[REPOST] rtc-isl1208: Add alarm support

Add alarm/wakeup support to rtc isl1208 driver

Signed-off-by: Ryan Mallon <ryan@bluewatersys.com>
---

On Mon, 21 Feb 2011, Ryan Mallon wrote:

> Add alarm/wakeup support to rtc isl1208 driver
> 

A few (very minor) comments below.


> Signed-off-by: Ryan Mallon <ryan@bluewatersys.com>
> ---
> 
> diff --git a/drivers/rtc/rtc-isl1208.c b/drivers/rtc/rtc-isl1208.c
> index 468200c..94aa4f5 100644
> --- a/drivers/rtc/rtc-isl1208.c
> +++ b/drivers/rtc/rtc-isl1208.c
> @@ -39,6 +39,8 @@
>  #define ISL1208_REG_SR_BAT     (1<<1)	/* battery */
>  #define ISL1208_REG_SR_RTCF    (1<<0)	/* rtc fail */
>  #define ISL1208_REG_INT 0x08
> +#define ISL1208_REG_INT_ALME   (1<<6)   /* alarm enable */
> +#define ISL1208_REG_INT_IM     (1<<7)   /* interrupt/alarm mode */
>  #define ISL1208_REG_09  0x09	/* reserved */
>  #define ISL1208_REG_ATR 0x0a
>  #define ISL1208_REG_DTR 0x0b
> @@ -202,6 +204,31 @@ isl1208_i2c_set_usr(struct i2c_client *client, u16 usr)
>  }
>  
>  static int
> +isl1208_rtc_toggle_alarm(struct i2c_client *client, int enable)
> +{
> +	int icr;
> +
> +	icr = i2c_smbus_read_byte_data(client, ISL1208_REG_INT);

int icr = i2c_smbus_read_byte_data(client, ISL1208_REG_INT);

??

No functional change, but cuts down on source size.


> +	if (icr < 0) {
> +		dev_err(&client->dev, "%s: reading INT failed\n", __func__);
> +		return icr;
> +	}
> +
> +	if (enable)
> +		icr |= ISL1208_REG_INT_ALME | ISL1208_REG_INT_IM;
> +	else
> +		icr &= ~(ISL1208_REG_INT_ALME | ISL1208_REG_INT_IM);
> +
> +	icr = i2c_smbus_write_byte_data(client, ISL1208_REG_INT, icr);
> +	if (icr < 0) {
> +		dev_err(&client->dev, "%s: writing INT failed\n", __func__);
> +		return icr;
> +	}
> +
> +	return 0;
> +}
> +
> +static int
>  isl1208_rtc_proc(struct device *dev, struct seq_file *seq)
>  {
>  	struct i2c_client *const client = to_i2c_client(dev);
> @@ -288,7 +315,7 @@ isl1208_i2c_read_alarm(struct i2c_client *client, struct rtc_wkalrm *alarm)
>  {
>  	struct rtc_time *const tm = &alarm->time;
>  	u8 regs[ISL1208_ALARM_SECTION_LEN] = { 0, };
> -	int sr;
> +	int icr, yr, sr;
>  
>  	sr = isl1208_i2c_get_sr(client);

Maybe it's just me, but I'd have written this as

int icr, yr;
int sr = isl1208_i2c_get_sr(client);


