[PATCH v7 0/5] fix the clks on/off mismatch issue and switch pwm-mtk-disp to atomic APIs

[PATCH v7 0/5] fix the clks on/off mismatch issue and switch pwm-mtk-disp to atomic APIs

[Jitao Shi]

Changes since v6:
 - fix commit msg of "pwm: mtk_disp: fix force reg to working reg".
   Expain the reg access only when mm and main clock on.

Changes since v5:
 - fix overflow.
 - Seperate the reg shadow as a single patch.

Changes since v4:
 - Squash the commit "move the commit to clock enabled" to "adjust the clocks to avoid them mismatch".
 - Drop the useless comment about MT2701.
 - Reenable the clks "mm" and "main" in .enable().
 - Fix typo.
 - Seperate get_state() operation as single patch.

Changes since v3:
 - Seperate the clock sequence as single patch.
 - Fixup the reg commit when clocks sequence changed.
 - Merge the apply and get_state as single patch.

Changes since v2:
 - Change commit messages to remove the clock operations for atomic APIs.
 - Rebase to v5.13 rc1.

Changes since v1:
 - Seperate clock operation as single patch.
 - Seperate apply() as single patch.
 - Seperate get_state() operation as single patch.

Jitao Shi (5):
  pwm: mtk-disp: adjust the clocks to avoid them mismatch
  pwm: mtk_disp: fix force reg to working reg.
  pwm: mtk_disp: implement atomic API .apply()
  pwm: mtk_disp: fix overflow in period and duty calcalation
  pwm: mtk_disp: implement atomic API .get_state()

 drivers/pwm/pwm-mtk-disp.c | 172 ++++++++++++++++++++-----------------
 1 file changed, 92 insertions(+), 80 deletions(-)

-- 
2.25.1

[PATCH v7 1/5] pwm: mtk-disp: adjust the clocks to avoid them mismatch

[Jitao Shi]

The clks "main" and "mm" are prepared in .probe() (and
unprepared in .remove()). This results in the clocks being on
during suspend which results in unnecessarily increased power
consumption.

Remove the clock operations from .probe() and .remove().
Add the clk_prepare_enable() in .enable().
Add the clk_disable_unprepare() in .disable().

Signed-off-by: Jitao Shi <jitao.shi@mediatek.com>
---
 drivers/pwm/pwm-mtk-disp.c | 72 ++++++++++++++++----------------------
 1 file changed, 31 insertions(+), 41 deletions(-)

diff --git a/drivers/pwm/pwm-mtk-disp.c b/drivers/pwm/pwm-mtk-disp.c
index 9b3ba401a3db..3ade525adcc3 100644
--- a/drivers/pwm/pwm-mtk-disp.c
+++ b/drivers/pwm/pwm-mtk-disp.c
@@ -74,6 +74,19 @@ static int mtk_disp_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
 	u64 div, rate;
 	int err;
 
+	err = clk_prepare_enable(mdp->clk_main);
+	if (err < 0) {
+		dev_err(chip->dev, "Can't enable mdp->clk_main: %pe\n", ERR_PTR(err));
+		return err;
+	}
+
+	err = clk_prepare_enable(mdp->clk_mm);
+	if (err < 0) {
+		dev_err(chip->dev, "Can't enable mdp->clk_mm: %pe\n", ERR_PTR(err));
+		clk_disable_unprepare(mdp->clk_main);
+		return err;
+	}
+
 	/*
 	 * Find period, high_width and clk_div to suit duty_ns and period_ns.
 	 * Calculate proper div value to keep period value in the bound.
@@ -87,8 +100,11 @@ static int mtk_disp_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
 	rate = clk_get_rate(mdp->clk_main);
 	clk_div = div_u64(rate * period_ns, NSEC_PER_SEC) >>
 			  PWM_PERIOD_BIT_WIDTH;
-	if (clk_div > PWM_CLKDIV_MAX)
+	if (clk_div > PWM_CLKDIV_MAX) {
+		clk_disable_unprepare(mdp->clk_mm);
+		clk_disable_unprepare(mdp->clk_main);
 		return -EINVAL;
+	}
 
 	div = NSEC_PER_SEC * (clk_div + 1);
 	period = div64_u64(rate * period_ns, div);
@@ -98,16 +114,6 @@ static int mtk_disp_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
 	high_width = div64_u64(rate * duty_ns, div);
 	value = period | (high_width << PWM_HIGH_WIDTH_SHIFT);
 
