From: Guru Das Srinagesh <gurus@codeaurora.org>
To: linux-pwm@vger.kernel.org
Cc: "Thierry Reding" <thierry.reding@gmail.com>,
"Uwe Kleine-König" <u.kleine-koenig@pengutronix.de>,
"Subbaraman Narayanamurthy" <subbaram@codeaurora.org>,
"David Collins" <collinsd@codeaurora.org>,
linux-kernel@vger.kernel.org,
"Guru Das Srinagesh" <gurus@codeaurora.org>,
"Alexander Shiyan" <shc_work@mail.ru>,
"Arnd Bergmann" <arnd@arndb.de>
Subject: [PATCH v12 04/11] pwm: clps711x: Cast period to u32 before use as divisor
Date: Wed, 8 Apr 2020 23:52:33 -0700 [thread overview]
Message-ID: <c3619bdd4856e881d6bdfd936c5f903be0c3ff57.1586414867.git.gurus@codeaurora.org> (raw)
In-Reply-To: <cover.1586414867.git.gurus@codeaurora.org>
In-Reply-To: <cover.1586414867.git.gurus@codeaurora.org>
Since the PWM framework is switching struct pwm_args.period's datatype
to u64, prepare for this transition by typecasting it to u32.
Also, since the dividend is still a 32-bit number, any divisor greater
than the numerator will cause the quotient to be zero, so return 0 in
that case to efficiently skip the division.
Cc: Alexander Shiyan <shc_work@mail.ru>
Cc: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Guru Das Srinagesh <gurus@codeaurora.org>
---
drivers/pwm/pwm-clps711x.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/drivers/pwm/pwm-clps711x.c b/drivers/pwm/pwm-clps711x.c
index 924d39a..0d368ac 100644
--- a/drivers/pwm/pwm-clps711x.c
+++ b/drivers/pwm/pwm-clps711x.c
@@ -43,7 +43,10 @@ static void clps711x_pwm_update_val(struct clps711x_chip *priv, u32 n, u32 v)
static unsigned int clps711x_get_duty(struct pwm_device *pwm, unsigned int v)
{
/* Duty cycle 0..15 max */
- return DIV_ROUND_CLOSEST(v * 0xf, pwm->args.period);
+ if ((u32)pwm->args.period > (v * 0xf))
+ return 0;
+
+ return DIV_ROUND_CLOSEST(v * 0xf, (u32)pwm->args.period);
}
static int clps711x_pwm_request(struct pwm_chip *chip, struct pwm_device *pwm)
--
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project
next prev parent reply other threads:[~2020-04-09 6:52 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-04-09 6:52 [PATCH v12 00/11] Convert PWM period and duty cycle to u64 Guru Das Srinagesh
2020-04-09 6:52 ` [PATCH v12 01/11] drm/i915: Use 64-bit division macro Guru Das Srinagesh
2020-04-09 6:52 ` [PATCH v12 02/11] hwmon: pwm-fan: " Guru Das Srinagesh
2020-04-09 6:52 ` [PATCH v12 03/11] ir-rx51: " Guru Das Srinagesh
2020-04-09 6:52 ` Guru Das Srinagesh [this message]
2020-04-09 6:52 ` [PATCH v12 05/11] pwm: pwm-imx-tpm: " Guru Das Srinagesh
2020-04-09 6:52 ` [PATCH v12 06/11] pwm: imx27: Use 64-bit division macro and function Guru Das Srinagesh
2020-04-10 19:16 ` Guru Das Srinagesh
2020-04-09 6:52 ` [PATCH v12 07/11] pwm: sifive: Use 64-bit division macro Guru Das Srinagesh
2020-04-09 6:52 ` [PATCH v12 08/11] pwm: sun4i: Use nsecs_to_jiffies to avoid a division Guru Das Srinagesh
2020-04-10 19:20 ` Guru Das Srinagesh
2020-04-11 5:49 ` Chen-Yu Tsai
2020-04-09 6:52 ` [PATCH v12 09/11] backlight: pwm_bl: Use 64-bit division function Guru Das Srinagesh
2020-04-16 9:44 ` Lee Jones
2020-04-16 17:55 ` Guru Das Srinagesh
2020-04-09 6:52 ` [PATCH v12 10/11] clk: pwm: " Guru Das Srinagesh
2020-04-10 19:15 ` Guru Das Srinagesh
2020-04-09 6:52 ` [PATCH v12 11/11] pwm: core: Convert period and duty cycle to u64 Guru Das Srinagesh
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