From a5e76d64a1c39d4bf7c61dc593f52fc9802d9b4b Mon Sep 17 00:00:00 2001 From: Greg Kroah-Hartman Date: Sat, 22 Apr 2023 17:32:32 +0200 Subject: [PATCH] 5.4-stable patches added patches: pwm-meson-explicitly-set-.polarity-in-.get_state.patch --- ...plicitly-set-.polarity-in-.get_state.patch | 62 +++++++++++++++++++ queue-5.4/series | 1 + 2 files changed, 63 insertions(+) create mode 100644 queue-5.4/pwm-meson-explicitly-set-.polarity-in-.get_state.patch diff --git a/queue-5.4/pwm-meson-explicitly-set-.polarity-in-.get_state.patch b/queue-5.4/pwm-meson-explicitly-set-.polarity-in-.get_state.patch new file mode 100644 index 00000000000..f138060a22c --- /dev/null +++ b/queue-5.4/pwm-meson-explicitly-set-.polarity-in-.get_state.patch @@ -0,0 +1,62 @@ +From 8caa81eb950cb2e9d2d6959b37d853162d197f57 Mon Sep 17 00:00:00 2001 +From: =?UTF-8?q?Uwe=20Kleine-K=C3=B6nig?= +Date: Wed, 22 Mar 2023 22:45:44 +0100 +Subject: pwm: meson: Explicitly set .polarity in .get_state() +MIME-Version: 1.0 +Content-Type: text/plain; charset=UTF-8 +Content-Transfer-Encoding: 8bit + +From: Uwe Kleine-König + +commit 8caa81eb950cb2e9d2d6959b37d853162d197f57 upstream. + +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: Greg Kroah-Hartman +--- + drivers/pwm/pwm-meson.c | 8 ++++++++ + 1 file changed, 8 insertions(+) + +--- a/drivers/pwm/pwm-meson.c ++++ b/drivers/pwm/pwm-meson.c +@@ -168,6 +168,12 @@ static int meson_pwm_calc(struct meson_p + 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; + +@@ -304,6 +310,8 @@ static int meson_pwm_apply(struct pwm_ch + meson_pwm_enable(meson, pwm); + } + ++ state->polarity = PWM_POLARITY_NORMAL; ++ + return 0; + } + diff --git a/queue-5.4/series b/queue-5.4/series index 1fe1b3bc172..1a7941e1bac 100644 --- a/queue-5.4/series +++ b/queue-5.4/series @@ -19,3 +19,4 @@ net-dsa-b53-mmap-add-phy-ops.patch s390-ptrace-fix-ptrace_get_last_break-error-handling.patch nvme-tcp-fix-a-possible-uaf-when-failing-to-allocate.patch xen-netback-use-same-error-messages-for-same-errors.patch +pwm-meson-explicitly-set-.polarity-in-.get_state.patch -- 2.47.3