| commit | 096ad8559d7ded9d8367694480f9addb6eba7be5 | [log] [tgz] |
|---|---|---|
| author | Andre Przywara <andre.przywara@arm.com> | Tue Nov 19 12:03:31 2019 +0000 |
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | Wed Jan 29 10:24:35 2020 +0100 |
| tree | 01b13bb0ece30604f69fdae97f0051b08df6fa23 | |
| parent | 18faefde87c627b353615f463d9ab4f5520adaa6 [diff] |
arm64: dts: juno: Fix UART frequency [ 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>