-	err = clk_enable(mdp->clk_main);
-	if (err < 0)
-		return err;
-
-	err = clk_enable(mdp->clk_mm);
-	if (err < 0) {
-		clk_disable(mdp->clk_main);
-		return err;
-	}
-
 	mtk_disp_pwm_update_bits(mdp, mdp->data->con0,
 				 PWM_CLKDIV_MASK,
 				 clk_div << PWM_CLKDIV_SHIFT);
@@ -124,8 +130,8 @@ static int mtk_disp_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
 					 0x0);
 	}
 
-	clk_disable(mdp->clk_mm);
-	clk_disable(mdp->clk_main);
+	clk_disable_unprepare(mdp->clk_mm);
+	clk_disable_unprepare(mdp->clk_main);
 
 	return 0;
 }
@@ -135,13 +141,16 @@ static int mtk_disp_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
 	struct mtk_disp_pwm *mdp = to_mtk_disp_pwm(chip);
 	int err;
 
-	err = clk_enable(mdp->clk_main);
-	if (err < 0)
+	err = clk_prepare_enable(mdp->clk_main);
+	if (err < 0) {
+		dev_err(chip->dev, "Can't enable mdp->clk_main: %pe\n", ERR_PTR(err));
 		return err;
+	}
 
-	err = clk_enable(mdp->clk_mm);
+	err = clk_prepare_enable(mdp->clk_mm);
 	if (err < 0) {
-		clk_disable(mdp->clk_main);
+		dev_err(chip->dev, "Can't enable mdp->clk_mm: %pe\n", ERR_PTR(err));
+		clk_disable_unprepare(mdp->clk_main);
 		return err;
 	}
 
@@ -158,8 +167,8 @@ static void mtk_disp_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
 	mtk_disp_pwm_update_bits(mdp, DISP_PWM_EN, mdp->data->enable_mask,
 				 0x0);
 
-	clk_disable(mdp->clk_mm);
-	clk_disable(mdp->clk_main);
+	clk_disable_unprepare(mdp->clk_mm);
+	clk_disable_unprepare(mdp->clk_main);
 }
 
 static const struct pwm_ops mtk_disp_pwm_ops = {
@@ -192,22 +201,14 @@ static int mtk_disp_pwm_probe(struct platform_device *pdev)
 	if (IS_ERR(mdp->clk_mm))
 		return PTR_ERR(mdp->clk_mm);
 
-	ret = clk_prepare(mdp->clk_main);
-	if (ret < 0)
-		return ret;
-
-	ret = clk_prepare(mdp->clk_mm);
-	if (ret < 0)
-		goto disable_clk_main;
-
 	mdp->chip.dev = &pdev->dev;
 	mdp->chip.ops = &mtk_disp_pwm_ops;
 	mdp->chip.npwm = 1;
 
 	ret = pwmchip_add(&mdp->chip);
 	if (ret < 0) {
-		dev_err(&pdev->dev, "pwmchip_add() failed: %d\n", ret);
-		goto disable_clk_mm;
+		dev_err(&pdev->dev, "pwmchip_add() failed: %pe\n", ERR_PTR(ret));
+		return ret;
 	}
 
 	platform_set_drvdata(pdev, mdp);
@@ -226,24 +227,13 @@ static int mtk_disp_pwm_probe(struct platform_device *pdev)
 	}
 
 	return 0;
-
-disable_clk_mm:
-	clk_unprepare(mdp->clk_mm);
-disable_clk_main:
-	clk_unprepare(mdp->clk_main);
-	return ret;
 }
 
 static int mtk_disp_pwm_remove(struct platform_device *pdev)
 {
 	struct mtk_disp_pwm *mdp = platform_get_drvdata(pdev);
-	int ret;
-
-	ret = pwmchip_remove(&mdp->chip);
-	clk_unprepare(mdp->clk_mm);
-	clk_unprepare(mdp->clk_main);
 
-	return ret;
+	return pwmchip_remove(&mdp->chip);
 }
 
 static const struct mtk_pwm_data mt2701_pwm_data = {
-- 
2.25.1

[PATCH v7 2/5] pwm: mtk_disp: fix force reg to working reg.

[Jitao Shi]

The reg can't access when the clock is off.
Because the clocks "mm" and "main" prepare() and enabel() move to
mtk_disp_pwm_config() from probe(). So move the reg accress of
"reg double buffer" to mtk_disp_pwm_config() to.

