Patchwork [V2] drivers/rtc/rtc-palmas.c: support for backup battery charging

login
register
mail settings
Submitter Laxman Dewangan
Date Aug. 1, 2013, 2:31 p.m.
Message ID <1375367471-29908-1-git-send-email-ldewangan@nvidia.com>
Download mbox | patch
Permalink /patch/264026/
State New
Headers show

Comments

Laxman Dewangan - Aug. 1, 2013, 2:31 p.m.
Palmas series device like TPS65913, TPS80036 supports the backup battery
for powering the RTC when no other energy source is available.

The backup battery is optional, connected to the VBACKUP pin, and can be
nonrechargeable or rechargeable. The rechargeable battery can be charged
from the system supply using the backup battery charger.

Add support for enabling charging of this backup battery.  Also add the DT
binding document and the new properties to have this support.

Signed-off-by: Laxman Dewangan <ldewangan@nvidia.com>
---
Changes from V1:
- Converted DT property to boolean.
- cleanups as use "...".

 .../devicetree/bindings/rtc/rtc-palmas.txt         |   28 ++++++++++++++++
 drivers/rtc/rtc-palmas.c                           |   35 ++++++++++++++++++++
 2 files changed, 63 insertions(+), 0 deletions(-)
 create mode 100644 Documentation/devicetree/bindings/rtc/rtc-palmas.txt
Felipe Balbi - Aug. 1, 2013, 3:09 p.m.
Hi,

On Thu, Aug 01, 2013 at 08:01:11PM +0530, Laxman Dewangan wrote:
> Palmas series device like TPS65913, TPS80036 supports the backup battery
> for powering the RTC when no other energy source is available.
> 
> The backup battery is optional, connected to the VBACKUP pin, and can be
> nonrechargeable or rechargeable. The rechargeable battery can be charged
> from the system supply using the backup battery charger.
> 
> Add support for enabling charging of this backup battery.  Also add the DT
> binding document and the new properties to have this support.
> 
> Signed-off-by: Laxman Dewangan <ldewangan@nvidia.com>
> ---
> Changes from V1:
> - Converted DT property to boolean.
> - cleanups as use "...".
> 
>  .../devicetree/bindings/rtc/rtc-palmas.txt         |   28 ++++++++++++++++
>  drivers/rtc/rtc-palmas.c                           |   35 ++++++++++++++++++++
>  2 files changed, 63 insertions(+), 0 deletions(-)
>  create mode 100644 Documentation/devicetree/bindings/rtc/rtc-palmas.txt
> 
> diff --git a/Documentation/devicetree/bindings/rtc/rtc-palmas.txt b/Documentation/devicetree/bindings/rtc/rtc-palmas.txt
> new file mode 100644
> index 0000000..c8c9def
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/rtc/rtc-palmas.txt
> @@ -0,0 +1,28 @@
> +Palmas RTC controller bindings
> +
> +Required properties:
> +- compatible:
> +  - "ti,palmas-rtc" for palma series of the RTC controller
> +- interrupt-parent: Parent interrupt device, must be handle of palmas node.
> +- interrupts: Interrupt number of RTC submodule on device.
> +
> +Optional properties:
> +- ti,back-battery-charge-enable: The palmas series device like TPS65913 or
> +	TPS80036 supports the battery backup for powering the RTC when main
> +	battery is removed or in very low power state. This flag will enable
> +	the backup battery charging.
> +- ti,back-charge-low-current: Configure lower charging current. Device supports the
> +	charging current as < 100mA or >100mA. Low current will set as <100mA.
> +
> +Example:
> +	palmas: tps65913@58 {
> +		...
> +		palmas_rtc: rtc {
> +			compatible = "ti,palmas-rtc";
> +			interrupt-parent = <&palmas>;
> +			interrupts = <8 0>;
> +			ti,back-battery-charge-enable;
> +			ti,back-charge-low-current;
> +		};
> +		...
> +	};
> diff --git a/drivers/rtc/rtc-palmas.c b/drivers/rtc/rtc-palmas.c
> index a1fecc8..7f34e33 100644
> --- a/drivers/rtc/rtc-palmas.c
> +++ b/drivers/rtc/rtc-palmas.c
> @@ -238,6 +238,15 @@ static int palmas_rtc_probe(struct platform_device *pdev)
>  	struct palmas *palmas = dev_get_drvdata(pdev->dev.parent);
>  	struct palmas_rtc *palmas_rtc = NULL;
>  	int ret;
> +	bool enable_bb_charging = false;
> +	bool low_bb_charging;
> +
> +	if (pdev->dev.of_node) {
> +		enable_bb_charging = of_property_read_bool(pdev->dev.of_node,
> +					"ti,back-battery-charge-enable");
> +		low_bb_charging = of_property_read_bool(pdev->dev.of_node,
> +					"ti,back-charge-low-current");
> +	}
>  
>  	palmas_rtc = devm_kzalloc(&pdev->dev, sizeof(struct palmas_rtc),
>  			GFP_KERNEL);
> @@ -254,6 +263,32 @@ static int palmas_rtc_probe(struct platform_device *pdev)
>  	palmas_rtc->dev = &pdev->dev;
>  	platform_set_drvdata(pdev, palmas_rtc);
>  
> +	if (enable_bb_charging) {
> +		unsigned reg = 0;
> +
> +		if (low_bb_charging)
> +			reg |= PALMAS_BACKUP_BATTERY_CTRL_BBS_BBC_LOW_ICHRG;
> +
> +		ret = palmas_update_bits(palmas, PALMAS_PMU_CONTROL_BASE,
> +			PALMAS_BACKUP_BATTERY_CTRL,
> +			PALMAS_BACKUP_BATTERY_CTRL_BBS_BBC_LOW_ICHRG, reg);
> +		if (ret < 0) {
> +			dev_err(&pdev->dev,
> +				"BACKUP_BATTERY_CTRL update failed, %d\n", ret);
> +			return ret;
> +		}
> +
> +		ret = palmas_update_bits(palmas, PALMAS_PMU_CONTROL_BASE,
> +			PALMAS_BACKUP_BATTERY_CTRL,
> +			PALMAS_BACKUP_BATTERY_CTRL_BB_CHG_EN,
> +			PALMAS_BACKUP_BATTERY_CTRL_BB_CHG_EN);
> +		if (ret < 0) {
> +			dev_err(&pdev->dev,
> +				"BACKUP_BATTERY_CTRL update failed, %d\n", ret);
> +			return ret;
> +		}

