc: jagan@amarulasolutions.com, trini@konsulko.com, u-boot@lists.denx.de
Subject: Re: [PATCH 1/1] sunxi: sun4i: add missing sdelay() to clock_init_safe()
Date: Thu, 1 Feb 2024 16:24:44 +0000 [thread overview]
Message-ID: <20240201162444.1cf81b0b@donnerap.manchester.arm.com> (raw)
In-Reply-To: <20240201084550.200913-1-ludwig.kormann@ict42.de>
On Thu, 1 Feb 2024 09:45:50 +0100
Ludwig Kormann <ludwig.kormann@ict42.de> wrote:
Hi,
> This delay is required after switching the clock source.
>
> See “A20 Reference manual v1.4” Page 50 / section
> “1.5.4.16. CPU/AHB/APB0 CLOCK RATIO”: “If the clock
> source is changed, at most to wait for 8 present running
> clock cycles.”
>
> This is already implemented in clock_set_pll1(), but was
> still missing in clock_init_safe().
>
> Signed-off-by: Ludwig Kormann <ludwig.kormann@ict42.de>
Good catch, thanks for sending this!
Reviewed-by: Andre Przywara <andre.przywara@arm.com>
Cheers,
Andre
> ---
> arch/arm/mach-sunxi/clock_sun4i.c | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/arch/arm/mach-sunxi/clock_sun4i.c b/arch/arm/mach-sunxi/clock_sun4i.c
> index 8f1d1b65f0..ac3b7a801f 100644
> --- a/arch/arm/mach-sunxi/clock_sun4i.c
> +++ b/arch/arm/mach-sunxi/clock_sun4i.c
> @@ -25,6 +25,7 @@ void clock_init_safe(void)
> APB0_DIV_1 << APB0_DIV_SHIFT |
> CPU_CLK_SRC_OSC24M << CPU_CLK_SRC_SHIFT,
> &ccm->cpu_ahb_apb0_cfg);
> + sdelay(20);
> writel(PLL1_CFG_DEFAULT, &ccm->pll1_cfg);
> sdelay(200);
> writel(AXI_DIV_1 << AXI_DIV_SHIFT |
> @@ -32,6 +33,7 @@ void clock_init_safe(void)
> APB0_DIV_1 << APB0_DIV_SHIFT |
> CPU_CLK_SRC_PLL1 << CPU_CLK_SRC_SHIFT,
> &ccm->cpu_ahb_apb0_cfg);
> + sdelay(20);
> #ifdef CONFIG_MACH_SUN7I
> setbits_le32(&ccm->ahb_gate0, 0x1 << AHB_GATE_OFFSET_DMA);
> #endif
parent reply other threads:[~2024-02-01 16:24 UTC|newest]
Thread overview: expand[flat|nested] mbox.gz Atom feed
[parent not found: <20240201084550.200913-1-ludwig.kormann@ict42.de>]
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