[PATCHv0 1/5] rtc: rtc-isl12057: add alarm support to Intersil ISL12057 RTC driver
Arnaud Ebalard
arno at natisbad.org
Sat Dec 13 17:42:14 PST 2014
This patch adds alarm support to Intersil ISL12057 driver. This allows
to configure the chip to generate an interrupt when the alarm matches
current time value. Alarm can be programmed up to one month in the
future and is accurate to the second.
The patch was developed to support two different configurations:
systems w/ and w/o RTC chip IRQ line connected to the main CPU.
The latter is the one found on current 3 kernel users of the chip
for which support was initially developed (Netgear ReadyNAS 102,
104 and 2120 NAS). On those devices, the IRQ#2 pin of the chip is not
connected to the SoC but to a PMIC. This allows setting an alarm,
powering off the device and have it wake up when the alarm rings.
To support that configuration the driver does the following:
1. it has alarm_irq_enable() function returns -ENOTTY when no IRQ
is passed to the driver.
2. it marks the device as a wakeup source if an IRQ is passed to
to the driver or if the boolean "can-wakeup-machine" is set
in system .dts file to have 'wakealarm' sysfs entry created.
3. it marks the device has not supporting UIE mode when no IRQ is
passed to the driver (see the commmit message of c9f5c7e7a84f)
This specific configuration was tested on a ReadyNAS 102 by setting
an alarm, powering off the device and see it reboot as expected
when the alarm rang.
The former configuration was tested on a Netgear ReadyNAS 102 after
some soldering of the IRQ#2 pin of the RTC chip to a MPP line of the
SoC (the one used usually handles the reset button). The test was
performed using a modified .dts file reflecting this change (see below)
and rtc-test.c program available in Documentation/rtc.txt. This test
program ran as expected, which validates alarm supports, including
interrupt support.
As a side note, the ISL12057 remains in the list of trivial devices,
i.e. no specific DT binding being added by this patch: i2c core
automatically handles extraction of IRQ line info from .dts file. For
instance, if one wants to reference the interrupt line for the
alarm in its .dts file, adding interrupt and interrupt-parent
properties works as expected (if the primary function of your
interrupt pin is not GPIO, you will need some additional pinctrl
properties):
isl12057: isl12057 at 68 {
compatible = "isil,isl12057";
interrupt-parent = <&gpio0>;
interrupts = <6 IRQ_TYPE_EDGE_FALLING>;
reg = <0x68>;
};
FWIW, if someone is looking for a way to test alarm support on a system
on which the chip IRQ line has the ability to boot the system (e.g.
ReadyNAS 102, 104, etc):
# echo `date '+%s' -d '+ 1 minutes'` > /sys/class/rtc/rtc0/wakealarm
# shutdown -h now
With the commands above, after a minute, the system comes back to life.
As a final note, the driver does not provide support for the second
alarm of the chip (this second alarm does not support second).
Signed-off-by: Arnaud Ebalard <arno at natisbad.org>
---
.../devicetree/bindings/rtc/isil,isl12057.txt | 71 +++++
drivers/rtc/rtc-isl12057.c | 350 ++++++++++++++++++++-
2 files changed, 411 insertions(+), 10 deletions(-)
create mode 100644 Documentation/devicetree/bindings/rtc/isil,isl12057.txt
diff --git a/Documentation/devicetree/bindings/rtc/isil,isl12057.txt b/Documentation/devicetree/bindings/rtc/isil,isl12057.txt
new file mode 100644
index 000000000000..111bb8a6c274
--- /dev/null
+++ b/Documentation/devicetree/bindings/rtc/isil,isl12057.txt
@@ -0,0 +1,71 @@
+Intersil ISL12057 I2C RTC/Alarm chip
+
+ISL12057 is a trivial I2C device (it has simple device tree bindings, consisting
+of a compatible field, an address and possibly an interrupt line).
+
+Nonetheless, it supports an additional boolean property ("can-wakeup-machine")
+to handle the specific use-case found on the three initial in-tree users of the
+chip (NETGEAR ReadyNAS 102, 104 and 2120 ARM-based NAS); On those devices, the
+IRQ#2 pin of the chip (associated with the alarm supported by the driver) is not
+connected to the SoC but to a PMIC. It allows the device to be powered up when
+RTC alarm rings. In order to mark the device has a wakeup source and get access
+to the 'wakealarm' sysfs entry, this specific property can be set when the IRQ#2
+pin of the chip is not connected to the SoC.
