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path: root/drivers/cpufreq/sun50i-cpufreq-nvmem.c
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2019-11-05cpufreq: sun50i: Fix CPU speed bin detectionOndrej Jirman
I have observed failures to boot on Orange Pi 3, because this driver determined that my SoC is from the normal bin, but my SoC only works reliably with the OPP values for the slowest bin. By querying H6 owners, it was found that e-fuse values found in the wild are in the range of 1-3, value of 7 was not reported, yet. From this and from unused defines in BSP code, it can be assumed that meaning of efuse values on H6 actually is: - 1 = slowest bin - 2 = normal bin - 3 = fastest bin Vendor code actually treats 0 and 2 as invalid efuse values, but later treats all invalid values as a normal bin. This looks like a mistake in bin detection code, that was plastered over by a hack in cpufreq code, so let's not repeat it here. It probably only works because there are no SoCs in the wild with efuse value of 0, and fast bin SoCs are made to use normal bin OPP tables, which is also safe. Let's play it safe and interpret 0 as the slowest bin, but fix detection of other bins to match this research. More research will be done before actual OPP tables are merged. Fixes: f328584f7bff ("cpufreq: Add sun50i nvmem based CPU scaling driver") Acked-by: Maxime Ripard <mripard@kernel.org> Signed-off-by: Ondrej Jirman <megous@megous.com> Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
2019-07-22cpufreq: Add sun50i nvmem based CPU scaling driverYangtao Li
For some SoCs, the CPU frequency subset and voltage value of each OPP varies based on the silicon variant in use. The sun50i-cpufreq-nvmem driver reads the efuse value from the SoC to provide the OPP framework with required information. Signed-off-by: Yangtao Li <tiny.windzz@gmail.com> Acked-by: Maxime Ripard <maxime.ripard@bootlin.com> Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>