From mboxrd@z Thu Jan 1 00:00:00 1970 From: maxime.ripard@bootlin.com (Maxime Ripard) Date: Wed, 28 Nov 2018 11:25:50 +0100 Subject: [PATCH 09/15] clk: sunxi-ng: r40: Force LOSC parent to RTC LOSC output In-Reply-To: <20181128093013.24442-11-wens@csie.org> References: <20181128093013.24442-1-wens@csie.org> <20181128093013.24442-11-wens@csie.org> Message-ID: <20181128102550.qsipssx67y3uexsr@flea> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Wed, Nov 28, 2018 at 05:30:07PM +0800, Chen-Yu Tsai wrote: > On the R40, in addition to a mux between the RTC's own RC oscillator and > an external 32768 Hz crystal, which are muxed inside the RTC module, the > CCU also has its own RC oscillator, which runs at around 2 MHz, and can > be muxed with the LOSC output from the RTC. This muxed output is called > "SYS 32K" in the module clock diagram, but otherwise referred to as the > LOSC throughout the CCU documentation. > > The RC oscillator is not very accurate, even though it has an undocumented > calibration function. We really want a precise clock at 32768 Hz, > instead of something at around 32 KHz. This patch forces the SYS 32K > clock to use the RTC output as its parent, and doesn't bother > registering the internal oscillator nor a clock mux. > > Signed-off-by: Chen-Yu Tsai Acked-by: Maxime Ripard Maxime -- Maxime Ripard, Bootlin Embedded Linux and Kernel engineering https://bootlin.com -------------- next part -------------- A non-text attachment was scrubbed... Name: signature.asc Type: application/pgp-signature Size: 228 bytes Desc: not available URL: