From 5e3b07ca5cc78cd4a987e78446849e41288d87cb Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Uwe=20Kleine-K=C3=B6nig?= <u.kleine-koenig@pengutronix.de>
Date: Fri, 8 Apr 2022 17:22:38 +0200
Subject: [PATCH] pwm: lp3943: Fix duty calculation in case period was clamped
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Git-commit: 5e3b07ca5cc78cd4a987e78446849e41288d87cb
Patch-mainline: v5.19-rc1
References: git-fixes

The hardware only supports periods <= 1.6 ms and if a bigger period is
requested it is clamped to 1.6 ms. In this case duty_cycle might be bigger
than 1.6 ms and then the duty cycle register is written with a value
bigger than LP3943_MAX_DUTY. So clamp duty_cycle accordingly.

Fixes: af66b3c0934e ("pwm: Add LP3943 PWM driver")
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 drivers/pwm/pwm-lp3943.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/pwm/pwm-lp3943.c b/drivers/pwm/pwm-lp3943.c
index ea17d446a627..2bd04ecb508c 100644
--- a/drivers/pwm/pwm-lp3943.c
+++ b/drivers/pwm/pwm-lp3943.c
@@ -125,6 +125,7 @@ static int lp3943_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
 	if (err)
 		return err;
 
+	duty_ns = min(duty_ns, period_ns);
 	val = (u8)(duty_ns * LP3943_MAX_DUTY / period_ns);
 
 	return lp3943_write_byte(lp3943, reg_duty, val);
-- 
2.35.3