[PATCH] rtc: add Abracon ABx80x driver

[PATCH] rtc: add Abracon ABx80x driver

[Alexandre Belloni]

Add support for the i2c RTC from Abracon.

Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
---
 drivers/rtc/Kconfig      |   9 +++
 drivers/rtc/Makefile     |   1 +
 drivers/rtc/rtc-abx80x.c | 203 +++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 213 insertions(+)
 create mode 100644 drivers/rtc/rtc-abx80x.c

diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig
index b5b5c3d485d6..e230722fce49 100644
--- a/drivers/rtc/Kconfig
+++ b/drivers/rtc/Kconfig
@@ -174,6 +174,15 @@ config RTC_DRV_AS3722
 	  This driver can also be built as a module. If so, the module
 	  will be called rtc-as3722.
 
+config RTC_DRV_ABX80X
+	tristate "Abracon ABx80x"
+	help
+	  If you say yes here you get support for Abracon AB080x and AB180x
+	  real-time clock chips.
+
+	  This driver can also be built as a module. If so, the module
+	  will be called rtc-abx80x.
+
 config RTC_DRV_DS1307
 	tristate "Dallas/Maxim DS1307/37/38/39/40, ST M41T00, EPSON RX-8025"
 	help
diff --git a/drivers/rtc/Makefile b/drivers/rtc/Makefile
index 69c87062b098..e8e60c2c8aeb 100644
--- a/drivers/rtc/Makefile
+++ b/drivers/rtc/Makefile
@@ -22,6 +22,7 @@ rtc-core-$(CONFIG_RTC_INTF_SYSFS) += rtc-sysfs.o
 
