Re: [U-Boot] [PATCH v2] rtc: ds3232/ds3231: Add support to generate 32KHz output for driver module

2019-07-23 Thread Wolfgang Denk 
Dear Chuanhua Han,

In message <20190723095745.37138-1-chuanhua@nxp.com> you wrote:
> This patch add an implementation of the rtc_enable_32khz_output() that
> uses the driver model i2c APIs.
>
> Signed-off-by: Chuanhua Han 
> ---
> Change in v2:
>   - Add RTC_ENABLE_32KHZ_OUTPUT option so this code compiles only 
> in that cases where it is really useful.

So when exactly is it useful?

If I understand correctly, there are no users of this code in
mainline.  Should the patch then not be part of a patch series that
adds such users?

Adding potentially "useful" code just on speculation is not nice
maintenance-wise.

I recommend to withdraw this patch and submit it together with some
real consumer of this feature.

Thanks.

Best regards,

Wolfgang Denk

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[U-Boot] [PATCH v2] rtc: ds3232/ds3231: Add support to generate 32KHz output for driver module

2019-07-23 Thread 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 
---
Change in v2:
- Add RTC_ENABLE_32KHZ_OUTPUT option so this code compiles only 
in that cases where it is really useful.

 drivers/rtc/Kconfig  | 10 ++
 drivers/rtc/ds3231.c | 21 +
 include/rtc.h|  6 ++
 3 files changed, 37 insertions(+)

diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig
index fd0009b..040d241 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
@@ -41,6 +47,10 @@ config RTC_PCF2127
  has a selectable I2C-bus or SPI-bus, a backup battery switch-over 
circuit, a
  programmable watchdog function, a timestamp function, and many other 
features.
 
+config DS3231_BUS_NUM
+   hex "I2C bus of the DS3231 device"
+   default 0
+
 config RTC_DS1307
bool "Enable DS1307 driver"
depends on DM_RTC
diff --git a/drivers/rtc/ds3231.c b/drivers/rtc/ds3231.c
index 79b026a..dbd77a6 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 +253,25 @@ static int ds3231_probe(struct udevice *dev)
return 0;
 }
 
+#ifdef CONFIG_RTC_ENABLE_32KHZ_OUTPUT
+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, );
+#else
+   ret = i2c_get_chip_for_busnum(0, CONFIG_SYS_I2C_RTC_ADDR, 1, );
+#endif
+   if (!ret)
+   dm_i2c_reg_write(dev, RTC_STAT_REG_ADDR,
+RTC_STAT_BIT_BB32KHZ |
+RTC_STAT_BIT_EN32KHZ);
+}
+#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..df7de09 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
+void rtc_enable_32khz_output(void);
+#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

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