FAILED: patch "[PATCH] pwm: mediatek: Fix duty and period setting" failed to apply to 5.15-stable tree

FAILED: patch "[PATCH] pwm: mediatek: Fix duty and period setting" failed to apply to 5.15-stable tree

[gregkh]

The patch below does not apply to the 5.15-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@vger.kernel.org>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.15.y
git checkout FETCH_HEAD
git cherry-pick -x f21d136caf8171f94159d975ea4620c164431bd9
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable@vger.kernel.org>' --in-reply-to '2025082142-splotchy-hypocrite-964a@gregkh' --subject-prefix 'PATCH 5.15.y' HEAD^..

Possible dependencies:



thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From f21d136caf8171f94159d975ea4620c164431bd9 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Uwe=20Kleine-K=C3=B6nig?= <u.kleine-koenig@baylibre.com>
Date: Mon, 28 Jul 2025 18:00:18 +0200
Subject: [PATCH] pwm: mediatek: Fix duty and period setting
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

The period generated by the hardware is

	(PWMDWIDTH + 1) << CLKDIV) / freq

according to my tests with a signal analyser and also the documentation.

The current algorithm doesn't consider the `+ 1` part and so configures
slightly too high periods. The same issue exists for the duty cycle
setting. So subtract 1 from both the register values for period and
duty cycle. If period is 0, bail out, if duty_cycle is 0, just disable
the PWM which results in a constant low output.

Fixes: caf065f8fd58 ("pwm: Add MediaTek PWM support")
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@baylibre.com>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Link: https://lore.kernel.org/r/6d1fa87a76f8020bfe3171529b8e19baffceab10.1753717973.git.u.kleine-koenig@baylibre.com
Cc: stable@vger.kernel.org
Signed-off-by: Uwe Kleine-König <ukleinek@kernel.org>

diff --git a/drivers/pwm/pwm-mediatek.c b/drivers/pwm/pwm-mediatek.c
index b6560e52c803..e4b595fc5a5e 100644
--- a/drivers/pwm/pwm-mediatek.c
+++ b/drivers/pwm/pwm-mediatek.c
@@ -170,7 +170,10 @@ static int pwm_mediatek_config(struct pwm_chip *chip, struct pwm_device *pwm,
 	do_div(resolution, clk_rate);
 
 	cnt_period = DIV_ROUND_CLOSEST_ULL((u64)period_ns * 1000, resolution);
-	while (cnt_period > 8191) {
+	if (!cnt_period)
+		return -EINVAL;
+
+	while (cnt_period > 8192) {
 		resolution *= 2;
 		clkdiv++;
 		cnt_period = DIV_ROUND_CLOSEST_ULL((u64)period_ns * 1000,
@@ -193,9 +196,16 @@ static int pwm_mediatek_config(struct pwm_chip *chip, struct pwm_device *pwm,
 	}
 
 	cnt_duty = DIV_ROUND_CLOSEST_ULL((u64)duty_ns * 1000, resolution);
+
 	pwm_mediatek_writel(pc, pwm->hwpwm, PWMCON, BIT(15) | clkdiv);
-	pwm_mediatek_writel(pc, pwm->hwpwm, reg_width, cnt_period);
-	pwm_mediatek_writel(pc, pwm->hwpwm, reg_thres, cnt_duty);
+	pwm_mediatek_writel(pc, pwm->hwpwm, reg_width, cnt_period - 1);
+
+	if (cnt_duty) {
+		pwm_mediatek_writel(pc, pwm->hwpwm, reg_thres, cnt_duty - 1);
+		pwm_mediatek_enable(chip, pwm);
+	} else {
+		pwm_mediatek_disable(chip, pwm);
+	}
 
 out:
 	pwm_mediatek_clk_disable(chip, pwm);
@@ -224,11 +234,8 @@ static int pwm_mediatek_apply(struct pwm_chip *chip, struct pwm_device *pwm,
 	if (err)
 		return err;
 
-	if (!pwm->state.enabled) {
+	if (!pwm->state.enabled)
 		err = pwm_mediatek_clk_enable(chip, pwm);
-		if (!err)
-			pwm_mediatek_enable(chip, pwm);
-	}
 
 	return err;
 }

[PATCH 5.15.y 1/3] pwm: mediatek: Implement .apply() callback

[Sasha Levin]

From: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>

[ Upstream commit 758de66f4bd2cac2b1d71db917c65c3d611d4e74 ]

To eventually get rid of all legacy drivers convert this driver to the
modern world implementing .apply().
This just pushed a variant of pwm_apply_legacy() into the driver that was
slightly simplified because the driver doesn't provide a .set_polarity()
callback.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
Stable-dep-of: f21d136caf81 ("pwm: mediatek: Fix duty and period setting")
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/pwm/pwm-mediatek.c | 29 ++++++++++++++++++++++++++---
 1 file changed, 26 insertions(+), 3 deletions(-)

diff --git a/drivers/pwm/pwm-mediatek.c b/drivers/pwm/pwm-mediatek.c
index d8a80b06a6f2..7b89ee0e3270 100644
--- a/drivers/pwm/pwm-mediatek.c
+++ b/drivers/pwm/pwm-mediatek.c
@@ -205,10 +205,33 @@ static void pwm_mediatek_disable(struct pwm_chip *chip, struct pwm_device *pwm)
 	pwm_mediatek_clk_disable(chip, pwm);
 }
 
