rtc: Add Epson RX8010SJ RTC driver

This driver supports the following functions:
 - reading and setting time
 - alarms when connected to an IRQ
 - reading and clearing the voltage low flags

Datasheet:
http://www.epsondevice.com/docs/qd/en/DownloadServlet?id=ID000956
Signed-off-by: Akshay Bhat <akshay.bhat@timesys.com>
---
 drivers/rtc/Kconfig      |  10 +
 drivers/rtc/Makefile     |   1 +
 drivers/rtc/rtc-rx8010.c | 570 +++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 581 insertions(+)
 create mode 100644 drivers/rtc/rtc-rx8010.c

Hi,

Wanted to check if there was any feedback on this patch?

Thanks,
Akshay

On 11/11/2015 05:31 PM, Akshay Bhat wrote:
> This driver supports the following functions:
>   - reading and setting time
>   - alarms when connected to an IRQ
>   - reading and clearing the voltage low flags
>
> Datasheet:
> http://www.epsondevice.com/docs/qd/en/DownloadServlet?id=ID000956
> Signed-off-by: Akshay Bhat <akshay.bhat@timesys.com>
> ---
>   drivers/rtc/Kconfig      |  10 +
>   drivers/rtc/Makefile     |   1 +
>   drivers/rtc/rtc-rx8010.c | 570 +++++++++++++++++++++++++++++++++++++++++++++++
>   3 files changed, 581 insertions(+)
>   create mode 100644 drivers/rtc/rtc-rx8010.c
>
> diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig
> index 2a52424..376322f 100644
> --- a/drivers/rtc/Kconfig
> +++ b/drivers/rtc/Kconfig
> @@ -558,6 +558,16 @@ config RTC_DRV_FM3130
>   	  This driver can also be built as a module. If so the module
>   	  will be called rtc-fm3130.
>
> +config RTC_DRV_RX8010
> +	tristate "Epson RX8010SJ"
> +	depends on I2C
> +	help
> +	  If you say yes here you get support for the Epson RX8010SJ RTC
> +	  chip.
> +
> +	  This driver can also be built as a module. If so, the module
> +	  will be called rtc-rx8010.
> +
>   config RTC_DRV_RX8581
>   	tristate "Epson RX-8581"
>   	help
> diff --git a/drivers/rtc/Makefile b/drivers/rtc/Makefile
> index 231f764..62d61b2 100644
> --- a/drivers/rtc/Makefile
> +++ b/drivers/rtc/Makefile
> @@ -128,6 +128,7 @@ obj-$(CONFIG_RTC_DRV_RS5C372)	+= rtc-rs5c372.o
>   obj-$(CONFIG_RTC_DRV_RV3029C2)	+= rtc-rv3029c2.o
>   obj-$(CONFIG_RTC_DRV_RV8803)	+= rtc-rv8803.o
>   obj-$(CONFIG_RTC_DRV_RX4581)	+= rtc-rx4581.o
> +obj-$(CONFIG_RTC_DRV_RX8010)	+= rtc-rx8010.o
>   obj-$(CONFIG_RTC_DRV_RX8025)	+= rtc-rx8025.o
>   obj-$(CONFIG_RTC_DRV_RX8581)	+= rtc-rx8581.o
>   obj-$(CONFIG_RTC_DRV_S35390A)	+= rtc-s35390a.o
> diff --git a/drivers/rtc/rtc-rx8010.c b/drivers/rtc/rtc-rx8010.c
> new file mode 100644
> index 0000000..9b8bd76
> --- /dev/null
> +++ b/drivers/rtc/rtc-rx8010.c
> @@ -0,0 +1,570 @@
> +/*
> + * Driver for the Epson RTC module RX-8010 SJ
> + *
> + * Copyright(C) Timesys Corporation 2015
> + * Copyright(C) General Electric Company 2015
> + * Copyright(C) SEIKO EPSON CORPORATION 2013. All rights reserved.
> + *
> + * Derived from RX-8025 driver:
> + * Copyright (C) 2009 Wolfgang Grandegger <wg@grandegger.com>
> + *
> + * Copyright (C) 2005 by Digi International Inc.
> + * All rights reserved.
> + *
> + * Modified by fengjh at rising.com.cn
> + * <http://lists.lm-sensors.org/mailman/listinfo/lm-sensors>
> + * 2006.11
> + *
> + * Code cleanup by Sergei Poselenov, <sposelenov@emcraft.com>
> + * Converted to new style by Wolfgang Grandegger <wg@grandegger.com>
> + * Alarm and periodic interrupt added by Dmitry Rakhchev <rda@emcraft.com>
> + *
> + * This driver software is distributed as is, without any warranty of any kind,
> + * either express or implied as further specified in the GNU Public License.
> + * This software may be used and distributed according to the terms of the GNU
> + * Public License, version 2 as published by the Free Software Foundation.
> + * See the file COPYING in the main directory of this archive for more details.
> + *
> + * You should have received a copy of the GNU General Public License along with
> + * this program. If not, see <http://www.gnu.org/licenses/>.
> + */
> +
> +#include <linux/bcd.h>
> +#include <linux/bitops.h>
> +#include <linux/i2c.h>
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +#include <linux/rtc.h>
> +
> +#define RX8010_SEC     0x10
> +#define RX8010_MIN     0x11
> +#define RX8010_HOUR    0x12
> +#define RX8010_WDAY    0x13
> +#define RX8010_MDAY    0x14
> +#define RX8010_MONTH   0x15
> +#define RX8010_YEAR    0x16
> +#define RX8010_YEAR    0x16
> +#define RX8010_RESV17  0x17
> +#define RX8010_ALMIN   0x18
> +#define RX8010_ALHOUR  0x19
> +#define RX8010_ALWDAY  0x1A
> +#define RX8010_TCOUNT0 0x1B
> +#define RX8010_TCOUNT1 0x1C
> +#define RX8010_EXT     0x1D
> +#define RX8010_FLAG    0x1E
> +#define RX8010_CTRL    0x1F
> +/* 0x20 to 0x2F are user registers */
> +#define RX8010_RESV30  0x30
