[U-Boot] [PATCH v4 1/4] rtc: ds3232/ds3231: Add support to generate 32KHz output for driver module

[Chuanhua Han]

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 at nxp.com>
---
depends on:
  - http://patchwork.ozlabs.org/project/uboot/list/?series=118772
  - http://patchwork.ozlabs.org/project/uboot/list/?series=117226

Changes in v4:
	- No change.
Changes in v3:
	- Delete something about DS3231_BUS_NUM
	- Modify the interface and definition of rtc_enable_32khz_output function
Changes in v2:
	- No change.

 drivers/rtc/Kconfig  |  6 ++++++
 drivers/rtc/ds3231.c | 17 +++++++++++++++++
 include/rtc.h        |  6 ++++++
 3 files changed, 29 insertions(+)

diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig
index fd0009b..cf15914 100644
--- a/drivers/rtc/Kconfig
+++ b/drivers/rtc/Kconfig
@@ -31,6 +31,12 @@ config TPL_DM_RTC
 	  drivers to perform the actual functions. See rtc.h for a
 	  description of the API.
 
+config RTC_ENABLE_32KHZ_OUTPUT
+	bool "Enable RTC 32Khz output"
+	help
+	   Some real-time clocks support the output of 32kHz square waves (such as ds3231),
+	   the config symbol choose Real Time Clock device 32Khz output feature.
+
 config RTC_PCF2127
 	bool "Enable PCF2127 driver"
 	depends on DM_RTC
diff --git a/drivers/rtc/ds3231.c b/drivers/rtc/ds3231.c
index 79b026a..fde4d86 100644
--- a/drivers/rtc/ds3231.c
+++ b/drivers/rtc/ds3231.c
@@ -148,11 +148,13 @@ void rtc_reset (void)
 /*
  * Enable 32KHz output
  */
+#ifdef CONFIG_RTC_ENABLE_32KHZ_OUTPUT
 void rtc_enable_32khz_output(void)
 {
 	rtc_write(RTC_STAT_REG_ADDR,
 		  RTC_STAT_BIT_BB32KHZ | RTC_STAT_BIT_EN32KHZ);
 }
+#endif
 
 /*
  * Helper functions
@@ -251,6 +253,21 @@ static int ds3231_probe(struct udevice *dev)
 	return 0;
 }
 
+#ifdef CONFIG_RTC_ENABLE_32KHZ_OUTPUT
+int rtc_enable_32khz_output(int busnum, int chip_addr)
+{
+	int ret;
+	struct udevice *dev;
+
+	ret = i2c_get_chip_for_busnum(busnum, chip_addr, 1, &dev);
+	if (!ret)
+		ret = dm_i2c_reg_write(dev, RTC_STAT_REG_ADDR,
+				       RTC_STAT_BIT_BB32KHZ |
+				       RTC_STAT_BIT_EN32KHZ);
+	return ret;
+}
+#endif
+
 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..7386d52 100644
--- a/include/rtc.h
+++ b/include/rtc.h
@@ -166,11 +166,17 @@ int rtc_read32(struct udevice *dev, unsigned int reg, u32 *valuep);
  */
 int rtc_write32(struct udevice *dev, unsigned int reg, u32 value);
 
+#ifdef CONFIG_RTC_ENABLE_32KHZ_OUTPUT
+int rtc_enable_32khz_output(int busnum, int chip_addr);
+#endif
+
 #else
 int rtc_get (struct rtc_time *);
 int rtc_set (struct rtc_time *);
 void rtc_reset (void);
+#ifdef CONFIG_RTC_ENABLE_32KHZ_OUTPUT
 void rtc_enable_32khz_output(void);
+#endif
 
 /**
  * rtc_read8() - Read an 8-bit register
-- 
2.9.5