[rtc-linux] [PATCH v3 0/2] drivers: rtc: rtc-tps65910: Add RTC calibration support

[rtc-linux] [PATCH v3 0/2] drivers: rtc: rtc-tps65910: Add RTC calibration support

[Vesa Jääskeläinen]

Texas Instrument's TPS65910 has support for compensating RTC crystal
inaccuracies. When enabled every hour RTC counter value will be compensated
with two's complement value.

Changes in v3:
  - changed to return 0 when compensation not enabled

Changes in v2:
  - changed to use offset interface

Vesa J=C3=A4=C3=A4skel=C3=A4inen (2):
  drivers: rtc: rtc-tps65910: Add RTC calibration support
  drivers: rtc: rtc-tps65910: use 'unsigned int' instead of 'unsigned'
    in arguments

 drivers/rtc/rtc-tps65910.c   | 146 +++++++++++++++++++++++++++++++++++++++=
+++-
 include/linux/mfd/tps65910.h |   1 +
 2 files changed, 146 insertions(+), 1 deletion(-)

--=20
2.1.4

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[rtc-linux] [PATCH v3 1/2] drivers: rtc: rtc-tps65910: Add RTC calibration support

[Vesa Jääskeläinen]

Texas Instrument's TPS65910 has support for compensating RTC crystal
inaccuracies. When enabled every hour RTC counter value will be compensated
with two's complement value.

Acked-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Vesa J=C3=A4=C3=A4skel=C3=A4inen <vesa.jaaskelainen@vaisala.=
com>
---
Changes in v3:
  - Changed to return 0 from offset when auto compensation is not enabled

Changes in v2:
  - Changed to use offset interface

 drivers/rtc/rtc-tps65910.c   | 143 +++++++++++++++++++++++++++++++++++++++=
++++
 include/linux/mfd/tps65910.h |   1 +
 2 files changed, 144 insertions(+)

