From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 7BDAA2F24 for ; Wed, 12 Apr 2023 08:46:53 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 03075C433D2; Wed, 12 Apr 2023 08:46:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1681289213; bh=UPSBXQrUPWEfNPDUuAdtUlcZe+56sNgmoQ7r0QlRKkk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=eFpbpmEQgfNDC1oQU/OamqleLNGdxIha1+C94ktS8f+92LG1u7/3UGywXqp56ETHk MxmqfPdST4og54S/XCVw3MwDX6Zikt3W4UBo5jkwPTKRhb4PoVyF461k3JoLsvk6nc T1ZNaoikYqUaeVVAGlMBr1Z+GUROHPf8/slGiRnA= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Munehisa Kamata , Martin Blumenstingl , =?UTF-8?q?Uwe=20Kleine-K=C3=B6nig?= , Thierry Reding , Sasha Levin Subject: [PATCH 6.2 014/173] pwm: meson: Explicitly set .polarity in .get_state() Date: Wed, 12 Apr 2023 10:32:20 +0200 Message-Id: <20230412082838.684701266@linuxfoundation.org> X-Mailer: git-send-email 2.40.0 In-Reply-To: <20230412082838.125271466@linuxfoundation.org> References: <20230412082838.125271466@linuxfoundation.org> User-Agent: quilt/0.67 Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: Uwe Kleine-König [ Upstream commit 8caa81eb950cb2e9d2d6959b37d853162d197f57 ] The driver only supports normal polarity. Complete the implementation of .get_state() by setting .polarity accordingly. This fixes a regression that was possible since commit c73a3107624d ("pwm: Handle .get_state() failures") which stopped to zero-initialize the state passed to the .get_state() callback. This was reported at https://forum.odroid.com/viewtopic.php?f=177&t=46360 . While this was an unintended side effect, the real issue is the driver's callback not setting the polarity. There is a complicating fact, that the .apply() callback fakes support for inversed polarity. This is not (and cannot) be matched by .get_state(). As fixing this isn't easy, only point it out in a comment to prevent authors of other drivers from copying that approach. Fixes: c375bcbaabdb ("pwm: meson: Read the full hardware state in meson_pwm_get_state()") Reported-by: Munehisa Kamata Acked-by: Martin Blumenstingl Link: https://lore.kernel.org/r/20230310191405.2606296-1-u.kleine-koenig@pengutronix.de Signed-off-by: Uwe Kleine-König Signed-off-by: Thierry Reding Signed-off-by: Sasha Levin --- drivers/pwm/pwm-meson.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/drivers/pwm/pwm-meson.c b/drivers/pwm/pwm-meson.c index 16d79ca5d8f53..5cd7b90872c62 100644 --- a/drivers/pwm/pwm-meson.c +++ b/drivers/pwm/pwm-meson.c @@ -162,6 +162,12 @@ static int meson_pwm_calc(struct meson_pwm *meson, struct pwm_device *pwm, duty = state->duty_cycle; period = state->period; + /* + * Note this is wrong. The result is an output wave that isn't really + * inverted and so is wrongly identified by .get_state as normal. + * Fixing this needs some care however as some machines might rely on + * this. + */ if (state->polarity == PWM_POLARITY_INVERSED) duty = period - duty; @@ -358,6 +364,8 @@ static int meson_pwm_get_state(struct pwm_chip *chip, struct pwm_device *pwm, state->duty_cycle = 0; } + state->polarity = PWM_POLARITY_NORMAL; + return 0; } -- 2.39.2