+static int pwm_mediatek_apply(struct pwm_chip *chip, struct pwm_device *pwm,
+			      const struct pwm_state *state)
+{
+	int err;
+
+	if (state->polarity != PWM_POLARITY_NORMAL)
+		return -EINVAL;
+
+	if (!state->enabled) {
+		if (pwm->state.enabled)
+			pwm_mediatek_disable(chip, pwm);
+
+		return 0;
+	}
+
+	err = pwm_mediatek_config(pwm->chip, pwm, state->duty_cycle, state->period);
+	if (err)
+		return err;
+
+	if (!pwm->state.enabled)
+		err = pwm_mediatek_enable(chip, pwm);
+
+	return err;
+}
+
 static const struct pwm_ops pwm_mediatek_ops = {
-	.config = pwm_mediatek_config,
-	.enable = pwm_mediatek_enable,
-	.disable = pwm_mediatek_disable,
+	.apply = pwm_mediatek_apply,
 	.owner = THIS_MODULE,
 };
 
-- 
2.50.1

[PATCH 5.15.y 2/3] pwm: mediatek: Handle hardware enable and clock enable separately

[Sasha Levin]

From: Uwe Kleine-König <u.kleine-koenig@baylibre.com>

[ Upstream commit 704d918341c378c5f9505dfdf32d315e256d3846 ]

Stop handling the clocks in pwm_mediatek_enable() and
pwm_mediatek_disable(). This is a preparing change for the next commit
that requires that clocks and the enable bit are handled separately.

Also move these two functions a bit further up in the source file to
make them usable in pwm_mediatek_config(), which is needed in the next
commit, too.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@baylibre.com>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Link: https://lore.kernel.org/r/55c94fe2917ece152ee1e998f4675642a7716f13.1753717973.git.u.kleine-koenig@baylibre.com
Cc: stable@vger.kernel.org
Signed-off-by: Uwe Kleine-König <ukleinek@kernel.org>
Stable-dep-of: f21d136caf81 ("pwm: mediatek: Fix duty and period setting")
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/pwm/pwm-mediatek.c | 60 ++++++++++++++++++--------------------
 1 file changed, 28 insertions(+), 32 deletions(-)

diff --git a/drivers/pwm/pwm-mediatek.c b/drivers/pwm/pwm-mediatek.c
index 7b89ee0e3270..a11e4f750d02 100644
--- a/drivers/pwm/pwm-mediatek.c
+++ b/drivers/pwm/pwm-mediatek.c
@@ -114,6 +114,26 @@ static inline void pwm_mediatek_writel(struct pwm_mediatek_chip *chip,
 	writel(value, chip->regs + pwm_mediatek_reg_offset[num] + offset);
 }
 
+static void pwm_mediatek_enable(struct pwm_chip *chip, struct pwm_device *pwm)
+{
+	struct pwm_mediatek_chip *pc = to_pwm_mediatek_chip(chip);
+	u32 value;
+
+	value = readl(pc->regs);
+	value |= BIT(pwm->hwpwm);
+	writel(value, pc->regs);
+}
+
+static void pwm_mediatek_disable(struct pwm_chip *chip, struct pwm_device *pwm)
+{
+	struct pwm_mediatek_chip *pc = to_pwm_mediatek_chip(chip);
+	u32 value;
+
+	value = readl(pc->regs);
+	value &= ~BIT(pwm->hwpwm);
+	writel(value, pc->regs);
+}
+
 static int pwm_mediatek_config(struct pwm_chip *chip, struct pwm_device *pwm,
 			       int duty_ns, int period_ns)
 {
@@ -176,35 +196,6 @@ static int pwm_mediatek_config(struct pwm_chip *chip, struct pwm_device *pwm,
 	return ret;
 }
 
-static int pwm_mediatek_enable(struct pwm_chip *chip, struct pwm_device *pwm)
-{
-	struct pwm_mediatek_chip *pc = to_pwm_mediatek_chip(chip);
-	u32 value;
-	int ret;
-
-	ret = pwm_mediatek_clk_enable(chip, pwm);
-	if (ret < 0)
-		return ret;
-
-	value = readl(pc->regs);
-	value |= BIT(pwm->hwpwm);
-	writel(value, pc->regs);
-
-	return 0;
-}
-
-static void pwm_mediatek_disable(struct pwm_chip *chip, struct pwm_device *pwm)
-{
-	struct pwm_mediatek_chip *pc = to_pwm_mediatek_chip(chip);
-	u32 value;
-
-	value = readl(pc->regs);
-	value &= ~BIT(pwm->hwpwm);
-	writel(value, pc->regs);
-
-	pwm_mediatek_clk_disable(chip, pwm);
-}
-
 static int pwm_mediatek_apply(struct pwm_chip *chip, struct pwm_device *pwm,
 			      const struct pwm_state *state)
 {
@@ -214,8 +205,10 @@ static int pwm_mediatek_apply(struct pwm_chip *chip, struct pwm_device *pwm,
 		return -EINVAL;
 