diff --git a/drivers/rtc/rtc-tps65910.c b/drivers/rtc/rtc-tps65910.c
index 5a3d53c..9dd1db9 100644
--- a/drivers/rtc/rtc-tps65910.c
+++ b/drivers/rtc/rtc-tps65910.c
@@ -21,6 +21,7 @@
 #include <linux/types.h>
 #include <linux/rtc.h>
 #include <linux/bcd.h>
+#include <linux/math64.h>
 #include <linux/platform_device.h>
 #include <linux/interrupt.h>
 #include <linux/mfd/tps65910.h>
@@ -33,6 +34,19 @@ struct tps65910_rtc {
 /* Total number of RTC registers needed to set time*/
 #define NUM_TIME_REGS	(TPS65910_YEARS - TPS65910_SECONDS + 1)
=20
+/* Total number of RTC registers needed to set compensation registers */
+#define NUM_COMP_REGS	(TPS65910_RTC_COMP_MSB - TPS65910_RTC_COMP_LSB + 1)
+
+/* Min and max values supported with 'offset' interface (swapped sign) */
+#define MIN_OFFSET	(-277761)
+#define MAX_OFFSET	(277778)
+
+/* Number of ticks per hour */
+#define TICKS_PER_HOUR	(32768 * 3600)
+
+/* Multiplier for ppb conversions */
+#define PPB_MULT	(1000000000LL)
+
 static int tps65910_rtc_alarm_irq_enable(struct device *dev, unsigned enab=
led)
 {
 	struct tps65910 *tps =3D dev_get_drvdata(dev->parent);
@@ -187,6 +201,133 @@ static int tps65910_rtc_set_alarm(struct device *dev,=
 struct rtc_wkalrm *alm)
 	return ret;
 }
=20
+static int tps65910_rtc_set_calibration(struct device *dev, int calibratio=
n)
+{
+	unsigned char comp_data[NUM_COMP_REGS];
+	struct tps65910 *tps =3D dev_get_drvdata(dev->parent);
+	s16 value;
+	int ret;
+
+	/*
+	 * TPS65910 uses two's complement 16 bit value for compensation for RTC
+	 * crystal inaccuracies. One time every hour when seconds counter
+	 * increments from 0 to 1 compensation value will be added to internal
+	 * RTC counter value.
+	 *
+	 * Compensation value 0x7FFF is prohibited value.
+	 *
+	 * Valid range for compensation value: [-32768 .. 32766]
+	 */
+	if ((calibration < -32768) || (calibration > 32766)) {
+		dev_err(dev, "RTC calibration value out of range: %d\n",
+			calibration);
+		return -EINVAL;
+	}
+
+	value =3D (s16)calibration;
+
+	comp_data[0] =3D (u16)value & 0xFF;
+	comp_data[1] =3D ((u16)value >> 8) & 0xFF;
+
+	/* Update all the compensation registers in one shot */
+	ret =3D regmap_bulk_write(tps->regmap, TPS65910_RTC_COMP_LSB,
+		comp_data, NUM_COMP_REGS);
+	if (ret < 0) {
+		dev_err(dev, "rtc_set_calibration error: %d\n", ret);
+		return ret;
+	}
+
+	/* Enable automatic compensation */
+	ret =3D regmap_update_bits(tps->regmap, TPS65910_RTC_CTRL,
+		TPS65910_RTC_CTRL_AUTO_COMP, TPS65910_RTC_CTRL_AUTO_COMP);
+	if (ret < 0)
+		dev_err(dev, "auto_comp enable failed with error: %d\n", ret);
+
+	return ret;
+}
+
+static int tps65910_rtc_get_calibration(struct device *dev, int *calibrati=
on)
+{
+	unsigned char comp_data[NUM_COMP_REGS];
+	struct tps65910 *tps =3D dev_get_drvdata(dev->parent);
+	unsigned int ctrl;
+	u16 value;
+	int ret;
+
+	ret =3D regmap_read(tps->regmap, TPS65910_RTC_CTRL, &ctrl);
+	if (ret < 0)
+		return ret;
+
+	/* If automatic compensation is not enabled report back zero */
+	if (!(ctrl & TPS65910_RTC_CTRL_AUTO_COMP)) {
+		*calibration =3D 0;
+		return 0;
+	}
+
+	ret =3D regmap_bulk_read(tps->regmap, TPS65910_RTC_COMP_LSB, comp_data,
+		NUM_COMP_REGS);
+	if (ret < 0) {
+		dev_err(dev, "rtc_get_calibration error: %d\n", ret);
+		return ret;
+	}
+
+	value =3D (u16)comp_data[0] | ((u16)comp_data[1] << 8);
+
+	*calibration =3D (s16)value;
+
+	return 0;
+}
+
+static int tps65910_read_offset(struct device *dev, long *offset)
+{
+	int calibration;
+	s64 tmp;
+	int ret;
+
+	ret =3D tps65910_rtc_get_calibration(dev, &calibration);
+	if (ret < 0)
+		return ret;
+
+	/* Convert from RTC calibration register format to ppb format */
+	tmp =3D calibration * (s64)PPB_MULT;
+	if (tmp < 0)
+		tmp -=3D TICKS_PER_HOUR / 2LL;
+	else
+		tmp +=3D TICKS_PER_HOUR / 2LL;
+	tmp =3D div_s64(tmp, TICKS_PER_HOUR);
+
+	/* Offset value operates in negative way, so swap sign */
+	*offset =3D (long)-tmp;
+
+	return 0;
+}
+
+static int tps65910_set_offset(struct device *dev, long offset)
+{
+	int calibration;
+	s64 tmp;
+	int ret;
+
+	/* Make sure offset value is within supported range */
+	if (offset < MIN_OFFSET || offset > MAX_OFFSET)
+		return -ERANGE;
+
+	/* Convert from ppb format to RTC calibration register format */
+	tmp =3D offset * (s64)TICKS_PER_HOUR;
+	if (tmp < 0)
+		tmp -=3D PPB_MULT / 2LL;
+	else
+		tmp +=3D PPB_MULT / 2LL;
+	tmp =3D div_s64(tmp, PPB_MULT);
+
+	/* Offset value operates in negative way, so swap sign */
+	calibration =3D (int)-tmp;
+
+	ret =3D tps65910_rtc_set_calibration(dev, calibration);
+
+	return ret;
+}
+
 static irqreturn_t tps65910_rtc_interrupt(int irq, void *rtc)
 {
 	struct device *dev =3D rtc;
@@ -219,6 +360,8 @@ static const struct rtc_class_ops tps65910_rtc_ops =3D =
{
 	.read_alarm	=3D tps65910_rtc_read_alarm,
 	.set_alarm	=3D tps65910_rtc_set_alarm,
 	.alarm_irq_enable =3D tps65910_rtc_alarm_irq_enable,
+	.read_offset	=3D tps65910_read_offset,
+	.set_offset	=3D tps65910_set_offset,
 };
=20
 static int tps65910_rtc_probe(struct platform_device *pdev)
diff --git a/include/linux/mfd/tps65910.h b/include/linux/mfd/tps65910.h
index 6483a6f..ffb21e7 100644
--- a/include/linux/mfd/tps65910.h
+++ b/include/linux/mfd/tps65910.h
@@ -134,6 +134,7 @@
=20
 /* RTC_CTRL_REG bitfields */
 #define TPS65910_RTC_CTRL_STOP_RTC			0x01 /*0=3Dstop, 1=3Drun */
+#define TPS65910_RTC_CTRL_AUTO_COMP			0x04
 #define TPS65910_RTC_CTRL_GET_TIME			0x40
=20
 /* RTC_STATUS_REG bitfields */
--=20
2.1.4

