build/patch/kernel/sunxi-dev/pwm-sun4i-Add-support-for-Allwinner-H6.patch

H6 PWM block is basically the same as A20 PWM, except that it also has
bus clock and reset line which needs to be handled accordingly.

Expand Allwinner PWM binding with H6 PWM specifics.

Signed-off-by: Jernej Skrabec <jernej.skrabec@siol.net>
---
 .../bindings/pwm/allwinner,sun4i-a10-pwm.yaml | 36 ++++++++++++++++++-
 1 file changed, 35 insertions(+), 1 deletion(-)

diff --git a/Documentation/devicetree/bindings/pwm/allwinner,sun4i-a10-pwm.yaml b/Documentation/devicetree/bindings/pwm/allwinner,sun4i-a10-pwm.yaml
index 0ac52f83a58c..deca5d81802f 100644
--- a/Documentation/devicetree/bindings/pwm/allwinner,sun4i-a10-pwm.yaml
+++ b/Documentation/devicetree/bindings/pwm/allwinner,sun4i-a10-pwm.yaml
@@ -30,13 +30,47 @@ properties:
       - items:
           - const: allwinner,sun50i-h5-pwm
           - const: allwinner,sun5i-a13-pwm
+      - const: allwinner,sun50i-h6-pwm
 
   reg:
     maxItems: 1
 
-  clocks:
+  # Even though it only applies to subschemas under the conditionals,
+  # not listing them here will trigger a warning because of the
+  # additionalsProperties set to false.
+  clocks: true
+  clock-names: true
+  resets:
     maxItems: 1
 
+allOf:
+  - if:
+      properties:
+        compatible:
+          contains:
+            const: allwinner,sun50i-h6-pwm
+
+    then:
+      properties:
+        clocks:
+          items:
+            - description: Module Clock
+            - description: Bus Clock
+
+        clock-names:
+          items:
+            - const: pwm
+            - const: bus
+
+      required:
+        - clock-names
+        - resets
+
+    else:
+      properties:
+        clocks:
+          maxItems: 1
+
 required:
   - "#pwm-cells"
   - compatible


H6 PWM core needs deasserted reset line in order to work.

Add a quirk for it.

Signed-off-by: Jernej Skrabec <jernej.skrabec@siol.net>
Acked-by: Maxime Ripard <maxime.ripard@bootlin.com>
---
 drivers/pwm/pwm-sun4i.c | 27 +++++++++++++++++++++++++--
 1 file changed, 25 insertions(+), 2 deletions(-)

diff --git a/drivers/pwm/pwm-sun4i.c b/drivers/pwm/pwm-sun4i.c
index de78c824bbfd..1b7be8fbde86 100644
--- a/drivers/pwm/pwm-sun4i.c
+++ b/drivers/pwm/pwm-sun4i.c
@@ -16,6 +16,7 @@
 #include <linux/of_device.h>
 #include <linux/platform_device.h>
 #include <linux/pwm.h>
+#include <linux/reset.h>
 #include <linux/slab.h>
 #include <linux/spinlock.h>
 #include <linux/time.h>
@@ -72,12 +73,14 @@ static const u32 prescaler_table[] = {
 
 struct sun4i_pwm_data {
 	bool has_prescaler_bypass;
+	bool has_reset;
 	unsigned int npwm;
 };
 
 struct sun4i_pwm_chip {
 	struct pwm_chip chip;
 	struct clk *clk;
+	struct reset_control *rst;
 	void __iomem *base;
 	spinlock_t ctrl_lock;
 	const struct sun4i_pwm_data *data;
@@ -371,6 +374,14 @@ static int sun4i_pwm_probe(struct platform_device *pdev)
 	if (IS_ERR(pwm->clk))
 		return PTR_ERR(pwm->clk);
 
+	if (pwm->data->has_reset) {
+		pwm->rst = devm_reset_control_get(&pdev->dev, NULL);
+		if (IS_ERR(pwm->rst))
+			return PTR_ERR(pwm->rst);
+
+		reset_control_deassert(pwm->rst);
+	}
+
 	pwm->chip.dev = &pdev->dev;
 	pwm->chip.ops = &sun4i_pwm_ops;
 	pwm->chip.base = -1;
@@ -383,19 +394,31 @@ static int sun4i_pwm_probe(struct platform_device *pdev)
 	ret = pwmchip_add(&pwm->chip);
 	if (ret < 0) {
 		dev_err(&pdev->dev, "failed to add PWM chip: %d\n", ret);
-		return ret;
+		goto err_pwm_add;
 	}
 
 	platform_set_drvdata(pdev, pwm);
 
 	return 0;
+
+err_pwm_add:
+	reset_control_assert(pwm->rst);
+
+	return ret;
 }
 
 static int sun4i_pwm_remove(struct platform_device *pdev)
 {
 	struct sun4i_pwm_chip *pwm = platform_get_drvdata(pdev);
+	int ret;
+
+	ret = pwmchip_remove(&pwm->chip);
+	if (ret)
+		return ret;
 
-	return pwmchip_remove(&pwm->chip);
+	reset_control_assert(pwm->rst);
+
+	return 0;
 }
 
 static struct platform_driver sun4i_pwm_driver = {

H6 PWM core needs bus clock to be enabled in order to work.