> +#define RX8010_RESV31  0x32
> +#define RX8010_IRQ     0x32
> +
> +#define RX8010_EXT_WADA  BIT(3)
> +
> +#define RX8010_FLAG_VLF  BIT(1)
> +#define RX8010_FLAG_AF   BIT(3)
> +#define RX8010_FLAG_TF   BIT(4)
> +#define RX8010_FLAG_UF   BIT(5)
> +
> +#define RX8010_CTRL_AIE  BIT(3)
> +#define RX8010_CTRL_UIE  BIT(5)
> +#define RX8010_CTRL_STOP BIT(6)
> +#define RX8010_CTRL_TEST BIT(7)
> +
> +#define RX8010_ALARM_AE  BIT(7)
> +
> +static const struct i2c_device_id rx8010_id[] = {
> +	{ "rx8010", 0 },
> +	{ }
> +};
> +MODULE_DEVICE_TABLE(i2c, rx8010_id);
> +
> +struct rx8010_data {
> +	struct i2c_client *client;
> +	struct rtc_device *rtc;
> +	u8 ctrlreg;
> +	spinlock_t flags_lock;
> +};
> +
> +static int rx8010_read_reg(struct i2c_client *client, int number, u8 *value)
> +{
> +	int ret = i2c_smbus_read_byte_data(client, number);
> +
> +	if (ret < 0)
> +		return ret;
> +
> +	*value = ret;
> +	return 0;
> +}
> +
> +static int rx8010_read_regs(struct i2c_client *client, int number, u8 length,
> +			u8 *values)
> +{
> +	int ret = i2c_smbus_read_i2c_block_data(client, number, length, values);
> +
> +	if (ret != length)
> +		return ret < 0 ? ret : -EIO;
> +
> +	return 0;
> +}
> +
> +static irqreturn_t rx8010_irq_1_handler(int irq, void *dev_id)
> +{
> +	struct i2c_client *client = dev_id;
> +	struct rx8010_data *rx8010 = i2c_get_clientdata(client);
> +	u8 flagreg;
> +
> +	spin_lock(&rx8010->flags_lock);
> +
> +	if (rx8010_read_reg(client, RX8010_FLAG, &flagreg)) {
> +		spin_unlock(&rx8010->flags_lock);
> +		return IRQ_NONE;
> +	}
> +
> +	if (flagreg & RX8010_FLAG_VLF)
> +		dev_warn(&client->dev, "Frequency stop detected\n");
> +
> +	if (flagreg & RX8010_FLAG_TF) {
> +		flagreg &= ~RX8010_FLAG_TF;
> +		rtc_update_irq(rx8010->rtc, 1, RTC_PF | RTC_IRQF);
> +	}
> +
> +	if (flagreg & RX8010_FLAG_AF) {
> +		flagreg &= ~RX8010_FLAG_AF;
> +		rtc_update_irq(rx8010->rtc, 1, RTC_AF | RTC_IRQF);
> +	}
> +
> +	if (flagreg & RX8010_FLAG_UF) {
> +		flagreg &= ~RX8010_FLAG_UF;
> +		rtc_update_irq(rx8010->rtc, 1, RTC_UF | RTC_IRQF);
> +	}
> +
> +	i2c_smbus_write_byte_data(client, RX8010_FLAG, flagreg);
> +
> +	spin_unlock(&rx8010->flags_lock);
> +	return IRQ_HANDLED;
> +}
> +
> +static int rx8010_get_time(struct device *dev, struct rtc_time *dt)
> +{
> +	struct rx8010_data *rx8010 = dev_get_drvdata(dev);
> +	u8 date[7];
> +	u8 flagreg;
> +	int err;
> +
> +	err = rx8010_read_reg(rx8010->client, RX8010_FLAG, &flagreg);
> +	if (err)
> +		return err;
> +
> +	if (flagreg & RX8010_FLAG_VLF) {
> +		dev_warn(dev, "Frequency stop detected\n");
> +		return -EINVAL;
> +	}
> +
> +	err = rx8010_read_regs(rx8010->client, RX8010_SEC, 7, date);
> +	if (err)
> +		return err;
> +
> +	dt->tm_sec = bcd2bin(date[RX8010_SEC-RX8010_SEC] & 0x7f);
> +	dt->tm_min = bcd2bin(date[RX8010_MIN-RX8010_SEC] & 0x7f);
> +	dt->tm_hour = bcd2bin(date[RX8010_HOUR-RX8010_SEC] & 0x3f);
> +	dt->tm_mday = bcd2bin(date[RX8010_MDAY-RX8010_SEC] & 0x3f);
> +	dt->tm_mon = bcd2bin(date[RX8010_MONTH-RX8010_SEC] & 0x1f) - 1;
> +	dt->tm_year = bcd2bin(date[RX8010_YEAR-RX8010_SEC]);
> +	dt->tm_wday = bcd2bin(date[RX8010_WDAY-RX8010_SEC] & 0x7f);
> +
> +	if (dt->tm_year < 70)
> +		dt->tm_year += 100;
> +
> +	return rtc_valid_tm(dt);
> +}
> +
> +static int rx8010_set_time(struct device *dev, struct rtc_time *dt)
> +{
> +	struct rx8010_data *rx8010 = dev_get_drvdata(dev);
> +	u8 date[7];
> +	u8 ctrl, flagreg;
> +	int ret;
> +	unsigned long irqflags;
> +
> +	/* BUG: The HW assumes every year that is a multiple of 4 to be a leap
> +	 * year.  Next time this is wrong is 2100, which will not be a leap
> +	 * year.
> +	 */
> +
> +	/* set STOP bit before changing clock/calendar */
> +	ret = rx8010_read_reg(rx8010->client, RX8010_CTRL, &ctrl);
> +	if (ret)
> +		return ret;
> +	rx8010->ctrlreg = ctrl | RX8010_CTRL_STOP;
> +	ret = i2c_smbus_write_byte_data(rx8010->client, RX8010_CTRL,
> +		rx8010->ctrlreg);
> +	if (ret < 0)
> +		return ret;
> +
> +	date[RX8010_SEC-RX8010_SEC] = bin2bcd(dt->tm_sec);
> +	date[RX8010_MIN-RX8010_SEC] = bin2bcd(dt->tm_min);
> +	date[RX8010_HOUR-RX8010_SEC] = bin2bcd(dt->tm_hour);
> +	date[RX8010_MDAY-RX8010_SEC] = bin2bcd(dt->tm_mday);
> +	date[RX8010_MONTH-RX8010_SEC] = bin2bcd(dt->tm_mon + 1);
> +	date[RX8010_YEAR-RX8010_SEC] = bin2bcd(dt->tm_year % 100);
> +	date[RX8010_WDAY-RX8010_SEC] = bin2bcd(dt->tm_wday);
> +
> +	ret = i2c_smbus_write_i2c_block_data(rx8010->client,
> +			RX8010_SEC, 7, date);
> +	if (ret < 0)
> +		return ret;
> +
> +	/* clear STOP bit after changing clock/calendar */
> +	ret = rx8010_read_reg(rx8010->client, RX8010_CTRL, &ctrl);
> +	if (ret)
> +		return ret;
> +	rx8010->ctrlreg = ctrl & ~RX8010_CTRL_STOP;
