[2/2] rtc: pcf85263/pcf85363: support PM, wakeup device, improve performance

From: Biwen Li
Date: Fri Aug 30 2019 - 05:27:37 EST

Add some features as follow:
- Set quartz oscillator load capacitance by DT
(generate more accuracy frequency)
- Set quartz oscillator drive control by DT
(reduce/increase the current consumption)
- Set low jitter mode by DT
(improve jitter performance)
- Set wakeup source by DT
(wakeup device from suspend
- Select interrupt output pin by DT
(INTA/TS(INTB)/NONE)
- Add power management
- Add ioctl to check rtc status
(check whether oscillator of pcf85263/pcf85363 is stopped)

Datasheet url:
- https://www.nxp.com/docs/en/data-sheet/PCF85263A.pdf
- https://www.nxp.com/docs/en/data-sheet/PCF85363A.pdf

Signed-off-by: Martin Fuzzey <mfuzzey@xxxxxxxxxxx>
Signed-off-by: Biwen Li <biwen.li@xxxxxxx>
---
drivers/rtc/rtc-pcf85363.c | 287 +++++++++++++++++++++++++++++++++++--
1 file changed, 274 insertions(+), 13 deletions(-)

diff --git a/drivers/rtc/rtc-pcf85363.c b/drivers/rtc/rtc-pcf85363.c
index a075e77617dc..f8916497efd4 100644
--- a/drivers/rtc/rtc-pcf85363.c
+++ b/drivers/rtc/rtc-pcf85363.c
@@ -18,6 +18,17 @@
#include <linux/of_device.h>
#include <linux/regmap.h>

+/* Quartz capacitance */
+#define PCF85363_QUARTZCAP_7pF 0
+#define PCF85363_QUARTZCAP_6pF 1
+#define PCF85363_QUARTZCAP_12p5pF 2
+
+/* Quartz drive strength */
+#define PCF85363_QUARTZDRIVE_NORMAL 0
+#define PCF85363_QUARTZDRIVE_LOW 1
+#define PCF85363_QUARTZDRIVE_HIGH 2
+
+
/*
* Date/Time registers
*/
@@ -96,10 +107,20 @@
#define FLAGS_PIF BIT(7)

#define PIN_IO_INTAPM GENMASK(1, 0)
-#define PIN_IO_INTA_CLK 0
-#define PIN_IO_INTA_BAT 1
-#define PIN_IO_INTA_OUT 2
-#define PIN_IO_INTA_HIZ 3
+#define PIN_IO_INTAPM_SHIFT 0
+#define PIN_IO_INTA_CLK (0 << PIN_IO_INTAPM_SHIFT)
+#define PIN_IO_INTA_BAT (1 << PIN_IO_INTAPM_SHIFT)
+#define PIN_IO_INTA_OUT (2 << PIN_IO_INTAPM_SHIFT)
+#define PIN_IO_INTA_HIZ (3 << PIN_IO_INTAPM_SHIFT)
+
+#define PIN_IO_TSPM GENMASK(3, 2)
+#define PIN_IO_TSPM_SHIFT 2
+#define PIN_IO_TS_DISABLE (0x0 << PIN_IO_TSPM_SHIFT)
+#define PIN_IO_TS_INTB_OUT (0x1 << PIN_IO_TSPM_SHIFT)
+#define PIN_IO_TS_CLK_OUT (0x2 << PIN_IO_TSPM_SHIFT)
+#define PIN_IO_TS_IN (0x3 << PIN_IO_TSPM_SHIFT)
+
+#define PIN_IO_CLKPM BIT(7) /* 0 = enable CLK pin,1 = disable CLK pin */

#define STOP_EN_STOP BIT(0)

