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[59.124.168.89]) by smtp.gmail.com with ESMTPSA id lf8-20020a170902fb4800b001db5ea825b2sm9412796plb.123.2024.02.22.00.12.47 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 22 Feb 2024 00:12:49 -0800 (PST) From: Nylon Chen To: linux-riscv@lists.infradead.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, linux-pwm@vger.kernel.org, conor@kernel.org, robh+dt@kernel.org, krzysztof.kozlowski+dt@linaro.org, palmer@dabbelt.com, paul.walmsley@sifive.com, aou@eecs.berkeley.edu, thierry.reding@gmail.com, u.kleine-koenig@pengutronix.de Cc: vincent.chen@sifive.com, zong.li@sifive.com, nylon.chen@sifive.com, nylon7717@gmail.com Subject: [PATCH v9 2/3] pwm: sifive: change the PWM algorithm Date: Thu, 22 Feb 2024 16:12:30 +0800 Message-ID: <20240222081231.213406-3-nylon.chen@sifive.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20240222081231.213406-1-nylon.chen@sifive.com> References: <20240222081231.213406-1-nylon.chen@sifive.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" 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. The reference is SiFive FU740-C000 Manual[0] Link: https://sifive.cdn.prismic.io/sifive/1a82e600-1f93-4f41-b2d8-86ed8b16= acba_fu740-c000-manual-v1p6.pdf [0] Co-developed-by: Zong Li Signed-off-by: Zong Li Co-developed-by: Vincent Chen Signed-off-by: Vincent Chen Signed-off-by: Nylon Chen --- drivers/pwm/pwm-sifive.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) diff --git a/drivers/pwm/pwm-sifive.c b/drivers/pwm/pwm-sifive.c index eabddb7c7820..a586cfe4191b 100644 --- a/drivers/pwm/pwm-sifive.c +++ b/drivers/pwm/pwm-sifive.c @@ -110,9 +110,10 @@ static int pwm_sifive_get_state(struct pwm_chip *chip,= struct pwm_device *pwm, struct pwm_state *state) { struct pwm_sifive_ddata *ddata =3D pwm_sifive_chip_to_ddata(chip); - u32 duty, val; + u32 duty, val, inactive; =20 - duty =3D readl(ddata->regs + PWM_SIFIVE_PWMCMP(pwm->hwpwm)); + inactive =3D readl(ddata->regs + PWM_SIFIVE_PWMCMP(pwm->hwpwm)); + duty =3D (1U << PWM_SIFIVE_CMPWIDTH) - 1 - inactive; =20 state->enabled =3D duty > 0; =20 @@ -123,7 +124,7 @@ static int pwm_sifive_get_state(struct pwm_chip *chip, = struct pwm_device *pwm, state->period =3D ddata->real_period; state->duty_cycle =3D (u64)duty * ddata->real_period >> PWM_SIFIVE_CMPWIDTH; - state->polarity =3D PWM_POLARITY_INVERSED; + state->polarity =3D PWM_POLARITY_NORMAL; =20 return 0; } @@ -139,7 +140,7 @@ static int pwm_sifive_apply(struct pwm_chip *chip, stru= ct pwm_device *pwm, int ret =3D 0; u32 frac; =20 - if (state->polarity !=3D PWM_POLARITY_INVERSED) + if (state->polarity !=3D PWM_POLARITY_NORMAL) return -EINVAL; =20 cur_state =3D pwm->state; @@ -159,6 +160,7 @@ static int pwm_sifive_apply(struct pwm_chip *chip, stru= ct pwm_device *pwm, frac =3D DIV64_U64_ROUND_CLOSEST(num, state->period); /* The hardware cannot generate a 100% duty cycle */ frac =3D min(frac, (1U << PWM_SIFIVE_CMPWIDTH) - 1); + frac =3D (1U << PWM_SIFIVE_CMPWIDTH) - 1 - frac; =20 mutex_lock(&ddata->lock); if (state->period !=3D ddata->approx_period) { --=20 2.43.0