> +	ret = i2c_smbus_write_byte_data(rx8010->client, RX8010_CTRL,
> +		rx8010->ctrlreg);
> +	if (ret < 0)
> +		return ret;
> +
> +	spin_lock_irqsave(&rx8010->flags_lock, irqflags);
> +
> +	ret = rx8010_read_reg(rx8010->client, RX8010_FLAG, &flagreg);
> +	if (ret) {
> +		spin_unlock_irqrestore(&rx8010->flags_lock, irqflags);
> +		return ret;
> +	}
> +
> +	if (flagreg & RX8010_FLAG_VLF)
> +		ret = i2c_smbus_write_byte_data(rx8010->client, RX8010_FLAG,
> +					flagreg & ~RX8010_FLAG_VLF);
> +
> +	spin_unlock_irqrestore(&rx8010->flags_lock, irqflags);
> +
> +	return 0;
> +}
> +
> +static int rx8010_init_client(struct i2c_client *client)
> +{
> +	struct rx8010_data *rx8010 = i2c_get_clientdata(client);
> +	u8 ctrl[3];
> +	int need_clear = 0, need_reset = 0, err = 0;
> +
> +	/* Initialize reserved registers as specified in datasheet */
> +	err = i2c_smbus_write_byte_data(client, RX8010_RESV17, 0xD8);
> +	if (err < 0)
> +		return err;
> +
> +	err = i2c_smbus_write_byte_data(client, RX8010_RESV30, 0x00);
> +	if (err < 0)
> +		return err;
> +
> +	err = i2c_smbus_write_byte_data(client, RX8010_RESV31, 0x08);
> +	if (err < 0)
> +		return err;
> +
> +	err = i2c_smbus_write_byte_data(client, RX8010_IRQ, 0x00);
> +	if (err < 0)
> +		return err;
> +
> +	err = rx8010_read_regs(rx8010->client, RX8010_EXT, 3, ctrl);
> +	if (err)
> +		return err;
> +
> +	if ((ctrl[1] & RX8010_FLAG_VLF)) {
> +		dev_warn(&client->dev, "Frequency stop was detected\n");
> +		need_reset = 1;
> +	}
> +
> +	if (ctrl[1] & RX8010_FLAG_AF) {
> +		dev_warn(&client->dev, "Alarm was detected\n");
> +		need_clear = 1;
> +	}
> +
> +	if (ctrl[1] & RX8010_FLAG_TF)
> +		need_clear = 1;
> +
> +	if (ctrl[1] & RX8010_FLAG_UF)
> +		need_clear = 1;
> +
> +	if (need_reset) {
> +		ctrl[0] = ctrl[1] = ctrl[2] = 0;
> +		err = i2c_smbus_write_i2c_block_data(client, RX8010_EXT,
> +				3, ctrl);
> +		if (err < 0)
> +			return err;
> +	} else if (need_clear) {
> +		err = i2c_smbus_write_byte_data(client, RX8010_FLAG, 0x00);
> +		if (err < 0)
> +			return err;
> +	}
> +
> +	rx8010->ctrlreg = (ctrl[2] & ~RX8010_CTRL_TEST);
> +
> +	return err;
> +}
> +
> +static int rx8010_read_alarm(struct device *dev, struct rtc_wkalrm *t)
> +{
> +	struct rx8010_data *rx8010 = dev_get_drvdata(dev);
> +	struct i2c_client *client = rx8010->client;
> +	u8 alarmvals[3];
> +	u8 flagreg;
> +	int err;
> +
> +	err = rx8010_read_regs(client, RX8010_ALMIN, 3, alarmvals);
> +	if (err)
> +		return err;
> +
> +	err = rx8010_read_reg(client, RX8010_FLAG, &flagreg);
> +	if (err)
> +		return err;
> +
> +	t->time.tm_sec = 0;
> +	t->time.tm_min = bcd2bin(alarmvals[0] & 0x7f);
> +	t->time.tm_hour = bcd2bin(alarmvals[1] & 0x3f);
> +
> +	if (alarmvals[2] & RX8010_ALARM_AE)
> +		t->time.tm_mday = -1;
> +	else
> +		t->time.tm_mday = bcd2bin(alarmvals[2] & 0x7f);
> +
> +	t->time.tm_wday = -1;
> +	t->time.tm_mon = -1;
> +	t->time.tm_year = -1;
> +
> +	t->enabled = !!(rx8010->ctrlreg & RX8010_CTRL_AIE);
> +	t->pending = (flagreg & RX8010_FLAG_AF) && t->enabled;
> +
> +	return err;
> +}
> +
> +static int rx8010_set_alarm(struct device *dev, struct rtc_wkalrm *t)
> +{
> +	struct i2c_client *client = to_i2c_client(dev);
> +	struct rx8010_data *rx8010 = dev_get_drvdata(dev);
> +	u8 alarmvals[3];
> +	u8 extreg, flagreg;
> +	int err;
> +	unsigned long irqflags;
> +
> +	spin_lock_irqsave(&rx8010->flags_lock, irqflags);
> +	err = rx8010_read_reg(client, RX8010_FLAG, &flagreg);
> +	if (err) {
> +		spin_unlock_irqrestore(&rx8010->flags_lock, irqflags);
> +		return err;
> +	}
> +
> +	if (rx8010->ctrlreg & (RX8010_CTRL_AIE | RX8010_CTRL_UIE)) {
> +		rx8010->ctrlreg &= ~(RX8010_CTRL_AIE | RX8010_CTRL_UIE);
> +		err = i2c_smbus_write_byte_data(rx8010->client, RX8010_CTRL,
> +			rx8010->ctrlreg);
> +		if (err < 0) {
> +			spin_unlock_irqrestore(&rx8010->flags_lock, irqflags);
> +			return err;
> +		}
> +	}
> +
> +	flagreg &= ~RX8010_FLAG_AF;
> +	err = i2c_smbus_write_byte_data(rx8010->client, RX8010_FLAG, flagreg);
> +	spin_unlock_irqrestore(&rx8010->flags_lock, irqflags);
> +	if (err < 0)
> +		return err;
> +
> +	alarmvals[0] = bin2bcd(t->time.tm_min);
> +	alarmvals[1] = bin2bcd(t->time.tm_hour);
> +	alarmvals[2] = bin2bcd(t->time.tm_mday);
> +
> +	err = i2c_smbus_write_i2c_block_data(rx8010->client, RX8010_ALMIN,
> +				2, alarmvals);
> +	if (err < 0)
> +		return err;
> +
> +	err = rx8010_read_reg(client, RX8010_EXT, &extreg);
> +	if (err)
> +		return err;
> +
> +	extreg |= RX8010_EXT_WADA;
> +	err = i2c_smbus_write_byte_data(rx8010->client, RX8010_EXT, extreg);
> +	if (err < 0)
> +		return err;
> +
> +	if (alarmvals[2] == 0)
> +		alarmvals[2] |= RX8010_ALARM_AE;
> +
> +	err = i2c_smbus_write_byte_data(rx8010->client, RX8010_ALWDAY,
> +				alarmvals[2]);
