[rtc-linux] [PATCH v2] rtc: add support for DS3232 RTC
Wan ZongShun
mcuos.com at gmail.com
Mon Jul 12 18:37:23 EST 2010
2010/7/12 Tiefei zang <tiefei.zang at gmail.com>:
> On Mon, Jul 12, 2010 at 3:08 PM, Wan ZongShun <mcuos.com at gmail.com> wrote:
>> 2010/7/12 Roy Zang <tie-fei.zang at freescale.com>:
>>> This patch adds the driver for RTC chip DS3232 via I2C bus.
>>>
>>
>> I noted this patch is the second version, maybe you can describe which
>> modifications you have done here.
>> and add [PATCH v2] to mail subject.
> I do not think the modification comparing previous version should go
> into the commit message.
> I buy in your comments in original version patch and update:
> 1. add rtc_valid_tm to check return value.
> 2. remove ioctl function, which do not used and tested.
> 3. add __devinit for ds3232 probe
> 4. put request irq after driver registration.
>
>>
>>> Signed-off-by: Mingkai Hu <Mingkai.hu at freescale.com>
>>> Signed-off-by: Jingchang Lu <b22599 at freescale.com>
>>> Signed-off-by: Srikanth Srinivasan <srikanth.srinivasan at freescale.com>
>>> Signed-off-by: Roy Zang <tie-fei.zang at freescale.com>
>>> ---
>>> Tested on MPC8536DS and P4080DS board
>>>
>>> drivers/rtc/Kconfig | 11 ++
>>> drivers/rtc/Makefile | 1 +
>>> drivers/rtc/rtc-ds3232.c | 427 ++++++++++++++++++++++++++++++++++++++++++++++
>>> 3 files changed, 439 insertions(+), 0 deletions(-)
>>> create mode 100644 drivers/rtc/rtc-ds3232.c
>>>
>>> diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig
>>> index 6a13037..13c2fdb 100644
>>> --- a/drivers/rtc/Kconfig
>>> +++ b/drivers/rtc/Kconfig
>>> @@ -166,6 +166,17 @@ config RTC_DRV_DS1672
>>> This driver can also be built as a module. If so, the module
>>> will be called rtc-ds1672.
>>>
>>> +config RTC_DRV_DS3232
>>> + tristate "Dallas/Maxim DS3232"
>>> + depends on RTC_CLASS && I2C
>>> + help
>>> + If you say yes here you get support for Dallas Semiconductor
>>> + DS3232 real-time clock chips. If an interrupt is associated
>>> + with the device, the alarm functionality is supported.
>>> +
>>> + This driver can also be built as a module. If so, the module
>>> + will be called rtc-ds3232.
>>> +
>>> config RTC_DRV_MAX6900
>>> tristate "Maxim MAX6900"
>>> help
>>> diff --git a/drivers/rtc/Makefile b/drivers/rtc/Makefile
>>> index 44ef194..0af190c 100644
>>> --- a/drivers/rtc/Makefile
>>> +++ b/drivers/rtc/Makefile
>>> @@ -39,6 +39,7 @@ obj-$(CONFIG_RTC_DRV_DS1511) += rtc-ds1511.o
>>> obj-$(CONFIG_RTC_DRV_DS1553) += rtc-ds1553.o
>>> obj-$(CONFIG_RTC_DRV_DS1672) += rtc-ds1672.o
>>> obj-$(CONFIG_RTC_DRV_DS1742) += rtc-ds1742.o
>>> +obj-$(CONFIG_RTC_DRV_DS3232) += rtc-ds3232.o
>>> obj-$(CONFIG_RTC_DRV_DS3234) += rtc-ds3234.o
>>> obj-$(CONFIG_RTC_DRV_EFI) += rtc-efi.o
>>> obj-$(CONFIG_RTC_DRV_EP93XX) += rtc-ep93xx.o
>>> diff --git a/drivers/rtc/rtc-ds3232.c b/drivers/rtc/rtc-ds3232.c
>>> new file mode 100644
>>> index 0000000..e36ec1c
>>> --- /dev/null
>>> +++ b/drivers/rtc/rtc-ds3232.c
>>> @@ -0,0 +1,427 @@
>>> +/*
>>> + * RTC client/driver for the Maxim/Dallas DS3232 Real-Time Clock over I2C
>>> + *
>>> + * Copyright (C) 2009-2010 Freescale Semiconductor.
>>> + *
>>> + * This program is free software; you can redistribute it and/or modify it
>>> + * under the terms of the GNU General Public License as published by the
>>> + * Free Software Foundation; either version 2 of the License, or (at your
>>> + * option) any later version.
>>> + */
>>> +/*
>>> + * It would be more efficient to use i2c msgs/i2c_transfer directly but, as
>>> + * recommened in .../Documentation/i2c/writing-clients section
>>> + * "Sending and receiving", using SMBus level communication is preferred.