+
+Required properties supported by the device:
+
+ - "compatible": must be "isil,isl12057"
+ - "reg": I2C bus address of the device
+
+Optional properties:
+
+ - "can-wakeup-machine": mark the chip as a wakeup source, independently of
+ the availability of an IRQ line connected to the SoC.
+
+
+Example isl12057 node without IRQ#2 pin connected (no alarm support):
+
+ isl12057: isl12057 at 68 {
+ compatible = "isil,isl12057";
+ reg = <0x68>;
+ };
+
+
+Example isl12057 node with IRQ#2 pin connected to main SoC via MPP6 (note
+that the pinctrl-related properties below are given for completeness and
+may not be required depending on your system or SoC, and the main function
+of the MPP used as IRQ line, i.e. "interrupt-parent" and "interrupts" are
+usually sufficient):
+
+ pinctrl {
+ ...
+
+ rtc_alarm_pin: rtc_alarm_pin {
+ marvell,pins = "mpp6";
+ marvell,function = "gpio";
+ };
+
+ ...
+
+ };
+
+ ...
+
+ isl12057: isl12057 at 68 {
+ compatible = "isil,isl12057";
+ reg = <0x68>;
+ pinctrl-0 = <&rtc_alarm_pin>;
+ pinctrl-names = "default";
+ interrupt-parent = <&gpio0>;
+ interrupts = <6 IRQ_TYPE_EDGE_FALLING>;
+ };
+
+
+Example isl12057 node without IRQ#2 pin connected to the SoC but to a
+PMIC, allowing the device to be started based on configured alarm:
+
+ isl12057: isl12057 at 68 {
+ compatible = "isil,isl12057";
+ reg = <0x68>;
+ can-wakeup-machine;
+ };
diff --git a/drivers/rtc/rtc-isl12057.c b/drivers/rtc/rtc-isl12057.c
index 6e1fcfb5d7e6..98adc2c1bdb0 100644
--- a/drivers/rtc/rtc-isl12057.c
+++ b/drivers/rtc/rtc-isl12057.c
@@ -1,5 +1,5 @@
/*
- * rtc-isl12057 - Driver for Intersil ISL12057 I2C Real Time Clock
+ * rtc-isl12057 - Driver for Intersil ISL12057 I2C Real Time Clock / Alarm
*
* Copyright (C) 2013, Arnaud EBALARD <arno at natisbad.org>
*
@@ -79,8 +79,10 @@
#define ISL12057_MEM_MAP_LEN 0x10
struct isl12057_rtc_data {
+ struct rtc_device *rtc;
struct regmap *regmap;
struct mutex lock;
+ int irq;
};
static void isl12057_rtc_regs_to_tm(struct rtc_time *tm, u8 *regs)
@@ -160,14 +162,47 @@ static int isl12057_i2c_validate_chip(struct regmap *regmap)
return 0;
}
-static int isl12057_rtc_read_time(struct device *dev, struct rtc_time *tm)
+static int _isl12057_rtc_clear_alarm(struct device *dev)
+{
+ struct isl12057_rtc_data *data = dev_get_drvdata(dev);
+ int ret;
+
+ ret = regmap_update_bits(data->regmap, ISL12057_REG_SR,
+ ISL12057_REG_SR_A1F, 0);
+ if (ret)
+ dev_err(dev, "%s: clearing alarm failed (%d)\n", __func__, ret);
+
+ return ret;
+}
+
+static int _isl12057_rtc_update_alarm(struct device *dev, int enable)
+{
+ struct isl12057_rtc_data *data = dev_get_drvdata(dev);
+ int ret;
+
+ ret = regmap_update_bits(data->regmap, ISL12057_REG_INT,
+ ISL12057_REG_INT_A1IE,
+ enable ? ISL12057_REG_INT_A1IE : 0);
+ if (ret)
+ dev_err(dev, "%s: changing alarm interrupt flag failed (%d)\n",
+ __func__, ret);
+
+ return ret;
+}
+
+/*
+ * Note: as we only read from device and do not perform any update, there is
+ * no need for an equivalent function which would try and get driver's main
+ * lock. Here, it is safe for everyone if we just use regmap internal lock
+ * on the device when reading.
