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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> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20240222_001251_709266_042324FA X-CRM114-Status: GOOD ( 11.55 ) X-BeenThere: linux-riscv@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-riscv" Errors-To: linux-riscv-bounces+linux-riscv=archiver.kernel.org@lists.infradead.org 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-b2d8-86ed8b16acba_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 = pwm_sifive_chip_to_ddata(chip); - u32 duty, val; + u32 duty, val, inactive; - duty = readl(ddata->regs + PWM_SIFIVE_PWMCMP(pwm->hwpwm)); + inactive = readl(ddata->regs + PWM_SIFIVE_PWMCMP(pwm->hwpwm)); + duty = (1U << PWM_SIFIVE_CMPWIDTH) - 1 - inactive; state->enabled = duty > 0; @@ -123,7 +124,7 @@ static int pwm_sifive_get_state(struct pwm_chip *chip, struct pwm_device *pwm, state->period = ddata->real_period; state->duty_cycle = (u64)duty * ddata->real_period >> PWM_SIFIVE_CMPWIDTH; - state->polarity = PWM_POLARITY_INVERSED; + state->polarity = PWM_POLARITY_NORMAL; return 0; } @@ -139,7 +140,7 @@ static int pwm_sifive_apply(struct pwm_chip *chip, struct pwm_device *pwm, int ret = 0; u32 frac; - if (state->polarity != PWM_POLARITY_INVERSED) + if (state->polarity != PWM_POLARITY_NORMAL) return -EINVAL; cur_state = pwm->state; @@ -159,6 +160,7 @@ static int pwm_sifive_apply(struct pwm_chip *chip, struct pwm_device *pwm, frac = DIV64_U64_ROUND_CLOSEST(num, state->period); /* The hardware cannot generate a 100% duty cycle */ frac = min(frac, (1U << PWM_SIFIVE_CMPWIDTH) - 1); + frac = (1U << PWM_SIFIVE_CMPWIDTH) - 1 - frac; mutex_lock(&ddata->lock); if (state->period != ddata->approx_period) {