 obj-$(CONFIG_RTC_DRV_88PM860X)  += rtc-88pm860x.o
 obj-$(CONFIG_RTC_DRV_88PM80X)	+= rtc-88pm80x.o
+obj-$(CONFIG_RTC_DRV_ABX80X)	+= rtc-abx80x.o
 obj-$(CONFIG_RTC_DRV_AB3100)	+= rtc-ab3100.o
 obj-$(CONFIG_RTC_DRV_AB8500)	+= rtc-ab8500.o
 obj-$(CONFIG_RTC_DRV_ABB5ZES3)	+= rtc-ab-b5ze-s3.o
diff --git a/drivers/rtc/rtc-abx80x.c b/drivers/rtc/rtc-abx80x.c
new file mode 100644
index 000000000000..e51ac5554a9e
--- /dev/null
+++ b/drivers/rtc/rtc-abx80x.c
@@ -0,0 +1,203 @@
+/*
+ * An I2C driver for the Abracon AB08xx
+ *
+ * Author: Alexandre Belloni <alexandre.belloni@free-electrons.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ */
+
+#include <linux/module.h>
+#include <linux/i2c.h>
+#include <linux/bcd.h>
+#include <linux/rtc.h>
+#include <linux/log2.h>
+
+#define AB08XX_REG_HTH		0x00
+#define AB08XX_REG_SC		0x01
+#define AB08XX_REG_MN		0x02
+#define AB08XX_REG_HR		0x03
+#define AB08XX_REG_DA		0x04
+#define AB08XX_REG_MO		0x05
+#define AB08XX_REG_YR		0x06
+#define AB08XX_REG_WD		0x07
+
+#define AB08XX_REG_CTRL1	0x10
+
+#define AB08XX_REG_PART0	0x28
+#define AB08XX_REG_PART1	0x29
+
+#define AB08XX_CTRL_WRITE	BIT(1)
+#define AB08XX_CTRL_12_24	BIT(6)
+
+enum ab08xx_chip {ABX80X, AB0801, AB0802, AB0803, AB0804, AB0805,
+		  AB1801, AB1802, AB1803, AB1804, AB1805};
+
+static int ab08xx_get_datetime(struct i2c_client *client, struct rtc_time *tm)
+{
+	unsigned char date[8];
+	int err;
+
+	/* Now read time and date */
+	err = i2c_smbus_read_i2c_block_data(client, AB08XX_REG_HTH,
+		8, date);
+	if (err < 0) {
+		dev_err(&client->dev, "Unable to read date\n");
+		return -EIO;
+	}
+
+	tm->tm_sec = bcd2bin(date[AB08XX_REG_SC] & 0x7F);
+	tm->tm_min = bcd2bin(date[AB08XX_REG_MN] & 0x7F);
+	tm->tm_hour = bcd2bin(date[AB08XX_REG_HR] & 0x3F);
+	tm->tm_wday = date[AB08XX_REG_WD] & 0x7;
+	tm->tm_mday = bcd2bin(date[AB08XX_REG_DA] & 0x3F);
+	tm->tm_mon = bcd2bin(date[AB08XX_REG_MO] & 0x1F) - 1;
+	tm->tm_year = bcd2bin(date[AB08XX_REG_YR]);
+	if (tm->tm_year < 70)
+		tm->tm_year += 100;
+
+	err = rtc_valid_tm(tm);
+	if (err < 0)
+		dev_err(&client->dev, "retrieved date/time is not valid.\n");
+
+	return err;
+}
+
+static int ab08xx_set_datetime(struct i2c_client *client, struct rtc_time *tm)
+{
+	int data, err;
+	unsigned char buf[8];
+
+	buf[AB08XX_REG_SC] = bin2bcd(tm->tm_sec);
+	buf[AB08XX_REG_MN] = bin2bcd(tm->tm_min);
+	buf[AB08XX_REG_HR] = bin2bcd(tm->tm_hour);
+	buf[AB08XX_REG_DA] = bin2bcd(tm->tm_mday);
+	buf[AB08XX_REG_MO] = bin2bcd(tm->tm_mon + 1);
+	buf[AB08XX_REG_YR] = bin2bcd(tm->tm_year % 100);
+	buf[AB08XX_REG_WD] = (0x1 << tm->tm_wday);
+
+	data = i2c_smbus_read_byte_data(client, AB08XX_REG_CTRL1);
+	if (data < 0) {
+		dev_err(&client->dev, "Unable to read control register\n");
+		return -EIO;
+	}
+
+	err = i2c_smbus_write_byte_data(client, AB08XX_REG_CTRL1,
+		(data | AB08XX_CTRL_WRITE));
+	if (err < 0) {
+		dev_err(&client->dev, "Unable to write control register\n");
+		return -EIO;
+	}
+
+	err = i2c_smbus_write_i2c_block_data(client, AB08XX_REG_SC, 7,
+					     &buf[AB08XX_REG_SC]);
+	if (err < 0) {
+		dev_err(&client->dev, "Unable to write to date registers\n");
+		return -EIO;
+	}
+
+	err = i2c_smbus_write_byte_data(client, AB08XX_REG_CTRL1,
+		(data & ~AB08XX_CTRL_WRITE));
+	if (err < 0) {
+		dev_err(&client->dev, "Unable to write control register\n");
+		return -EIO;
+	}
+
+	return 0;
+}
+
+static int ab08xx_rtc_read_time(struct device *dev, struct rtc_time *tm)
+{
+	return ab08xx_get_datetime(to_i2c_client(dev), tm);
+}
+
+static int ab08xx_rtc_set_time(struct device *dev, struct rtc_time *tm)
+{
+	return ab08xx_set_datetime(to_i2c_client(dev), tm);
+}
+
+static const struct rtc_class_ops ab08xx_rtc_ops = {
+	.read_time	= ab08xx_rtc_read_time,
+	.set_time	= ab08xx_rtc_set_time,
+};
+
+static int ab08xx_probe(struct i2c_client *client,
+			const struct i2c_device_id *id)
+{
+	struct rtc_device *rtc;
+	int data, err, part0, part1;
+
+	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
+		return -ENODEV;
+
+
+	part0 = i2c_smbus_read_byte_data(client, AB08XX_REG_PART0);
+	part1 = i2c_smbus_read_byte_data(client, AB08XX_REG_PART1);
+	if ((part0 < 0) || (part1 < 0)) {
+		dev_err(&client->dev, "Unable to read part number\n");
+		return -EIO;
+	}
+	dev_info(&client->dev, "chip found %2x%2x\n", part0, part1);
+
+	data = i2c_smbus_read_byte_data(client, AB08XX_REG_CTRL1);
+	if (data < 0) {
+		dev_err(&client->dev, "Unable to read control register\n");
+		return -EIO;
+	}
+
+	err = i2c_smbus_write_byte_data(client, AB08XX_REG_CTRL1,
+		(data & ~AB08XX_CTRL_12_24));
+	if (err < 0) {
+		dev_err(&client->dev, "Unable to write control register\n");
+		return -EIO;
+	}
+
+	rtc = devm_rtc_device_register(&client->dev, "rtc-ab08xx",
+					&ab08xx_rtc_ops, THIS_MODULE);
+
+	if (IS_ERR(rtc))
+		return PTR_ERR(rtc);
+
+	i2c_set_clientdata(client, rtc);
+
+	return 0;
+}
+
+static int ab08xx_remove(struct i2c_client *client)
+{
+	return 0;
+}
+
+static const struct i2c_device_id ab08xx_id[] = {
+	{ "abx80x", ABX80X },
+	{ "ab0801", AB0801 },
+	{ "ab0802", AB0802 },
+	{ "ab0803", AB0803 },
+	{ "ab0804", AB0804 },
+	{ "ab0805", AB0805 },
+	{ "ab1801", AB1801 },
+	{ "ab1802", AB1802 },
+	{ "ab1803", AB1803 },
+	{ "ab1804", AB1804 },
+	{ "ab1805", AB1805 },
+	{ }
+};
+MODULE_DEVICE_TABLE(i2c, ab08xx_id);
+
+static struct i2c_driver ab08xx_driver = {
+	.driver		= {
+		.name	= "rtc-ab08xx",
+		.owner	= THIS_MODULE,
+	},
+	.probe		= ab08xx_probe,
+	.remove		= ab08xx_remove,
+	.id_table	= ab08xx_id,
+};
+
+module_i2c_driver(ab08xx_driver);
+
+MODULE_AUTHOR("Alexandre Belloni <alexandre.belloni@free-electrons.com>");
+MODULE_DESCRIPTION("Abracon AB08xx RTC driver");
+MODULE_LICENSE("GPL");
-- 
2.1.0

