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gpio: mvebu: Armada 8K/7K PWM support

PATCH Superseded Baruch Siach 2 participants 6 messages Jan 5, 2021

Subsystems (4)

v5 of 7 Superseded Latest is v7 →

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#0 lore raw

v5 cover gpio: mvebu: Armada 8K/7K PWM support

Changes in v5:

* Add a fix for get_state

* Fix typo in patch #4 subject line

* Add Rob's review tag on the binding documentation patch

Changes in v4:

* Remove patches that are in LinusW linux-gpio for-next and fixes

* Rename the 'pwm-offset' property to 'marvell,pwm-offset' as suggested by Rob Herring

The original cover letter follows (with DT property name updated).

The gpio-mvebu driver supports the PWM functionality of the GPIO block for earlier Armada variants like XP, 370 and 38x. This series extends support to newer Armada variants that use CP11x and AP80x, like Armada 8K and 7K.

This series adds adds the 'marvell,pwm-offset' property to DT binding. 'marvell,pwm-offset' points to the base of A/B counter registers that determine the PWM period and duty cycle.

The existing PWM DT binding reflects an arbitrary decision to allocate the A counter to the first GPIO block, and B counter to the other one. In attempt to provide better future flexibility, the new 'marvell,pwm-offset' property always points to the base address of both A/B counters. The driver code still allocates the counters in the same way, but this might change in the future with no change to the DT.

Tested AP806 and CP110 (both) on Armada 8040 based system.

Baruch Siach (4):
gpio: mvebu: fix pwm get_state period calculation
gpio: mvebu: add pwm support for Armada 8K/7K
arm64: dts: armada: add pwm offsets for ap/cp gpios
dt-bindings: ap806: document gpio marvell,pwm-offset property

 .../arm/marvell/ap80x-system-controller.txt   |   8 ++
 arch/arm64/boot/dts/marvell/armada-ap80x.dtsi |   3 +
 arch/arm64/boot/dts/marvell/armada-cp11x.dtsi |  10 ++
 drivers/gpio/gpio-mvebu.c                     | 117 +++++++++++-------
 4 files changed, 95 insertions(+), 43 deletions(-)
Signature · 1 line
2.29.2
#1 lore raw

PATCH v5 1/4 gpio: mvebu: fix pwm get_state period calculation

The period is the sum of on and off values.

Fixes 757642f9a584e ("gpio: mvebu: Add limited PWM support")
---
 drivers/gpio/gpio-mvebu.c | 16 ++++++----------
 1 file changed, 6 insertions(+), 10 deletions(-)
drivers/gpio/gpio-mvebu.c +6 -10
index 672681a976f5..ac7cb6d3702e 100644
@@ -679,17 +679,13 @@ static void mvebu_pwm_get_state(struct pwm_chip *chip,
 	regmap_read(mvpwm->regs, mvebu_pwmreg_blink_off_duration(mvpwm), &u);
 	val = (unsigned long long) u * NSEC_PER_SEC;
 	do_div(val, mvpwm->clk_rate);
-	if (val < state->duty_cycle) {
+	val += state->duty_cycle;
+	if (val > UINT_MAX)
+		state->period = UINT_MAX;
+	else if (val)
+		state->period = val;
+	else
 		state->period = 1;
-	} else {
-		val -= state->duty_cycle;
-		if (val > UINT_MAX)
-			state->period = UINT_MAX;
-		else if (val)
-			state->period = val;
-		else
-			state->period = 1;
-	}
 
 	regmap_read(mvchip->regs, GPIO_BLINK_EN_OFF + mvchip->offset, &u);
 	if (u)
Signature · 1 line
2.29.2
#2 lore raw

Re: [PATCH v5 1/4] gpio: mvebu: fix pwm get_state period calculation

Quoted 15 lines · Baruch Siach

The period is the sum of on and off values.

