[PATCH 07/10] rtc: pcf2127: add support for PCF2131 RTC

From: Hugo Villeneuve
Date: Tue Jan 25 2022 - 15:01:32 EST

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From: Hugo Villeneuve <hvilleneuve@xxxxxxxxxxxx>

This RTC is very similar in functionality to the PCF2127/29.

Basically it:
-supports two new control registers at offsets 4 and 5
-supports a new reset register (not implemented in this driver)
-supports 4 tamper detection functions instead of 1
-has no nvmem (like the PCF2129)
-has two output interrupt pins

Because of that, most of the register addresses are very different,
although they still follow the same layout. For example, the tamper
registers have a different base address, but the offsets are all the same.

Signed-off-by: Hugo Villeneuve <hvilleneuve@xxxxxxxxxxxx>
---
drivers/rtc/Kconfig | 4 +-
drivers/rtc/rtc-pcf2127.c | 234 ++++++++++++++++++++++++++++++++++----
2 files changed, 215 insertions(+), 23 deletions(-)

diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig
index d85a3c31347c..9b083ca6b4c4 100644
--- a/drivers/rtc/Kconfig
+++ b/drivers/rtc/Kconfig
@@ -899,9 +899,9 @@ config RTC_DRV_PCF2127
select REGMAP_SPI if SPI_MASTER
select WATCHDOG_CORE if WATCHDOG
help
- If you say yes here you get support for the NXP PCF2127/29 RTC
+ If you say yes here you get support for the NXP PCF2127/29/31 RTC
chips with integrated quartz crystal for industrial applications.
- Both chips also have watchdog timer and tamper switch detection
+ These chips also have watchdog timer and tamper switch detection
features.

PCF2127 has an additional feature of 512 bytes battery backed
diff --git a/drivers/rtc/rtc-pcf2127.c b/drivers/rtc/rtc-pcf2127.c
index e806d65e4504..fdce31e169a6 100644
--- a/drivers/rtc/rtc-pcf2127.c
+++ b/drivers/rtc/rtc-pcf2127.c
@@ -1,16 +1,27 @@
// SPDX-License-Identifier: GPL-2.0-only
/*
- * An I2C and SPI driver for the NXP PCF2127/29 RTC
+ * An I2C and SPI driver for the NXP PCF2127/29/31 RTC
* Copyright 2013 Til-Technologies
+ * Copyright 2021 DimOnOff
*
* Author: Renaud Cerrato <r.cerrato@xxxxxxxxxxxxxxxxxxx>
*
* Watchdog and tamper functions
* Author: Bruno Thomsen <bruno.thomsen@xxxxxxxxx>
*
+ * PCF2131 support
+ * Author: Hugo Villeneuve <hvilleneuve@xxxxxxxxxxxx>
+ *
* based on the other drivers in this same directory.
*
- * Datasheet: https://www.nxp.com/docs/en/data-sheet/PCF2127.pdf
+ * Datasheets: https://www.nxp.com/docs/en/data-sheet/PCF2127.pdf
+ * https://www.nxp.com/docs/en/data-sheet/PCF2131DS.pdf
+ */
+
+/*
+ * The following features are not yet implemented for the PCF2131:
+ * - support for reset register
+ * - support for 1/100th seconds
*/