> +	if (err < 0)
> +		return err;
> +
> +	if (t->enabled) {
> +		if (rx8010->rtc->uie_rtctimer.enabled)
> +			rx8010->ctrlreg |= RX8010_CTRL_UIE;
> +		if (rx8010->rtc->aie_timer.enabled)
> +			rx8010->ctrlreg |=
> +				(RX8010_CTRL_AIE | RX8010_CTRL_UIE);
> +
> +		err = i2c_smbus_write_byte_data(rx8010->client, RX8010_CTRL,
> +			rx8010->ctrlreg);
> +		if (err < 0)
> +			return err;
> +	}
> +
> +	return 0;
> +}
> +
> +static int rx8010_alarm_irq_enable(struct device *dev,
> +	unsigned int enabled)
> +{
> +	struct i2c_client *client = to_i2c_client(dev);
> +	struct rx8010_data *rx8010 = dev_get_drvdata(dev);
> +	u8 flagreg;
> +	u8 ctrl;
> +	int err;
> +
> +	ctrl = rx8010->ctrlreg;
> +
> +	if (enabled) {
> +		if (rx8010->rtc->uie_rtctimer.enabled)
> +			ctrl |= RX8010_CTRL_UIE;
> +		if (rx8010->rtc->aie_timer.enabled)
> +			ctrl |= (RX8010_CTRL_AIE | RX8010_CTRL_UIE);
> +	} else {
> +		if (!rx8010->rtc->uie_rtctimer.enabled)
> +			ctrl &= ~RX8010_CTRL_UIE;
> +		if (!rx8010->rtc->aie_timer.enabled)
> +			ctrl &= ~RX8010_CTRL_AIE;
> +	}
> +
> +	err = rx8010_read_reg(client, RX8010_FLAG, &flagreg);
> +	if (err)
> +		return err;
> +	flagreg &= ~RX8010_FLAG_AF;
> +	err = i2c_smbus_write_byte_data(rx8010->client, RX8010_FLAG, flagreg);
> +	if (err < 0)
> +		return err;
> +
> +	if (ctrl != rx8010->ctrlreg) {
> +		rx8010->ctrlreg = ctrl;
> +		err = i2c_smbus_write_byte_data(rx8010->client, RX8010_CTRL,
> +			rx8010->ctrlreg);
> +		if (err < 0)
> +			return err;
> +	}
> +
> +	return 0;
> +}
> +
> +static int rx8010_ioctl(struct device *dev, unsigned int cmd, unsigned long arg)
> +{
> +	struct i2c_client *client = to_i2c_client(dev);
> +	struct rx8010_data *rx8010 = dev_get_drvdata(dev);
> +	int ret, tmp;
> +	u8 flagreg;
> +	unsigned long irqflags;
> +
> +	switch (cmd) {
> +	case RTC_VL_READ:
> +		ret = rx8010_read_reg(rx8010->client, RX8010_FLAG, &flagreg);
> +		if (ret)
> +			return ret;
> +
> +		tmp = !!(flagreg & RX8010_FLAG_VLF);
> +		if (copy_to_user((void __user *)arg, &tmp, sizeof(int)))
> +			return -EFAULT;
> +
> +		return 0;
> +
> +	case RTC_VL_CLR:
> +		spin_lock_irqsave(&rx8010->flags_lock, irqflags);
> +		ret = rx8010_read_reg(rx8010->client, RX8010_FLAG, &flagreg);
> +		if (ret < 0) {
> +			spin_unlock_irqrestore(&rx8010->flags_lock, irqflags);
> +			return ret;
> +		}
> +
> +		flagreg &= ~RX8010_FLAG_VLF;
> +		ret = i2c_smbus_write_byte_data(client, RX8010_FLAG, flagreg);
> +		spin_unlock_irqrestore(&rx8010->flags_lock, irqflags);
> +		if (ret < 0)
> +			return ret;
> +
> +		return 0;
> +
> +	default:
> +		return -ENOIOCTLCMD;
> +	}
> +}
> +
> +static struct rtc_class_ops rx8010_rtc_ops = {
> +	.read_time = rx8010_get_time,
> +	.set_time = rx8010_set_time,
> +	.ioctl = rx8010_ioctl,
> +};
> +
> +static int rx8010_probe(struct i2c_client *client,
> +	const struct i2c_device_id *id)
> +{
> +	struct i2c_adapter *adapter = to_i2c_adapter(client->dev.parent);
> +	struct rx8010_data *rx8010;
> +	int err = 0;
> +
> +	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA
> +		| I2C_FUNC_SMBUS_I2C_BLOCK)) {
> +		dev_err(&adapter->dev, "doesn't support required functionality\n");
> +		return -EIO;
> +	}
> +
> +	rx8010 = devm_kzalloc(&client->dev, sizeof(struct rx8010_data),
> +		GFP_KERNEL);
> +	if (!rx8010)
> +		return -ENOMEM;
> +
> +	rx8010->client = client;
> +	i2c_set_clientdata(client, rx8010);
> +
> +	spin_lock_init(&rx8010->flags_lock);
> +
> +	err = rx8010_init_client(client);
> +	if (err)
> +		return err;
> +
> +	if (client->irq > 0) {
> +		dev_info(&client->dev, "IRQ %d supplied\n", client->irq);
> +		err = devm_request_threaded_irq(&client->dev, client->irq, NULL,
> +			rx8010_irq_1_handler, IRQF_TRIGGER_LOW | IRQF_ONESHOT,
> +			"rx8010", client);
> +
> +		if (err) {
> +			dev_err(&client->dev, "unable to request IRQ\n");
> +			client->irq = 0;
> +		} else {
> +			rx8010_rtc_ops.read_alarm = rx8010_read_alarm;
> +			rx8010_rtc_ops.set_alarm = rx8010_set_alarm;
> +			rx8010_rtc_ops.alarm_irq_enable = rx8010_alarm_irq_enable;
> +		}
> +	}
> +
> +	rx8010->rtc = devm_rtc_device_register(&client->dev, client->name,
> +		&rx8010_rtc_ops, THIS_MODULE);
> +
> +	if (IS_ERR(rx8010->rtc)) {
> +		dev_err(&client->dev, "unable to register the class device\n");
> +		return PTR_ERR(rx8010->rtc);
> +	}
> +
> +	rx8010->rtc->max_user_freq = 1;
> +
> +	return err;
> +}
> +
> +static struct i2c_driver rx8010_driver = {
> +	.driver = {
> +		.name = "rtc-rx8010",
> +	},
> +	.probe		= rx8010_probe,
> +	.id_table	= rx8010_id,
> +};
> +
> +module_i2c_driver(rx8010_driver);
> +
> +MODULE_AUTHOR("Akshay Bhat <akshay.bhat@timesys.com>");
> +MODULE_DESCRIPTION("Epson RX8010SJ RTC driver");
> +MODULE_LICENSE("GPL");
>

