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From: Sasha Levin <sashal@kernel.org>
To: linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc: Sasha Levin <sashal@kernel.org>,
	devicetree@vger.kernel.org,
	Andre Przywara <andre.przywara@arm.com>,
	Liviu Dudau <liviu.dudau@arm.com>,
	Sudeep Holla <sudeep.holla@arm.com>,
	linux-arm-kernel@lists.infradead.org
Subject: [PATCH AUTOSEL 4.9 249/251] arm64: dts: juno: Fix UART frequency
Date: Thu, 16 Jan 2020 12:36:38 -0500
Message-ID: <20200116173641.22137-209-sashal@kernel.org> (raw)
In-Reply-To: <20200116173641.22137-1-sashal@kernel.org>

From: Andre Przywara <andre.przywara@arm.com>

[ Upstream commit 39a1a8941b27c37f79508426e27a2ec29829d66c ]

Older versions of the Juno *SoC* TRM [1] recommended that the UART clock
source should be 7.2738 MHz, whereas the *system* TRM [2] stated a more
correct value of 7.3728 MHz. Somehow the wrong value managed to end up in
our DT.

Doing a prime factorisation, a modulo divide by 115200 and trying
to buy a 7.2738 MHz crystal at your favourite electronics dealer suggest
that the old value was actually a typo. The actual UART clock is driven
by a PLL, configured via a parameter in some board.txt file in the
firmware, which reads 7.37 MHz (sic!).

Fix this to correct the baud rate divisor calculation on the Juno board.

[1] http://infocenter.arm.com/help/topic/com.arm.doc.ddi0515b.b/DDI0515B_b_juno_arm_development_platform_soc_trm.pdf
[2] http://infocenter.arm.com/help/topic/com.arm.doc.100113_0000_07_en/arm_versatile_express_juno_development_platform_(v2m_juno)_technical_reference_manual_100113_0000_07_en.pdf

Fixes: 71f867ec130e ("arm64: Add Juno board device tree.")
Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Acked-by: Liviu Dudau <liviu.dudau@arm.com>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 arch/arm64/boot/dts/arm/juno-clocks.dtsi | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/arm64/boot/dts/arm/juno-clocks.dtsi b/arch/arm64/boot/dts/arm/juno-clocks.dtsi
index 25352ed943e6..00bcbf7688c7 100644
--- a/arch/arm64/boot/dts/arm/juno-clocks.dtsi
+++ b/arch/arm64/boot/dts/arm/juno-clocks.dtsi
@@ -8,10 +8,10 @@
  */
 
 	/* SoC fixed clocks */
-	soc_uartclk: refclk7273800hz {
+	soc_uartclk: refclk7372800hz {
 		compatible = "fixed-clock";
 		#clock-cells = <0>;
-		clock-frequency = <7273800>;
+		clock-frequency = <7372800>;
 		clock-output-names = "juno:uartclk";
 	};
 
