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From: "Marek Behún" <marek.behun@nic.cz>
To: Stefan Roese <sr@denx.de>
Cc: "Pali Rohár" <pali@kernel.org>, u-boot@lists.denx.de
Subject: Re: [PATCH v2] arm: mvebu: a37xx: Define CONFIG_SYS_REF_CLK and use it instead of get_ref_clk()
Date: Tue, 17 Aug 2021 14:50:10 +0200	[thread overview]
Message-ID: <20210817145010.32f295f5@thinkpad> (raw)
In-Reply-To: <c9b895bb-ed1b-12e7-42c0-dd73b6be2b9d@denx.de>

> > +#elif defined(CONFIG_ARMADA_3700)
> > +/* SAR values for Armada 3700 */
> > +#define MVEBU_TEST_PIN_LATCH_N	MVEBU_REGISTER(0x13808)
> > +#define MVEBU_XTAL_MODE_MASK	BIT(9)
> > +#define CONFIG_SYS_REF_CLK	((readl(MVEBU_TEST_PIN_LATCH_N) & MVEBU_XTAL_MODE_MASK) ? \
> > +				 40000000 : 25000000)

Stefan,

we discussed this with Pali yesterday. For now, I am okay with it, but
I consider this bad design.

This either should be done via the clk API or, if we insist on keeping
it simple, via a static inline function, with caching via a static
variable, so that the register needs to be read only once (at least for
each compilation unit).

Regarding the clk API kernel has driver for armada-37xx-xtal. But I am
thinking about expanding the clk-fixed-mmio driver so that it would be
more generic and could be used for this.

What do you think?

Marek

  reply	other threads:[~2021-08-17 12:50 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-08-11 18:53 [PATCH 1/2] arm: mvebu: axp: Properly check for Armada XP in mach/soc.h Pali Rohár
2021-08-11 18:53 ` [PATCH 2/2] arm: mvebu: a37xx: Define CONFIG_SYS_REF_CLK and use it instead of get_ref_clk() Pali Rohár
2021-08-16 10:02   ` [PATCH v2] " Pali Rohár
2021-08-17  7:47     ` Stefan Roese
2021-08-17 12:50       ` Marek Behún [this message]
2021-08-17 12:56         ` Stefan Roese
2021-09-01  9:12     ` Stefan Roese
2021-09-01 12:14       ` Tom Rini
2021-09-01 12:32         ` Pali Rohár
2021-09-01 12:35           ` Tom Rini
2021-09-01 12:40             ` Pali Rohár
2021-09-01 12:41               ` Tom Rini
2021-09-01 12:46                 ` Pali Rohár
2021-09-01 12:58                   ` Tom Rini
2021-09-01 12:56                 ` Tom Rini
2021-08-16  7:58 ` [PATCH 1/2] arm: mvebu: axp: Properly check for Armada XP in mach/soc.h Stefan Roese
2021-09-01  9:09 ` Stefan Roese

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