Re: [PATCH] rtc: add Abracon ABx80x driver

[Joe Perches]

On Sat, 2015-02-28 at 20:14 +0100, Alexandre Belloni wrote:
> Add support for the i2c RTC from Abracon.

Perhaps you can run this through
$ ./scripts/checkpatch.pl --strict --fix-inplace

Is there going to be a MAINTAINERS entry for this driver?

> diff --git a/drivers/rtc/Makefile b/drivers/rtc/Makefile
[]
> @@ -22,6 +22,7 @@ rtc-core-$(CONFIG_RTC_INTF_SYSFS) += rtc-sysfs.o
>  
>  obj-$(CONFIG_RTC_DRV_88PM860X)  += rtc-88pm860x.o
>  obj-$(CONFIG_RTC_DRV_88PM80X)	+= rtc-88pm80x.o
> +obj-$(CONFIG_RTC_DRV_ABX80X)	+= rtc-abx80x.o

alphabetic order?

>  obj-$(CONFIG_RTC_DRV_AB3100)	+= rtc-ab3100.o
>  obj-$(CONFIG_RTC_DRV_AB8500)	+= rtc-ab8500.o
>  obj-$(CONFIG_RTC_DRV_ABB5ZES3)	+= rtc-ab-b5ze-s3.o

[]

> diff --git a/drivers/rtc/rtc-abx80x.c b/drivers/rtc/rtc-abx80x.c
[]
> +static int ab08xx_get_datetime(struct i2c_client *client, struct rtc_time *tm)
> +{
> +	unsigned char date[8];
> +	int err;
> +
> +	/* Now read time and date */
> +	err = i2c_smbus_read_i2c_block_data(client, AB08XX_REG_HTH,
> +		8, date);
> +	if (err < 0) {
> +		dev_err(&client->dev, "Unable to read date\n");
> +		return -EIO;
> +	}
> +
> +	tm->tm_sec = bcd2bin(date[AB08XX_REG_SC] & 0x7F);
> +	tm->tm_min = bcd2bin(date[AB08XX_REG_MN] & 0x7F);
> +	tm->tm_hour = bcd2bin(date[AB08XX_REG_HR] & 0x3F);
> +	tm->tm_wday = date[AB08XX_REG_WD] & 0x7;
> +	tm->tm_mday = bcd2bin(date[AB08XX_REG_DA] & 0x3F);
> +	tm->tm_mon = bcd2bin(date[AB08XX_REG_MO] & 0x1F) - 1;
> +	tm->tm_year = bcd2bin(date[AB08XX_REG_YR]);
> +	if (tm->tm_year < 70)
> +		tm->tm_year += 100;
> +
> +	err = rtc_valid_tm(tm);
> +	if (err < 0)
> +		dev_err(&client->dev, "retrieved date/time is not valid.\n");

Is setting the date to a known bad value really the desired thing?