>>> + */
>>> +
>>> +#include <linux/kernel.h>
>>> +#include <linux/module.h>
>>> +#include <linux/interrupt.h>
>>> +#include <linux/i2c.h>
>>> +#include <linux/rtc.h>
>>> +#include <linux/bcd.h>
>>> +#include <linux/workqueue.h>
>>> +#include <linux/slab.h>
>>> +
>>> +#define DS3232_REG_SECONDS 0x00
>>> +#define DS3232_REG_MINUTES 0x01
>>> +#define DS3232_REG_HOURS 0x02
>>> +#define DS3232_REG_AMPM 0x02
>>> +#define DS3232_REG_DAY 0x03
>>> +#define DS3232_REG_DATE 0x04
>>> +#define DS3232_REG_MONTH 0x05
>>> +#define DS3232_REG_CENTURY 0x05
>>> +#define DS3232_REG_YEAR 0x06
>>> +#define DS3232_REG_ALARM1 0x07 /* Alarm 1 BASE */
>>> +#define DS3232_REG_ALARM2 0x0B /* Alarm 2 BASE */
>>> +#define DS3232_REG_CR 0x0E /* Control register */
>>> +# define DS3232_REG_CR_nEOSC 0x80
>>> +# define DS3232_REG_CR_INTCN 0x04
>>> +# define DS3232_REG_CR_A2IE 0x02
>>> +# define DS3232_REG_CR_A1IE 0x01
>>> +
>>> +#define DS3232_REG_SR 0x0F /* control/status register */
>>> +# define DS3232_REG_SR_OSF 0x80
>>> +# define DS3232_REG_SR_BSY 0x04
>>> +# define DS3232_REG_SR_A2F 0x02
>>> +# define DS3232_REG_SR_A1F 0x01
>>> +
>>> +struct ds3232 {
>>> + struct i2c_client *client;
>>> + struct rtc_device *rtc;
>>> + struct work_struct work;
>>> +
>>> + /* The mutex protects alarm operations, and prevents a race
>>> + * between the enable_irq() in the workqueue and the free_irq()
>>> + * in the remove function.
>>> + */
>>> + struct mutex mutex;
>>> + int exiting;
>>> +};
>>> +
>>> +static struct i2c_driver ds3232_driver;
>>> +
>>> +static int ds3232_check_rtc_status(struct i2c_client *client)
>>> +{
>>> + int ret = 0;
>>> + int control, stat;
>>> +
>>> + stat = i2c_smbus_read_byte_data(client, DS3232_REG_SR);
>>> + if (stat < 0)
>>> + return stat;
>>> +
>>> + if (stat & DS3232_REG_SR_OSF)
>>> + dev_warn(&client->dev,
>>> + "oscillator discontinuity flagged, "
>>> + "time unreliable\n");
>>> +
>>> + stat &= ~(DS3232_REG_SR_OSF | DS3232_REG_SR_A1F | DS3232_REG_SR_A2F);
>>> +
>>> + ret = i2c_smbus_write_byte_data(client, DS3232_REG_SR, stat);
>>> + if (ret < 0)
>>> + return ret;
>>> +
>>> + /* If the alarm is pending, clear it before requesting
>>> + * the interrupt, so an interrupt event isn't reported
>>> + * before everything is initialized.