Signed-off-by: Jitao Shi <jitao.shi@mediatek.com>
---
 drivers/pwm/pwm-mtk-disp.c | 24 +++++++++++-------------
 1 file changed, 11 insertions(+), 13 deletions(-)

diff --git a/drivers/pwm/pwm-mtk-disp.c b/drivers/pwm/pwm-mtk-disp.c
index 3ade525adcc3..1070d78d4940 100644
--- a/drivers/pwm/pwm-mtk-disp.c
+++ b/drivers/pwm/pwm-mtk-disp.c
@@ -128,6 +128,17 @@ static int mtk_disp_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
 		mtk_disp_pwm_update_bits(mdp, mdp->data->commit,
 					 mdp->data->commit_mask,
 					 0x0);
+	} else {
+	/*
+	 * For MT2701, disable double buffer before writing register
+	 * and select manual mode and use PWM_PERIOD/PWM_HIGH_WIDTH.
+	 */
+		mtk_disp_pwm_update_bits(mdp, mdp->data->bls_debug,
+					 mdp->data->bls_debug_mask,
+					 mdp->data->bls_debug_mask);
+		mtk_disp_pwm_update_bits(mdp, mdp->data->con0,
+					 mdp->data->con0_sel,
+					 mdp->data->con0_sel);
 	}
 
 	clk_disable_unprepare(mdp->clk_mm);
@@ -213,19 +224,6 @@ static int mtk_disp_pwm_probe(struct platform_device *pdev)
 
 	platform_set_drvdata(pdev, mdp);
 
-	/*
-	 * For MT2701, disable double buffer before writing register
-	 * and select manual mode and use PWM_PERIOD/PWM_HIGH_WIDTH.
-	 */
-	if (!mdp->data->has_commit) {
-		mtk_disp_pwm_update_bits(mdp, mdp->data->bls_debug,
-					 mdp->data->bls_debug_mask,
-					 mdp->data->bls_debug_mask);
-		mtk_disp_pwm_update_bits(mdp, mdp->data->con0,
-					 mdp->data->con0_sel,
-					 mdp->data->con0_sel);
-	}
-
 	return 0;
 }
 
-- 
2.25.1

[PATCH v7 3/5] pwm: mtk_disp: implement atomic API .apply()

[Jitao Shi]

Switch the driver to support the .apply() method.

Signed-off-by: Jitao Shi <jitao.shi@mediatek.com>
---
 drivers/pwm/pwm-mtk-disp.c | 93 ++++++++++++++++----------------------
 1 file changed, 38 insertions(+), 55 deletions(-)

diff --git a/drivers/pwm/pwm-mtk-disp.c b/drivers/pwm/pwm-mtk-disp.c
index 1070d78d4940..599d7dd8ecab 100644
--- a/drivers/pwm/pwm-mtk-disp.c
+++ b/drivers/pwm/pwm-mtk-disp.c
@@ -47,6 +47,7 @@ struct mtk_disp_pwm {
 	struct clk *clk_main;
 	struct clk *clk_mm;
 	void __iomem *base;
+	bool enabled;
 };
 
 static inline struct mtk_disp_pwm *to_mtk_disp_pwm(struct pwm_chip *chip)
@@ -66,25 +67,42 @@ static void mtk_disp_pwm_update_bits(struct mtk_disp_pwm *mdp, u32 offset,
 	writel(value, address);
 }
 
-static int mtk_disp_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
-			       int duty_ns, int period_ns)
+static int mtk_disp_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
+			      const struct pwm_state *state)
 {
 	struct mtk_disp_pwm *mdp = to_mtk_disp_pwm(chip);
 	u32 clk_div, period, high_width, value;
 	u64 div, rate;
 	int err;
 
-	err = clk_prepare_enable(mdp->clk_main);
-	if (err < 0) {
-		dev_err(chip->dev, "Can't enable mdp->clk_main: %pe\n", ERR_PTR(err));
-		return err;
+	if (state->polarity != PWM_POLARITY_NORMAL)
+		return -EINVAL;
+
+	if (!state->enabled) {
+		mtk_disp_pwm_update_bits(mdp, DISP_PWM_EN, mdp->data->enable_mask,
+					 0x0);
+		if (mdp->enabled) {
+			clk_disable_unprepare(mdp->clk_mm);
+			clk_disable_unprepare(mdp->clk_main);
+		}
+		mdp->enabled = false;
+		return 0;
 	}
 
