[PATCH v3 07/14] rtc: pcf2127: add support for PCF2131 RTC

[Hugo Villeneuve <hugo@hugovil.com>]

From: Hugo Villeneuve <hvilleneuve@dimonoff.com>

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@dimonoff.com>
---
 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 2bb640d1521d..3d4043ce0057 100644
--- a/drivers/rtc/Kconfig
+++ b/drivers/rtc/Kconfig
@@ -910,9 +910,9 @@ 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 3265878edc48..4148e135f935 100644
--- a/drivers/rtc/rtc-pcf2127.c
+++ b/drivers/rtc/rtc-pcf2127.c
@@ -1,16 +1,26 @@
 // 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@til-technologies.fr>
  *
  * Watchdog and tamper functions
  * Author: Bruno Thomsen <bruno.thomsen@gmail.com>
  *
+ * PCF2131 support
+ * Author: Hugo Villeneuve <hvilleneuve@dimonoff.com>
+ *
  * 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 1/100th seconds
  */
 
 #include <linux/i2c.h>
@@ -43,8 +53,30 @@
 #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. */
+#define PCF2131_SR_RESET_RESET_CMD	0x2C /* SR is bit 3. */
 /* 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,
 };
 
@@ -555,30 +617,64 @@ 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;
+
+		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_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 (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 (ctrl2 & PCF2127_CTRL2_IRQ_MASK)
-		regmap_write(pcf2127->regmap, PCF2127_REG_CTRL2,
-			ctrl2 & ~PCF2127_CTRL2_IRQ_MASK);
+		if (!(ctrl4 & PCF2131_CTRL4_IRQ_MASK || ctrl2 & PCF2131_CTRL2_IRQ_MASK))
+			return IRQ_NONE;
+
+		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);
@@ -650,6 +746,27 @@ 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)
@@ -714,16 +831,46 @@ 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
 };
 
@@ -774,6 +921,48 @@ 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,
+		},
+	},
 };
 
 /*
@@ -922,7 +1111,7 @@ 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.
@@ -982,6 +1171,7 @@ 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);
@@ -1069,6 +1259,7 @@ static const struct i2c_device_id pcf2127_i2c_id[] = {
 	{ "pcf2127", PCF2127 },
 	{ "pcf2129", PCF2129 },
 	{ "pca2129", PCF2129 },
+	{ "pcf2131", PCF2131 },
 	{ }
 };
 MODULE_DEVICE_TABLE(i2c, pcf2127_i2c_id);
@@ -1190,6 +1381,7 @@ static const struct spi_device_id pcf2127_spi_id[] = {
 	{ "pcf2127", PCF2127 },
 	{ "pcf2129", PCF2129 },
 	{ "pca2129", PCF2129 },
+	{ "pcf2131", PCF2131 },
 	{ }
 };
 MODULE_DEVICE_TABLE(spi, pcf2127_spi_id);
@@ -1254,5 +1446,5 @@ static void __exit pcf2127_exit(void)
 module_exit(pcf2127_exit)
 
 MODULE_AUTHOR("Renaud Cerrato <r.cerrato@til-technologies.fr>");
-MODULE_DESCRIPTION("NXP PCF2127/29 RTC driver");
+MODULE_DESCRIPTION("NXP PCF2127/29/31 RTC driver");
 MODULE_LICENSE("GPL v2");
-- 
2.30.2