>>> + */
>>> +
>>> + control = i2c_smbus_read_byte_data(client, DS3232_REG_CR);
>>> + if (control < 0)
>>> + return control;
>>> +
>>> + control &= ~(DS3232_REG_CR_A1IE | DS3232_REG_CR_A2IE);
>>> + control |= DS3232_REG_CR_INTCN;
>>> +
>>> + return i2c_smbus_write_byte_data(client, DS3232_REG_CR, control);
>>> +}
>>> +
>>> +static int ds3232_read_time(struct device *dev, struct rtc_time *time)
>>> +{
>>> + struct i2c_client *client = to_i2c_client(dev);
>>> + int ret;
>>> + u8 buf[7];
>>> + unsigned int year, month, day, hour, minute, second;
>>> + unsigned int week, twelve_hr, am_pm;
>>> + unsigned int century, add_century = 0;
>>> +
>>> + ret = i2c_smbus_read_i2c_block_data(client, DS3232_REG_SECONDS, 7, buf);
>>> +
>>> + if (ret < 0)
>>> + return ret;
>>> + if (ret < 7)
>>> + return -EIO;
>>> +
>>> + second = buf[0];
>>> + minute = buf[1];
>>> + hour = buf[2];
>>> + week = buf[3];
>>> + day = buf[4];
>>> + month = buf[5];
>>> + year = buf[6];
>>> +
>>> + /* Extract additional information for AM/PM and century */
>>> +
>>> + twelve_hr = hour & 0x40;
>>> + am_pm = hour & 0x20;
>>> + century = month & 0x80;
>>> +
>>> + /* Write to rtc_time structure */
>>> +
>>> + time->tm_sec = bcd2bin(second);
>>> + time->tm_min = bcd2bin(minute);
>>> + if (twelve_hr) {
>>> + /* Convert to 24 hr */
>>> + if (am_pm)
>>> + time->tm_hour = bcd2bin(hour & 0x1F) + 12;
>>> + else
>>> + time->tm_hour = bcd2bin(hour & 0x1F);
>>> + } else {
>>> + time->tm_hour = bcd2bin(hour);
>>> + }
>>> +
>>> + time->tm_wday = bcd2bin(week);
>>> + time->tm_mday = bcd2bin(day);
>>> + time->tm_mon = bcd2bin(month & 0x7F);
>>> + if (century)
>>> + add_century = 100;
>>> +
>>> + time->tm_year = bcd2bin(year) + add_century;
>>> +
>>> + return rtc_valid_tm(time);
>>> +}
>>> +
>>> +static int ds3232_set_time(struct device *dev, struct rtc_time *time)
>>> +{
>>> + struct i2c_client *client = to_i2c_client(dev);
>>> + u8 buf[7];
>>> +
>>> + /* Extract time from rtc_time and load into ds3232*/
>>> +
>>> + buf[0] = bin2bcd(time->tm_sec);
>>> + buf[1] = bin2bcd(time->tm_min);
>>> + buf[2] = bin2bcd(time->tm_hour);
>>> + buf[3] = bin2bcd(time->tm_wday); /* Day of the week */
>>> + buf[4] = bin2bcd(time->tm_mday); /* Date */
>>> + buf[5] = bin2bcd(time->tm_mon);
>>> + if (time->tm_year >= 100) {
>>> + buf[5] |= 0x80;
>>> + buf[6] = bin2bcd(time->tm_year - 100);
>>> + } else {
>>> + buf[6] = bin2bcd(time->tm_year);
>>> + }
>>> +
>>> + return i2c_smbus_write_i2c_block_data(client,
>>> + DS3232_REG_SECONDS, 7, buf);
>>> +}
>>> +
>>> +/*
>>> + * DS3232 has two alarm, we only use alarm1
>>> + * According to linux specification, only support one-shot alarm
>>> + * no periodic alarm mode
>>> + */
>>> +static int ds3232_read_alarm(struct device *dev, struct rtc_wkalrm *alarm)
>>> +{
>>> + struct i2c_client *client = to_i2c_client(dev);
>>> + struct ds3232 *ds3232 = i2c_get_clientdata(client);
>>> + int control, stat;
>>> + int ret = 0;
>>> + u8 buf[4];
>>> +
>>> + mutex_lock(&ds3232->mutex);
>>> + stat = ret = i2c_smbus_read_byte_data(client, DS3232_REG_SR);
>>> + if (stat < 0)
>>> + goto out;
>>> +
>>> + control = ret = i2c_smbus_read_byte_data(client, DS3232_REG_CR);
>>> + if (control < 0)
>>> + goto out;
>>> +
>>> + ret = i2c_smbus_read_i2c_block_data(client, DS3232_REG_ALARM1, 4, buf);
>>> + if (ret < 0)
>>> + goto out;
>>> +
>>> + alarm->time.tm_sec = bcd2bin(buf[0] & 0x7F);
>>> + alarm->time.tm_min = bcd2bin(buf[1] & 0x7F);
>>> + alarm->time.tm_hour = bcd2bin(buf[2] & 0x7F);
>>> + alarm->time.tm_mday = bcd2bin(buf[3] & 0x7F);
>>> +
>>> + alarm->time.tm_mon = -1;
>>> + alarm->time.tm_year = -1;
>>> + alarm->time.tm_wday = -1;
>>> + alarm->time.tm_yday = -1;
>>> + alarm->time.tm_isdst = -1;
>>> +
>>> + alarm->enabled = !!(control & DS3232_REG_CR_A1IE);
>>> + alarm->pending = !!(stat & DS3232_REG_SR_A1F);
>>> +out:
>>> + mutex_unlock(&ds3232->mutex);
>>> +
>>> + return ret;
