[PATCH 0/3] axp20x backup battery charging

[PATCH 0/3] axp20x backup battery charging

[Paul Kocialkowski]

This series introduces support for axp20x backup battery charging, with
a dedicated device-tree property.

I wondered whether to include this in a power-supply driver or not.
Since it does not, in fact, supply power to the whole system and
because no status changes over time, I thought it would be inappropriate
to craft a power supply driver only for this.
I also wondered whether to stick this into an existing power-supply
driver, as is done by e.g. twl4030, but we have two distinct supply
drivers for the axp20x (ac and usb), that may be used together or not.
Also, the backup battery isn't tied to the power supply anyway.

This is why I thought it would make more sense to put this in the mfd
driver directly. What do you think?

[PATCH 1/3] dt-bindings: mfd: axp20x: Document backup battery charging property

[Paul Kocialkowski]

This adds documentation for the "backup" property of the axp20x driver,
that controls the charging mechanism for the backup battery on axp20x.

Signed-off-by: Paul Kocialkowski <contact-W9ppeneeCTY@public.gmane.org>

diff --git a/Documentation/devicetree/bindings/mfd/axp20x.txt b/Documentation/devicetree/bindings/mfd/axp20x.txt
index 9455503b0299..382776b29932 100644
--- a/Documentation/devicetree/bindings/mfd/axp20x.txt
+++ b/Documentation/devicetree/bindings/mfd/axp20x.txt
@@ -58,6 +58,11 @@ Optional properties:
 	      See Documentation/devicetree/bindings/regulator/regulator.txt
 	      for more information on standard regulator bindings.
 
+- backup: An array of two integers for backup battery charging (axp20x-only),
+	  describing the charging voltage in mV first and the charging current
+	  in uA second. Backup battery charging is only enabled when these two
+	  fields are filled.
+
 Optional properties for DCDC regulators:
 - x-powers,dcdc-workmode: 1 for PWM mode, 0 for AUTO (PWM/PFM) mode
 			  Default: Current hardware setting
@@ -256,4 +261,6 @@ axp209: pmic@34 {
 			/* unused but preferred to be managed by OS */
 		};
 	};
+
+	backup = <3000 200>;
 };
-- 
2.15.1

Re: [PATCH 1/3] dt-bindings: mfd: axp20x: Document backup battery charging property

[Lee Jones]

On Sat, 30 Dec 2017, Paul Kocialkowski wrote:

> This adds documentation for the "backup" property of the axp20x driver,
> that controls the charging mechanism for the backup battery on axp20x.
> 
> Signed-off-by: Paul Kocialkowski <contact-W9ppeneeCTY@public.gmane.org>
> 
> diff --git a/Documentation/devicetree/bindings/mfd/axp20x.txt b/Documentation/devicetree/bindings/mfd/axp20x.txt
> index 9455503b0299..382776b29932 100644
> --- a/Documentation/devicetree/bindings/mfd/axp20x.txt
> +++ b/Documentation/devicetree/bindings/mfd/axp20x.txt
> @@ -58,6 +58,11 @@ Optional properties:
>  	      See Documentation/devicetree/bindings/regulator/regulator.txt
>  	      for more information on standard regulator bindings.
>  
> +- backup: An array of two integers for backup battery charging (axp20x-only),
> +	  describing the charging voltage in mV first and the charging current
> +	  in uA second. Backup battery charging is only enabled when these two
> +	  fields are filled.
> +
>  Optional properties for DCDC regulators:
>  - x-powers,dcdc-workmode: 1 for PWM mode, 0 for AUTO (PWM/PFM) mode
>  			  Default: Current hardware setting
> @@ -256,4 +261,6 @@ axp209: pmic@34 {
>  			/* unused but preferred to be managed by OS */
>  		};
>  	};
> +
> +	backup = <3000 200>;

It's unlikely that this will become a generic property, so you should
prefix it with your vendor ID.

>  };

-- 
Lee Jones
Linaro Services Technical Lead
Linaro.org │ Open source software for ARM SoCs
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Re: [PATCH 1/3] dt-bindings: mfd: axp20x: Document backup battery charging property

[Pavel Machek]

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Hi!