> +static int ab08xx_probe(struct i2c_client *client,
> +			const struct i2c_device_id *id)
> +{
> +	struct rtc_device *rtc;
> +	int data, err, part0, part1;
> +
> +	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
> +		return -ENODEV;
> +
> +
> +	part0 = i2c_smbus_read_byte_data(client, AB08XX_REG_PART0);
> +	part1 = i2c_smbus_read_byte_data(client, AB08XX_REG_PART1);
> +	if ((part0 < 0) || (part1 < 0)) {
> +		dev_err(&client->dev, "Unable to read part number\n");
> +		return -EIO;
> +	}
> +	dev_info(&client->dev, "chip found %2x%2x\n", part0, part1);

	"%02x%02x" ?

Re: [PATCH] rtc: add Abracon ABx80x driver

[Alexandre Belloni]

On 28/02/2015 at 11:32:15 -0800, Joe Perches wrote :
> On Sat, 2015-02-28 at 20:14 +0100, Alexandre Belloni wrote:
> > Add support for the i2c RTC from Abracon.
> 
> Perhaps you can run this through
> $ ./scripts/checkpatch.pl --strict --fix-inplace
> 

Right, I'll fix those

> Is there going to be a MAINTAINERS entry for this driver?
> 

If necessary, I can maintain it however, I'm not sure I'll have access
to the hardware indefinitely.

> > diff --git a/drivers/rtc/Makefile b/drivers/rtc/Makefile
> []
> > @@ -22,6 +22,7 @@ rtc-core-$(CONFIG_RTC_INTF_SYSFS) += rtc-sysfs.o
> >  
> >  obj-$(CONFIG_RTC_DRV_88PM860X)  += rtc-88pm860x.o
> >  obj-$(CONFIG_RTC_DRV_88PM80X)	+= rtc-88pm80x.o
> > +obj-$(CONFIG_RTC_DRV_ABX80X)	+= rtc-abx80x.o
> 
> alphabetic order?
> 

I renamed the driver from rtc-ab080x and forgot to move it. I will do.
I'll also rename the functions in the driver.

> >  obj-$(CONFIG_RTC_DRV_AB3100)	+= rtc-ab3100.o
> >  obj-$(CONFIG_RTC_DRV_AB8500)	+= rtc-ab8500.o
> >  obj-$(CONFIG_RTC_DRV_ABB5ZES3)	+= rtc-ab-b5ze-s3.o
> 
> []
> 
> > diff --git a/drivers/rtc/rtc-abx80x.c b/drivers/rtc/rtc-abx80x.c
> []
> > +static int ab08xx_get_datetime(struct i2c_client *client, struct rtc_time *tm)
> > +{
> > +	unsigned char date[8];
> > +	int err;
> > +
> > +	/* Now read time and date */
> > +	err = i2c_smbus_read_i2c_block_data(client, AB08XX_REG_HTH,
> > +		8, date);
> > +	if (err < 0) {
> > +		dev_err(&client->dev, "Unable to read date\n");
> > +		return -EIO;
> > +	}
> > +
> > +	tm->tm_sec = bcd2bin(date[AB08XX_REG_SC] & 0x7F);
> > +	tm->tm_min = bcd2bin(date[AB08XX_REG_MN] & 0x7F);
> > +	tm->tm_hour = bcd2bin(date[AB08XX_REG_HR] & 0x3F);
> > +	tm->tm_wday = date[AB08XX_REG_WD] & 0x7;
> > +	tm->tm_mday = bcd2bin(date[AB08XX_REG_DA] & 0x3F);
> > +	tm->tm_mon = bcd2bin(date[AB08XX_REG_MO] & 0x1F) - 1;
> > +	tm->tm_year = bcd2bin(date[AB08XX_REG_YR]);
> > +	if (tm->tm_year < 70)
> > +		tm->tm_year += 100;
> > +
> > +	err = rtc_valid_tm(tm);
> > +	if (err < 0)
> > +		dev_err(&client->dev, "retrieved date/time is not valid.\n");
> 
> Is setting the date to a known bad value really the desired thing?

I'm not sure what you mean here, isn't that what is done in almost all
the rtc drivers? A lot of those are simply using return
rtc_valid_tm(tm); My guess is that a userspace program must not try to
use tm when errno is not 0.

