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| author | Nylon Chen <nylon.chen@sifive.com> | 2025-05-29 11:53:40 +0800 |
|---|---|---|
| committer | Uwe Kleine-König <ukleinek@kernel.org> | 2025-07-07 08:39:34 +0200 |
| commit | 7dbc4432ea6bf9d709391eb57f1e9fb44e99845a (patch) | |
| tree | 3deab3d9770eeb4960ea9b946ad4efbdaed28f2d /tools/perf/scripts/python/parallel-perf.py | |
| parent | f4bcf818e5d6474c981ef16153827458a2b57181 (diff) | |
pwm: sifive: Fix PWM algorithm and clarify inverted compare behavior
The `frac` variable represents the pulse inactive time, and the result
of this algorithm is the pulse active time. Therefore, we must reverse
the result.
Although the SiFive Reference Manual states "pwms >= pwmcmpX -> HIGH",
the hardware behavior is inverted due to a fixed XNOR with 0. As a result,
the pwmcmp register actually defines the low (inactive) portion of the pulse.
The reference is SiFive FU740-C000 Manual[0]
Link: https://sifive.cdn.prismic.io/sifive/1a82e600-1f93-4f41-b2d8-86ed8b16acba_fu740-c000-manual-v1p6.pdf [0]
Co-developed-by: Zong Li <zong.li@sifive.com>
Signed-off-by: Zong Li <zong.li@sifive.com>
Co-developed-by: Vincent Chen <vincent.chen@sifive.com>
Signed-off-by: Vincent Chen <vincent.chen@sifive.com>
Signed-off-by: Nylon Chen <nylon.chen@sifive.com>
Link: https://lore.kernel.org/r/20250529035341.51736-3-nylon.chen@sifive.com
Signed-off-by: Uwe Kleine-König <ukleinek@kernel.org>
Diffstat (limited to 'tools/perf/scripts/python/parallel-perf.py')
0 files changed, 0 insertions, 0 deletions