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drivers/rtc/rtc-palmas.c: support for backup battery charging

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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>
Reviewed-by: Felipe Balbi <balbi@ti.com>
Acked-by: Kumar Gala <galak@codeaurora.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Laxman Dewangan 2013-09-11 14:24:19 -07:00 committed by Linus Torvalds
parent 8af750e3f5
commit 666a584d3a
2 changed files with 68 additions and 0 deletions
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33
Documentation/devicetree/bindings/rtc/rtc-palmas.txt Normal file
View file

@ -0,0 +1,33 @@
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,backup-battery-chargeable: The Palmas series device like TPS65913 or
TPS80036 supports the backup battery for powering the RTC when main
battery is removed or in very low power state. The backup battery
can be chargeable or non-chargeable. This flag will tells whether
battery is chargeable or not. If charging battery then driver can
enable the charging.
- ti,backup-battery-charge-high-current: Enable high current charging in
backup battery. Device supports the < 100mA and > 100mA charging.
The high current will be > 100mA. Absence of this property will
charge battery to lower current i.e. < 100mA.
Example:
palmas: tps65913@58 {
...
palmas_rtc: rtc {
compatible = "ti,palmas-rtc";
interrupt-parent = <&palmas>;
interrupts = <8 0>;
ti,backup-battery-chargeable;
ti,backup-battery-charge-high-current;
};
...
};

35
drivers/rtc/rtc-palmas.c
View file

@ -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 high_bb_charging;
if (pdev->dev.of_node) {
enable_bb_charging = of_property_read_bool(pdev->dev.of_node,
"ti,backup-battery-chargeable");
high_bb_charging = of_property_read_bool(pdev->dev.of_node,
"ti,backup-battery-charge-high-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 = PALMAS_BACKUP_BATTERY_CTRL_BBS_BBC_LOW_ICHRG;
if (high_bb_charging)
reg = 0;
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,