>>> +}
>>> +
>>> +/*
>>> + * linux rtc-module does not support wday alarm
>>> + * and only 24h time mode supported indeed
>>> + */
>>> +static int ds3232_set_alarm(struct device *dev, struct rtc_wkalrm *alarm)
>>> +{
>>> + struct i2c_client *client = to_i2c_client(dev);
>>> + struct ds3232 *ds3232 = i2c_get_clientdata(client);
>>> + int control, stat;
>>> + int ret = 0;
>>> + u8 buf[4];
>>> +
>>> + if (client->irq <= 0)
>>> + return -EINVAL;
>>> +
>>> + mutex_lock(&ds3232->mutex);
>>> +
>>> + buf[0] = bin2bcd(alarm->time.tm_sec);
>>> + buf[1] = bin2bcd(alarm->time.tm_min);
>>> + buf[2] = bin2bcd(alarm->time.tm_hour);
>>> + buf[3] = bin2bcd(alarm->time.tm_mday);
>>> +
>>> + /* clear alarm interrupt enable bit */
>>> + ret = control = i2c_smbus_read_byte_data(client, DS3232_REG_CR);
>>> + if (ret < 0)
>>> + goto out;
>>> + control &= ~(DS3232_REG_CR_A1IE | DS3232_REG_CR_A2IE);
>>> + ret = i2c_smbus_write_byte_data(client, DS3232_REG_CR, control);
>>> + if (ret < 0)
>>> + goto out;
>>> +
>>> + /* clear any pending alarm flag */
>>> + stat = i2c_smbus_read_byte_data(client, DS3232_REG_SR);
>>> + if (stat < 0)
>>> + return stat;
>>> +
>>> + stat &= ~(DS3232_REG_SR_A1F | DS3232_REG_SR_A2F);
>>> +
>>> + ret = i2c_smbus_write_byte_data(client, DS3232_REG_SR, stat);
>>> + if (ret < 0)
>>> + return ret;
>>> +
>>> + ret = i2c_smbus_write_i2c_block_data(client,
>>> + DS3232_REG_ALARM1, 4, buf);
>>> +
>>> + if (alarm->enabled) {
>>> + control |= DS3232_REG_CR_A1IE;
>>> + ret = i2c_smbus_write_byte_data(client, DS3232_REG_CR, control);
>>> + }
>>> +out:
>>> + mutex_unlock(&ds3232->mutex);
>>> + return ret;
>>> +}
>>> +
>>> +static irqreturn_t ds3232_irq(int irq, void *dev_id)
>>> +{
>>> + struct i2c_client *client = dev_id;
>>> + struct ds3232 *ds3232 = i2c_get_clientdata(client);
>>> +
>>> + disable_irq_nosync(irq);
>>> + schedule_work(&ds3232->work);
>>> + return IRQ_HANDLED;
>>> +}
>>> +
>>> +static void ds3232_work(struct work_struct *work)
>>> +{
>>> + struct ds3232 *ds3232 = container_of(work, struct ds3232, work);
>>> + struct i2c_client *client = ds3232->client;
>>> + int stat, control;
>>> +
>>> + mutex_lock(&ds3232->mutex);
>>> +
>>> + stat = i2c_smbus_read_byte_data(client, DS3232_REG_SR);
>>> + if (stat < 0)
>>> + goto unlock;
>>> +
>>> + if (stat & DS3232_REG_SR_A1F) {
>>> + control = i2c_smbus_read_byte_data(client, DS3232_REG_CR);
>>> + if (control < 0)
>>> + goto out;
>>> + /* disable alarm1 interrupt */
>>> + control &= ~(DS3232_REG_CR_A1IE);
>>> + i2c_smbus_write_byte_data(client, DS3232_REG_CR, control);
>>> +
>>> + /* clear the alarm pend flag */
>>> + stat &= ~DS3232_REG_SR_A1F;
>>> + i2c_smbus_write_byte_data(client, DS3232_REG_SR, stat);
>>> +
>>> + rtc_update_irq(ds3232->rtc, 1, RTC_AF | RTC_IRQF);
>>> + }
>>> +
>>> +out:
>>> + if (!ds3232->exiting)
>>> + enable_irq(client->irq);
>>> +unlock:
>>> + mutex_unlock(&ds3232->mutex);
>>> +}
>>> +
>>> +static const struct rtc_class_ops ds3232_rtc_ops = {
>>> + .read_time = ds3232_read_time,
>>> + .set_time = ds3232_set_time,
>>> + .read_alarm = ds3232_read_alarm,
>>> + .set_alarm = ds3232_set_alarm,
>>> +};
>>
>> I sew that you have discarded the .ioctl function, which is used to
>> enable/disable the alarm irq in previous driver patch.
>> but,at the same time, you didnot implement .alarm_irq_enable function
>> , so is there no need to enable or disable the alarm irq bit in
>> current version patch?
> Right. This is not needed in current patch. Alarm is not used and tested.
> Thanks.
Sorry for forgetting to comment this,
If the alarm is not used, please remove all the alarm parts, should
not we make sure all drivers submitted to linux mainline
can work good?
When you want to use the alarm, you can send one patch to add it again.
> Roy
>
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> before submitting a driver.
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