From: Nylon Chen <nylon.chen@sifive.com>
To: aou@eecs.berkeley.edu, conor@kernel.org,
emil.renner.berthing@canonical.com, geert+renesas@glider.be,
heiko@sntech.de, krzysztof.kozlowski+dt@linaro.org,
palmer@dabbelt.com, paul.walmsley@sifive.com, robh+dt@kernel.org,
thierry.reding@gmail.com, u.kleine-koenig@pengutronix.de,
devicetree@vger.kernel.org, linux-pwm@vger.kernel.org,
linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org
Cc: nylon.chen@sifive.com, nylon7717@gmail.com, zong.li@sifive.com,
greentime.hu@sifive.com, vincent.chen@sifive.com
Subject: [PATCH v2 0/2] Change PWM-controlled LED pin active mode and algorithm
Date: Mon, 30 Jan 2023 17:32:27 +0800 [thread overview]
Message-ID: <20230130093229.27489-1-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.
[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 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 | 4 ----
arch/riscv/boot/dts/sifive/hifive-unmatched-a00.dts | 4 ----
drivers/pwm/pwm-sifive.c | 1 +
3 files changed, 1 insertion(+), 8 deletions(-)
--
2.36.1
next reply other threads:[~2023-01-30 9:34 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-01-30 9:32 Nylon Chen [this message]
2023-01-30 9:32 ` [PATCH v2 1/2] riscv: dts: sifive: unleashed/unmatched: Remove PWM controlled LED's active-low properties Nylon Chen
2023-01-31 18:31 ` Conor Dooley
2023-02-01 8:59 ` Nylon Chen
2023-01-30 9:32 ` [PATCH v2 2/2] pwm: sifive: change the PWM controlled LED algorithm Nylon Chen
2023-01-30 9:53 ` Geert Uytterhoeven
2023-02-01 8:51 ` Nylon Chen
2023-01-30 10:17 ` Uwe Kleine-König
2023-02-01 8:56 ` Nylon Chen
2023-03-01 9:20 ` Uwe Kleine-König
2023-03-02 10:41 ` Nylon Chen
2023-02-03 8:06 ` Nylon Chen
2023-02-21 5:54 ` Nylon Chen
2023-09-08 10:41 ` Nylon Chen
2023-09-08 14:49 ` Uwe Kleine-König
2023-09-10 13:16 ` Nylon Chen
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