+ */
+static int _isl12057_rtc_read_time(struct device *dev, struct rtc_time *tm)
{
struct isl12057_rtc_data *data = dev_get_drvdata(dev);
u8 regs[ISL12057_RTC_SEC_LEN];
unsigned int sr;
int ret;
- mutex_lock(&data->lock);
ret = regmap_read(data->regmap, ISL12057_REG_SR, &sr);
if (ret) {
dev_err(dev, "%s: unable to read oscillator status flag (%d)\n",
@@ -187,8 +222,6 @@ static int isl12057_rtc_read_time(struct device *dev, struct rtc_time *tm)
__func__, ret);
out:
- mutex_unlock(&data->lock);
-
if (ret)
return ret;
@@ -197,6 +230,168 @@ out:
return rtc_valid_tm(tm);
}
+static int isl12057_rtc_update_alarm(struct device *dev, int enable)
+{
+ struct isl12057_rtc_data *data = dev_get_drvdata(dev);
+ int ret;
+
+ mutex_lock(&data->lock);
+ ret = _isl12057_rtc_update_alarm(dev, enable);
+ mutex_unlock(&data->lock);
+
+ return ret;
+}
+
+static int isl12057_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alarm)
+{
+ struct isl12057_rtc_data *data = dev_get_drvdata(dev);
+ struct rtc_time rtc_tm, *alarm_tm = &alarm->time;
+ unsigned long rtc_secs, alarm_secs;
+ u8 regs[ISL12057_A1_SEC_LEN];
+ unsigned int ir;
+ int ret;
+
+ mutex_lock(&data->lock);
+ ret = regmap_bulk_read(data->regmap, ISL12057_REG_A1_SC, regs,
+ ISL12057_A1_SEC_LEN);
+ if (ret) {
+ dev_err(dev, "%s: reading alarm section failed (%d)\n",
+ __func__, ret);
+ goto err_unlock;
+ }
+
+ alarm_tm->tm_sec = bcd2bin(regs[0] & 0x7f);
+ alarm_tm->tm_min = bcd2bin(regs[1] & 0x7f);
+ alarm_tm->tm_hour = bcd2bin(regs[2] & 0x3f);
+ alarm_tm->tm_mday = bcd2bin(regs[3] & 0x3f);
+ alarm_tm->tm_wday = -1;
+
+ /*
+ * The alarm section does not store year/month. We use the ones in rtc
+ * section as a basis and increment month and then year if needed to get
+ * alarm after current time.
+ */
+ ret = _isl12057_rtc_read_time(dev, &rtc_tm);
+ if (ret)
+ goto err_unlock;
+
+ alarm_tm->tm_year = rtc_tm.tm_year;
+ alarm_tm->tm_mon = rtc_tm.tm_mon;
+
+ ret = rtc_tm_to_time(&rtc_tm, &rtc_secs);
+ if (ret)
+ goto err_unlock;
+
+ ret = rtc_tm_to_time(alarm_tm, &alarm_secs);
+ if (ret)
+ goto err_unlock;
+
+ if (alarm_secs < rtc_secs) {
+ if (alarm_tm->tm_mon == 11) {
+ alarm_tm->tm_mon = 0;
+ alarm_tm->tm_year += 1;
+ } else {
+ alarm_tm->tm_mon += 1;
+ }
+ }
+
+ ret = regmap_read(data->regmap, ISL12057_REG_INT, &ir);
+ if (ret) {
+ dev_err(dev, "%s: reading alarm interrupt flag failed (%d)\n",
+ __func__, ret);
+ goto err_unlock;
+ }
+
+ alarm->enabled = !!(ir & ISL12057_REG_INT_A1IE);
+
+err_unlock:
+ mutex_unlock(&data->lock);
+
+ return ret;
+}
+
+static int isl12057_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alarm)
+{
+ struct isl12057_rtc_data *data = dev_get_drvdata(dev);
+ struct rtc_time *alarm_tm = &alarm->time;
+ unsigned long rtc_secs, alarm_secs;
+ u8 regs[ISL12057_A1_SEC_LEN];
+ struct rtc_time rtc_tm;
+ int ret, enable = 1;
+
+ mutex_lock(&data->lock);
+ ret = _isl12057_rtc_read_time(dev, &rtc_tm);
+ if (ret)
+ goto err_unlock;
+
+ ret = rtc_tm_to_time(&rtc_tm, &rtc_secs);
+ if (ret)
+ goto err_unlock;
+
+ ret = rtc_tm_to_time(alarm_tm, &alarm_secs);
+ if (ret)
+ goto err_unlock;
+
+ /* If alarm time is before current time, disable the alarm */
+ if (!alarm->enabled || alarm_secs <= rtc_secs) {
+ enable = 0;
+ } else {
+ /*
+ * Chip only support alarms up to one month in the future. Let's
+ * return an error if we get something after that limit.
+ * Comparison is done by incrementing rtc_tm month field by one
+ * and checking alarm value is still below.