#include <linux/i2c.h>
@@ -43,8 +54,29 @@
#define PCF2127_BIT_CTRL3_BLF BIT(2)
#define PCF2127_BIT_CTRL3_BF BIT(3)
#define PCF2127_BIT_CTRL3_BTSE BIT(4)
+/* Control register 4 */
+#define PCF2131_REG_CTRL4 0x03
+#define PCF2131_BIT_CTRL4_TSF4 BIT(4)
+#define PCF2131_BIT_CTRL4_TSF3 BIT(5)
+#define PCF2131_BIT_CTRL4_TSF2 BIT(6)
+#define PCF2131_BIT_CTRL4_TSF1 BIT(7)
+/* Control register 5 */
+#define PCF2131_REG_CTRL5 0x04
+#define PCF2131_BIT_CTRL5_TSIE4 BIT(4)
+#define PCF2131_BIT_CTRL5_TSIE3 BIT(5)
+#define PCF2131_BIT_CTRL5_TSIE2 BIT(6)
+#define PCF2131_BIT_CTRL5_TSIE1 BIT(7)
+/* Software reset register */
+#define PCF2131_REG_SR_RESET 0x05
+#define PCF2131_SR_RESET_READ_PATTERN 0b00100100 /* Fixed pattern. */
/* Time and date registers */
#define PCF2127_REG_TIME_DATE_BASE 0x03
+#define PCF2131_REG_TIME_DATE_BASE 0x07 /* Register 0x06 is 100th seconds,
+ * but we do not support it. By
+ * using offset 0x07, we can be
+ * compatible with existing
+ * time/date functions.
+ */
/* Time and date registers offsets (starting from base register) */
#define PCF2127_OFFSET_TD_SC 0
#define PCF2127_OFFSET_TD_MN 1
@@ -57,6 +89,7 @@
#define PCF2127_BIT_SC_OSF BIT(7)
/* Alarm registers */
#define PCF2127_REG_ALARM_BASE 0x0A
+#define PCF2131_REG_ALARM_BASE 0x0E
/* Alarm registers offsets (starting from base register) */
#define PCF2127_OFFSET_ALARM_SC 0
#define PCF2127_OFFSET_ALARM_MN 1
@@ -67,16 +100,26 @@
#define PCF2127_BIT_ALARM_AE BIT(7)
/* CLKOUT control register */
#define PCF2127_REG_CLKOUT 0x0f
+#define PCF2131_REG_CLKOUT 0x13
#define PCF2127_BIT_CLKOUT_OTPR BIT(5)
/* Watchdog registers */
#define PCF2127_REG_WD_CTL 0x10
+#define PCF2131_REG_WD_CTL 0x35
#define PCF2127_BIT_WD_CTL_TF0 BIT(0)
#define PCF2127_BIT_WD_CTL_TF1 BIT(1)
#define PCF2127_BIT_WD_CTL_CD0 BIT(6)
#define PCF2127_BIT_WD_CTL_CD1 BIT(7)
#define PCF2127_REG_WD_VAL 0x11
+#define PCF2131_REG_WD_VAL 0x36
/* Tamper timestamp1 registers */
#define PCF2127_REG_TS1_BASE 0x12
+#define PCF2131_REG_TS1_BASE 0x14
+/* Tamper timestamp2 registers */
+#define PCF2131_REG_TS2_BASE 0x1B
+/* Tamper timestamp3 registers */
+#define PCF2131_REG_TS3_BASE 0x22
+/* Tamper timestamp4 registers */
+#define PCF2131_REG_TS4_BASE 0x29
/* Tamper timestamp registers common offsets (starting from base register) */
#define PCF2127_OFFSET_TS_CTL 0
#define PCF2127_OFFSET_TS_SC 1
@@ -92,11 +135,22 @@
* RAM registers
* PCF2127 has 512 bytes general-purpose static RAM (SRAM) that is
* battery backed and can survive a power outage.
- * PCF2129 doesn't have this feature.
+ * PCF2129/31 doesn't have this feature.
*/
#define PCF2127_REG_RAM_ADDR_MSB 0x1A
#define PCF2127_REG_RAM_WRT_CMD 0x1C
#define PCF2127_REG_RAM_RD_CMD 0x1D
+/* Interrupt mask registers */
+#define PCF2131_REG_INT_A_MASK1 0x31
+#define PCF2131_REG_INT_A_MASK2 0x32
+#define PCF2131_REG_INT_B_MASK1 0x33
+#define PCF2131_REG_INT_B_MASK2 0x34
+#define PCF2131_BIT_INT_BLIE BIT(0)
+#define PCF2131_BIT_INT_BIE BIT(1)
+#define PCF2131_BIT_INT_AIE BIT(2)
+#define PCF2131_BIT_INT_WD_CD BIT(3)
+#define PCF2131_BIT_INT_SI BIT(4)
+#define PCF2131_BIT_INT_MI BIT(5)