I wonder if this should be exposed via power_supply class, although it's
not really a power supply. So perhaps not needed :-s

looks good though (can't test as I don't have any boards available right
now):

Reviewed-by: Felipe Balbi <balbi@ti.com>
Laxman Dewangan - Aug. 1, 2013, 3:33 p.m.
On Thursday 01 August 2013 08:39 PM, Felipe Balbi wrote:
> * PGP Signed by an unknown key
>
> Hi,
>
> On Thu, Aug 01, 2013 at 08:01:11PM +0530, Laxman Dewangan wrote:
> I wonder if this should be exposed via power_supply class, although it's
> not really a power supply. So perhaps not needed :-s

Yes, there is another charger module on the device which actually need 
the driver through power supply. Charger submodule used for charging the 
main battery through USB VBUS.




>
> looks good though (can't test as I don't have any boards available right
> now):
>
> Reviewed-by: Felipe Balbi <balbi@ti.com>

Thanks for review.
>
Stephen Warren - Aug. 1, 2013, 4:44 p.m.
On 08/01/2013 08:31 AM, Laxman Dewangan wrote:
> Palmas series device like TPS65913, TPS80036 supports the backup battery
> for powering the RTC when no other energy source is available.
> 
> The backup battery is optional, connected to the VBACKUP pin, and can be
> nonrechargeable or rechargeable. The rechargeable battery can be charged
> from the system supply using the backup battery charger.
> 
> Add support for enabling charging of this backup battery.  Also add the DT
> binding document and the new properties to have this support.

> diff --git a/Documentation/devicetree/bindings/rtc/rtc-palmas.txt b/Documentation/devicetree/bindings/rtc/rtc-palmas.txt

> +Palmas RTC controller bindings
> +
> +Required properties:
> +- compatible:
> +  - "ti,palmas-rtc" for palma series of the RTC controller

Nit: Here is another Palma -vs- Palmas inconsistency. What is the
correct name for the device; Palma or Palmas? Either way, the should
always have an initial capital letter in free-form text (i.e. but not in
property/node names).