> This adds documentation for the "backup" property of the axp20x driver,
> that controls the charging mechanism for the backup battery on axp20x.
> 
> Signed-off-by: Paul Kocialkowski <contact@paulk.fr>
> 
> diff --git a/Documentation/devicetree/bindings/mfd/axp20x.txt b/Documentation/devicetree/bindings/mfd/axp20x.txt
> index 9455503b0299..382776b29932 100644
> --- a/Documentation/devicetree/bindings/mfd/axp20x.txt
> +++ b/Documentation/devicetree/bindings/mfd/axp20x.txt
> @@ -58,6 +58,11 @@ Optional properties:
>  	      See Documentation/devicetree/bindings/regulator/regulator.txt
>  	      for more information on standard regulator bindings.
>  
> +- backup: An array of two integers for backup battery charging (axp20x-only),
> +	  describing the charging voltage in mV first and the charging current
> +	  in uA second. Backup battery charging is only enabled when these two
> +	  fields are filled.

Well...

We do want to charge batteries other than your backup
battery. Probably this should get separate "backup battery" node with
properties explaining how it is charged?
									Pavel

-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html

[-- Attachment #2: Digital signature --]
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[PATCH 2/3] mfd: axp20x: Add support for backup battery charging

[Paul Kocialkowski]

This adds support for backup battery charging for axp20x PMICs, that is
configured through a dedicated device-tree property.

It supports 4 different charging voltages and as many charging currents.
This is especially useful to allow the on-chip RTC (on the SoC side) to
be powered when the rest of the system is off.

Signed-off-by: Paul Kocialkowski <contact-W9ppeneeCTY@public.gmane.org>

diff --git a/drivers/mfd/axp20x.c b/drivers/mfd/axp20x.c
index 2468b431bb22..7847f5d0b979 100644
--- a/drivers/mfd/axp20x.c
+++ b/drivers/mfd/axp20x.c
@@ -34,6 +34,16 @@
 #define AXP806_REG_ADDR_EXT_ADDR_MASTER_MODE	0
 #define AXP806_REG_ADDR_EXT_ADDR_SLAVE_MODE	BIT(4)
 
+#define AXP20X_CHRG_BAK_CTRL_ENABLE		BIT(7)
+#define AXP20X_CHRG_BAK_VOLTAGE_3100_MV		(0 << 5)
+#define AXP20X_CHRG_BAK_VOLTAGE_3000_MV		(1 << 5)
+#define AXP20X_CHRG_BAK_VOLTAGE_3600_MV		(2 << 5)
+#define AXP20X_CHRG_BAK_VOLTAGE_2500_MV		(3 << 5)
+#define AXP20X_CHRG_BAK_CURRENT_50_UA		(0 << 0)
+#define AXP20X_CHRG_BAK_CURRENT_100_UA		(1 << 0)
+#define AXP20X_CHRG_BAK_CURRENT_200_UA		(2 << 0)
+#define AXP20X_CHRG_BAK_CURRENT_400_UA		(3 << 0)
+
 static const char * const axp20x_model_names[] = {
 	"AXP152",
 	"AXP202",
@@ -894,6 +904,63 @@ static void axp20x_power_off(void)
 	msleep(500);
 }
 
