[U-Boot] [PATCH] rtc: ds3232/ds3231: Add support to generate 32KHz output for driver module

[Chuanhua Han <chuanhua.han@nxp.com>]

This patch add an implementation of the rtc_enable_32khz_output() that
uses the driver model i2c APIs.

Signed-off-by: Chuanhua Han <chuanhua.han@nxp.com>
---
 drivers/rtc/ds3231.c | 17 +++++++++++++++++
 include/rtc.h        |  1 +
 2 files changed, 18 insertions(+)

diff --git a/drivers/rtc/ds3231.c b/drivers/rtc/ds3231.c
index 79b026a..2f7bbc2 100644
--- a/drivers/rtc/ds3231.c
+++ b/drivers/rtc/ds3231.c
@@ -251,6 +251,23 @@ static int ds3231_probe(struct udevice *dev)
 	return 0;
 }
 
+void rtc_enable_32khz_output(void)
+{
+	int ret;
+	struct udevice *dev;
+
+#ifdef CONFIG_DS3231_BUS_NUM
+	ret = i2c_get_chip_for_busnum(CONFIG_DS3231_BUS_NUM,
+				      CONFIG_SYS_I2C_RTC_ADDR, 1, &dev);
+#else
+	ret = i2c_get_chip_for_busnum(0, CONFIG_SYS_I2C_RTC_ADDR, 1, &dev);
+#endif
+	if (!ret)
+		dm_i2c_reg_write(dev, RTC_STAT_REG_ADDR,
+				 RTC_STAT_BIT_BB32KHZ |
+				 RTC_STAT_BIT_EN32KHZ);
+}
+
 static const struct rtc_ops ds3231_rtc_ops = {
 	.get = ds3231_rtc_get,
 	.set = ds3231_rtc_set,
diff --git a/include/rtc.h b/include/rtc.h
index b255bdc..690391e 100644
--- a/include/rtc.h
+++ b/include/rtc.h
@@ -166,6 +166,7 @@ int rtc_read32(struct udevice *dev, unsigned int reg, u32 *valuep);
  */
 int rtc_write32(struct udevice *dev, unsigned int reg, u32 value);
 
+void rtc_enable_32khz_output(void);
 #else
 int rtc_get (struct rtc_time *);
 int rtc_set (struct rtc_time *);
-- 
2.9.5