@@ -107,9 +128,35 @@

#define NVRAM_SIZE 0x40

+#define DT_SECS_OS BIT(7)
+
+#define CTRL_OSCILLATOR_CL_MASK GENMASK(1, 0)
+#define CTRL_OSCILLATOR_CL_SHIFT 0
+#define CTRL_OSCILLATOR_OSCD_MASK GENMASK(3, 2)
+#define CTRL_OSCILLATOR_OSCD_SHIFT 2
+#define CTRL_OSCILLATOR_LOWJ BIT(4)
+
+#define CTRL_FUNCTION_COF_OFF 0x7 /* No clock output */
+
+enum pcf85363_irqpin {
+ IRQPIN_NONE,
+ IRQPIN_INTA,
+ IRQPIN_INTB
+};
+
+static const char *const pcf85363_irqpin_names[] = {
+ [IRQPIN_NONE] = "NONE",
+ [IRQPIN_INTA] = "INTA",
+ [IRQPIN_INTB] = "INTB"
+};
+
+
struct pcf85363 {
+ struct device *dev;
struct rtc_device *rtc;
struct regmap *regmap;
+ enum pcf85363_irqpin irq_pin;
+ int irq;
};

struct pcf85x63_config {
@@ -205,14 +252,29 @@ static int _pcf85363_rtc_alarm_irq_enable(struct pcf85363 *pcf85363, unsigned
{
unsigned int alarm_flags = ALRM_SEC_A1E | ALRM_MIN_A1E | ALRM_HR_A1E |
ALRM_DAY_A1E | ALRM_MON_A1E;
- int ret;
+ int ret, reg;

ret = regmap_update_bits(pcf85363->regmap, DT_ALARM_EN, alarm_flags,
enabled ? alarm_flags : 0);
if (ret)
return ret;

- ret = regmap_update_bits(pcf85363->regmap, CTRL_INTA_EN,
+ switch (pcf85363->irq_pin) {
+ case IRQPIN_NONE:
+ return 0;
+
+ case IRQPIN_INTA:
+ reg = CTRL_INTA_EN;
+ break;
+
+ case IRQPIN_INTB:
+ reg = CTRL_INTB_EN;
+ break;
+
+ default:
+ return -EINVAL;
+ }
+ ret = regmap_update_bits(pcf85363->regmap, reg,
INT_A1IE, enabled ? INT_A1IE : 0);

if (ret || enabled)
@@ -277,12 +339,55 @@ static irqreturn_t pcf85363_rtc_handle_irq(int irq, void *dev_id)
return IRQ_NONE;
}

+static int pcf85363_osc_is_stopped(struct pcf85363 *pcf85363)
+{
+ unsigned int regval;
+ int ret;
+
+ ret = regmap_read(pcf85363->regmap, DT_SECS, &regval);
+ if (ret)
+ return ret;
+
+ ret = regval & DT_SECS_OS ? 1 : 0;
+ if (ret)
+ dev_warn(pcf85363->dev, "Oscillator stop detected, date/time is not reliable.\n");
+
+ return ret;
+}
+
+static int pcf85363_ioctl(struct device *dev,
+ unsigned int cmd, unsigned long arg)
+{
+ struct pcf85363 *pcf85363 = dev_get_drvdata(dev);
+ int ret;
+
+ switch (cmd) {
+ case RTC_VL_READ:
+ ret = pcf85363_osc_is_stopped(pcf85363);
+ if (ret < 0)
+ return ret;
+
+ if (copy_to_user((void __user *)arg, &ret, sizeof(int)))
+ return -EFAULT;
+ return 0;
+
+ case RTC_VL_CLR:
+ return regmap_update_bits(pcf85363->regmap,
+ DT_SECS,
+ DT_SECS_OS, 0);
+ default:
+ return -ENOIOCTLCMD;
+ }
+}
+
static const struct rtc_class_ops rtc_ops = {
+ .ioctl = pcf85363_ioctl,
.read_time = pcf85363_rtc_read_time,
.set_time = pcf85363_rtc_set_time,
};

static const struct rtc_class_ops rtc_ops_alarm = {
+ .ioctl = pcf85363_ioctl,
.read_time = pcf85363_rtc_read_time,
.set_time = pcf85363_rtc_set_time,
.read_alarm = pcf85363_rtc_read_alarm,
@@ -350,6 +455,110 @@ static const struct pcf85x63_config pcf_85363_config = {
.num_nvram = 2
};

