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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next prev 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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