Fixes 757642f9a584e ("gpio: mvebu: Add limited PWM support")
---
 drivers/gpio/gpio-mvebu.c | 16 ++++++----------
 1 file changed, 6 insertions(+), 10 deletions(-)
drivers/gpio/gpio-mvebu.c +0 -0
index 672681a976f5..ac7cb6d3702e 100644
@@ -679,17 +679,13 @@ static void mvebu_pwm_get_state(struct pwm_chip *chip,
 	regmap_read(mvpwm->regs, mvebu_pwmreg_blink_off_duration(mvpwm), &u);

drivers/gpio/gpio-mvebu.c static void mvebu_pwm_get_state(struct pwm_chip *chip, · line 688

Quoted 10 lines
drivers/gpio/gpio-mvebu.c +6 -1
 	val = (unsigned long long) u * NSEC_PER_SEC;
 	do_div(val, mvpwm->clk_rate);
-	if (val < state->duty_cycle) {
+	val += state->duty_cycle;
+	if (val > UINT_MAX)
+		state->period = UINT_MAX;
+	else if (val)
+		state->period = val;
+	else
 		state->period = 1;

Are you sure this is the correct solution? Aren't you introducing rounding errors?

The hardware will count to (on + off) clock ticks, so the right way to convert that is to add the two together and then convert to nanoseconds, which may result in a single rounding error. If you convert each individually to nanoseconds, then you can end up with two sets of rounding errors.

Signature · 2 lines
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#3 lore raw

PATCH v5 2/4 gpio: mvebu: add pwm support for Armada 8K/7K

In reply to Baruch Siach

Use the marvell,pwm-offset DT property to store the location of PWM signal duration registers.

Since we have more than two GPIO chips per system, we can't use the alias id to differentiate between them. Use the offset value for that.

---
v3: Split mvebu_pwm_probe() move out of this patch into a separate fix
(Andrew Lunn)

---
 drivers/gpio/gpio-mvebu.c | 101 +++++++++++++++++++++++++-------------
 1 file changed, 68 insertions(+), 33 deletions(-)
drivers/gpio/gpio-mvebu.c +68 -33
index ac7cb6d3702e..1a8259efd5e5 100644
@@ -70,7 +70,12 @@
  */
 #define PWM_BLINK_ON_DURATION_OFF	0x0
 #define PWM_BLINK_OFF_DURATION_OFF	0x4
+#define PWM_BLINK_COUNTER_B_OFF		0x8
 
+/* Armada 8k variant gpios register offsets */
+#define AP80X_GPIO0_OFF_A8K		0x1040
+#define CP11X_GPIO0_OFF_A8K		0x100
+#define CP11X_GPIO1_OFF_A8K		0x140
 
 /* The MV78200 has per-CPU registers for edge mask and level mask */
 #define GPIO_EDGE_MASK_MV78200_OFF(cpu)	  ((cpu) ? 0x30 : 0x18)
@@ -93,6 +98,7 @@
 
 struct mvebu_pwm {
 	struct regmap		*regs;
+	u32			 offset;
 	unsigned long		 clk_rate;
 	struct gpio_desc	*gpiod;
 	struct pwm_chip		 chip;
@@ -283,12 +289,12 @@ mvebu_gpio_write_level_mask(struct mvebu_gpio_chip *mvchip, u32 val)
  */
 static unsigned int mvebu_pwmreg_blink_on_duration(struct mvebu_pwm *mvpwm)
 {
-	return PWM_BLINK_ON_DURATION_OFF;
+	return mvpwm->offset + PWM_BLINK_ON_DURATION_OFF;
 }
 
 static unsigned int mvebu_pwmreg_blink_off_duration(struct mvebu_pwm *mvpwm)
 {
-	return PWM_BLINK_OFF_DURATION_OFF;
+	return mvpwm->offset + PWM_BLINK_OFF_DURATION_OFF;
 }
 
 /*
@@ -777,51 +783,80 @@ static int mvebu_pwm_probe(struct platform_device *pdev,
 	struct device *dev = &pdev->dev;
 	struct mvebu_pwm *mvpwm;
 	void __iomem *base;
+	u32 offset;
 	u32 set;
 