 	if (!state->enabled) {
-		if (pwm->state.enabled)
+		if (pwm->state.enabled) {
 			pwm_mediatek_disable(chip, pwm);
+			pwm_mediatek_clk_disable(chip, pwm);
+		}
 
 		return 0;
 	}
@@ -224,8 +217,11 @@ static int pwm_mediatek_apply(struct pwm_chip *chip, struct pwm_device *pwm,
 	if (err)
 		return err;
 
-	if (!pwm->state.enabled)
-		err = pwm_mediatek_enable(chip, pwm);
+	if (!pwm->state.enabled) {
+		err = pwm_mediatek_clk_enable(chip, pwm);
+		if (!err)
+			pwm_mediatek_enable(chip, pwm);
+	}
 
 	return err;
 }
-- 
2.50.1

[PATCH 5.15.y 3/3] pwm: mediatek: Fix duty and period setting

[Sasha Levin]

From: Uwe Kleine-König <u.kleine-koenig@baylibre.com>

[ Upstream commit f21d136caf8171f94159d975ea4620c164431bd9 ]

The period generated by the hardware is

	(PWMDWIDTH + 1) << CLKDIV) / freq

according to my tests with a signal analyser and also the documentation.

The current algorithm doesn't consider the `+ 1` part and so configures
slightly too high periods. The same issue exists for the duty cycle
setting. So subtract 1 from both the register values for period and
duty cycle. If period is 0, bail out, if duty_cycle is 0, just disable
the PWM which results in a constant low output.

Fixes: caf065f8fd58 ("pwm: Add MediaTek PWM support")
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@baylibre.com>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Link: https://lore.kernel.org/r/6d1fa87a76f8020bfe3171529b8e19baffceab10.1753717973.git.u.kleine-koenig@baylibre.com
Cc: stable@vger.kernel.org
Signed-off-by: Uwe Kleine-König <ukleinek@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/pwm/pwm-mediatek.c | 21 ++++++++++++++-------
 1 file changed, 14 insertions(+), 7 deletions(-)

diff --git a/drivers/pwm/pwm-mediatek.c b/drivers/pwm/pwm-mediatek.c
index a11e4f750d02..8d0f6e6ad9f3 100644
--- a/drivers/pwm/pwm-mediatek.c
+++ b/drivers/pwm/pwm-mediatek.c
@@ -163,7 +163,10 @@ static int pwm_mediatek_config(struct pwm_chip *chip, struct pwm_device *pwm,
 	do_div(resolution, clk_rate);
 
 	cnt_period = DIV_ROUND_CLOSEST_ULL((u64)period_ns * 1000, resolution);
-	while (cnt_period > 8191) {
+	if (!cnt_period)
+		return -EINVAL;
+
+	while (cnt_period > 8192) {
 		resolution *= 2;
 		clkdiv++;
 		cnt_period = DIV_ROUND_CLOSEST_ULL((u64)period_ns * 1000,
@@ -186,9 +189,16 @@ static int pwm_mediatek_config(struct pwm_chip *chip, struct pwm_device *pwm,
 	}
 
 	cnt_duty = DIV_ROUND_CLOSEST_ULL((u64)duty_ns * 1000, resolution);
+
 	pwm_mediatek_writel(pc, pwm->hwpwm, PWMCON, BIT(15) | clkdiv);
-	pwm_mediatek_writel(pc, pwm->hwpwm, reg_width, cnt_period);
-	pwm_mediatek_writel(pc, pwm->hwpwm, reg_thres, cnt_duty);
+	pwm_mediatek_writel(pc, pwm->hwpwm, reg_width, cnt_period - 1);
+
+	if (cnt_duty) {
+		pwm_mediatek_writel(pc, pwm->hwpwm, reg_thres, cnt_duty - 1);
+		pwm_mediatek_enable(chip, pwm);
+	} else {
+		pwm_mediatek_disable(chip, pwm);
+	}
 
 out:
 	pwm_mediatek_clk_disable(chip, pwm);
@@ -217,11 +227,8 @@ static int pwm_mediatek_apply(struct pwm_chip *chip, struct pwm_device *pwm,
 	if (err)
 		return err;
 
-	if (!pwm->state.enabled) {
+	if (!pwm->state.enabled)
 		err = pwm_mediatek_clk_enable(chip, pwm);
-		if (!err)
-			pwm_mediatek_enable(chip, pwm);
-	}
 
 	return err;
 }
-- 
2.50.1