Hi,

On 01/12/2015 at 11:00:16 -0500, Akshay Bhat wrote :
> Hi,
> 
> Wanted to check if there was any feedback on this patch?
> 

I'm planning to review it this week.

On 11/11/2015 at 17:31:58 -0500, Akshay Bhat wrote :
> diff --git a/drivers/rtc/rtc-rx8010.c b/drivers/rtc/rtc-rx8010.c
> new file mode 100644
> index 0000000..9b8bd76
> --- /dev/null
> +++ b/drivers/rtc/rtc-rx8010.c
> @@ -0,0 +1,570 @@
> +/*
> + * Driver for the Epson RTC module RX-8010 SJ
> + *
> + * Copyright(C) Timesys Corporation 2015
> + * Copyright(C) General Electric Company 2015
> + * Copyright(C) SEIKO EPSON CORPORATION 2013. All rights reserved.
> + *
> + * Derived from RX-8025 driver:
> + * Copyright (C) 2009 Wolfgang Grandegger <wg@grandegger.com>
> + *
> + * Copyright (C) 2005 by Digi International Inc.
> + * All rights reserved.
> + *
> + * Modified by fengjh at rising.com.cn
> + * <http://lists.lm-sensors.org/mailman/listinfo/lm-sensors>
> + * 2006.11
> + *
> + * Code cleanup by Sergei Poselenov, <sposelenov@emcraft.com>
> + * Converted to new style by Wolfgang Grandegger <wg@grandegger.com>
> + * Alarm and periodic interrupt added by Dmitry Rakhchev <rda@emcraft.com>
> + *

Please remove all those unnecessary copyrights, the original
rx-8025 has been heavily rewritten anyway.

> +static int rx8010_read_reg(struct i2c_client *client, int number, u8 *value)
> +{
> +	int ret = i2c_smbus_read_byte_data(client, number);
> +
> +	if (ret < 0)
> +		return ret;
> +
> +	*value = ret;
> +	return 0;
> +}

I don't see the benefit of that function, calling
i2c_smbus_read_byte_data directly is more efficient.

> +
> +static int rx8010_read_regs(struct i2c_client *client, int number, u8 length,
> +			u8 *values)
> +{
> +	int ret = i2c_smbus_read_i2c_block_data(client, number, length, values);
> +
> +	if (ret != length)
> +		return ret < 0 ? ret : -EIO;
> +
> +	return 0;
> +}

Apart from the error handling, I'd say the same for that function.

> +
> +static irqreturn_t rx8010_irq_1_handler(int irq, void *dev_id)
> +{
> +	struct i2c_client *client = dev_id;
> +	struct rx8010_data *rx8010 = i2c_get_clientdata(client);
> +	u8 flagreg;
> +
> +	spin_lock(&rx8010->flags_lock);
> +
> +	if (rx8010_read_reg(client, RX8010_FLAG, &flagreg)) {
> +		spin_unlock(&rx8010->flags_lock);
> +		return IRQ_NONE;
> +	}
> +
> +	if (flagreg & RX8010_FLAG_VLF)
> +		dev_warn(&client->dev, "Frequency stop detected\n");
> +
> +	if (flagreg & RX8010_FLAG_TF) {
> +		flagreg &= ~RX8010_FLAG_TF;
> +		rtc_update_irq(rx8010->rtc, 1, RTC_PF | RTC_IRQF);
> +	}
> +
> +	if (flagreg & RX8010_FLAG_AF) {
> +		flagreg &= ~RX8010_FLAG_AF;
> +		rtc_update_irq(rx8010->rtc, 1, RTC_AF | RTC_IRQF);
> +	}
> +
> +	if (flagreg & RX8010_FLAG_UF) {
> +		flagreg &= ~RX8010_FLAG_UF;
> +		rtc_update_irq(rx8010->rtc, 1, RTC_UF | RTC_IRQF);
> +	}
> +
> +	i2c_smbus_write_byte_data(client, RX8010_FLAG, flagreg);
> +
> +	spin_unlock(&rx8010->flags_lock);
> +	return IRQ_HANDLED;
> +}
> +
> +static int rx8010_get_time(struct device *dev, struct rtc_time *dt)
> +{
> +	struct rx8010_data *rx8010 = dev_get_drvdata(dev);
> +	u8 date[7];
> +	u8 flagreg;
> +	int err;
> +
> +	err = rx8010_read_reg(rx8010->client, RX8010_FLAG, &flagreg);
> +	if (err)
> +		return err;
> +
> +	if (flagreg & RX8010_FLAG_VLF) {
> +		dev_warn(dev, "Frequency stop detected\n");
> +		return -EINVAL;
> +	}
> +
> +	err = rx8010_read_regs(rx8010->client, RX8010_SEC, 7, date);
> +	if (err)
> +		return err;
> +
> +	dt->tm_sec = bcd2bin(date[RX8010_SEC-RX8010_SEC] & 0x7f);
> +	dt->tm_min = bcd2bin(date[RX8010_MIN-RX8010_SEC] & 0x7f);
> +	dt->tm_hour = bcd2bin(date[RX8010_HOUR-RX8010_SEC] & 0x3f);
> +	dt->tm_mday = bcd2bin(date[RX8010_MDAY-RX8010_SEC] & 0x3f);
> +	dt->tm_mon = bcd2bin(date[RX8010_MONTH-RX8010_SEC] & 0x1f) - 1;
> +	dt->tm_year = bcd2bin(date[RX8010_YEAR-RX8010_SEC]);
> +	dt->tm_wday = bcd2bin(date[RX8010_WDAY-RX8010_SEC] & 0x7f);
> +

This is not the correct value for tm_wday, you should use ffs(), not
that anybody actually cares.