Aside from that, the binding looks fine to me now, assuming it's fully
describing the RTC module's functionality. So, the binding,

Reviewed-by: Stephen Warren <swarren@nvidia.com>

Patch

diff --git a/Documentation/devicetree/bindings/rtc/rtc-palmas.txt b/Documentation/devicetree/bindings/rtc/rtc-palmas.txt
new file mode 100644
index 0000000..c8c9def
--- /dev/null
+++ b/Documentation/devicetree/bindings/rtc/rtc-palmas.txt
@@ -0,0 +1,28 @@ 
+Palmas RTC controller bindings
+
+Required properties:
+- compatible:
+  - "ti,palmas-rtc" for palma series of the RTC controller
+- interrupt-parent: Parent interrupt device, must be handle of palmas node.
+- interrupts: Interrupt number of RTC submodule on device.
+
+Optional properties:
+- ti,back-battery-charge-enable: The palmas series device like TPS65913 or
+	TPS80036 supports the battery backup for powering the RTC when main
+	battery is removed or in very low power state. This flag will enable
+	the backup battery charging.
+- ti,back-charge-low-current: Configure lower charging current. Device supports the
+	charging current as < 100mA or >100mA. Low current will set as <100mA.
+
+Example:
+	palmas: tps65913@58 {
+		...
+		palmas_rtc: rtc {
+			compatible = "ti,palmas-rtc";
+			interrupt-parent = <&palmas>;
+			interrupts = <8 0>;
+			ti,back-battery-charge-enable;
+			ti,back-charge-low-current;
+		};
+		...
+	};
diff --git a/drivers/rtc/rtc-palmas.c b/drivers/rtc/rtc-palmas.c
index a1fecc8..7f34e33 100644
--- a/drivers/rtc/rtc-palmas.c
+++ b/drivers/rtc/rtc-palmas.c
@@ -238,6 +238,15 @@  static int palmas_rtc_probe(struct platform_device *pdev)
 	struct palmas *palmas = dev_get_drvdata(pdev->dev.parent);
 	struct palmas_rtc *palmas_rtc = NULL;
 	int ret;
+	bool enable_bb_charging = false;
+	bool low_bb_charging;
+
+	if (pdev->dev.of_node) {
+		enable_bb_charging = of_property_read_bool(pdev->dev.of_node,
+					"ti,back-battery-charge-enable");
+		low_bb_charging = of_property_read_bool(pdev->dev.of_node,
+					"ti,back-charge-low-current");
+	}
 
 	palmas_rtc = devm_kzalloc(&pdev->dev, sizeof(struct palmas_rtc),
 			GFP_KERNEL);
@@ -254,6 +263,32 @@  static int palmas_rtc_probe(struct platform_device *pdev)
 	palmas_rtc->dev = &pdev->dev;
 	platform_set_drvdata(pdev, palmas_rtc);
 
+	if (enable_bb_charging) {
+		unsigned reg = 0;
+
+		if (low_bb_charging)
+			reg |= PALMAS_BACKUP_BATTERY_CTRL_BBS_BBC_LOW_ICHRG;
+
+		ret = palmas_update_bits(palmas, PALMAS_PMU_CONTROL_BASE,
+			PALMAS_BACKUP_BATTERY_CTRL,
+			PALMAS_BACKUP_BATTERY_CTRL_BBS_BBC_LOW_ICHRG, reg);
+		if (ret < 0) {
+			dev_err(&pdev->dev,
+				"BACKUP_BATTERY_CTRL update failed, %d\n", ret);
+			return ret;
+		}
+
+		ret = palmas_update_bits(palmas, PALMAS_PMU_CONTROL_BASE,
+			PALMAS_BACKUP_BATTERY_CTRL,
+			PALMAS_BACKUP_BATTERY_CTRL_BB_CHG_EN,
+			PALMAS_BACKUP_BATTERY_CTRL_BB_CHG_EN);
+		if (ret < 0) {
+			dev_err(&pdev->dev,
+				"BACKUP_BATTERY_CTRL update failed, %d\n", ret);
+			return ret;
+		}
+	}
+
 	/* Start RTC */
 	ret = palmas_update_bits(palmas, PALMAS_RTC_BASE, PALMAS_RTC_CTRL_REG,
 			PALMAS_RTC_CTRL_REG_STOP_RTC,