[rtc-linux] [PATCH v2] rtc: add support for DS3232 RTC
Tiefei zang
tiefei.zang at gmail.com
Mon Jul 12 18:12:02 EST 2010
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.
Roy
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