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[59.124.168.89]) by smtp.gmail.com with ESMTPSA id e3-20020a056a0000c300b006da14f68ac1sm8348585pfj.198.2024.01.15.20.11.14 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 15 Jan 2024 20:11:16 -0800 (PST) From: Nylon Chen To: paul.walmsley@sifive.com, palmer@dabbelt.com, conor+dt@kernel.org, krzysztof.kozlowski+dt@linaro.org, robh+dt@kernel.org, u.kleine-koenig@pengutronix.de, thierry.reding@gmail.com, aou@eecs.berkeley.edu Cc: zong.li@sifve.com, vincent.chen@sifive.com, linux-pwm@vger.kernel.org, linux-kernel@vger.kernel.org, linux-riscv@lists.infradead.org, devicetree@vger.kernel.org, nylon7717@gmail.com, Nylon Chen Subject: [v6 2/3] pwm: sifive: change the PWM controlled LED algorithm Date: Tue, 16 Jan 2024 12:10:53 +0800 Message-ID: <20240116041054.11641-3-nylon.chen@sifive.com> X-Mailer: git-send-email 2.42.0 In-Reply-To: <20240116041054.11641-1-nylon.chen@sifive.com> References: <20240116041054.11641-1-nylon.chen@sifive.com> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20240115_201117_883633_8270504A X-CRM114-Status: GOOD ( 10.26 ) 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 | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/drivers/pwm/pwm-sifive.c b/drivers/pwm/pwm-sifive.c index eabddb7c7820..b07c8598bb21 100644 --- a/drivers/pwm/pwm-sifive.c +++ b/drivers/pwm/pwm-sifive.c @@ -113,6 +113,7 @@ static int pwm_sifive_get_state(struct pwm_chip *chip, struct pwm_device *pwm, u32 duty, val; duty = readl(ddata->regs + PWM_SIFIVE_PWMCMP(pwm->hwpwm)); + duty = (1U << PWM_SIFIVE_CMPWIDTH) - 1 - duty; state->enabled = duty > 0; @@ -123,11 +124,10 @@ 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; } - static int pwm_sifive_apply(struct pwm_chip *chip, struct pwm_device *pwm, const struct pwm_state *state) { @@ -139,7 +139,7 @@ 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 +159,7 @@ 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) {