From: Uwe Kleine-König <u.kleine-koenig@baylibre.com>
Date: Fri, 21 Jun 2024 14:37:12 +0000 (+0200)
Subject: pwm: stm32: Refuse too small period requests
X-Git-Tag: v6.1.97~15
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=d2b5636883e81679200e9555aac28c5aa533c046;p=thirdparty%2Fkernel%2Fstable.git

pwm: stm32: Refuse too small period requests

commit c45fcf46ca2368dafe7e5c513a711a6f0f974308 upstream.

If period_ns is small, prd might well become 0. Catch that case because
otherwise with

	regmap_write(priv->regmap, TIM_ARR, prd - 1);

a few lines down quite a big period is configured.

Fixes: 7edf7369205b ("pwm: Add driver for STM32 plaftorm")
Cc: stable@vger.kernel.org
Reviewed-by: Trevor Gamblin <tgamblin@baylibre.com>
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@baylibre.com>
Link: https://lore.kernel.org/r/b86f62f099983646f97eeb6bfc0117bb2d0c340d.1718979150.git.u.kleine-koenig@baylibre.com
Signed-off-by: Uwe Kleine-König <ukleinek@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/drivers/pwm/pwm-stm32.c b/drivers/pwm/pwm-stm32.c
index bdcdb7f38312b..c40a6548ce7d4 100644
--- a/drivers/pwm/pwm-stm32.c
+++ b/drivers/pwm/pwm-stm32.c
@@ -340,6 +340,9 @@ static int stm32_pwm_config(struct stm32_pwm *priv, int ch,
 
 	prd = div;
 
+	if (!prd)
+		return -EINVAL;
+
 	if (prescaler > MAX_TIM_PSC)
 		return -EINVAL;