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[rtc-linux] Re: [PATCH v3 1/2] drivers: rtc: rtc-tps65910: Add RTC calibration support

[Lee Jones]

On Fri, 23 Dec 2016, Vesa J=C3=A4=C3=A4skel=C3=A4inen wrote:

> Texas Instrument's TPS65910 has support for compensating RTC crystal
> inaccuracies. When enabled every hour RTC counter value will be compensat=
ed
> with two's complement value.
>=20
> Acked-by: Lee Jones <lee.jones@linaro.org>
> Signed-off-by: Vesa J=C3=A4=C3=A4skel=C3=A4inen <vesa.jaaskelainen@vaisal=
a.com>
> ---
> Changes in v3:
>   - Changed to return 0 from offset when auto compensation is not enabled
>=20
> Changes in v2:
>   - Changed to use offset interface
>=20
>  drivers/rtc/rtc-tps65910.c   | 143 +++++++++++++++++++++++++++++++++++++=
++++++
>  include/linux/mfd/tps65910.h |   1 +

Acked-by: Lee Jones <lee.jones@linaro.org>

>  2 files changed, 144 insertions(+)
>=20
> diff --git a/drivers/rtc/rtc-tps65910.c b/drivers/rtc/rtc-tps65910.c
> index 5a3d53c..9dd1db9 100644
> --- a/drivers/rtc/rtc-tps65910.c
> +++ b/drivers/rtc/rtc-tps65910.c
> @@ -21,6 +21,7 @@
>  #include <linux/types.h>
>  #include <linux/rtc.h>
>  #include <linux/bcd.h>
> +#include <linux/math64.h>
>  #include <linux/platform_device.h>
>  #include <linux/interrupt.h>
>  #include <linux/mfd/tps65910.h>
> @@ -33,6 +34,19 @@ struct tps65910_rtc {
>  /* Total number of RTC registers needed to set time*/
>  #define NUM_TIME_REGS	(TPS65910_YEARS - TPS65910_SECONDS + 1)
> =20
> +/* Total number of RTC registers needed to set compensation registers */
> +#define NUM_COMP_REGS	(TPS65910_RTC_COMP_MSB - TPS65910_RTC_COMP_LSB + 1=
)
> +
> +/* Min and max values supported with 'offset' interface (swapped sign) *=
/
> +#define MIN_OFFSET	(-277761)
> +#define MAX_OFFSET	(277778)
> +
> +/* Number of ticks per hour */
> +#define TICKS_PER_HOUR	(32768 * 3600)
> +
> +/* Multiplier for ppb conversions */
> +#define PPB_MULT	(1000000000LL)
> +
>  static int tps65910_rtc_alarm_irq_enable(struct device *dev, unsigned en=
abled)
>  {
>  	struct tps65910 *tps =3D dev_get_drvdata(dev->parent);
> @@ -187,6 +201,133 @@ static int tps65910_rtc_set_alarm(struct device *de=
v, struct rtc_wkalrm *alm)
>  	return ret;
>  }
> =20
> +static int tps65910_rtc_set_calibration(struct device *dev, int calibrat=
ion)
> +{
> +	unsigned char comp_data[NUM_COMP_REGS];
> +	struct tps65910 *tps =3D dev_get_drvdata(dev->parent);
> +	s16 value;
> +	int ret;
> +
> +	/*
> +	 * TPS65910 uses two's complement 16 bit value for compensation for RTC
> +	 * crystal inaccuracies. One time every hour when seconds counter
> +	 * increments from 0 to 1 compensation value will be added to internal
> +	 * RTC counter value.
> +	 *
> +	 * Compensation value 0x7FFF is prohibited value.
> +	 *
> +	 * Valid range for compensation value: [-32768 .. 32766]
> +	 */
> +	if ((calibration < -32768) || (calibration > 32766)) {
> +		dev_err(dev, "RTC calibration value out of range: %d\n",
> +			calibration);
> +		return -EINVAL;
> +	}
> +
> +	value =3D (s16)calibration;
> +
> +	comp_data[0] =3D (u16)value & 0xFF;
> +	comp_data[1] =3D ((u16)value >> 8) & 0xFF;
> +
> +	/* Update all the compensation registers in one shot */
> +	ret =3D regmap_bulk_write(tps->regmap, TPS65910_RTC_COMP_LSB,
> +		comp_data, NUM_COMP_REGS);
> +	if (ret < 0) {
> +		dev_err(dev, "rtc_set_calibration error: %d\n", ret);
