linux/arch/arm64
Andre Przywara 39a1a8941b arm64: dts: juno: Fix UART frequency
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: 71f867ec13 ("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>
2019-11-25 17:43:51 +00:00
..
boot arm64: dts: juno: Fix UART frequency 2019-11-25 17:43:51 +00:00
configs arm64: defconfig: Enable Qualcomm QUSB2 PHY 2019-09-04 17:15:29 +02:00
crypto crypto: arm64/aes-neonbs - implement ciphertext stealing for XTS 2019-09-09 17:35:39 +10:00
include mm: treewide: clarify pgtable_page_{ctor,dtor}() naming 2019-09-26 10:10:44 -07:00
kernel arm64, mm: make randomization selected by generic topdown mmap layout 2019-09-24 15:54:11 -07:00
kvm * s390: ioctl hardening, selftests 2019-09-18 09:49:13 -07:00
lib Merge branch 'for-next/atomics' into for-next/core 2019-08-30 12:55:39 +01:00
mm mm: treewide: clarify pgtable_page_{ctor,dtor}() naming 2019-09-26 10:10:44 -07:00
net arm64: bpf: optimize modulo operation 2019-09-03 15:44:40 +02:00
xen treewide: Add SPDX license identifier - Makefile/Kconfig 2019-05-21 10:50:46 +02:00
Kbuild arm64: add arch/arm64/Kbuild 2019-08-21 18:47:15 +01:00
Kconfig Merge branch 'next-lockdown' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security 2019-09-28 08:14:15 -07:00
Kconfig.debug treewide: Add SPDX license identifier - Makefile/Kconfig 2019-05-21 10:50:46 +02:00
Kconfig.platforms arm64: exynos: Enable exynos-chipid driver 2019-09-04 22:43:26 +02:00
Makefile Kbuild updates for v5.4 2019-09-20 08:36:47 -07:00