-- 
2.20.1


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Thread overview: 34+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-01-16 17:33 [PATCH AUTOSEL 4.9 041/251] media: s5p-jpeg: Correct step and max values for V4L2_CID_JPEG_RESTART_INTERVAL Sasha Levin
2020-01-16 17:33 ` [PATCH AUTOSEL 4.9 043/251] ASoC: imx-sgtl5000: put of nodes if finding codec fails Sasha Levin
2020-01-16 17:33 ` [PATCH AUTOSEL 4.9 046/251] clk: sunxi-ng: sun8i-a23: Enable PLL-MIPI LDOs when ungating it Sasha Levin
2020-01-16 17:33 ` [PATCH AUTOSEL 4.9 050/251] ARM: dts: lpc32xx: add required clocks property to keypad device node Sasha Levin
2020-01-16 17:33 ` [PATCH AUTOSEL 4.9 051/251] ARM: dts: lpc32xx: reparent keypad controller to SIC1 Sasha Levin
2020-01-16 17:33 ` [PATCH AUTOSEL 4.9 052/251] ARM: dts: lpc32xx: fix ARM PrimeCell LCD controller variant Sasha Levin
2020-01-16 17:33 ` [PATCH AUTOSEL 4.9 053/251] ARM: dts: lpc32xx: fix ARM PrimeCell LCD controller clocks property Sasha Levin
2020-01-16 17:33 ` [PATCH AUTOSEL 4.9 054/251] ARM: dts: lpc32xx: phy3250: fix SD card regulator voltage Sasha Levin
2020-01-16 17:33 ` [PATCH AUTOSEL 4.9 058/251] thermal: mediatek: fix register index error Sasha Levin
2020-01-16 17:33 ` [PATCH AUTOSEL 4.9 085/251] clocksource/drivers/sun5i: Fail gracefully when clock rate is unavailable Sasha Levin
2020-01-16 17:33 ` [PATCH AUTOSEL 4.9 086/251] clocksource/drivers/exynos_mct: Fix error path in timer resources initialization Sasha Levin
2020-01-16 17:33 ` [PATCH AUTOSEL 4.9 087/251] mmc: sdhci-brcmstb: handle mmc_of_parse() errors during probe Sasha Levin
2020-01-16 17:33 ` [PATCH AUTOSEL 4.9 088/251] ARM: 8847/1: pm: fix HYP/SVC mode mismatch when MCPM is used Sasha Levin
2020-01-16 17:33 ` [PATCH AUTOSEL 4.9 089/251] ARM: 8848/1: virt: Align GIC version check with arm64 counterpart Sasha Levin
2020-01-16 17:34 ` [PATCH AUTOSEL 4.9 104/251] ARM: OMAP2+: Fix potentially uninitialized return value for _setup_reset() Sasha Levin
2020-01-16 17:34 ` [PATCH AUTOSEL 4.9 110/251] soc/fsl/qe: Fix an error code in qe_pin_request() Sasha Levin
2020-01-16 17:34 ` [PATCH AUTOSEL 4.9 111/251] spi: bcm2835aux: fix driver to not allow 65535 (=-1) cs-gpios Sasha Levin
2020-01-16 17:34 ` [PATCH AUTOSEL 4.9 114/251] ARM: pxa: ssp: Fix "WARNING: invalid free of devm_ allocated data" Sasha Levin
2020-01-16 17:34 ` [PATCH AUTOSEL 4.9 118/251] ARM: dts: ls1021: Fix SGMII PCS link remaining down after PHY disconnect Sasha Levin
2020-01-16 17:34 ` [PATCH AUTOSEL 4.9 138/251] pwm: meson: Don't disable PWM when setting duty repeatedly Sasha Levin
2020-01-16 17:34 ` [PATCH AUTOSEL 4.9 139/251] ARM: riscpc: fix lack of keyboard interrupts after irq conversion Sasha Levin
2020-01-16 17:34 ` [PATCH AUTOSEL 4.9 146/251] serial: stm32: fix transmit_chars when tx is stopped Sasha Levin
2020-01-16 17:35 ` [PATCH AUTOSEL 4.9 184/251] ASoC: sun4i-i2s: RX and TX counter registers are swapped Sasha Levin
2020-01-16 17:35 ` [PATCH AUTOSEL 4.9 205/251] net: stmmac: dwmac-meson8b: Fix signedness bug in probe Sasha Levin
2020-01-16 17:35 ` [PATCH AUTOSEL 4.9 207/251] net: ethernet: stmmac: Fix signedness bug in ipq806x_gmac_of_parse() Sasha Levin
2020-01-16 17:35 ` [PATCH AUTOSEL 4.9 210/251] net: stmmac: gmac4+: Not all Unicast addresses may be available Sasha Levin
2020-01-16 17:36 ` [PATCH AUTOSEL 4.9 214/251] net: stmmac: fix length of PTP clock's name string Sasha Levin
2020-01-16 17:36 ` [PATCH AUTOSEL 4.9 218/251] dmaengine: imx-sdma: fix size check for sdma script_number Sasha Levin
2020-01-16 17:36 ` [PATCH AUTOSEL 4.9 224/251] mt7601u: fix bbp version check in mt7601u_wait_bbp_ready Sasha Levin
2020-01-16 17:36 ` [PATCH AUTOSEL 4.9 229/251] spi: atmel: fix handling of cs_change set on non-last xfer Sasha Levin
2020-01-16 17:36 ` [PATCH AUTOSEL 4.9 232/251] clk: samsung: exynos5420: Preserve CPU clocks configuration during suspend/resume Sasha Levin
2020-01-16 17:36 ` [PATCH AUTOSEL 4.9 235/251] media: exynos4-is: Fix recursive locking in isp_video_release() Sasha Levin
2020-01-16 17:36 ` [PATCH AUTOSEL 4.9 240/251] tty: serial: imx: use the sg count from dma_map_sg Sasha Levin
2020-01-16 17:36 ` Sasha Levin [this message]

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