Also, checkpatch --strict complains about missing spaces around those '-'
and a few alignments are not correct, can fix those?


> +	if (dt->tm_year < 70)
> +		dt->tm_year += 100;
> +

I'd say that we don't care about handling dates before 2000 and that the
range should be 2000-2100 as this is actually the range where the leap
year calculation is correct. Also your are not respecting that in
rx8010_set_time() so setting a date in 2072 will end up reading 1972.

> +	return rtc_valid_tm(dt);
> +}
> +
> +static int rx8010_set_time(struct device *dev, struct rtc_time *dt)
> +{
> +	struct rx8010_data *rx8010 = dev_get_drvdata(dev);
> +	u8 date[7];
> +	u8 ctrl, flagreg;
> +	int ret;
> +	unsigned long irqflags;
> +
> +	/* BUG: The HW assumes every year that is a multiple of 4 to be a leap
> +	 * year.  Next time this is wrong is 2100, which will not be a leap
> +	 * year.
> +	 */
> +

Then, return -EINVAL if the year is out of the 100-200 range.


> +	/* set STOP bit before changing clock/calendar */
> +	ret = rx8010_read_reg(rx8010->client, RX8010_CTRL, &ctrl);
> +	if (ret)
> +		return ret;
> +	rx8010->ctrlreg = ctrl | RX8010_CTRL_STOP;
> +	ret = i2c_smbus_write_byte_data(rx8010->client, RX8010_CTRL,
> +		rx8010->ctrlreg);
> +	if (ret < 0)
> +		return ret;
> +
> +	date[RX8010_SEC-RX8010_SEC] = bin2bcd(dt->tm_sec);
> +	date[RX8010_MIN-RX8010_SEC] = bin2bcd(dt->tm_min);
> +	date[RX8010_HOUR-RX8010_SEC] = bin2bcd(dt->tm_hour);
> +	date[RX8010_MDAY-RX8010_SEC] = bin2bcd(dt->tm_mday);
> +	date[RX8010_MONTH-RX8010_SEC] = bin2bcd(dt->tm_mon + 1);
> +	date[RX8010_YEAR-RX8010_SEC] = bin2bcd(dt->tm_year % 100);
> +	date[RX8010_WDAY-RX8010_SEC] = bin2bcd(dt->tm_wday);

this is not the expected value for RX8010_WDAY, it must be 1 <<
dt->tm_wday, see the datasheet.

> +
> +	ret = i2c_smbus_write_i2c_block_data(rx8010->client,
> +			RX8010_SEC, 7, date);
> +	if (ret < 0)
> +		return ret;
> +
> +	/* clear STOP bit after changing clock/calendar */
> +	ret = rx8010_read_reg(rx8010->client, RX8010_CTRL, &ctrl);
> +	if (ret)
> +		return ret;
> +	rx8010->ctrlreg = ctrl & ~RX8010_CTRL_STOP;
> +	ret = i2c_smbus_write_byte_data(rx8010->client, RX8010_CTRL,
> +		rx8010->ctrlreg);
> +	if (ret < 0)
> +		return ret;
> +
> +	spin_lock_irqsave(&rx8010->flags_lock, irqflags);
> +
> +	ret = rx8010_read_reg(rx8010->client, RX8010_FLAG, &flagreg);
> +	if (ret) {
> +		spin_unlock_irqrestore(&rx8010->flags_lock, irqflags);
> +		return ret;
> +	}
> +
> +	if (flagreg & RX8010_FLAG_VLF)
> +		ret = i2c_smbus_write_byte_data(rx8010->client, RX8010_FLAG,
> +					flagreg & ~RX8010_FLAG_VLF);
> +
> +	spin_unlock_irqrestore(&rx8010->flags_lock, irqflags);
> +
> +	return 0;
> +}
> +
> +static int rx8010_init_client(struct i2c_client *client)
> +{
> +	struct rx8010_data *rx8010 = i2c_get_clientdata(client);
> +	u8 ctrl[3];
> +	int need_clear = 0, need_reset = 0, err = 0;
> +
> +	/* Initialize reserved registers as specified in datasheet */
> +	err = i2c_smbus_write_byte_data(client, RX8010_RESV17, 0xD8);
> +	if (err < 0)
> +		return err;
> +
> +	err = i2c_smbus_write_byte_data(client, RX8010_RESV30, 0x00);
> +	if (err < 0)
> +		return err;
> +
> +	err = i2c_smbus_write_byte_data(client, RX8010_RESV31, 0x08);
> +	if (err < 0)
> +		return err;
> +
> +	err = i2c_smbus_write_byte_data(client, RX8010_IRQ, 0x00);
> +	if (err < 0)
> +		return err;
> +
> +	err = rx8010_read_regs(rx8010->client, RX8010_EXT, 3, ctrl);
> +	if (err)
> +		return err;
> +
> +	if ((ctrl[1] & RX8010_FLAG_VLF)) {
> +		dev_warn(&client->dev, "Frequency stop was detected\n");
> +		need_reset = 1;
> +	}
> +
> +	if (ctrl[1] & RX8010_FLAG_AF) {
> +		dev_warn(&client->dev, "Alarm was detected\n");
> +		need_clear = 1;
> +	}
> +
> +	if (ctrl[1] & RX8010_FLAG_TF)
> +		need_clear = 1;
> +
> +	if (ctrl[1] & RX8010_FLAG_UF)
> +		need_clear = 1;
> +
> +	if (need_reset) {
> +		ctrl[0] = ctrl[1] = ctrl[2] = 0;
> +		err = i2c_smbus_write_i2c_block_data(client, RX8010_EXT,
> +				3, ctrl);
> +		if (err < 0)
> +			return err;

Please don't do that, reseting RX8010_FLAG_VLF will make userspace
believe that the bogus date is valid.

