[rtc-linux] [PATCH v2] rtc: add support for DS3232 RTC
Tiefei zang
tiefei.zang at gmail.com
Mon Jul 12 18:41:15 EST 2010
On Mon, Jul 12, 2010 at 4:37 PM, Wan ZongShun <mcuos.com at gmail.com> wrote:
> 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.
This makes sense to me. I will send a new patch.
Roy
More information about the Linuxppc-dev
mailing list