>  	if (sr < 0) {
> @@ -313,6 +340,73 @@ isl1208_i2c_read_alarm(struct i2c_client *client, struct rtc_wkalrm *alarm)
>  		bcd2bin(regs[ISL1208_REG_MOA - ISL1208_REG_SCA] & 0x1f) - 1;
>  	tm->tm_wday = bcd2bin(regs[ISL1208_REG_DWA - ISL1208_REG_SCA] & 0x03);
>  
> +	/* The alarm doesn't store the year so get it from the rtc section */
> +	yr = i2c_smbus_read_byte_data(client, ISL1208_REG_YR);
> +	if (yr < 0) {
> +		dev_err(&client->dev, "%s: reading RTC YR failed\n", __func__);
> +		return yr;
> +	}
> +	tm->tm_year = bcd2bin(yr) + 100;
> +
> +	icr = i2c_smbus_read_byte_data(client, ISL1208_REG_INT);
> +	if (icr < 0) {
> +		dev_err(&client->dev, "%s: reading INT failed\n", __func__);
> +		return icr;
> +	}
> +	alarm->enabled = !!(icr & ISL1208_REG_INT_ALME);
> +
> +	return 0;
> +}
> +
> +static int
> +isl1208_i2c_set_alarm(struct i2c_client *client, struct rtc_wkalrm *alarm)
> +{
> +	struct rtc_time *alarm_tm = &alarm->time;
> +	u8 regs[ISL1208_ALARM_SECTION_LEN] = { 0, };
> +	const int offs = ISL1208_REG_SCA;
> +	unsigned long rtc_secs, alarm_secs;
> +	struct rtc_time rtc_tm;
> +	int err, enable;
> +
> +	err = isl1208_i2c_read_time(client, &rtc_tm);
> +	if (err)
> +		return err;
> +	err = rtc_tm_to_time(&rtc_tm, &rtc_secs);
> +	if (err)
> +		return err;
> +	err = rtc_tm_to_time(alarm_tm, &alarm_secs);
> +	if (err)
> +		return err;
> +
> +	/* If the alarm time is before the current time disable the alarm */
> +	if (!alarm->enabled || alarm_secs <= rtc_secs)
> +		enable = 0x00;
> +	else
> +		enable = 0x80;
> +
> +	/* Program the alarm and enable it for each setting */
> +	regs[ISL1208_REG_SCA - offs] = bin2bcd(alarm_tm->tm_sec) | enable;
> +	regs[ISL1208_REG_MNA - offs] = bin2bcd(alarm_tm->tm_min) | enable;
> +	regs[ISL1208_REG_HRA - offs] = bin2bcd(alarm_tm->tm_hour) |
> +		ISL1208_REG_HR_MIL | enable;
> +
> +	regs[ISL1208_REG_DTA - offs] = bin2bcd(alarm_tm->tm_mday) | enable;
> +	regs[ISL1208_REG_MOA - offs] = bin2bcd(alarm_tm->tm_mon + 1) | enable;
> +	regs[ISL1208_REG_DWA - offs] = bin2bcd(alarm_tm->tm_wday & 7) | enable;
> +
> +	/* write ALARM registers */
> +	err = isl1208_i2c_set_regs(client, offs, regs,
> +				  ISL1208_ALARM_SECTION_LEN);
> +	if (err < 0) {
> +		dev_err(&client->dev, "%s: writing ALARM section failed\n",
> +			__func__);
> +		return err;
> +	}
> +
> +	err = isl1208_rtc_toggle_alarm(client, enable);
> +	if (err)
> +		return err;
> +
>  	return 0;
>  }
>  
> @@ -391,12 +485,63 @@ isl1208_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alarm)
>  	return isl1208_i2c_read_alarm(to_i2c_client(dev), alarm);
>  }
>  
> +static int
> +isl1208_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alarm)
> +{
> +	return isl1208_i2c_set_alarm(to_i2c_client(dev), alarm);
> +}
> +
> +static irqreturn_t
> +isl1208_rtc_interrupt(int irq, void *data)
> +{
> +	unsigned long timeout = jiffies + msecs_to_jiffies(1000);
> +	struct i2c_client *client = data;
> +	int handled = 0, sr, err;
> +
> +	/*
> +	 * I2C reads get NAK'ed if we read straight away after an interrupt?
> +	 * Using a mdelay/msleep didn't seem to help either, so we work around
> +	 * this by continually trying to read the register for a short time.
> +	 */
> +	while (1) {
> +		sr = isl1208_i2c_get_sr(client);
> +		if (sr >= 0)
> +			break;
> +
> +		if (time_after(jiffies, timeout)) {
> +			dev_dbg(&client->dev, "%s: reading SR failed\n",
> +				__func__);
> +			return sr;
> +		}
> +	}
> +
> +	if (sr & ISL1208_REG_SR_ALM) {
> +		dev_dbg(&client->dev, "alarm!\n");
> +
> +		/* Clear the alarm */
> +		sr &= ~ISL1208_REG_SR_ALM;
> +		sr = i2c_smbus_write_byte_data(client, ISL1208_REG_SR, sr);
> +		if (sr < 0)
> +			dev_err(&client->dev, "%s: writing SR failed\n",
> +				__func__);
> +		else
> +			handled = 1;
> +
> +		/* Disable the alarm */
> +		err = isl1208_rtc_toggle_alarm(client, 0);
> +		if (err)
> +			return err;
> +	}
> +
> +	return handled ? IRQ_HANDLED : IRQ_NONE;
> +}
> +
>  static const struct rtc_class_ops isl1208_rtc_ops = {
>  	.proc = isl1208_rtc_proc,
>  	.read_time = isl1208_rtc_read_time,
>  	.set_time = isl1208_rtc_set_time,
>  	.read_alarm = isl1208_rtc_read_alarm,
> -	/*.set_alarm    = isl1208_rtc_set_alarm, */
> +	.set_alarm = isl1208_rtc_set_alarm,
>  };
>  
>  /* sysfs interface */
> @@ -488,11 +633,29 @@ isl1208_probe(struct i2c_client *client, const struct i2c_device_id *id)
>  	dev_info(&client->dev,
>  		 "chip found, driver version " DRV_VERSION "\n");
>  
> +	if (client->irq > 0) {
> +		rc = request_threaded_irq(client->irq, NULL,
> +					  isl1208_rtc_interrupt,
> +					  IRQF_SHARED,
> +					  isl1208_driver.driver.name, client);
> +		if (!rc) {
> +			device_init_wakeup(&client->dev, 1);
> +			enable_irq_wake(client->irq);
> +		} else {
> +			dev_err(&client->dev,
> +				"Unable to request irq %d, no alarm support\n",
> +				client->irq);
> +			client->irq = 0;
> +		}
> +	}
> +
>  	rtc = rtc_device_register(isl1208_driver.driver.name,
>  				  &client->dev, &isl1208_rtc_ops,
>  				  THIS_MODULE);
> -	if (IS_ERR(rtc))
> -		return PTR_ERR(rtc);
> +	if (IS_ERR(rtc)) {
> +		rc = PTR_ERR(rtc);
> +		goto exit_free_irq;
> +	}
>  
>  	i2c_set_clientdata(client, rtc);
>  
> @@ -514,6 +677,9 @@ isl1208_probe(struct i2c_client *client, const struct i2c_device_id *id)
>  
>  exit_unregister:
>  	rtc_device_unregister(rtc);
> +exit_free_irq:
> +	if (client->irq)
> +		free_irq(client->irq, client);

I didn't dig deep into this, but from a cursory look it seems that 
free_irq() should be fine being handed NULL. If that's right, then the 
condifional "if" is not needed here..


>  
>  	return rc;
>  }
> @@ -525,6 +691,8 @@ isl1208_remove(struct i2c_client *client)
>  
>  	sysfs_remove_group(&client->dev.kobj, &isl1208_rtc_sysfs_files);
>  	rtc_device_unregister(rtc);
> +	if (client->irq)
> +		free_irq(client->irq, client);
>  
>  	return 0;
>  }
>