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From: "Jernej Škrabec" <jernej.skrabec@gmail.com>
To: Maxime Ripard <maxime@cerno.tech>
Cc: Icenowy Zheng <icenowy@sipeed.com>,
	Rob Herring <robh+dt@kernel.org>, Chen-Yu Tsai <wens@csie.org>,
	Ulf Hansson <ulf.hansson@linaro.org>,
	Linus Walleij <linus.walleij@linaro.org>,
	Alexandre Belloni <alexandre.belloni@bootlin.com>,
	Andre Przywara <andre.przywara@arm.com>,
	Samuel Holland <samuel@sholland.org>,
	devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
	linux-sunxi@lists.linux.dev, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 10/17] clk: sunxi=ng: add support for R329 R-CCU
Date: Wed, 25 Aug 2021 17:03:30 +0200	[thread overview]
Message-ID: <3221818.pD4rYpbbZ1@jernej-laptop> (raw)
In-Reply-To: <20210825145027.ixc7wnh3x5w6wzny@gilmour>

Dne sreda, 25. avgust 2021 ob 16:50:27 CEST je Maxime Ripard napisal(a):
> Hi,
> 
> On Fri, Aug 20, 2021 at 06:34:38AM +0200, Jernej Škrabec wrote:
> > > > +static void __init sun50i_r329_r_ccu_setup(struct device_node *node)
> > > > +{
> > > > +	void __iomem *reg;
> > > > +	u32 val;
> > > > +	int i;
> > > > +
> > > > +	reg = of_io_request_and_map(node, 0, of_node_full_name(node));
> > > > +	if (IS_ERR(reg)) {
> > > > +		pr_err("%pOF: Could not map clock registers\n", node);
> > > > +		return;
> > > > +	}
> > > > +
> > > > +	/* Enable the lock bits and the output enable bits on all PLLs */
> > > > +	for (i = 0; i < ARRAY_SIZE(pll_regs); i++) {
> > > > +		val = readl(reg + pll_regs[i]);
> > > > +		val |= BIT(29) | BIT(27);
> > > > +		writel(val, reg + pll_regs[i]);
> > > > +	}
> > > > +
> > > > +	/*
> > > > +	 * Force the I/O dividers of PLL-AUDIO1 to reset default value
> > > > +	 *
> > > > +	 * See the comment before pll-audio1 definition for the reason.
> > > > +	 */
> > > > +
> > > > +	val = readl(reg + SUN50I_R329_PLL_AUDIO1_REG);
> > > > +	val &= ~BIT(1);
> > > > +	val |= BIT(0);
> > > > +	writel(val, reg + SUN50I_R329_PLL_AUDIO1_REG);
> > > > +
> > > > +	i = sunxi_ccu_probe(node, reg, &sun50i_r329_r_ccu_desc);
> > > > +	if (i)
> > > > +		pr_err("%pOF: probing clocks fails: %d\n", node, i);
> > > > +}
> > > > +
> > > > +CLK_OF_DECLARE(sun50i_r329_r_ccu, "allwinner,sun50i-r329-r-ccu",
> > > > +	       sun50i_r329_r_ccu_setup);
> > > 
> > > Please make this a platform driver. There is no particular reason why it
> > > needs to be an early OF clock provider.
> > 
> > Why? It's good to have it as early clock provider. It has no dependencies
> > and other drivers that depends on it, like IR, can be deferred, if this
> > is loaded later.
> 
> No, Samuel is right, we should make them regular drivers as much as we
> can.
> 
> The reason we had CLK_OF_DECLARE in the first place is that timers
> usually have a parent clock, and you need the timers before the device
> model is set up.
> 
> Fortunately for us, since the A20, the architected timers don't require
> a parent clock from us, and we can thus boot up fine.

There are other timers. A lot of SoCs, newer than A20 (like H6), have High 
Speed Timer, which requires parent clock to be enabled. We just choose not to 
add node for it to DT, even if it's there and driver already exists.