/* Watchdog timer value constants */
#define PCF2127_WD_VAL_STOP 0
@@ -110,6 +164,14 @@
PCF2127_BIT_CTRL2_AF | \
PCF2127_BIT_CTRL2_WDTF | \
PCF2127_BIT_CTRL2_TSF2)
+#define PCF2131_CTRL2_IRQ_MASK ( \
+ PCF2127_BIT_CTRL2_AF | \
+ PCF2127_BIT_CTRL2_WDTF)
+#define PCF2131_CTRL4_IRQ_MASK ( \
+ PCF2131_BIT_CTRL4_TSF4 | \
+ PCF2131_BIT_CTRL4_TSF3 | \
+ PCF2131_BIT_CTRL4_TSF2 | \
+ PCF2131_BIT_CTRL4_TSF1)

struct pcf21xx_ts_config {
u8 regs_base; /* Base register to read timestamp values. */
@@ -370,7 +432,7 @@ static int pcf2127_wdt_set_timeout(struct watchdog_device *wdd,
}

static const struct watchdog_info pcf2127_wdt_info = {
- .identity = "NXP PCF2127/PCF2129 Watchdog",
+ .identity = "NXP PCF2127/29/31 Watchdog",
.options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT,
};

@@ -554,30 +616,64 @@ static void pcf2127_rtc_ts_snapshot(struct device *dev, int ts_id)
static irqreturn_t pcf2127_rtc_irq(int irq, void *dev)
{
struct pcf2127 *pcf2127 = dev_get_drvdata(dev);
- unsigned int ctrl1, ctrl2;
+ unsigned int ctrl2;
int ret = 0;

- ret = regmap_read(pcf2127->regmap, PCF2127_REG_CTRL1, &ctrl1);
- if (ret)
- return IRQ_NONE;
-
ret = regmap_read(pcf2127->regmap, PCF2127_REG_CTRL2, &ctrl2);
if (ret)
return IRQ_NONE;

- if (!(ctrl1 & PCF2127_CTRL1_IRQ_MASK || ctrl2 & PCF2127_CTRL2_IRQ_MASK))
- return IRQ_NONE;
+ if (pcf2127->cfg->ts_count == 1) {
+ /* PCF2127/29 */
+ unsigned int ctrl1;

- if (ctrl1 & PCF2127_BIT_CTRL1_TSF1 || ctrl2 & PCF2127_BIT_CTRL2_TSF2)
- pcf2127_rtc_ts_snapshot(dev, 0);
+ ret = regmap_read(pcf2127->regmap, PCF2127_REG_CTRL1, &ctrl1);
+ if (ret)
+ return IRQ_NONE;
+
+ if (!(ctrl1 & PCF2127_CTRL1_IRQ_MASK || ctrl2 & PCF2127_CTRL2_IRQ_MASK))
+ return IRQ_NONE;
+
+ if (ctrl1 & PCF2127_BIT_CTRL1_TSF1 || ctrl2 & PCF2127_BIT_CTRL2_TSF2)
+ pcf2127_rtc_ts_snapshot(dev, 0);
+
+ if (ctrl1 & PCF2127_CTRL1_IRQ_MASK)
+ regmap_write(pcf2127->regmap, PCF2127_REG_CTRL1,
+ ctrl1 & ~PCF2127_CTRL1_IRQ_MASK);
+
+ if (ctrl2 & PCF2127_CTRL2_IRQ_MASK)
+ regmap_write(pcf2127->regmap, PCF2127_REG_CTRL2,
+ ctrl2 & ~PCF2127_CTRL2_IRQ_MASK);
+ } else {
+ /* PCF2131. */
+ unsigned int ctrl4;
+
+ ret = regmap_read(pcf2127->regmap, PCF2131_REG_CTRL4, &ctrl4);
+ if (ret)
+ return IRQ_NONE;

- if (ctrl1 & PCF2127_CTRL1_IRQ_MASK)
- regmap_write(pcf2127->regmap, PCF2127_REG_CTRL1,
- ctrl1 & ~PCF2127_CTRL1_IRQ_MASK);
+ if (!(ctrl4 & PCF2131_CTRL4_IRQ_MASK || ctrl2 & PCF2131_CTRL2_IRQ_MASK))
+ return IRQ_NONE;