+static void axp20x_backup_setup(struct axp20x_dev *axp20x)
+{
+	u32 backup[2];
+	int reg;
+	int ret;
+
+	ret = of_property_read_u32_array(axp20x->dev->of_node, "backup", backup,
+					 2);
+	if (ret != 0)
+		return;
+
+	switch (axp20x->variant) {
+	case AXP202_ID:
+	case AXP209_ID:
+		reg = AXP20X_CHRG_BAK_CTRL_ENABLE;
+
+		/* Charging voltage. */
+		switch (backup[0]) {
+		case 2500:
+			reg |= AXP20X_CHRG_BAK_VOLTAGE_2500_MV;
+			break;
+		case 3000:
+			reg |= AXP20X_CHRG_BAK_VOLTAGE_3000_MV;
+			break;
+		case 3100:
+			reg |= AXP20X_CHRG_BAK_VOLTAGE_3100_MV;
+			break;
+		case 3600:
+			reg |= AXP20X_CHRG_BAK_VOLTAGE_3600_MV;
+			break;
+		default:
+			return;
+		}
+
+		/* Charging current. */
+		switch (backup[1]) {
+		case 50:
+			reg |= AXP20X_CHRG_BAK_CURRENT_50_UA;
+			break;
+		case 100:
+			reg |= AXP20X_CHRG_BAK_CURRENT_100_UA;
+			break;
+		case 200:
+			reg |= AXP20X_CHRG_BAK_CURRENT_200_UA;
+			break;
+		case 400:
+			reg |= AXP20X_CHRG_BAK_CURRENT_400_UA;
+			break;
+		default:
+			return;
+		}
+
+		regmap_write(axp20x->regmap, AXP20X_CHRG_BAK_CTRL, reg);
+		break;
+	}
+}
+
 int axp20x_match_device(struct axp20x_dev *axp20x)
 {
 	struct device *dev = axp20x->dev;
@@ -1023,6 +1090,9 @@ int axp20x_device_probe(struct axp20x_dev *axp20x)
 				     AXP806_REG_ADDR_EXT_ADDR_SLAVE_MODE);
 	}
 
+	/* Backup RTC battery. */
+	axp20x_backup_setup(axp20x);
+
 	ret = regmap_add_irq_chip(axp20x->regmap, axp20x->irq,
 			  IRQF_ONESHOT | IRQF_SHARED | axp20x->irq_flags,
 			   -1, axp20x->regmap_irq_chip, &axp20x->regmap_irqc);
-- 
2.15.1

Re: [PATCH 2/3] mfd: axp20x: Add support for backup battery charging

[Lee Jones]

On Sat, 30 Dec 2017, Paul Kocialkowski wrote:

> This adds support for backup battery charging for axp20x PMICs, that is
> configured through a dedicated device-tree property.
> 
> It supports 4 different charging voltages and as many charging currents.
> This is especially useful to allow the on-chip RTC (on the SoC side) to
> be powered when the rest of the system is off.
> 
> Signed-off-by: Paul Kocialkowski <contact-W9ppeneeCTY@public.gmane.org>
> 
> diff --git a/drivers/mfd/axp20x.c b/drivers/mfd/axp20x.c
> index 2468b431bb22..7847f5d0b979 100644
> --- a/drivers/mfd/axp20x.c
> +++ b/drivers/mfd/axp20x.c
> @@ -34,6 +34,16 @@
>  #define AXP806_REG_ADDR_EXT_ADDR_MASTER_MODE	0
>  #define AXP806_REG_ADDR_EXT_ADDR_SLAVE_MODE	BIT(4)
>  
> +#define AXP20X_CHRG_BAK_CTRL_ENABLE		BIT(7)
> +#define AXP20X_CHRG_BAK_VOLTAGE_3100_MV		(0 << 5)
> +#define AXP20X_CHRG_BAK_VOLTAGE_3000_MV		(1 << 5)
> +#define AXP20X_CHRG_BAK_VOLTAGE_3600_MV		(2 << 5)
> +#define AXP20X_CHRG_BAK_VOLTAGE_2500_MV		(3 << 5)
> +#define AXP20X_CHRG_BAK_CURRENT_50_UA		(0 << 0)
> +#define AXP20X_CHRG_BAK_CURRENT_100_UA		(1 << 0)
> +#define AXP20X_CHRG_BAK_CURRENT_200_UA		(2 << 0)
> +#define AXP20X_CHRG_BAK_CURRENT_400_UA		(3 << 0)
> +
>  static const char * const axp20x_model_names[] = {
>  	"AXP152",
>  	"AXP202",
> @@ -894,6 +904,63 @@ static void axp20x_power_off(void)
>  	msleep(500);
>  }
>  
> +static void axp20x_backup_setup(struct axp20x_dev *axp20x)
> +{
> +	u32 backup[2];
> +	int reg;
> +	int ret;
> +
> +	ret = of_property_read_u32_array(axp20x->dev->of_node, "backup", backup,
> +					 2);
> +	if (ret != 0)

Nit:
        if (ret)

> +		return;
> +
> +	switch (axp20x->variant) {
> +	case AXP202_ID:
> +	case AXP209_ID:

Nested switch statements, hmm ...

