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From: "Uwe Kleine-König" <u.kleine-koenig@pengutronix.de>
To: Thierry Reding <thierry.reding@gmail.com>
Cc: Wan Jiabing <wanjiabing@vivo.com>,
	kernel@pengutronix.de, linux-pwm@vger.kernel.org,
	linux-riscv@lists.infradead.org,
	Palmer Dabbelt <palmer@dabbelt.com>,
	Paul Walmsley <paul.walmsley@sifive.com>,
	Yash Shah <yash.shah@sifive.com>,
	Atish Patra <atishp@atishpatra.org>,
	"Wesley W. Terpstra" <wesley@sifive.com>
Subject: [PATCH 4/7] pwm: sifive: Enable clk only after period check in .apply()
Date: Thu, 21 Jul 2022 12:31:26 +0200	[thread overview]
Message-ID: <20220721103129.304697-4-u.kleine-koenig@pengutronix.de> (raw)
In-Reply-To: <20220721103129.304697-1-u.kleine-koenig@pengutronix.de>

For the period check and the initial calculations of register values there
is no hardware access needed. So delay enabling the clk a bit to simplify
the code flow a bit.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
---
 drivers/pwm/pwm-sifive.c | 18 ++++++++----------
 1 file changed, 8 insertions(+), 10 deletions(-)

diff --git a/drivers/pwm/pwm-sifive.c b/drivers/pwm/pwm-sifive.c
index 6017e311a879..d833536b5e7a 100644
--- a/drivers/pwm/pwm-sifive.c
+++ b/drivers/pwm/pwm-sifive.c
@@ -139,12 +139,6 @@ static int pwm_sifive_apply(struct pwm_chip *chip, struct pwm_device *pwm,
 	if (state->polarity != PWM_POLARITY_INVERSED)
 		return -EINVAL;
 
-	ret = clk_enable(ddata->clk);
-	if (ret) {
-		dev_err(ddata->chip.dev, "Enable clk failed\n");
-		return ret;
-	}
-
 	cur_state = pwm->state;
 	enabled = cur_state.enabled;
 
@@ -167,14 +161,19 @@ static int pwm_sifive_apply(struct pwm_chip *chip, struct pwm_device *pwm,
 	if (state->period != ddata->approx_period) {
 		if (ddata->user_count != 1) {
 			mutex_unlock(&ddata->lock);
-			ret = -EBUSY;
-			goto exit;
+			return -EBUSY;
 		}
 		ddata->approx_period = state->period;
 		pwm_sifive_update_clock(ddata, clk_get_rate(ddata->clk));
 	}
 	mutex_unlock(&ddata->lock);
 
+	ret = clk_enable(ddata->clk);
+	if (ret) {
+		dev_err(ddata->chip.dev, "Enable clk failed\n");
+		return ret;
+	}
+
 	writel(frac, ddata->regs + PWM_SIFIVE_PWMCMP(pwm->hwpwm));
 
 	if (state->enabled != enabled) {
@@ -186,9 +185,8 @@ static int pwm_sifive_apply(struct pwm_chip *chip, struct pwm_device *pwm,
 		}
 	}
 
-exit:
 	clk_disable(ddata->clk);
-	return ret;
+	return 0;
 }
 
 static const struct pwm_ops pwm_sifive_ops = {
-- 
2.36.1


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  parent reply	other threads:[~2022-07-21 10:32 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-07-21 10:31 [PATCH 1/7] pwm: sifive: Simplify offset calculation for PWMCMP registers Uwe Kleine-König
2022-07-21 10:31 ` [PATCH 2/7] pwm: sifive: Fold pwm_sifive_enable() into its only caller Uwe Kleine-König
2022-07-21 10:31 ` [PATCH 3/7] pwm: sifive: Reduce time the controller lock is held Uwe Kleine-König
2022-07-21 10:31 ` Uwe Kleine-König [this message]
2022-07-21 10:31 ` [PATCH 5/7] pwm: sifive: Simplify clk handling Uwe Kleine-König
2022-07-21 10:31 ` [PATCH 6/7] pwm: sifive: Ensure the clk is enabled exactly one per running PWM Uwe Kleine-König
2022-07-21 20:45   ` Uwe Kleine-König
2022-07-28 17:10     ` Thierry Reding
2022-07-21 10:31 ` [PATCH 7/7] pwm: sifive: Shut down hardware only after pwmchip_remove() completed Uwe Kleine-König
2022-07-22 17:45   ` Emil Renner Berthing
2022-07-28 17:12     ` Thierry Reding
2022-07-28 17:45       ` Conor.Dooley
2022-07-28 17:12 ` [PATCH 1/7] pwm: sifive: Simplify offset calculation for PWMCMP registers Thierry Reding

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