- if (ctrl2 & PCF2127_CTRL2_IRQ_MASK)
- regmap_write(pcf2127->regmap, PCF2127_REG_CTRL2,
- ctrl2 & ~PCF2127_CTRL2_IRQ_MASK);
+ if (ctrl4 & PCF2131_CTRL4_IRQ_MASK) {
+ int i;
+ int tsf_bit = PCF2131_BIT_CTRL4_TSF1; /* Start at bit 7. */
+
+ for (i = 0; i < pcf2127->cfg->ts_count; i++) {
+ if (ctrl4 & tsf_bit)
+ pcf2127_rtc_ts_snapshot(dev, i);
+
+ tsf_bit = tsf_bit >> 1;
+ }
+
+ regmap_write(pcf2127->regmap, PCF2131_REG_CTRL4,
+ ctrl4 & ~PCF2131_CTRL4_IRQ_MASK);
+ }
+
+ if (ctrl2 & PCF2131_CTRL2_IRQ_MASK)
+ regmap_write(pcf2127->regmap, PCF2127_REG_CTRL2,
+ ctrl2 & ~PCF2131_CTRL2_IRQ_MASK);
+ }

if (ctrl2 & PCF2127_BIT_CTRL2_AF)
rtc_update_irq(pcf2127->rtc, 1, RTC_IRQF | RTC_AF);
@@ -649,6 +745,27 @@ static ssize_t timestamp0_store(struct device *dev,
return timestamp_store(dev, attr, buf, count, 0);
};

+static ssize_t timestamp1_store(struct device *dev,
+ struct device_attribute *attr,
+ const char *buf, size_t count)
+{
+ return timestamp_store(dev, attr, buf, count, 1);
+};
+
+static ssize_t timestamp2_store(struct device *dev,
+ struct device_attribute *attr,
+ const char *buf, size_t count)
+{
+ return timestamp_store(dev, attr, buf, count, 2);
+};
+
+static ssize_t timestamp3_store(struct device *dev,
+ struct device_attribute *attr,
+ const char *buf, size_t count)
+{
+ return timestamp_store(dev, attr, buf, count, 3);
+};
+
static ssize_t timestamp_show(struct device *dev,
struct device_attribute *attr, char *buf,
int ts_id)
@@ -713,16 +830,46 @@ static ssize_t timestamp0_show(struct device *dev,
return timestamp_show(dev, attr, buf, 0);
};

+static ssize_t timestamp1_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ return timestamp_show(dev, attr, buf, 1);
+};
+
+static ssize_t timestamp2_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ return timestamp_show(dev, attr, buf, 2);
+};
+
+static ssize_t timestamp3_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ return timestamp_show(dev, attr, buf, 3);
+};
+
static DEVICE_ATTR_RW(timestamp0);
+static DEVICE_ATTR_RW(timestamp1);
+static DEVICE_ATTR_RW(timestamp2);
+static DEVICE_ATTR_RW(timestamp3);

static struct attribute *pcf2127_attrs[] = {
&dev_attr_timestamp0.attr,
NULL
};

+static struct attribute *pcf2131_attrs[] = {
+ &dev_attr_timestamp0.attr,
+ &dev_attr_timestamp1.attr,
+ &dev_attr_timestamp2.attr,
+ &dev_attr_timestamp3.attr,
+ NULL
+};
+
enum pcf21xx_type {
PCF2127,
PCF2129,
+ PCF2131,
PCF21XX_LAST_ID
};