Best regards,
Jernej

> 
> Since the dependencies are minimal, it should probe fairly early and
> with the on-demand probing from the device links you might not even tell
> the difference for most consumers.
> 
> Maxime





  reply	other threads:[~2021-08-25 15:03 UTC|newest]

Thread overview: 51+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-08-02  6:21 [PATCH 00/17] Basical Allwinner R329 support Icenowy Zheng
2021-08-02  6:21 ` [PATCH 01/17] rtc: sun6i: Fix time overflow handling Icenowy Zheng
2021-08-02  6:21 ` [PATCH 02/17] rtc: sun6i: Add support for linear day storage Icenowy Zheng
2021-08-02  6:21 ` [PATCH 03/17] rtc: sun6i: Add support for broken-down alarm registers Icenowy Zheng
2021-08-02  6:21 ` [PATCH 04/17] dt-bindings: rtc: sun6i: add compatible string for R329 RTC Icenowy Zheng
2021-08-06 21:39   ` Rob Herring
2021-08-02  6:22 ` [PATCH 05/17] rtc: sun6i: add support " Icenowy Zheng
2021-08-02  6:22 ` [PATCH 06/17] dt-bindings: pinctrl: document Allwinner R329 PIO and R-PIO Icenowy Zheng
2021-08-06 21:40   ` Rob Herring
2021-08-18  8:48   ` Maxime Ripard
2021-08-19  2:40   ` Samuel Holland
2021-08-02  6:22 ` [PATCH 07/17] pinctrl: sunxi: add support for R329 CPUX pin controller Icenowy Zheng
2021-08-11  9:23   ` Linus Walleij
2021-08-18  8:48   ` Maxime Ripard
2021-08-19  3:09   ` Samuel Holland
2021-08-02  6:22 ` [PATCH 08/17] pinctrl: sunxi: add support for R329 R-PIO " Icenowy Zheng
2021-08-18  8:52   ` Maxime Ripard
2021-08-19  3:22   ` Samuel Holland
2021-08-02  6:22 ` [PATCH 09/17] dt-bindings: clock: sunxi-ng: add compatibles for R329 CCUs Icenowy Zheng
2021-08-06 21:41   ` Rob Herring
2021-08-02  6:22 ` [PATCH 10/17] clk: sunxi=ng: add support for R329 R-CCU Icenowy Zheng
2021-08-06 21:42   ` Rob Herring
2021-08-18  8:50   ` Maxime Ripard
2021-08-20  0:55   ` Samuel Holland
2021-08-20  4:34     ` Jernej Škrabec
2021-08-25 14:50       ` Maxime Ripard
2021-08-25 15:03         ` Jernej Škrabec [this message]
2021-08-25 15:37           ` Maxime Ripard
2021-08-26  0:20       ` Samuel Holland
2021-08-02  6:22 ` [PATCH 11/17] clk: sunxi-ng: add support for Allwinner R329 CCU Icenowy Zheng
2021-08-06 21:42   ` Rob Herring
2021-08-20  2:41   ` Samuel Holland
2021-08-25 14:54     ` Maxime Ripard
2021-08-02  6:22 ` [PATCH 12/17] dt-bindings: mmc: sunxi-mmc: add R329 MMC compatible string Icenowy Zheng
2021-08-06 21:42   ` Rob Herring
2021-08-18  8:47   ` Maxime Ripard
2021-08-02  6:22 ` [PATCH 13/17] mmc: sunxi: add support for R329 MMC controllers Icenowy Zheng
2021-08-18  8:47   ` Maxime Ripard
2021-08-20  2:43   ` Samuel Holland
2021-08-02  6:22 ` [PATCH 14/17] dt-bindings: arm: sunxi: add compatible strings for Sipeed MaixSense Icenowy Zheng
2021-08-06 21:43   ` Rob Herring
2021-08-18  9:03   ` Maxime Ripard
2021-08-02  6:22 ` [PATCH 15/17] arm64: allwinner: dts: add DTSI file for R329 SoC Icenowy Zheng
2021-08-18  9:01   ` Maxime Ripard
     [not found]     ` <74F51516-2470-4A49-972B-E19D8EDD9A3D@sipeed.com>
2021-08-19  2:32       ` Samuel Holland
2021-08-20  3:06         ` Samuel Holland
2021-08-25 15:00           ` Maxime Ripard
2021-08-20  2:59   ` Samuel Holland
2021-08-02  6:22 ` [PATCH 16/17] arm64: allwinner: dts: r329: add DTSI file for Sipeed Maix IIA Icenowy Zheng
2021-08-02  6:22 ` [PATCH 17/17] arm64: allwinner: dts: r329: add support for Sipeed MaixSense Icenowy Zheng
2021-08-10 11:04 ` [PATCH 00/17] Basical Allwinner R329 support Ulf Hansson

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