Add a quirk for it.

Signed-off-by: Jernej Skrabec <jernej.skrabec@siol.net>
---
 drivers/pwm/pwm-sun4i.c | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/drivers/pwm/pwm-sun4i.c b/drivers/pwm/pwm-sun4i.c
index 1b7be8fbde86..7d3ac3f2dc3f 100644
--- a/drivers/pwm/pwm-sun4i.c
+++ b/drivers/pwm/pwm-sun4i.c
@@ -72,6 +72,7 @@ static const u32 prescaler_table[] = {
 };
 
 struct sun4i_pwm_data {
+	bool has_bus_clock;
 	bool has_prescaler_bypass;
 	bool has_reset;
 	unsigned int npwm;
@@ -79,6 +80,7 @@ struct sun4i_pwm_data {
 
 struct sun4i_pwm_chip {
 	struct pwm_chip chip;
+	struct clk *bus_clk;
 	struct clk *clk;
 	struct reset_control *rst;
 	void __iomem *base;
@@ -382,6 +384,16 @@ static int sun4i_pwm_probe(struct platform_device *pdev)
 		reset_control_deassert(pwm->rst);
 	}
 
+	if (pwm->data->has_bus_clock) {
+		pwm->bus_clk = devm_clk_get(&pdev->dev, "bus");
+		if (IS_ERR(pwm->bus_clk)) {
+			ret = PTR_ERR(pwm->bus_clk);
+			goto err_bus;
+		}
+
+		clk_prepare_enable(pwm->bus_clk);
+	}
+
 	pwm->chip.dev = &pdev->dev;
 	pwm->chip.ops = &sun4i_pwm_ops;
 	pwm->chip.base = -1;
@@ -402,6 +414,8 @@ static int sun4i_pwm_probe(struct platform_device *pdev)
 	return 0;
 
 err_pwm_add:
+	clk_disable_unprepare(pwm->bus_clk);
+err_bus:
 	reset_control_assert(pwm->rst);
 
 	return ret;
@@ -416,6 +430,7 @@ static int sun4i_pwm_remove(struct platform_device *pdev)
 	if (ret)
 		return ret;
 
+	clk_disable_unprepare(pwm->bus_clk);
 	reset_control_assert(pwm->rst);
 
 	return 0;


Note that while H6 PWM has two channels, only first one is wired to
output pin. Second channel is used as a clock source to companion AC200
chip which is bundled into same package.

Signed-off-by: Jernej Skrabec <jernej.skrabec@siol.net>
---
 drivers/pwm/pwm-sun4i.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/drivers/pwm/pwm-sun4i.c b/drivers/pwm/pwm-sun4i.c
index 7d3ac3f2dc3f..9e0eca79ff88 100644
--- a/drivers/pwm/pwm-sun4i.c
+++ b/drivers/pwm/pwm-sun4i.c
@@ -331,6 +331,13 @@ static const struct sun4i_pwm_data sun4i_pwm_single_bypass = {
 	.npwm = 1,
 };
 
+static const struct sun4i_pwm_data sun50i_pwm_dual_bypass_clk_rst = {
+	.has_bus_clock = true,
+	.has_prescaler_bypass = true,
+	.has_reset = true,
+	.npwm = 2,
+};
+
 static const struct of_device_id sun4i_pwm_dt_ids[] = {
 	{
 		.compatible = "allwinner,sun4i-a10-pwm",
@@ -347,6 +354,9 @@ static const struct of_device_id sun4i_pwm_dt_ids[] = {
 	}, {
 		.compatible = "allwinner,sun8i-h3-pwm",
 		.data = &sun4i_pwm_single_bypass,
+	}, {
+		.compatible = "allwinner,sun50i-h6-pwm",
+		.data = &sun50i_pwm_dual_bypass_clk_rst,
 	}, {
 		/* sentinel */
 	},


This mode of operation is needed to achieve high enough frequency to
serve as clock source for AC200 chip, which is integrated into same
package as H6 SoC.