-	err = clk_prepare_enable(mdp->clk_mm);
-	if (err < 0) {
-		dev_err(chip->dev, "Can't enable mdp->clk_mm: %pe\n", ERR_PTR(err));
-		clk_disable_unprepare(mdp->clk_main);
-		return err;
+	if (!mdp->enabled) {
+		err = clk_prepare_enable(mdp->clk_main);
+		if (err < 0) {
+			dev_err(chip->dev, "Can't enable mdp->clk_main: %pe\n",
+				ERR_PTR(err));
+			return err;
+		}
+		err = clk_prepare_enable(mdp->clk_mm);
+		if (err < 0) {
+			dev_err(chip->dev, "Can't enable mdp->clk_mm: %pe\n",
+				ERR_PTR(err));
+			clk_disable_unprepare(mdp->clk_main);
+			return err;
+		}
 	}
 
 	/*
@@ -98,20 +116,22 @@ static int mtk_disp_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
 	 * high_width = (PWM_CLK_RATE * duty_ns) / (10^9 * (clk_div + 1))
 	 */
 	rate = clk_get_rate(mdp->clk_main);
-	clk_div = div_u64(rate * period_ns, NSEC_PER_SEC) >>
+	clk_div = div_u64(rate * state->period, NSEC_PER_SEC) >>
 			  PWM_PERIOD_BIT_WIDTH;
 	if (clk_div > PWM_CLKDIV_MAX) {
-		clk_disable_unprepare(mdp->clk_mm);
-		clk_disable_unprepare(mdp->clk_main);
+		if (!mdp->enabled) {
+			clk_disable_unprepare(mdp->clk_mm);
+			clk_disable_unprepare(mdp->clk_main);
+		}
 		return -EINVAL;
 	}
 
 	div = NSEC_PER_SEC * (clk_div + 1);
-	period = div64_u64(rate * period_ns, div);
+	period = div64_u64(rate * state->period, div);
 	if (period > 0)
 		period--;
 
-	high_width = div64_u64(rate * duty_ns, div);
+	high_width = div64_u64(rate * state->duty_cycle, div);
 	value = period | (high_width << PWM_HIGH_WIDTH_SHIFT);
 
 	mtk_disp_pwm_update_bits(mdp, mdp->data->con0,
@@ -140,52 +160,15 @@ static int mtk_disp_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
 					 mdp->data->con0_sel,
 					 mdp->data->con0_sel);
 	}
-
-	clk_disable_unprepare(mdp->clk_mm);
-	clk_disable_unprepare(mdp->clk_main);
-
-	return 0;
-}
-
-static int mtk_disp_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
-{
-	struct mtk_disp_pwm *mdp = to_mtk_disp_pwm(chip);
-	int err;
-
-	err = clk_prepare_enable(mdp->clk_main);
-	if (err < 0) {
-		dev_err(chip->dev, "Can't enable mdp->clk_main: %pe\n", ERR_PTR(err));
-		return err;
-	}
-
-	err = clk_prepare_enable(mdp->clk_mm);
-	if (err < 0) {
-		dev_err(chip->dev, "Can't enable mdp->clk_mm: %pe\n", ERR_PTR(err));
-		clk_disable_unprepare(mdp->clk_main);
-		return err;
-	}
-
 	mtk_disp_pwm_update_bits(mdp, DISP_PWM_EN, mdp->data->enable_mask,
 				 mdp->data->enable_mask);
+	mdp->enabled = true;
 
 	return 0;
 }
 
-static void mtk_disp_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
-{
-	struct mtk_disp_pwm *mdp = to_mtk_disp_pwm(chip);
-
-	mtk_disp_pwm_update_bits(mdp, DISP_PWM_EN, mdp->data->enable_mask,
-				 0x0);
-
-	clk_disable_unprepare(mdp->clk_mm);
-	clk_disable_unprepare(mdp->clk_main);
-}
-
 static const struct pwm_ops mtk_disp_pwm_ops = {
-	.config = mtk_disp_pwm_config,
-	.enable = mtk_disp_pwm_enable,
-	.disable = mtk_disp_pwm_disable,
+	.apply = mtk_disp_pwm_apply,
 	.owner = THIS_MODULE,
 };
 
-- 
2.25.1

[PATCH v7 4/5] pwm: mtk_disp: fix overflow in period and duty calcalation

[Jitao Shi]

Current calculation for period and high_width may have
64-bit overflow. state->period and rate are u64.
rate * state->period will overflow.

clk_div = div_u64(rate * state->period, NSEC_PER_SEC)
period = div64_u64(rate * state->period, div);
high_width = div64_u64(rate * state->duty_cycle, div);

This patch is to resolve it by using mul_u64_u64_div_u64().