> +	} else if (need_clear) {
> +		err = i2c_smbus_write_byte_data(client, RX8010_FLAG, 0x00);
> +		if (err < 0)
> +			return err;
> +	}
> +
> +	rx8010->ctrlreg = (ctrl[2] & ~RX8010_CTRL_TEST);
> +

BTW, I'm not sure about the necessity to cache ctrl. It actually only saves one
i2c read in the alarm functions.

> +	return err;
> +}
> +

Thanks for the detailed feedback and mentioning --strict option for 
checkpatch :) I have fixed all the issues in the v2 version of the 
patch: https://lkml.org/lkml/2015/12/3/606

On 12/02/2015 06:40 PM, Alexandre Belloni wrote:
> On 11/11/2015 at 17:31:58 -0500, Akshay Bhat wrote :
>> diff --git a/drivers/rtc/rtc-rx8010.c b/drivers/rtc/rtc-rx8010.c
>> new file mode 100644
>> index 0000000..9b8bd76
>> --- /dev/null
>> +++ b/drivers/rtc/rtc-rx8010.c
>> @@ -0,0 +1,570 @@
>> +/*
>> + * Driver for the Epson RTC module RX-8010 SJ
>> + *
>> + * Copyright(C) Timesys Corporation 2015
>> + * Copyright(C) General Electric Company 2015
>> + * Copyright(C) SEIKO EPSON CORPORATION 2013. All rights reserved.
>> + *
>> + * Derived from RX-8025 driver:
>> + * Copyright (C) 2009 Wolfgang Grandegger <wg@grandegger.com>
>> + *
>> + * Copyright (C) 2005 by Digi International Inc.
>> + * All rights reserved.
>> + *
>> + * Modified by fengjh at rising.com.cn
>> + * <http://lists.lm-sensors.org/mailman/listinfo/lm-sensors>
>> + * 2006.11
>> + *
>> + * Code cleanup by Sergei Poselenov, <sposelenov@emcraft.com>
>> + * Converted to new style by Wolfgang Grandegger <wg@grandegger.com>
>> + * Alarm and periodic interrupt added by Dmitry Rakhchev <rda@emcraft.com>
>> + *
>
> Please remove all those unnecessary copyrights, the original
> rx-8025 has been heavily rewritten anyway.
>
>> +static int rx8010_read_reg(struct i2c_client *client, int number, u8 *value)
>> +{
>> +	int ret = i2c_smbus_read_byte_data(client, number);
>> +
>> +	if (ret < 0)
>> +		return ret;
>> +
>> +	*value = ret;
>> +	return 0;
>> +}
>
> I don't see the benefit of that function, calling
> i2c_smbus_read_byte_data directly is more efficient.
>
>> +
>> +static int rx8010_read_regs(struct i2c_client *client, int number, u8 length,
>> +			u8 *values)
>> +{
>> +	int ret = i2c_smbus_read_i2c_block_data(client, number, length, values);
>> +
>> +	if (ret != length)
>> +		return ret < 0 ? ret : -EIO;
>> +
>> +	return 0;
>> +}
>
> Apart from the error handling, I'd say the same for that function.
>
>> +
>> +static irqreturn_t rx8010_irq_1_handler(int irq, void *dev_id)
>> +{
>> +	struct i2c_client *client = dev_id;
>> +	struct rx8010_data *rx8010 = i2c_get_clientdata(client);
>> +	u8 flagreg;
>> +
>> +	spin_lock(&rx8010->flags_lock);
>> +
>> +	if (rx8010_read_reg(client, RX8010_FLAG, &flagreg)) {
>> +		spin_unlock(&rx8010->flags_lock);
>> +		return IRQ_NONE;
>> +	}
>> +
>> +	if (flagreg & RX8010_FLAG_VLF)
>> +		dev_warn(&client->dev, "Frequency stop detected\n");
>> +
>> +	if (flagreg & RX8010_FLAG_TF) {
>> +		flagreg &= ~RX8010_FLAG_TF;
>> +		rtc_update_irq(rx8010->rtc, 1, RTC_PF | RTC_IRQF);
>> +	}
>> +
>> +	if (flagreg & RX8010_FLAG_AF) {
>> +		flagreg &= ~RX8010_FLAG_AF;
>> +		rtc_update_irq(rx8010->rtc, 1, RTC_AF | RTC_IRQF);
>> +	}
>> +
>> +	if (flagreg & RX8010_FLAG_UF) {
>> +		flagreg &= ~RX8010_FLAG_UF;
>> +		rtc_update_irq(rx8010->rtc, 1, RTC_UF | RTC_IRQF);
>> +	}
>> +
>> +	i2c_smbus_write_byte_data(client, RX8010_FLAG, flagreg);
>> +
>> +	spin_unlock(&rx8010->flags_lock);
>> +	return IRQ_HANDLED;
>> +}
>> +
>> +static int rx8010_get_time(struct device *dev, struct rtc_time *dt)
>> +{
>> +	struct rx8010_data *rx8010 = dev_get_drvdata(dev);
>> +	u8 date[7];
>> +	u8 flagreg;
>> +	int err;
>> +
>> +	err = rx8010_read_reg(rx8010->client, RX8010_FLAG, &flagreg);
>> +	if (err)
>> +		return err;
>> +
>> +	if (flagreg & RX8010_FLAG_VLF) {
>> +		dev_warn(dev, "Frequency stop detected\n");
>> +		return -EINVAL;
>> +	}
>> +
>> +	err = rx8010_read_regs(rx8010->client, RX8010_SEC, 7, date);
>> +	if (err)
>> +		return err;
>> +
>> +	dt->tm_sec = bcd2bin(date[RX8010_SEC-RX8010_SEC] & 0x7f);
>> +	dt->tm_min = bcd2bin(date[RX8010_MIN-RX8010_SEC] & 0x7f);
>> +	dt->tm_hour = bcd2bin(date[RX8010_HOUR-RX8010_SEC] & 0x3f);
>> +	dt->tm_mday = bcd2bin(date[RX8010_MDAY-RX8010_SEC] & 0x3f);
>> +	dt->tm_mon = bcd2bin(date[RX8010_MONTH-RX8010_SEC] & 0x1f) - 1;
>> +	dt->tm_year = bcd2bin(date[RX8010_YEAR-RX8010_SEC]);
>> +	dt->tm_wday = bcd2bin(date[RX8010_WDAY-RX8010_SEC] & 0x7f);
>> +
>
> This is not the correct value for tm_wday, you should use ffs(), not
> that anybody actually cares.
>
> Also, checkpatch --strict complains about missing spaces around those '-'