Instead, what if you either only invoked this function for supported
devices, or at least returned early for non-supported ones?

if (axp20x->variant != AXP202_ID && axp20x->variant != AXP209_ID)
        return;

> +		reg = AXP20X_CHRG_BAK_CTRL_ENABLE;
> +
> +		/* Charging voltage. */
> +		switch (backup[0]) {
> +		case 2500:
> +			reg |= AXP20X_CHRG_BAK_VOLTAGE_2500_MV;
> +			break;
> +		case 3000:
> +			reg |= AXP20X_CHRG_BAK_VOLTAGE_3000_MV;
> +			break;
> +		case 3100:
> +			reg |= AXP20X_CHRG_BAK_VOLTAGE_3100_MV;
> +			break;
> +		case 3600:
> +			reg |= AXP20X_CHRG_BAK_VOLTAGE_3600_MV;
> +			break;
> +		default:
> +			return;
> +		}
> +
> +		/* Charging current. */
> +		switch (backup[1]) {
> +		case 50:
> +			reg |= AXP20X_CHRG_BAK_CURRENT_50_UA;
> +			break;
> +		case 100:
> +			reg |= AXP20X_CHRG_BAK_CURRENT_100_UA;
> +			break;
> +		case 200:
> +			reg |= AXP20X_CHRG_BAK_CURRENT_200_UA;
> +			break;
> +		case 400:
> +			reg |= AXP20X_CHRG_BAK_CURRENT_400_UA;
> +			break;
> +		default:
> +			return;
> +		}
> +
> +		regmap_write(axp20x->regmap, AXP20X_CHRG_BAK_CTRL, reg);
> +		break;
> +	}
> +}
> +
>  int axp20x_match_device(struct axp20x_dev *axp20x)
>  {
>  	struct device *dev = axp20x->dev;
> @@ -1023,6 +1090,9 @@ int axp20x_device_probe(struct axp20x_dev *axp20x)
>  				     AXP806_REG_ADDR_EXT_ADDR_SLAVE_MODE);
>  	}
>  
> +	/* Backup RTC battery. */
> +	axp20x_backup_setup(axp20x);
> +
>  	ret = regmap_add_irq_chip(axp20x->regmap, axp20x->irq,
>  			  IRQF_ONESHOT | IRQF_SHARED | axp20x->irq_flags,
>  			   -1, axp20x->regmap_irq_chip, &axp20x->regmap_irqc);

-- 
Lee Jones
Linaro Services Technical Lead
Linaro.org │ Open source software for ARM SoCs
Follow Linaro: Facebook | Twitter | Blog

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[PATCH 3/3] ARM: dts: sun7i: lamobo-r1: Add backup battery charging property

[Paul Kocialkowski]

This adds the axp20x backup property to the lamobo-r1 device-tree,
that allows charging the backup battery attached to its AXP209.

It is especially useful since the battery is used for the RTC module.

Signed-off-by: Paul Kocialkowski <contact-W9ppeneeCTY@public.gmane.org>

diff --git a/arch/arm/boot/dts/sun7i-a20-lamobo-r1.dts b/arch/arm/boot/dts/sun7i-a20-lamobo-r1.dts
index 442f3c755f36..e218fd8ea94f 100644
--- a/arch/arm/boot/dts/sun7i-a20-lamobo-r1.dts
+++ b/arch/arm/boot/dts/sun7i-a20-lamobo-r1.dts
@@ -207,6 +207,8 @@
 		reg = <0x34>;
 		interrupt-parent = <&nmi_intc>;
 		interrupts = <0 IRQ_TYPE_LEVEL_LOW>;
+
+		backup = <3000 200>;
 	};
 };
 
-- 
2.15.1