+/*
+ * On some boards the interrupt line may not be wired to the CPU but only to
+ * a power supply circuit.
+ * In that case no interrupt will be specified in the device tree but the
+ * wakeup-source DT property may be used to enable wakeup programming in
+ * sysfs
+ */
+static bool pcf85363_can_wakeup_machine(struct pcf85363 *pcf85363)
+{
+ return pcf85363->irq ||
+ of_property_read_bool(pcf85363->dev->of_node, "wakeup-source");
+}
+
+static int pcf85363_init_hw(struct pcf85363 *pcf85363)
+{
+ struct device_node *np = pcf85363->dev->of_node;
+ unsigned int regval;
+ u32 propval;
+ int ret;
+
+ /* Determine if oscilator has been stopped (probably low power) */
+ ret = pcf85363_osc_is_stopped(pcf85363);
+ if (ret < 0) {
+ /* Log here since this is the first hw access on probe */
+ dev_err(pcf85363->dev, "Unable to read register\n");
+
+ return ret;
+ }
+
+ ret = regmap_read(pcf85363->regmap, CTRL_OSCILLATOR, &regval);
+ if (ret)
+ return ret;
+
+ /* Set oscilator register */
+ propval = PCF85363_QUARTZCAP_12p5pF;
+ of_property_read_u32(np, "quartz-load-capacitance", &propval);
+ regval |= ((propval << CTRL_OSCILLATOR_CL_SHIFT)
+ & CTRL_OSCILLATOR_CL_MASK);
+
+ propval = PCF85363_QUARTZDRIVE_NORMAL;
+ of_property_read_u32(np, "quartz-drive-strength", &propval);
+ regval |= ((propval << CTRL_OSCILLATOR_OSCD_SHIFT)
+ & CTRL_OSCILLATOR_OSCD_MASK);
+
+ if (of_property_read_bool(np, "quartz-low-jitter"))
+ regval |= CTRL_OSCILLATOR_LOWJ;
+
+ ret = regmap_write(pcf85363->regmap, CTRL_OSCILLATOR, regval);
+ if (ret)
+ return ret;
+
+ /* Set function register
+ * (100th second disabled
+ * no periodic interrupt
+ * real-time clock mode
+ * RTC stop is controlled by STOP bit only
+ * no clock output)
+ */
+ ret = regmap_write(pcf85363->regmap, CTRL_FUNCTION,
+ CTRL_FUNCTION_COF_OFF);
+ if (ret)
+ return ret;
+
+ /* Set all interrupts to disabled, level mode */
+ ret = regmap_write(pcf85363->regmap, CTRL_INTA_EN,
+ INT_ILP);
+ if (ret)
+ return ret;
+ ret = regmap_write(pcf85363->regmap, CTRL_INTB_EN,
+ INT_ILP);
+ if (ret)
+ return ret;
+
+ /* Determine which interrupt pin the board uses */
+ if (pcf85363_can_wakeup_machine(pcf85363)) {
+ if (of_property_match_string(pcf85363->dev->of_node,
+ "interrupt-output-pin",
+ "INTB") >= 0)
+ pcf85363->irq_pin = IRQPIN_INTB;
+ else
+ pcf85363->irq_pin = IRQPIN_INTA;
+ } else {
+ pcf85363->irq_pin = IRQPIN_NONE;
+ }
+
+ /* Setup IO pin config register */
+ regval = PIN_IO_CLKPM; /* disable CLK pin*/
+ switch (pcf85363->irq_pin) {
+ case IRQPIN_INTA:
+ regval |= (PIN_IO_INTA_OUT | PIN_IO_TS_DISABLE);
+ break;
+ case IRQPIN_INTB:
+ regval |= (PIN_IO_INTA_HIZ | PIN_IO_TS_INTB_OUT);
+ break;
+ case IRQPIN_NONE:
+ regval |= (PIN_IO_INTA_HIZ | PIN_IO_TS_DISABLE);
+ break;
+ }
+ ret = regmap_write(pcf85363->regmap, CTRL_PIN_IO, regval);
+
+ return ret;
+}
+
+
static int pcf85363_probe(struct i2c_client *client,
const struct i2c_device_id *id)
{
@@ -389,9 +598,11 @@ static int pcf85363_probe(struct i2c_client *client,
return PTR_ERR(pcf85363->regmap);
}

