This patch introduces device tree binding for the RTC backup battery charger
on TWL4030.
Tested on Gumstix Overo (OMAP3) Tobi.
Signed-off-by: Adam YH Lee <adam.yh.lee@xxxxxxxxx>
---
Documentation/devicetree/bindings/rtc/twl-rtc.txt | 20 ++++++++++++
drivers/rtc/rtc-twl.c | 39 +++++++++++++++++++++++
2 files changed, 59 insertions(+)
diff --git a/Documentation/devicetree/bindings/rtc/twl-rtc.txt b/Documentation/devicetree/bindings/rtc/twl-rtc.txt
index 596e0c9..fcb0c4d 100644
--- a/Documentation/devicetree/bindings/rtc/twl-rtc.txt
+++ b/Documentation/devicetree/bindings/rtc/twl-rtc.txt
@@ -5,8 +5,28 @@ The TWL family (twl4030/6030) contains a RTC.
Required properties:
- compatible : Should be twl4030-rtc
+Optional properties:
+- enable-battery-charge: Boolean, enable RTC battery charge
+
+- charge-rate : should contain trickle charge rate:
+
+ 25uA - <0x0>
+ 150uA - <0x1>
+ 500uA - <0x2>
+ 1mA - <0x3>
+
+- charge-voltage : should contain charge voltage:
+
+ 2.5v - <0x0>
+ 3.0v - <0x4>
+ 3.1v - <0x8>
+ 3.2v - <0xc>
+
Examples:
rtc@0 {
compatible = "ti,twl4030-rtc";
+ enable-battery-charge;
+ charge-rate = <0x1>;
+ charge-voltage = <0x8>;
};
diff --git a/drivers/rtc/rtc-twl.c b/drivers/rtc/rtc-twl.c
index 1915464..0c3e855 100644
--- a/drivers/rtc/rtc-twl.c
+++ b/drivers/rtc/rtc-twl.c
@@ -31,6 +31,13 @@
#include <linux/i2c/twl.h>
+/*
+ * PM_RECEIVER block register offsets (use TWL4030_MODULE_PM_RECEIVER)
+ */
+#define REG_BB_CFG 0x12
+
+/* PM_RECEIVER BB_CFG bitfield */
+#define BIT_PM_RECEIVER_BB_CFG_BBCHEN 0x10
/*
* RTC block register offsets (use TWL_MODULE_RTC)
@@ -474,8 +481,11 @@ static struct rtc_class_ops twl_rtc_ops = {
static int twl_rtc_probe(struct platform_device *pdev)
{
struct rtc_device *rtc;
+ struct device_node *node = pdev->dev.of_node;
int ret = -EINVAL;
int irq = platform_get_irq(pdev, 0);
+ const __be32 *charge_volt = NULL;
+ const __be32 *charge_rate = NULL;
u8 rd_reg;
if (irq <= 0)
@@ -543,6 +553,35 @@ static int twl_rtc_probe(struct platform_device *pdev)
return ret;
}
+#ifdef CONFIG_OF
+ if (of_property_read_bool(node, "enable-battery-charge") == true) {
+ charge_rate = of_get_property(node, "charge-rate", NULL);
+ if (charge_rate == NULL) {
+ dev_err(&pdev->dev, "Backup battery charge rate is missing\n");
+ return ret;
+ }
+ charge_volt = of_get_property(node, "charge-voltage", NULL);
+ if (charge_volt == NULL) {
+ dev_err(&pdev->dev, "Backup battery charge voltage is missing\n");
+ return ret;
+ }
+ ret = twl_i2c_write_u8(TWL_MODULE_PM_RECEIVER,
+ BIT_PM_RECEIVER_BB_CFG_BBCHEN |
+ be32_to_cpup(charge_volt) |
+ be32_to_cpup(charge_rate),
+ REG_BB_CFG);
+ if (ret < 0) {
+ dev_err(&pdev->dev, "Failed to enable backup battery charging\n");
+ return ret;
+ }
+
+ dev_info(&pdev->dev, "RTC backup charge enabled\n");
+ } else {
+ twl_i2c_write_u8(TWL_MODULE_PM_RECEIVER, 0x0, REG_BB_CFG);
+ dev_info(&pdev->dev, "RTC backup charge disabled\n");
+ }
+#endif
+
platform_set_drvdata(pdev, rtc);
return 0;
}
--
1.9.1
--
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