[U-Boot] [PATCH v3] rtc: Add DM support to ds3231

[Lukasz Majewski]

On Fri, 21 Jun 2019 12:17:00 +0800
Chuanhua Han <chuanhua.han at nxp.com> wrote:

> Add an implementation of the ds3231 driver that uses the driver
> model i2c APIs.
> 
> Signed-off-by: Chuanhua Han <chuanhua.han at nxp.com>
> ---
> Changes in v3:
> 	- Update copyright information.
> 
> Changes in v2: 
>         - Replace "#ifndef CONFIG_DM_RTC" with
> "#if !CONFIG_IS_ENABLED(DM_RTC)"
> 
>  drivers/rtc/ds3231.c | 108
> +++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 108
> insertions(+)
> 
> diff --git a/drivers/rtc/ds3231.c b/drivers/rtc/ds3231.c
> index 9352ff87a2..86f1c3e899 100644
> --- a/drivers/rtc/ds3231.c
> +++ b/drivers/rtc/ds3231.c
> @@ -2,6 +2,9 @@
>  /*
>   * (C) Copyright 2006
>   * Markus Klotzbuecher, mk at denx.de
> + *
> + * (C) Copyright 2019 NXP
> + * Chuanhua Han <chuanhua.han at nxp.com>
>   */
>  
>  /*
> @@ -13,6 +16,7 @@
>  
>  #include <common.h>
>  #include <command.h>
> +#include <dm.h>
>  #include <rtc.h>
>  #include <i2c.h>
>  
> @@ -50,6 +54,7 @@
>  #define RTC_STAT_BIT_EN32KHZ	0x8	/* Enable 32KHz
> Output  */ 
>  
> +#if !CONFIG_IS_ENABLED(DM_RTC)
>  static uchar rtc_read (uchar reg);
>  static void rtc_write (uchar reg, uchar val);
>  
> @@ -164,3 +169,106 @@ static void rtc_write (uchar reg, uchar val)
>  {
>  	i2c_reg_write (CONFIG_SYS_I2C_RTC_ADDR, reg, val);
>  }
> +#else
> +static int ds3231_rtc_get(struct udevice *dev, struct rtc_time *tmp)
> +{
> +	int rel = 0;
> +	uchar sec, min, hour, mday, wday, mon_cent, year, status;
> +
> +	status = dm_i2c_reg_read(dev, RTC_STAT_REG_ADDR);
> +	sec = dm_i2c_reg_read(dev, RTC_SEC_REG_ADDR);
> +	min = dm_i2c_reg_read(dev, RTC_MIN_REG_ADDR);
> +	hour = dm_i2c_reg_read(dev, RTC_HR_REG_ADDR);
> +	wday = dm_i2c_reg_read(dev, RTC_DAY_REG_ADDR);
> +	mday = dm_i2c_reg_read(dev, RTC_DATE_REG_ADDR);
> +	mon_cent = dm_i2c_reg_read(dev, RTC_MON_REG_ADDR);
> +	year = dm_i2c_reg_read(dev, RTC_YR_REG_ADDR);
> +
> +	if (status & RTC_STAT_BIT_OSF) {
> +		printf("### Warning: RTC oscillator has stopped\n");
> +		/* clear the OSF flag */
> +		dm_i2c_reg_write(dev, RTC_STAT_REG_ADDR,
> +				 dm_i2c_reg_read(dev,
> RTC_STAT_REG_ADDR)
> +						& ~RTC_STAT_BIT_OSF);
> +		rel = -1;

A few remarks regarding above code:

1. By conversion we do use 'ret' instead of 'rel'. Is the 'rel' name
itself here important?

2. The OSF bit - why shall we return from ds3231_rtc_get() with -1 (by
convention it is an error) if this flag is set? 

3. The '-1' value does not show the real reason for the error. Maybe
some standard value (like e.g. -EINVAL, -ENODEV, -EIO) from errno.h
would be more appropriate?

