From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 51C4D6FCB for ; Thu, 1 Dec 2022 15:22:35 +0000 (UTC) Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 01A8AD6E; Thu, 1 Dec 2022 07:22:41 -0800 (PST) Received: from e110479.cambridge.arm.com (e110479.cambridge.arm.com [10.1.38.59]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 342893F67D; Thu, 1 Dec 2022 07:22:32 -0800 (PST) From: Andre Przywara To: Thierry Reding , =?UTF-8?q?Uwe=20Kleine-K=C3=B6nig?= Cc: Chen-Yu Tsai , Jernej Skrabec , Samuel Holland , linux-pwm@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-sunxi@lists.linux.dev Subject: [PATCH] pwm: sun4i: Propagate errors in .get_state() to the caller Date: Thu, 1 Dec 2022 15:22:23 +0000 Message-Id: <20221201152223.3133-1-andre.przywara@arm.com> X-Mailer: git-send-email 2.17.1 Precedence: bulk X-Mailing-List: linux-sunxi@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: .get_state() can return an error indication now. Make use of it to propagate an impossible prescaler encoding, should that have sneaked in somehow. Also check the return value of clk_get_rate(). That's unlikely to fail, but we use that in two divide operations down in the code, so let's avoid a divide-by-zero condition on the way. Signed-off-by: Andre Przywara --- Hi, this goes on top of Uwe's series to introduce and observe .get_state failures: https://lore.kernel.org/linux-pwm/20221130152148.2769768-12-u.kleine-koenig@pengutronix.de/T/#m9af39aa03bbd9bb7b31b3600f110c65ee0e8e70b Actually it only relies on patch 01/11 from that. Cheers, Andre drivers/pwm/pwm-sun4i.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/drivers/pwm/pwm-sun4i.c b/drivers/pwm/pwm-sun4i.c index 37d75e252d4e..b973da73e9ab 100644 --- a/drivers/pwm/pwm-sun4i.c +++ b/drivers/pwm/pwm-sun4i.c @@ -118,6 +118,8 @@ static int sun4i_pwm_get_state(struct pwm_chip *chip, unsigned int prescaler; clk_rate = clk_get_rate(sun4i_pwm->clk); + if (!clk_rate) + return -EINVAL; val = sun4i_pwm_readl(sun4i_pwm, PWM_CTRL_REG); @@ -142,7 +144,7 @@ static int sun4i_pwm_get_state(struct pwm_chip *chip, prescaler = prescaler_table[PWM_REG_PRESCAL(val, pwm->hwpwm)]; if (prescaler == 0) - return 0; + return -EINVAL; if (val & BIT_CH(PWM_ACT_STATE, pwm->hwpwm)) state->polarity = PWM_POLARITY_NORMAL; -- 2.17.1