Signed-off-by: Jitao Shi <jitao.shi@mediatek.com>
---
 drivers/pwm/pwm-mtk-disp.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/pwm/pwm-mtk-disp.c b/drivers/pwm/pwm-mtk-disp.c
index 599d7dd8ecab..4f6de6f24484 100644
--- a/drivers/pwm/pwm-mtk-disp.c
+++ b/drivers/pwm/pwm-mtk-disp.c
@@ -116,7 +116,7 @@ static int mtk_disp_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
 	 * high_width = (PWM_CLK_RATE * duty_ns) / (10^9 * (clk_div + 1))
 	 */
 	rate = clk_get_rate(mdp->clk_main);
-	clk_div = div_u64(rate * state->period, NSEC_PER_SEC) >>
+	clk_div = mul_u64_u64_div_u64(state->period, rate, NSEC_PER_SEC) >>
 			  PWM_PERIOD_BIT_WIDTH;
 	if (clk_div > PWM_CLKDIV_MAX) {
 		if (!mdp->enabled) {
@@ -127,11 +127,11 @@ static int mtk_disp_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
 	}
 
 	div = NSEC_PER_SEC * (clk_div + 1);
-	period = div64_u64(rate * state->period, div);
+	period = mul_u64_u64_div_u64(state->period, rate, div);
 	if (period > 0)
 		period--;
 
-	high_width = div64_u64(rate * state->duty_cycle, div);
+	high_width = mul_u64_u64_div_u64(state->duty_cycle, rate, div);
 	value = period | (high_width << PWM_HIGH_WIDTH_SHIFT);
 
 	mtk_disp_pwm_update_bits(mdp, mdp->data->con0,
-- 
2.25.1

[PATCH v7 5/5] pwm: mtk_disp: implement atomic API .get_state()

[Jitao Shi]

Switch the driver to support the .get_state() method.

Signed-off-by: Jitao Shi <jitao.shi@mediatek.com>
---
 drivers/pwm/pwm-mtk-disp.c | 41 ++++++++++++++++++++++++++++++++++++++
 1 file changed, 41 insertions(+)

diff --git a/drivers/pwm/pwm-mtk-disp.c b/drivers/pwm/pwm-mtk-disp.c
index 4f6de6f24484..a1cd7c208743 100644
--- a/drivers/pwm/pwm-mtk-disp.c
+++ b/drivers/pwm/pwm-mtk-disp.c
@@ -167,8 +167,49 @@ static int mtk_disp_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
 	return 0;
 }
 
+static void mtk_disp_pwm_get_state(struct pwm_chip *chip,
+				   struct pwm_device *pwm,
+				   struct pwm_state *state)
+{
+	struct mtk_disp_pwm *mdp = to_mtk_disp_pwm(chip);
+	u32 clk_div, con0, con1;
+	u64 rate, period, high_width;
+	int err;
+
+	err = clk_prepare_enable(mdp->clk_main);
+	if (err < 0) {
+		dev_err(chip->dev, "Can't enable mdp->clk_main: %pe\n", ERR_PTR(err));
+		return;
+	}
+	err = clk_prepare_enable(mdp->clk_mm);
+	if (err < 0) {
+		dev_err(chip->dev, "Can't enable mdp->clk_mm: %pe\n", ERR_PTR(err));
+		clk_disable_unprepare(mdp->clk_main);
+		return;
+	}
+
+	rate = clk_get_rate(mdp->clk_main);
+	con0 = readl(mdp->base + mdp->data->con0);
+	con1 = readl(mdp->base + mdp->data->con1);
+	state->enabled = !!(con0 & BIT(0));
+	clk_div = FIELD_GET(PWM_CLKDIV_MASK, con0);
+	period = FIELD_GET(PWM_PERIOD_MASK, con1);
+	/*
+	 * period has 12 bits, clk_div 11 and NSEC_PER_SEC has 30,
+	 * so period * (clk_div + 1) * NSEC_PER_SEC doesn't overflow.
+	 */
+	state->period = DIV64_U64_ROUND_UP(period * (clk_div + 1) * NSEC_PER_SEC, rate);
+	high_width = FIELD_GET(PWM_HIGH_WIDTH_MASK, con1);
+	state->duty_cycle = DIV64_U64_ROUND_UP(high_width * (clk_div + 1) * NSEC_PER_SEC,
+					       rate);
+	state->polarity = PWM_POLARITY_NORMAL;
+	clk_disable_unprepare(mdp->clk_mm);
+	clk_disable_unprepare(mdp->clk_main);
+}
+
 static const struct pwm_ops mtk_disp_pwm_ops = {
 	.apply = mtk_disp_pwm_apply,
+	.get_state = mtk_disp_pwm_get_state,
 	.owner = THIS_MODULE,
 };
 
-- 
2.25.1