> +		return ret;
> +	}
> +
> +	/* Enable automatic compensation */
> +	ret =3D regmap_update_bits(tps->regmap, TPS65910_RTC_CTRL,
> +		TPS65910_RTC_CTRL_AUTO_COMP, TPS65910_RTC_CTRL_AUTO_COMP);
> +	if (ret < 0)
> +		dev_err(dev, "auto_comp enable failed with error: %d\n", ret);
> +
> +	return ret;
> +}
> +
> +static int tps65910_rtc_get_calibration(struct device *dev, int *calibra=
tion)
> +{
> +	unsigned char comp_data[NUM_COMP_REGS];
> +	struct tps65910 *tps =3D dev_get_drvdata(dev->parent);
> +	unsigned int ctrl;
> +	u16 value;
> +	int ret;
> +
> +	ret =3D regmap_read(tps->regmap, TPS65910_RTC_CTRL, &ctrl);
> +	if (ret < 0)
> +		return ret;
> +
> +	/* If automatic compensation is not enabled report back zero */
> +	if (!(ctrl & TPS65910_RTC_CTRL_AUTO_COMP)) {
> +		*calibration =3D 0;
> +		return 0;
> +	}
> +
> +	ret =3D regmap_bulk_read(tps->regmap, TPS65910_RTC_COMP_LSB, comp_data,
> +		NUM_COMP_REGS);
> +	if (ret < 0) {
> +		dev_err(dev, "rtc_get_calibration error: %d\n", ret);
> +		return ret;
> +	}
> +
> +	value =3D (u16)comp_data[0] | ((u16)comp_data[1] << 8);
> +
> +	*calibration =3D (s16)value;
> +
> +	return 0;
> +}
> +
> +static int tps65910_read_offset(struct device *dev, long *offset)
> +{
> +	int calibration;
> +	s64 tmp;
> +	int ret;
> +
> +	ret =3D tps65910_rtc_get_calibration(dev, &calibration);
> +	if (ret < 0)
> +		return ret;
> +
> +	/* Convert from RTC calibration register format to ppb format */
> +	tmp =3D calibration * (s64)PPB_MULT;
> +	if (tmp < 0)
> +		tmp -=3D TICKS_PER_HOUR / 2LL;
> +	else
> +		tmp +=3D TICKS_PER_HOUR / 2LL;
> +	tmp =3D div_s64(tmp, TICKS_PER_HOUR);
> +
> +	/* Offset value operates in negative way, so swap sign */
> +	*offset =3D (long)-tmp;
> +
> +	return 0;
> +}
> +
> +static int tps65910_set_offset(struct device *dev, long offset)
> +{
> +	int calibration;
> +	s64 tmp;
> +	int ret;
> +
> +	/* Make sure offset value is within supported range */
> +	if (offset < MIN_OFFSET || offset > MAX_OFFSET)
> +		return -ERANGE;
> +
> +	/* Convert from ppb format to RTC calibration register format */
> +	tmp =3D offset * (s64)TICKS_PER_HOUR;
> +	if (tmp < 0)
> +		tmp -=3D PPB_MULT / 2LL;
> +	else
> +		tmp +=3D PPB_MULT / 2LL;
> +	tmp =3D div_s64(tmp, PPB_MULT);
> +
> +	/* Offset value operates in negative way, so swap sign */
> +	calibration =3D (int)-tmp;
> +
> +	ret =3D tps65910_rtc_set_calibration(dev, calibration);
> +
> +	return ret;
> +}
> +
>  static irqreturn_t tps65910_rtc_interrupt(int irq, void *rtc)
>  {
>  	struct device *dev =3D rtc;
> @@ -219,6 +360,8 @@ static const struct rtc_class_ops tps65910_rtc_ops =
=3D {
>  	.read_alarm	=3D tps65910_rtc_read_alarm,
>  	.set_alarm	=3D tps65910_rtc_set_alarm,
>  	.alarm_irq_enable =3D tps65910_rtc_alarm_irq_enable,
> +	.read_offset	=3D tps65910_read_offset,
> +	.set_offset	=3D tps65910_set_offset,
>  };
> =20
>  static int tps65910_rtc_probe(struct platform_device *pdev)
> diff --git a/include/linux/mfd/tps65910.h b/include/linux/mfd/tps65910.h
> index 6483a6f..ffb21e7 100644
> --- a/include/linux/mfd/tps65910.h
> +++ b/include/linux/mfd/tps65910.h
> @@ -134,6 +134,7 @@
> =20
>  /* RTC_CTRL_REG bitfields */
>  #define TPS65910_RTC_CTRL_STOP_RTC			0x01 /*0=3Dstop, 1=3Drun */
> +#define TPS65910_RTC_CTRL_AUTO_COMP			0x04
>  #define TPS65910_RTC_CTRL_GET_TIME			0x40
> =20
>  /* RTC_STATUS_REG bitfields */