+ */
+ if (rtc_tm.tm_mon == 11) { /* handle year wrapping */
+ rtc_tm.tm_mon = 0;
+ rtc_tm.tm_year += 1;
+ } else {
+ rtc_tm.tm_mon += 1;
+ }
+
+ ret = rtc_tm_to_time(&rtc_tm, &rtc_secs);
+ if (ret)
+ goto err_unlock;
+
+ if (alarm_secs > rtc_secs) {
+ dev_err(dev, "%s: max for alarm is one month (%d)\n",
+ __func__, ret);
+ ret = -EINVAL;
+ goto err_unlock;
+ }
+ }
+
+ /* Disable the alarm before modifying it */
+ ret = _isl12057_rtc_update_alarm(dev, 0);
+ if (ret < 0) {
+ dev_err(dev, "%s: unable to disable the alarm (%d)\n",
+ __func__, ret);
+ goto err_unlock;
+ }
+
+ /* Program alarm registers */
+ regs[0] = bin2bcd(alarm_tm->tm_sec) & 0x7f;
+ regs[1] = bin2bcd(alarm_tm->tm_min) & 0x7f;
+ regs[2] = bin2bcd(alarm_tm->tm_hour) & 0x3f;
+ regs[3] = bin2bcd(alarm_tm->tm_mday) & 0x3f;
+
+ ret = regmap_bulk_write(data->regmap, ISL12057_REG_A1_SC, regs,
+ ISL12057_A1_SEC_LEN);
+ if (ret < 0) {
+ dev_err(dev, "%s: writing alarm section failed (%d)\n",
+ __func__, ret);
+ goto err_unlock;
+ }
+
+ /* Enable or disable alarm */
+ ret = _isl12057_rtc_update_alarm(dev, enable);
+
+err_unlock:
+ mutex_unlock(&data->lock);
+
+ return ret;
+}
+
static int isl12057_rtc_set_time(struct device *dev, struct rtc_time *tm)
{
struct isl12057_rtc_data *data = dev_get_drvdata(dev);
@@ -262,9 +457,82 @@ static int isl12057_check_rtc_status(struct device *dev, struct regmap *regmap)
return 0;
}
+#ifdef CONFIG_OF
+/*
+ * One would expect the device to be marked as a wakeup source only
+ * when an IRQ pin of the RTC is routed to an interrupt line of the
+ * CPU. In practice, such an IRQ pin can be connected to a PMIC and
+ * this allows the device to be powered up when RTC alarm rings. This
+ * is for instance the case on ReadyNAS 102, 104 and 2120. On those
+ * devices with no IRQ driectly connected to the SoC, the RTC chip
+ * can be forced as a wakeup source by stating that explicitly in
+ * the device's .dts file using the "can-wakeup-machine" boolean
+ * property. This will guarantee 'wakealarm' sysfs entry is available
+ * on the device.
+ *
+ * The function below returns 1, i.e. the capability of the chip to
+ * wakeup the device, based on IRQ availability or if the boolean
+ * property has been set in the .dts file. Otherwise, it returns 0.
+ */
+
+static bool isl12057_can_wakeup_machine(struct device *dev)
+{
+ struct isl12057_rtc_data *data = dev_get_drvdata(dev);
+
+ return (data->irq ||
+ of_property_read_bool(dev->of_node, "can-wakeup-machine"));
+}
+#else
+static bool isl12057_can_wakeup_machine(struct device *dev)
+{
+ struct isl12057_rtc_data *data = dev_get_drvdata(dev);
+
+ return !!data->irq;
+}
+#endif
+
+static int isl12057_rtc_alarm_irq_enable(struct device *dev,
+ unsigned int enable)
+{
+ struct isl12057_rtc_data *rtc_data = dev_get_drvdata(dev);
+ int ret = -ENOTTY;
+
+ if (rtc_data->irq)
+ ret = isl12057_rtc_update_alarm(dev, enable);
+
+ return ret;
+}
+
+static irqreturn_t isl12057_rtc_interrupt(int irq, void *data)
+{
+ struct i2c_client *client = data;
+ struct isl12057_rtc_data *rtc_data = dev_get_drvdata(&client->dev);
+ struct rtc_device *rtc = rtc_data->rtc;
+ int ret, handled = IRQ_NONE;
+ unsigned int sr;
+
+ ret = regmap_read(rtc_data->regmap, ISL12057_REG_SR, &sr);