> and a few alignments are not correct, can fix those?
>
>
>> +	if (dt->tm_year < 70)
>> +		dt->tm_year += 100;
>> +
>
> I'd say that we don't care about handling dates before 2000 and that the
> range should be 2000-2100 as this is actually the range where the leap
> year calculation is correct. Also your are not respecting that in
> rx8010_set_time() so setting a date in 2072 will end up reading 1972.
>
>> +	return rtc_valid_tm(dt);
>> +}
>> +
>> +static int rx8010_set_time(struct device *dev, struct rtc_time *dt)
>> +{
>> +	struct rx8010_data *rx8010 = dev_get_drvdata(dev);
>> +	u8 date[7];
>> +	u8 ctrl, flagreg;
>> +	int ret;
>> +	unsigned long irqflags;
>> +
>> +	/* BUG: The HW assumes every year that is a multiple of 4 to be a leap
>> +	 * year.  Next time this is wrong is 2100, which will not be a leap
>> +	 * year.
>> +	 */
>> +
>
> Then, return -EINVAL if the year is out of the 100-200 range.
>
>
>> +	/* set STOP bit before changing clock/calendar */
>> +	ret = rx8010_read_reg(rx8010->client, RX8010_CTRL, &ctrl);
>> +	if (ret)
>> +		return ret;
>> +	rx8010->ctrlreg = ctrl | RX8010_CTRL_STOP;
>> +	ret = i2c_smbus_write_byte_data(rx8010->client, RX8010_CTRL,
>> +		rx8010->ctrlreg);
>> +	if (ret < 0)
>> +		return ret;
>> +
>> +	date[RX8010_SEC-RX8010_SEC] = bin2bcd(dt->tm_sec);
>> +	date[RX8010_MIN-RX8010_SEC] = bin2bcd(dt->tm_min);
>> +	date[RX8010_HOUR-RX8010_SEC] = bin2bcd(dt->tm_hour);
>> +	date[RX8010_MDAY-RX8010_SEC] = bin2bcd(dt->tm_mday);
>> +	date[RX8010_MONTH-RX8010_SEC] = bin2bcd(dt->tm_mon + 1);
>> +	date[RX8010_YEAR-RX8010_SEC] = bin2bcd(dt->tm_year % 100);
>> +	date[RX8010_WDAY-RX8010_SEC] = bin2bcd(dt->tm_wday);
>
> this is not the expected value for RX8010_WDAY, it must be 1 <<
> dt->tm_wday, see the datasheet.
>
>> +
>> +	ret = i2c_smbus_write_i2c_block_data(rx8010->client,
>> +			RX8010_SEC, 7, date);
>> +	if (ret < 0)
>> +		return ret;
>> +
>> +	/* clear STOP bit after changing clock/calendar */
>> +	ret = rx8010_read_reg(rx8010->client, RX8010_CTRL, &ctrl);
>> +	if (ret)
>> +		return ret;
>> +	rx8010->ctrlreg = ctrl & ~RX8010_CTRL_STOP;
>> +	ret = i2c_smbus_write_byte_data(rx8010->client, RX8010_CTRL,
>> +		rx8010->ctrlreg);
>> +	if (ret < 0)
>> +		return ret;
>> +
>> +	spin_lock_irqsave(&rx8010->flags_lock, irqflags);
>> +
>> +	ret = rx8010_read_reg(rx8010->client, RX8010_FLAG, &flagreg);
>> +	if (ret) {
>> +		spin_unlock_irqrestore(&rx8010->flags_lock, irqflags);
>> +		return ret;
>> +	}
>> +
>> +	if (flagreg & RX8010_FLAG_VLF)
>> +		ret = i2c_smbus_write_byte_data(rx8010->client, RX8010_FLAG,
>> +					flagreg & ~RX8010_FLAG_VLF);
>> +
>> +	spin_unlock_irqrestore(&rx8010->flags_lock, irqflags);
>> +
>> +	return 0;
>> +}
>> +
>> +static int rx8010_init_client(struct i2c_client *client)
>> +{
>> +	struct rx8010_data *rx8010 = i2c_get_clientdata(client);
>> +	u8 ctrl[3];
>> +	int need_clear = 0, need_reset = 0, err = 0;
>> +
>> +	/* Initialize reserved registers as specified in datasheet */
>> +	err = i2c_smbus_write_byte_data(client, RX8010_RESV17, 0xD8);
>> +	if (err < 0)
>> +		return err;
>> +
>> +	err = i2c_smbus_write_byte_data(client, RX8010_RESV30, 0x00);
>> +	if (err < 0)
>> +		return err;
>> +
>> +	err = i2c_smbus_write_byte_data(client, RX8010_RESV31, 0x08);
>> +	if (err < 0)
>> +		return err;
>> +
>> +	err = i2c_smbus_write_byte_data(client, RX8010_IRQ, 0x00);
>> +	if (err < 0)
>> +		return err;
>> +
>> +	err = rx8010_read_regs(rx8010->client, RX8010_EXT, 3, ctrl);
>> +	if (err)
>> +		return err;
>> +
>> +	if ((ctrl[1] & RX8010_FLAG_VLF)) {
>> +		dev_warn(&client->dev, "Frequency stop was detected\n");
>> +		need_reset = 1;
>> +	}
>> +
>> +	if (ctrl[1] & RX8010_FLAG_AF) {
>> +		dev_warn(&client->dev, "Alarm was detected\n");
>> +		need_clear = 1;
>> +	}
>> +
>> +	if (ctrl[1] & RX8010_FLAG_TF)
>> +		need_clear = 1;
>> +
>> +	if (ctrl[1] & RX8010_FLAG_UF)
>> +		need_clear = 1;
>> +
>> +	if (need_reset) {
>> +		ctrl[0] = ctrl[1] = ctrl[2] = 0;
>> +		err = i2c_smbus_write_i2c_block_data(client, RX8010_EXT,
>> +				3, ctrl);
>> +		if (err < 0)
>> +			return err;
>
> Please don't do that, reseting RX8010_FLAG_VLF will make userspace
> believe that the bogus date is valid.
>
>> +	} else if (need_clear) {
>> +		err = i2c_smbus_write_byte_data(client, RX8010_FLAG, 0x00);
>> +		if (err < 0)
>> +			return err;
>> +	}
>> +
>> +	rx8010->ctrlreg = (ctrl[2] & ~RX8010_CTRL_TEST);
>> +
>
> BTW, I'm not sure about the necessity to cache ctrl. It actually only saves one
> i2c read in the alarm functions.
>
>> +	return err;
>> +}
>> +
>
>