--=20
Lee Jones
Linaro STMicroelectronics Landing Team Lead
Linaro.org =E2=94=82 Open source software for ARM SoCs
Follow Linaro: Facebook | Twitter | Blog

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[rtc-linux] Re: [PATCH v3 1/2] drivers: rtc: rtc-tps65910: Add RTC calibration support

[Alexandre Belloni]

On 23/12/2016 at 13:15:58 +0200, Vesa J=C3=A4=C3=A4skel=C3=A4inen wrote :
> Texas Instrument's TPS65910 has support for compensating RTC crystal
> inaccuracies. When enabled every hour RTC counter value will be compensat=
ed
> with two's complement value.
>=20
> Acked-by: Lee Jones <lee.jones@linaro.org>
> Signed-off-by: Vesa J=C3=A4=C3=A4skel=C3=A4inen <vesa.jaaskelainen@vaisal=
a.com>
> ---
> Changes in v3:
>   - Changed to return 0 from offset when auto compensation is not enabled
>=20
> Changes in v2:
>   - Changed to use offset interface
>=20
>  drivers/rtc/rtc-tps65910.c   | 143 +++++++++++++++++++++++++++++++++++++=
++++++
>  include/linux/mfd/tps65910.h |   1 +
>  2 files changed, 144 insertions(+)
>=20
Applied, thanks.

--=20
Alexandre Belloni, Free Electrons
Embedded Linux and Kernel engineering
http://free-electrons.com

--=20
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[rtc-linux] [PATCH v3 2/2] drivers: rtc: rtc-tps65910: use 'unsigned int' instead of 'unsigned' in arguments

[Vesa Jääskeläinen]

Fixes checkpatch.pl warning:
WARNING: Prefer 'unsigned int' to bare use of 'unsigned'

Signed-off-by: Vesa J=C3=A4=C3=A4skel=C3=A4inen <vesa.jaaskelainen@vaisala.=
com>
---
 drivers/rtc/rtc-tps65910.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/rtc/rtc-tps65910.c b/drivers/rtc/rtc-tps65910.c
index 9dd1db9..d0244d7 100644
--- a/drivers/rtc/rtc-tps65910.c
+++ b/drivers/rtc/rtc-tps65910.c
@@ -47,7 +47,8 @@ struct tps65910_rtc {
 /* Multiplier for ppb conversions */
 #define PPB_MULT	(1000000000LL)
=20
-static int tps65910_rtc_alarm_irq_enable(struct device *dev, unsigned enab=
led)
+static int tps65910_rtc_alarm_irq_enable(struct device *dev,
+					 unsigned int enabled)
 {
 	struct tps65910 *tps =3D dev_get_drvdata(dev->parent);
 	u8 val =3D 0;
--=20
2.1.4

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[rtc-linux] Re: [PATCH v3 2/2] drivers: rtc: rtc-tps65910: use 'unsigned int' instead of 'unsigned' in arguments

[Alexandre Belloni]

On 23/12/2016 at 13:15:59 +0200, Vesa J=C3=A4=C3=A4skel=C3=A4inen wrote :
> Fixes checkpatch.pl warning:
> WARNING: Prefer 'unsigned int' to bare use of 'unsigned'
>=20
> Signed-off-by: Vesa J=C3=A4=C3=A4skel=C3=A4inen <vesa.jaaskelainen@vaisal=
a.com>
> ---
>  drivers/rtc/rtc-tps65910.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
>=20
Applied, thanks.

--=20
Alexandre Belloni, Free Electrons
Embedded Linux and Kernel engineering
http://free-electrons.com

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