Signed-off-by: Jernej Skrabec <jernej.skrabec@siol.net>
---
 drivers/pwm/pwm-sun4i.c | 31 ++++++++++++++++++++++++++++++-
 1 file changed, 30 insertions(+), 1 deletion(-)

diff --git a/drivers/pwm/pwm-sun4i.c b/drivers/pwm/pwm-sun4i.c
index 9e0eca79ff88..848cff26f385 100644
--- a/drivers/pwm/pwm-sun4i.c
+++ b/drivers/pwm/pwm-sun4i.c
@@ -120,6 +120,19 @@ static void sun4i_pwm_get_state(struct pwm_chip *chip,
 
 	val = sun4i_pwm_readl(sun4i_pwm, PWM_CTRL_REG);
 
+	/*
+	 * PWM chapter in H6 manual has a diagram which explains that if bypass
+	 * bit is set, no other setting has any meaning. Even more, experiment
+	 * proved that also enable bit is ignored in this case.
+	 */
+	if (val & BIT_CH(PWM_BYPASS, pwm->hwpwm)) {
+		state->period = DIV_ROUND_CLOSEST_ULL(NSEC_PER_SEC, clk_rate);
+		state->duty_cycle = state->period / 2;
+		state->polarity = PWM_POLARITY_NORMAL;
+		state->enabled = true;
+		return;
+	}
+
 	if ((PWM_REG_PRESCAL(val, pwm->hwpwm) == PWM_PRESCAL_MASK) &&
 	    sun4i_pwm->data->has_prescaler_bypass)
 		prescaler = 1;
@@ -211,7 +224,8 @@ static int sun4i_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
 {
 	struct sun4i_pwm_chip *sun4i_pwm = to_sun4i_pwm_chip(chip);
 	struct pwm_state cstate;
-	u32 ctrl;
+	u32 ctrl, clk_rate;
+	bool bypass;
 	int ret;
 	unsigned int delay_us;
 	unsigned long now;
@@ -226,6 +240,16 @@ static int sun4i_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
 		}
 	}
 
+	/*
+	 * Although it would make much more sense to check for bypass in
+	 * sun4i_pwm_calculate(), value of bypass bit also depends on "enabled".
+	 * Period is allowed to be rounded up or down.
+	 */
+	clk_rate = clk_get_rate(sun4i_pwm->clk);
+	bypass = (state->period == NSEC_PER_SEC / clk_rate ||
+		 state->period == DIV_ROUND_UP(NSEC_PER_SEC, clk_rate)) &&
+		 state->enabled;
+
 	spin_lock(&sun4i_pwm->ctrl_lock);
 	ctrl = sun4i_pwm_readl(sun4i_pwm, PWM_CTRL_REG);
 
@@ -273,6 +297,11 @@ static int sun4i_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
 		ctrl &= ~BIT_CH(PWM_CLK_GATING, pwm->hwpwm);
 	}
 
+	if (bypass)
+		ctrl |= BIT_CH(PWM_BYPASS, pwm->hwpwm);
+	else
+		ctrl &= ~BIT_CH(PWM_BYPASS, pwm->hwpwm);
+
 	sun4i_pwm_writel(sun4i_pwm, ctrl, PWM_CTRL_REG);
 
 	spin_unlock(&sun4i_pwm->ctrl_lock);

Allwinner H6 PWM is similar to that in A20 except that it has additional
bus clock and reset line.

Note that first PWM channel is connected to output pin and second
channel is used internally, as a clock source to AC200 co-packaged chip.
This means that any combination of these two channels can be used and
thus it doesn't make sense to add pinctrl nodes at this point.

Signed-off-by: Jernej Skrabec <jernej.skrabec@siol.net>
---
 arch/arm64/boot/dts/allwinner/sun50i-h6.dtsi | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/arch/arm64/boot/dts/allwinner/sun50i-h6.dtsi b/arch/arm64/boot/dts/allwinner/sun50i-h6.dtsi
index e8bed58e7246..c1abd805cfdc 100644
--- a/arch/arm64/boot/dts/allwinner/sun50i-h6.dtsi
+++ b/arch/arm64/boot/dts/allwinner/sun50i-h6.dtsi
@@ -229,6 +229,16 @@
 			status = "disabled";
 		};
 
+		pwm: pwm@300a000 {
+			compatible = "allwinner,sun50i-h6-pwm";
+			reg = <0x0300a000 0x400>;
+			clocks = <&osc24M>, <&ccu CLK_BUS_PWM>;
+			clock-names = "pwm", "bus";
+			resets = <&ccu RST_BUS_PWM>;
+			#pwm-cells = <3>;
+			status = "disabled";
+		};
+
 		pio: pinctrl@300b000 {
 			compatible = "allwinner,sun50i-h6-pinctrl";
 			reg = <0x0300b000 0x400>;