> +	}
> +
> +	tmp->tm_sec  = bcd2bin(sec & 0x7F);
> +	tmp->tm_min  = bcd2bin(min & 0x7F);
> +	tmp->tm_hour = bcd2bin(hour & 0x3F);
> +	tmp->tm_mday = bcd2bin(mday & 0x3F);
> +	tmp->tm_mon  = bcd2bin(mon_cent & 0x1F);
> +	tmp->tm_year = bcd2bin(year) + ((mon_cent & 0x80) ? 2000 :
> 1900);
> +	tmp->tm_wday = bcd2bin((wday - 1) & 0x07);
> +	tmp->tm_yday = 0;
> +	tmp->tm_isdst = 0;
> +
> +	debug("Get DATE: %4d-%02d-%02d (wday=%d)  TIME:
> %2d:%02d:%02d\n",
> +	      tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_wday,
> +	      tmp->tm_hour, tmp->tm_min, tmp->tm_sec);
> +
> +	return rel;
> +}
> +
> +static int ds3231_rtc_set(struct udevice *dev, const struct rtc_time
> *tmp) +{
> +	uchar century;
> +
> +	debug("Set DATE: %4d-%02d-%02d (wday=%d)  TIME:
> %2d:%02d:%02d\n",
> +	      tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_wday,
> +	      tmp->tm_hour, tmp->tm_min, tmp->tm_sec);
> +
> +	dm_i2c_reg_write(dev, RTC_YR_REG_ADDR, bin2bcd(tmp->tm_year
> % 100)); +
> +	century = (tmp->tm_year >= 2000) ? 0x80 : 0;
> +	dm_i2c_reg_write(dev, RTC_MON_REG_ADDR, bin2bcd(tmp->tm_mon)
> | century); +
> +	dm_i2c_reg_write(dev, RTC_DAY_REG_ADDR, bin2bcd(tmp->tm_wday
> + 1));
> +	dm_i2c_reg_write(dev, RTC_DATE_REG_ADDR,
> bin2bcd(tmp->tm_mday));
> +	dm_i2c_reg_write(dev, RTC_HR_REG_ADDR,
> bin2bcd(tmp->tm_hour));
> +	dm_i2c_reg_write(dev, RTC_MIN_REG_ADDR,
> bin2bcd(tmp->tm_min));
> +	dm_i2c_reg_write(dev, RTC_SEC_REG_ADDR,
> bin2bcd(tmp->tm_sec)); +
> +	return 0;
> +}
> +
> +static int ds3231_rtc_reset(struct udevice *dev)
> +{
> +	int ret;
> +
> +	ret = dm_i2c_reg_write(dev, RTC_CTL_REG_ADDR,
> +			       RTC_CTL_BIT_RS1 | RTC_CTL_BIT_RS2);
> +	if (ret < 0)
> +		return ret;
> +
> +	return 0;
> +}
> +
> +static int ds3231_probe(struct udevice *dev)
> +{
> +	i2c_set_chip_flags(dev, DM_I2C_CHIP_RD_ADDRESS |
> +			DM_I2C_CHIP_WR_ADDRESS);
> +
> +	return 0;
> +}
> +
> +static const struct rtc_ops ds3231_rtc_ops = {
> +	.get = ds3231_rtc_get,
> +	.set = ds3231_rtc_set,
> +	.reset = ds3231_rtc_reset,
> +};
> +
> +static const struct udevice_id ds3231_rtc_ids[] = {
> +	{ .compatible = "dallas,ds3231" },
> +	{ .compatible = "dallas,ds3232" },
> +	{ }
> +};
> +
> +U_BOOT_DRIVER(rtc_ds3231) = {
> +	.name   = "rtc-ds3231",
> +	.id     = UCLASS_RTC,
> +	.probe  = ds3231_probe,
> +	.of_match = ds3231_rtc_ids,
> +	.ops    = &ds3231_rtc_ops,
> +};
> +#endif




Best regards,

Lukasz Majewski

--

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