-	if (!of_device_is_compatible(mvchip->chip.of_node,
-				     "marvell,armada-370-gpio"))
-		return 0;
-
-	/*
-	 * There are only two sets of PWM configuration registers for
-	 * all the GPIO lines on those SoCs which this driver reserves
-	 * for the first two GPIO chips. So if the resource is missing
-	 * we can't treat it as an error.
-	 */
-	if (!platform_get_resource_byname(pdev, IORESOURCE_MEM, "pwm"))
+	if (of_device_is_compatible(mvchip->chip.of_node,
+				    "marvell,armada-370-gpio")) {
+		/*
+		 * There are only two sets of PWM configuration registers for
+		 * all the GPIO lines on those SoCs which this driver reserves
+		 * for the first two GPIO chips. So if the resource is missing
+		 * we can't treat it as an error.
+		 */
+		if (!platform_get_resource_byname(pdev, IORESOURCE_MEM, "pwm"))
+			return 0;
+		offset = 0;
+	} else if (mvchip->soc_variant == MVEBU_GPIO_SOC_VARIANT_A8K) {
+		int ret = of_property_read_u32(dev->of_node,
+					       "marvell,pwm-offset", &offset);
+		if (ret < 0)
+			return 0;
+	} else {
 		return 0;
+	}
 
 	if (IS_ERR(mvchip->clk))
 		return PTR_ERR(mvchip->clk);
 
-	/*
-	 * Use set A for lines of GPIO chip with id 0, B for GPIO chip
-	 * with id 1. Don't allow further GPIO chips to be used for PWM.
-	 */
-	if (id == 0)
-		set = 0;
-	else if (id == 1)
-		set = U32_MAX;
-	else
-		return -EINVAL;
-	regmap_write(mvchip->regs,
-		     GPIO_BLINK_CNT_SELECT_OFF + mvchip->offset, set);
-
 	mvpwm = devm_kzalloc(dev, sizeof(struct mvebu_pwm), GFP_KERNEL);
 	if (!mvpwm)
 		return -ENOMEM;
 	mvchip->mvpwm = mvpwm;
 	mvpwm->mvchip = mvchip;
+	mvpwm->offset = offset;
+
+	if (mvchip->soc_variant == MVEBU_GPIO_SOC_VARIANT_A8K) {
+		mvpwm->regs = mvchip->regs;
+
+		switch (mvchip->offset) {
+		case AP80X_GPIO0_OFF_A8K:
+		case CP11X_GPIO0_OFF_A8K:
+			/* Blink counter A */
+			set = 0;
+			break;
+		case CP11X_GPIO1_OFF_A8K:
+			/* Blink counter B */
+			set = U32_MAX;
+			mvpwm->offset += PWM_BLINK_COUNTER_B_OFF;
+			break;
+		default:
+			return -EINVAL;
+		}
+	} else {
+		base = devm_platform_ioremap_resource_byname(pdev, "pwm");
+		if (IS_ERR(base))
+			return PTR_ERR(base);
 
-	base = devm_platform_ioremap_resource_byname(pdev, "pwm");
-	if (IS_ERR(base))
-		return PTR_ERR(base);
+		mvpwm->regs = devm_regmap_init_mmio(&pdev->dev, base,
+						    &mvebu_gpio_regmap_config);
+		if (IS_ERR(mvpwm->regs))
+			return PTR_ERR(mvpwm->regs);
 
-	mvpwm->regs = devm_regmap_init_mmio(&pdev->dev, base,
-					    &mvebu_gpio_regmap_config);
-	if (IS_ERR(mvpwm->regs))
-		return PTR_ERR(mvpwm->regs);
+		/*
+		 * Use set A for lines of GPIO chip with id 0, B for GPIO chip
+		 * with id 1. Don't allow further GPIO chips to be used for PWM.
+		 */
+		if (id == 0)
+			set = 0;
+		else if (id == 1)
+			set = U32_MAX;
+		else
+			return -EINVAL;
+	}
+
+	regmap_write(mvchip->regs,
+		     GPIO_BLINK_CNT_SELECT_OFF + mvchip->offset, set);
 
 	mvpwm->clk_rate = clk_get_rate(mvchip->clk);
 	if (!mvpwm->clk_rate) {
Signature · 1 line
2.29.2
#4 lore raw

PATCH v5 3/4 arm64: dts: armada: add pwm offsets for ap/cp gpios

In reply to Baruch Siach

The 'marvell,pwm-offset' property of both GPIO blocks (per CP component) point to the same counter registers offset. The driver will decide how to use counters A/B.

This is different from the convention of pwm on earlier Armada series (370/38x). On those systems the assignment of A/B counters to GPIO blocks is coded in both DT and the driver. The actual behaviour of the current driver on Armada 8K/7K is the same as earlier systems.

