drivers/rtc/rtc-isl1208.c: add alarm support

Add alarm/wakeup support to rtc isl1208 driver

Signed-off-by: Ryan Mallon <ryan@bluewatersys.com>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 171 insertions, 5 deletions

diff --git a/drivers/rtc/rtc-isl1208.c b/drivers/rtc/rtc-isl1208.c
index 468200c38ecb..da8beb8cae51 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 +204,30 @@ isl1208_i2c_set_usr(struct i2c_client *client, u16 usr)
 }
 
 static int
+isl1208_rtc_toggle_alarm(struct i2c_client *client, int enable)
+{
+        int 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;
+        }
+
+        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);
@@ -288,9 +314,8 @@ 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 = isl1208_i2c_get_sr(client);
 
-        sr = isl1208_i2c_get_sr(client);
         if (sr < 0) {
                 dev_err(&client->dev, "%s: reading SR failed\n", __func__);
                 return sr;
@@ -313,6 +338,73 @@ 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 +483,63 @@ 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_err(&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 +631,29 @@ 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 +675,9 @@ 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);
 
         return rc;
 }
@@ -525,6 +689,8 @@ 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;
 }