> 
> > +static int ab08xx_probe(struct i2c_client *client,
> > +			const struct i2c_device_id *id)
> > +{
> > +	struct rtc_device *rtc;
> > +	int data, err, part0, part1;
> > +
> > +	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
> > +		return -ENODEV;
> > +
> > +
> > +	part0 = i2c_smbus_read_byte_data(client, AB08XX_REG_PART0);
> > +	part1 = i2c_smbus_read_byte_data(client, AB08XX_REG_PART1);
> > +	if ((part0 < 0) || (part1 < 0)) {
> > +		dev_err(&client->dev, "Unable to read part number\n");
> > +		return -EIO;
> > +	}
> > +	dev_info(&client->dev, "chip found %2x%2x\n", part0, part1);
> 
> 	"%02x%02x" ?
> 

Indeed, I'm not sure how but I believe I saw it zero padded at some
point.


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

Re: [PATCH] rtc: add Abracon ABx80x driver

[Joe Perches]

On Sat, 2015-02-28 at 21:52 +0100, Alexandre Belloni wrote:
> > > diff --git a/drivers/rtc/rtc-abx80x.c b/drivers/rtc/rtc-abx80x.c
> > []
> > > +static int ab08xx_get_datetime(struct i2c_client *client, struct rtc_time *tm)
[]
> > > +	tm->tm_sec = bcd2bin(date[AB08XX_REG_SC] & 0x7F);
> > > +	tm->tm_min = bcd2bin(date[AB08XX_REG_MN] & 0x7F);
> > > +	tm->tm_hour = bcd2bin(date[AB08XX_REG_HR] & 0x3F);
> > > +	tm->tm_wday = date[AB08XX_REG_WD] & 0x7;
> > > +	tm->tm_mday = bcd2bin(date[AB08XX_REG_DA] & 0x3F);
> > > +	tm->tm_mon = bcd2bin(date[AB08XX_REG_MO] & 0x1F) - 1;
> > > +	tm->tm_year = bcd2bin(date[AB08XX_REG_YR]);
> > > +	if (tm->tm_year < 70)
> > > +		tm->tm_year += 100;
> > > +
> > > +	err = rtc_valid_tm(tm);
> > > +	if (err < 0)
> > > +		dev_err(&client->dev, "retrieved date/time is not valid.\n");
> > 
> > Is setting the date to a known bad value really the desired thing?
> 
> I'm not sure what you mean here, isn't that what is done in almost all
> the rtc drivers?

Dunno.

> A lot of those are simply using return
> rtc_valid_tm(tm); My guess is that a userspace program must not try to
> use tm when errno is not 0.

My thought was that it might be better to
use a local struct rtc_time r like

	r.tm_sec = bcd2bin(date[AB08XX_REG_SC] & 0x7F);
	r.tm_min = bcd2bin(date[AB08XX_REG_MN] & 0x7F);
	r.tm_hour = bcd2bin(date[AB08XX_REG_HR] & 0x3F);
	r.tm_wday = date[AB08XX_REG_WD] & 0x7;
	r.tm_mday = bcd2bin(date[AB08XX_REG_DA] & 0x3F);
	r.tm_mon = bcd2bin(date[AB08XX_REG_MO] & 0x1F) - 1;
	r.tm_year = bcd2bin(date[AB08XX_REG_YR]);
	if (r.tm_year < 70)
		r.tm_year += 100;

	err = rtc_valid_tm(&r);
	if (!err)
		*tm = r;
	else
		dev_err(&client->dev, "retrieved date/time is not valid\n");

	return err;

Re: [PATCH] rtc: add Abracon ABx80x driver

[Alexandre Belloni]

On 28/02/2015 at 13:22:54 -0800, Joe Perches wrote :
> My thought was that it might be better to
> use a local struct rtc_time r like
> 
> 	r.tm_sec = bcd2bin(date[AB08XX_REG_SC] & 0x7F);
> 	r.tm_min = bcd2bin(date[AB08XX_REG_MN] & 0x7F);
> 	r.tm_hour = bcd2bin(date[AB08XX_REG_HR] & 0x3F);
> 	r.tm_wday = date[AB08XX_REG_WD] & 0x7;
> 	r.tm_mday = bcd2bin(date[AB08XX_REG_DA] & 0x3F);
> 	r.tm_mon = bcd2bin(date[AB08XX_REG_MO] & 0x1F) - 1;
> 	r.tm_year = bcd2bin(date[AB08XX_REG_YR]);
> 	if (r.tm_year < 70)
> 		r.tm_year += 100;
> 
> 	err = rtc_valid_tm(&r);
> 	if (!err)
> 		*tm = r;
> 	else
> 		dev_err(&client->dev, "retrieved date/time is not valid\n");
> 
> 	return err;
> 

I'm sure this is not needed as userspace has to bail out if the ioctl
fails. I'll let that up to the rtc maintainers though.

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