Add also clock properties for base pwm frequency reference.

---
 arch/arm64/boot/dts/marvell/armada-ap80x.dtsi |  3 +++
 arch/arm64/boot/dts/marvell/armada-cp11x.dtsi | 10 ++++++++++
 2 files changed, 13 insertions(+)
arch/arm64/boot/dts/marvell/armada-ap80x.dtsi +3 -0
index 12e477f1aeb9..6614472100c2 100644
@@ -281,6 +281,9 @@ ap_gpio: gpio@1040 {
 					gpio-controller;
 					#gpio-cells = <2>;
 					gpio-ranges = <&ap_pinctrl 0 0 20>;
+					marvell,pwm-offset = <0x10c0>;
+					#pwm-cells = <2>;
+					clocks = <&ap_clk 3>;
 				};
 			};
 
arch/arm64/boot/dts/marvell/armada-cp11x.dtsi +10 -0
index 994a2fce449a..d774a39334d9 100644
@@ -234,12 +234,17 @@ CP11X_LABEL(gpio1): gpio@100 {
 				gpio-controller;
 				#gpio-cells = <2>;
 				gpio-ranges = <&CP11X_LABEL(pinctrl) 0 0 32>;
+				marvell,pwm-offset = <0x1f0>;
+				#pwm-cells = <2>;
 				interrupt-controller;
 				interrupts = <86 IRQ_TYPE_LEVEL_HIGH>,
 					<85 IRQ_TYPE_LEVEL_HIGH>,
 					<84 IRQ_TYPE_LEVEL_HIGH>,
 					<83 IRQ_TYPE_LEVEL_HIGH>;
 				#interrupt-cells = <2>;
+				clock-names = "core", "axi";
+				clocks = <&CP11X_LABEL(clk) 1 21>,
+					 <&CP11X_LABEL(clk) 1 17>;
 				status = "disabled";
 			};
 
@@ -250,12 +255,17 @@ CP11X_LABEL(gpio2): gpio@140 {
 				gpio-controller;
 				#gpio-cells = <2>;
 				gpio-ranges = <&CP11X_LABEL(pinctrl) 0 32 31>;
+				marvell,pwm-offset = <0x1f0>;
+				#pwm-cells = <2>;
 				interrupt-controller;
 				interrupts = <82 IRQ_TYPE_LEVEL_HIGH>,
 					<81 IRQ_TYPE_LEVEL_HIGH>,
 					<80 IRQ_TYPE_LEVEL_HIGH>,
 					<79 IRQ_TYPE_LEVEL_HIGH>;
 				#interrupt-cells = <2>;
+				clock-names = "core", "axi";
+				clocks = <&CP11X_LABEL(clk) 1 21>,
+					 <&CP11X_LABEL(clk) 1 17>;
 				status = "disabled";
 			};
 		};
Signature · 1 line
2.29.2
#5 lore raw

PATCH v5 4/4 dt-bindings: ap806: document gpio marvell, pwm-offset property

In reply to Baruch Siach

Update the example as well. Add the '#pwm-cells' and 'clocks' properties for a complete working example.

---
 .../bindings/arm/marvell/ap80x-system-controller.txt      | 8 ++++++++
 1 file changed, 8 insertions(+)
Documentation/devicetree/bindings/arm/marvell/ap80x-system-controller.txt +8 -0
index e31511255d8e..052a967c1f28 100644
@@ -80,6 +80,11 @@ Required properties:
 
 - offset: offset address inside the syscon block
 
+Optional properties:
+
+- marvell,pwm-offset: offset address of PWM duration control registers inside
+  the syscon block
+
 Example:
 ap_syscon: system-controller@6f4000 {
 	compatible = "syscon", "simple-mfd";
@@ -101,6 +106,9 @@ ap_syscon: system-controller@6f4000 {
 		gpio-controller;
 		#gpio-cells = <2>;
 		gpio-ranges = <&ap_pinctrl 0 0 19>;
+		marvell,pwm-offset = <0x10c0>;
+		#pwm-cells = <2>;
+		clocks = <&ap_clk 3>;
 	};
 };
 
Signature · 1 line
2.29.2