+ pcf85363->irq = client->irq;
+ pcf85363->dev = &client->dev;
i2c_set_clientdata(client, pcf85363);

- pcf85363->rtc = devm_rtc_allocate_device(&client->dev);
+ pcf85363->rtc = devm_rtc_allocate_device(pcf85363->dev);
if (IS_ERR(pcf85363->rtc))
return PTR_ERR(pcf85363->rtc);

@@ -399,20 +610,28 @@ static int pcf85363_probe(struct i2c_client *client,
pcf85363->rtc->range_min = RTC_TIMESTAMP_BEGIN_2000;
pcf85363->rtc->range_max = RTC_TIMESTAMP_END_2099;

- if (client->irq > 0) {
+ ret = pcf85363_init_hw(pcf85363);
+ if (ret)
+ return ret;
+
+ if (pcf85363->irq > 0) {
regmap_write(pcf85363->regmap, CTRL_FLAGS, 0);
- regmap_update_bits(pcf85363->regmap, CTRL_PIN_IO,
- PIN_IO_INTA_OUT, PIN_IO_INTAPM);
- ret = devm_request_threaded_irq(&client->dev, client->irq,
+ ret = devm_request_threaded_irq(pcf85363->dev, pcf85363->irq,
NULL, pcf85363_rtc_handle_irq,
- IRQF_TRIGGER_LOW | IRQF_ONESHOT,
+ IRQF_TRIGGER_FALLING |
+ IRQF_ONESHOT,
"pcf85363", client);
- if (ret)
+ if (ret) {
dev_warn(&client->dev, "unable to request IRQ, alarms disabled\n");
+ pcf85363->irq = 0;
+ }
else
pcf85363->rtc->ops = &rtc_ops_alarm;
}

+ if (pcf85363_can_wakeup_machine(pcf85363))
+ device_init_wakeup(pcf85363->dev, true);
+
ret = rtc_register_device(pcf85363->rtc);

for (i = 0; i < config->num_nvram; i++) {
@@ -420,6 +639,10 @@ static int pcf85363_probe(struct i2c_client *client,
rtc_nvmem_register(pcf85363->rtc, &nvmem_cfg[i]);
}

+ /* We cannot support UIE mode if we do not have an IRQ line */
+ if (!pcf85363->irq)
+ pcf85363->rtc->uie_unsupported = 1;
+
return ret;
}

@@ -430,12 +653,50 @@ static const struct of_device_id dev_ids[] = {
};
MODULE_DEVICE_TABLE(of, dev_ids);

+static int pcf85363_remove(struct i2c_client *client)
+{
+ struct pcf85363 *pcf85363 = i2c_get_clientdata(client);
+
+ if (pcf85363_can_wakeup_machine(pcf85363))
+ device_init_wakeup(pcf85363->dev, false);
+
+ return 0;
+}
+
+#ifdef CONFIG_PM_SLEEP
+static int pcf85363_suspend(struct device *dev)
+{
+ struct pcf85363 *pcf85363 = dev_get_drvdata(dev);
+ int ret = 0;
+
+ if (device_may_wakeup(dev))
+ ret = enable_irq_wake(pcf85363->irq);
+
+ return ret;
+}
+
+static int pcf85363_resume(struct device *dev)
+{
+ struct pcf85363 *pcf85363 = dev_get_drvdata(dev);
+ int ret = 0;
+
+ if (device_may_wakeup(dev))
+ ret = disable_irq_wake(pcf85363->irq);
+
+ return ret;
+}
+#endif
+
+static SIMPLE_DEV_PM_OPS(pcf85363_pm_ops, pcf85363_suspend, pcf85363_resume);
+
static struct i2c_driver pcf85363_driver = {
.driver = {
.name = "pcf85363",
.of_match_table = of_match_ptr(dev_ids),
+ .pm = &pcf85363_pm_ops,
},
.probe = pcf85363_probe,
+ .remove = pcf85363_remove,
};

module_i2c_driver(pcf85363_driver);
--
2.17.1