From: Nylon Chen <nylon.chen@sifive.com>
To: linux-pwm@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-riscv@lists.infradead.org, devicetree@vger.kernel.org,
robh+dt@kernel.org, krzysztof.kozlowski+dt@linaro.org,
conor+dt@kernel.org, paul.walmsley@sifive.com,
palmer@dabbelt.com, aou@eecs.berkeley.edu,
thierry.reding@gmail.com, u.kleine-koenig@pengutronix.de,
emil.renner.berthing@canonical.com, vincent.chen@sifive.com
Cc: nylon.chen@sifive.com, greentime.hu@sifive.com,
zong.li@sifive.com, nylon7717@gmail.com
Subject: [v5 0/2] Change PWM-controlled LED pin active mode and algorithm
Date: Tue, 24 Oct 2023 18:19:00 +0800 [thread overview]
Message-ID: <20231024101902.6689-1-nylon.chen@sifive.com> (raw)
According to the circuit diagram of User LEDs - RGB described in the
manual hifive-unleashed-a00.pdf[0] and hifive-unmatched-schematics-v3.pdf[1].
The behavior of PWM is acitve-high.
According to the descriptionof PWM for pwmcmp in SiFive FU740-C000 Manual[2].
The pwm algorithm is (PW) pulse active time = (D) duty * (T) period.
The `frac` variable is pulse "inactive" time so we need to invert it.
So this patchset removes active-low in DTS and adds reverse logic to the driver.
Updated patches: 1
New patches: 1
Unchanged patches: 1
Links:
- [0]: https://sifive.cdn.prismic.io/sifive/c52a8e32-05ce-4aaf-95c8-7bf8453f8698_hifive-unleashed-a00-schematics-1.pdf
- [1]: https://sifive.cdn.prismic.io/sifive/6a06d6c0-6e66-49b5-8e9e-e68ce76f4192_hifive-unmatched-schematics-v3.pdf
- [2]: https://sifive.cdn.prismic.io/sifive/1a82e600-1f93-4f41-b2d8-86ed8b16acba_fu740-c000-manual-v1p6.pdf
Changed in v5:
- Add the updates to the PWM algorithm based on version 2 back in.
- Replace div64_ul with DIV_ROUND_UP_ULL to correct the error in the period value of the idempotent test in pwm_apply_state_debug.
Changed in v4:
- Remove previous updates to the PWM algorithm.
Changed in v3:
- Convert the reference link to standard link.
- Move the inverted function before taking the minimum value.
- Change polarity check condition(high and low).
- Pick the biggest period length possible that is not bigger than the requested period.
Changed in v2:
- Convert the reference link to standard link.
- Fix typo: s/sifive unmatched:/sifive: unmatched:/.
- Remove active-low from hifive-unleashed-a00.dts.
- Include this reference link in the dts and pwm commit messages.
Nylon Chen (2):
riscv: dts: sifive: unleashed/unmatched: Remove PWM controlled LED's
active-low properties
pwm: sifive: change the PWM controlled LED algorithm
arch/riscv/boot/dts/sifive/hifive-unleashed-a00.dts | 8 ++++----
arch/riscv/boot/dts/sifive/hifive-unmatched-a00.dts | 12 ++++--------
drivers/pwm/pwm-sifive.c | 10 ++++++----
3 files changed, 14 insertions(+), 16 deletions(-)
--
2.42.0
next reply other threads:[~2023-10-24 10:19 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-10-24 10:19 Nylon Chen [this message]
2023-10-24 10:19 ` [v5 1/2] riscv: dts: sifive: unleashed/unmatched: Remove PWM controlled LED's active-low properties Nylon Chen
2023-10-24 14:55 ` Conor Dooley
2023-10-25 9:32 ` Nylon Chen
2023-10-25 14:14 ` Conor Dooley
2023-10-27 8:54 ` Nylon Chen
2023-12-11 20:42 ` Uwe Kleine-König
2023-10-24 10:19 ` [v5 2/2] pwm: sifive: change the PWM controlled LED algorithm Nylon Chen
2023-11-09 7:02 ` Nylon Chen
2023-11-09 8:22 ` Krzysztof Kozlowski
2023-12-06 2:35 ` Nylon Chen
2023-12-11 20:49 ` Uwe Kleine-König
2024-01-08 8:27 ` Nylon Chen
2024-01-08 9:25 ` Uwe Kleine-König
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