@@ -773,6 +920,48 @@ static struct pcf21xx_config pcf21xx_cfg[] = {
.attrs = pcf2127_attrs,
},
},
+ [PCF2131] = {
+ .max_register = 0x36,
+ .has_nvmem = 0,
+ .has_bit_wd_ctl_cd0 = 0,
+ .regs_td_base = PCF2131_REG_TIME_DATE_BASE,
+ .regs_alarm_base = PCF2131_REG_ALARM_BASE,
+ .reg_wd_ctl = PCF2131_REG_WD_CTL,
+ .reg_wd_val = PCF2131_REG_WD_VAL,
+ .reg_clkout = PCF2131_REG_CLKOUT,
+ .ts_count = 4,
+ .ts[0] = {
+ .regs_base = PCF2131_REG_TS1_BASE,
+ .low_reg = PCF2131_REG_CTRL4,
+ .low_bit = PCF2131_BIT_CTRL4_TSF1,
+ .ie_reg = PCF2131_REG_CTRL5,
+ .ie_bit = PCF2131_BIT_CTRL5_TSIE1,
+ },
+ .ts[1] = {
+ .regs_base = PCF2131_REG_TS2_BASE,
+ .low_reg = PCF2131_REG_CTRL4,
+ .low_bit = PCF2131_BIT_CTRL4_TSF2,
+ .ie_reg = PCF2131_REG_CTRL5,
+ .ie_bit = PCF2131_BIT_CTRL5_TSIE2,
+ },
+ .ts[2] = {
+ .regs_base = PCF2131_REG_TS3_BASE,
+ .low_reg = PCF2131_REG_CTRL4,
+ .low_bit = PCF2131_BIT_CTRL4_TSF3,
+ .ie_reg = PCF2131_REG_CTRL5,
+ .ie_bit = PCF2131_BIT_CTRL5_TSIE3,
+ },
+ .ts[3] = {
+ .regs_base = PCF2131_REG_TS4_BASE,
+ .low_reg = PCF2131_REG_CTRL4,
+ .low_bit = PCF2131_BIT_CTRL4_TSF4,
+ .ie_reg = PCF2131_REG_CTRL5,
+ .ie_bit = PCF2131_BIT_CTRL5_TSIE4,
+ },
+ .attribute_group = {
+ .attrs = pcf2131_attrs,
+ },
+ },
};

/*
@@ -910,7 +1099,7 @@ static int pcf2127_probe(struct device *dev, struct regmap *regmap,
* Watchdog timer enabled and reset pin /RST activated when timed out.
* Select 1Hz clock source for watchdog timer.
* Note: Countdown timer disabled and not available.
- * For pca2129, pcf2129, only bit[7] is for Symbol WD_CD
+ * For pca2129, pcf2129 and pcf2131, only bit[7] is for Symbol WD_CD
* of register watchdg_tim_ctl. The bit[6] is labeled
* as T. Bits labeled as T must always be written with
* logic 0.
@@ -970,6 +1159,7 @@ static const struct of_device_id pcf2127_of_match[] = {
{ .compatible = "nxp,pcf2127", .data = &pcf21xx_cfg[PCF2127] },
{ .compatible = "nxp,pcf2129", .data = &pcf21xx_cfg[PCF2129] },
{ .compatible = "nxp,pca2129", .data = &pcf21xx_cfg[PCF2129] },
+ { .compatible = "nxp,pcf2131", .data = &pcf21xx_cfg[PCF2131] },
{}
};
MODULE_DEVICE_TABLE(of, pcf2127_of_match);
@@ -1099,6 +1289,7 @@ static const struct i2c_device_id pcf2127_i2c_id[] = {
{ "pcf2127", PCF2127 },
{ "pcf2129", PCF2129 },
{ "pca2129", PCF2129 },
+ { "pcf2131", PCF2131 },
{ }
};
MODULE_DEVICE_TABLE(i2c, pcf2127_i2c_id);
@@ -1181,6 +1372,7 @@ static const struct spi_device_id pcf2127_spi_id[] = {
{ "pcf2127", PCF2127 },
{ "pcf2129", PCF2129 },
{ "pca2129", PCF2129 },
+ { "pcf2131", PCF2131 },
{ }
};
MODULE_DEVICE_TABLE(spi, pcf2127_spi_id);
@@ -1245,5 +1437,5 @@ static void __exit pcf2127_exit(void)
module_exit(pcf2127_exit)

MODULE_AUTHOR("Renaud Cerrato <r.cerrato@xxxxxxxxxxxxxxxxxxx>");
-MODULE_DESCRIPTION("NXP PCF2127/29 RTC driver");
+MODULE_DESCRIPTION("NXP PCF2127/29/31 RTC driver");
MODULE_LICENSE("GPL v2");
--
2.30.2

Next message: Hugo Villeneuve: "[PATCH 09/10] dt-bindings: rtc: pcf2127: add PCF2131"
Previous message: Hugo Villeneuve: "[PATCH 08/10] rtc: pcf2127: add support for PCF2131 alarm interrupt on outputs INT_A/B"
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