+ if (!ret && (sr & ISL12057_REG_SR_A1F)) {
+ dev_dbg(&client->dev, "RTC alarm!\n");
+
+ rtc_update_irq(rtc, 1, RTC_IRQF | RTC_AF);
+
+ /* Acknowledge and disable the alarm */
+ _isl12057_rtc_clear_alarm(&client->dev);
+ _isl12057_rtc_update_alarm(&client->dev, 0);
+
+ handled = IRQ_HANDLED;
+ }
+
+ return handled;
+}
+
static const struct rtc_class_ops rtc_ops = {
- .read_time = isl12057_rtc_read_time,
+ .read_time = _isl12057_rtc_read_time,
.set_time = isl12057_rtc_set_time,
+ .read_alarm = isl12057_rtc_read_alarm,
+ .set_alarm = isl12057_rtc_set_alarm,
+ .alarm_irq_enable = isl12057_rtc_alarm_irq_enable,
};
static struct regmap_config isl12057_rtc_regmap_config = {
@@ -277,7 +545,6 @@ static int isl12057_probe(struct i2c_client *client,
{
struct device *dev = &client->dev;
struct isl12057_rtc_data *data;
- struct rtc_device *rtc;
struct regmap *regmap;
int ret;
@@ -310,9 +577,70 @@ static int isl12057_probe(struct i2c_client *client,
data->regmap = regmap;
dev_set_drvdata(dev, data);
- rtc = devm_rtc_device_register(dev, DRV_NAME, &rtc_ops, THIS_MODULE);
- return PTR_ERR_OR_ZERO(rtc);
+ if (client->irq > 0) {
+ ret = devm_request_threaded_irq(dev, client->irq, NULL,
+ isl12057_rtc_interrupt,
+ IRQF_SHARED|IRQF_ONESHOT,
+ DRV_NAME, client);
+ if (!ret)
+ data->irq = client->irq;
+ else
+ dev_err(dev, "%s: irq %d unavailable (%d)\n", __func__,
+ client->irq, ret);
+ }
+
+ if (isl12057_can_wakeup_machine(dev))
+ device_init_wakeup(dev, true);
+
+ data->rtc = devm_rtc_device_register(dev, DRV_NAME, &rtc_ops,
+ THIS_MODULE);
+ ret = PTR_ERR_OR_ZERO(data->rtc);
+ if (ret) {
+ dev_err(dev, "%s: unable to register RTC device (%d)\n",
+ __func__, ret);
+ goto err;
+ }
+
+ /* We cannot support UIE mode if we do not have an IRQ line */
+ if (!data->irq)
+ data->rtc->uie_unsupported = 1;
+
+err:
+ return ret;
+}
+
+static int isl12057_remove(struct i2c_client *client)
+{
+ if (isl12057_can_wakeup_machine(&client->dev))
+ device_init_wakeup(&client->dev, false);
+
+ return 0;
+}
+
+#ifdef CONFIG_PM_SLEEP
+static int isl12057_rtc_suspend(struct device *dev)
+{
+ struct isl12057_rtc_data *rtc_data = dev_get_drvdata(dev);
+
+ if (rtc_data->irq && device_may_wakeup(dev))
+ return enable_irq_wake(rtc_data->irq);
+
+ return 0;
+}
+
+static int isl12057_rtc_resume(struct device *dev)
+{
+ struct isl12057_rtc_data *rtc_data = dev_get_drvdata(dev);
+
+ if (rtc_data->irq && device_may_wakeup(dev))
+ return disable_irq_wake(rtc_data->irq);
+
+ return 0;
}
+#endif
+
+static SIMPLE_DEV_PM_OPS(isl12057_rtc_pm_ops, isl12057_rtc_suspend,
+ isl12057_rtc_resume);
#ifdef CONFIG_OF
static const struct of_device_id isl12057_dt_match[] = {
@@ -331,13 +659,15 @@ static struct i2c_driver isl12057_driver = {
.driver = {
.name = DRV_NAME,
.owner = THIS_MODULE,
+ .pm = &isl12057_rtc_pm_ops,
.of_match_table = of_match_ptr(isl12057_dt_match),
},
.probe = isl12057_probe,
+ .remove = isl12057_remove,
.id_table = isl12057_id,
};
module_i2c_driver(isl12057_driver);
MODULE_AUTHOR("Arnaud EBALARD <arno at natisbad.org>");
-MODULE_DESCRIPTION("Intersil ISL12057 RTC driver");
+MODULE_DESCRIPTION("Intersil ISL12057 RTC/Alarm driver");
MODULE_LICENSE("GPL");
--
2.1.1
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