linux-kernel - [PATCH v3 2/3] pwm: meson: Add check for error from clk_round

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Message-ID: <20240425171253.2752877-3-gnstark@salutedevices.com>
Date: Thu, 25 Apr 2024 20:12:52 +0300
From: George Stark <gnstark@...utedevices.com>
To: <u.kleine-koenig@...gutronix.de>, <neil.armstrong@...aro.org>,
	<khilman@...libre.com>, <jbrunet@...libre.com>,
	<martin.blumenstingl@...glemail.com>, <thierry.reding@...il.com>,
	<hkallweit1@...il.com>
CC: <linux-pwm@...r.kernel.org>, <linux-amlogic@...ts.infradead.org>,
	<linux-arm-kernel@...ts.infradead.org>, <linux-kernel@...r.kernel.org>,
	<kernel@...utedevices.com>, George Stark <gnstark@...utedevices.com>, Dmitry
 Rokosov <ddrokosov@...utedevices.com>
Subject: [PATCH v3 2/3] pwm: meson: Add check for error from clk_round_rate()

clk_round_rate() can return not only zero if requested frequency can not
be provided but also negative error code so add check for it too.

Also change type of variable holding clk_round_rate() result from
unsigned long to long. It's safe due to clk_round_rate() returns long.

Fixes: 329db102a26d ("pwm: meson: make full use of common clock framework")
Signed-off-by: Dmitry Rokosov <ddrokosov@...utedevices.com>
Signed-off-by: George Stark <gnstark@...utedevices.com>
---
 drivers/pwm/pwm-meson.c | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/drivers/pwm/pwm-meson.c b/drivers/pwm/pwm-meson.c
index f4d70da621ec..4a652d500dfc 100644
--- a/drivers/pwm/pwm-meson.c
+++ b/drivers/pwm/pwm-meson.c
@@ -148,7 +148,7 @@ static int meson_pwm_calc(struct pwm_chip *chip, struct pwm_device *pwm,
 	struct meson_pwm *meson = to_meson_pwm(chip);
 	struct meson_pwm_channel *channel = &meson->channels[pwm->hwpwm];
 	unsigned int cnt, duty_cnt;
-	unsigned long fin_freq;
+	long fin_freq;
 	u64 duty, period, freq;
 
 	duty = state->duty_cycle;
@@ -168,12 +168,13 @@ static int meson_pwm_calc(struct pwm_chip *chip, struct pwm_device *pwm,
 		freq = ULONG_MAX;
 
 	fin_freq = clk_round_rate(channel->clk, freq);
-	if (fin_freq == 0) {
-		dev_err(pwmchip_parent(chip), "invalid source clock frequency\n");
-		return -EINVAL;
+	if (fin_freq <= 0) {
+		dev_err(pwmchip_parent(chip),
+			"invalid source clock frequency %llu\n", freq);
+		return fin_freq ? fin_freq : -EINVAL;
 	}
 
-	dev_dbg(pwmchip_parent(chip), "fin_freq: %lu Hz\n", fin_freq);
+	dev_dbg(pwmchip_parent(chip), "fin_freq: %ld Hz\n", fin_freq);
 
 	cnt = div_u64(fin_freq * period, NSEC_PER_SEC);
 	if (cnt > 0xffff) {
-- 
2.25.1