[PATCH v2 1/3] drivers: rtc: add pcf2131 rtc driver

Joy Zou joy.zou at nxp.com
Fri Jun 2 10:10:33 CEST 2023


Adding support for pcf2131 RTC chip.

The pcf2131 is similar to the pcf2127. The driver support rtc register
read/write by using rtc cmd and rtc date set/get by using date cmd.

Signed-off-by: Joy Zou <joy.zou at nxp.com>
---
Changes in v1:
1. delete the unnecessary initialization in v2.
2. retrun directly function insteand of redundancy return ret in v2.
3. delete the unnecessary comment line.
---
 drivers/rtc/Kconfig   |  10 +++
 drivers/rtc/Makefile  |   1 +
 drivers/rtc/pcf2131.c | 184 ++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 195 insertions(+)
 create mode 100644 drivers/rtc/pcf2131.c

diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig
index 23173139e0..507dc6cbcb 100644
--- a/drivers/rtc/Kconfig
+++ b/drivers/rtc/Kconfig
@@ -64,6 +64,16 @@ config RTC_PCF2127
 	  has a selectable I2C-bus or SPI-bus, a backup battery switch-over circuit, a
 	  programmable watchdog function, a timestamp function, and many other features.
 
+config RTC_PCF2131
+	bool "Enable PCF2131 driver"
+	depends on DM_RTC
+	help
+	  The PCF2131 is a CMOS Real Time Clock (RTC) and calendar with an integrated
+	  Temperature Compensated Crystal (Xtal) Oscillator (TCXO) and a 32.768 kHz quartz
+	  crystal optimized for very high accuracy and very low power consumption. The PCF2127
+	  has a selectable I2C-bus or SPI-bus, a backup battery switch-over circuit, a
+	  programmable watchdog function, a timestamp function, and many other features.
+
 config RTC_DS1307
 	bool "Enable DS1307 driver"
 	depends on DM_RTC
diff --git a/drivers/rtc/Makefile b/drivers/rtc/Makefile
index 308fab8da9..722f2be98f 100644
--- a/drivers/rtc/Makefile
+++ b/drivers/rtc/Makefile
@@ -27,6 +27,7 @@ obj-$(CONFIG_RTC_MV) += mvrtc.o
 obj-$(CONFIG_RTC_MXS) += mxsrtc.o
 obj-$(CONFIG_RTC_PCF8563) += pcf8563.o
 obj-$(CONFIG_RTC_PCF2127) += pcf2127.o
+obj-$(CONFIG_RTC_PCF2131) += pcf2131.o
 obj-$(CONFIG_RTC_PL031) += pl031.o
 obj-$(CONFIG_RTC_PT7C4338) += pt7c4338.o
 obj-$(CONFIG_RTC_RV3028) += rv3028.o
diff --git a/drivers/rtc/pcf2131.c b/drivers/rtc/pcf2131.c
new file mode 100644
index 0000000000..c3f16b07bb
--- /dev/null
+++ b/drivers/rtc/pcf2131.c
@@ -0,0 +1,184 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * The NXP PCF2131 RTC uboot driver.
+ * Copyright 2023 NXP
+ * Date & Time support for PCF2131 RTC
+ */
+
+#include <common.h>
+#include <command.h>
+#include <dm.h>
+#include <i2c.h>
+#include <log.h>
+#include <rtc.h>
+
+#define PCF2131_REG_CTRL1               0x00
+#define PCF2131_BIT_CTRL1_STOP          BIT(5)
+#define PCF2131_BIT_CTRL1_100TH_S_DIS   BIT(4)
+#define PCF2131_REG_CTRL2               0x01
+#define PCF2131_REG_CTRL3               0x02
+#define PCF2131_REG_SR_RESET            0x05
+#define PCF2131_SR_VAL_Clr_Pres         0xa4
+#define PCF2131_REG_SC                  0x07
+#define PCF2131_REG_MN                  0x08
+#define PCF2131_REG_HR                  0x09
+#define PCF2131_REG_DM                  0x0a
+#define PCF2131_REG_DW                  0x0b
+#define PCF2131_REG_MO                  0x0c
+#define PCF2131_REG_YR                  0x0d
+
+static int pcf2131_rtc_read(struct udevice *dev, uint offset, u8 *buffer, uint len)
+{
+	struct dm_i2c_chip *chip = dev_get_parent_plat(dev);
+	struct i2c_msg msg;
+	int ret;
+
+	/* Set the address of the start register to be read */
+	ret = dm_i2c_write(dev, offset, NULL, 0);
+	if (ret < 0)
+		return ret;
+
+	/* Read register's data */
+	msg.addr = chip->chip_addr;
+	msg.flags |= I2C_M_RD;
+	msg.len = len;
+	msg.buf = buffer;
+
+	return dm_i2c_xfer(dev, &msg, 1);
+}
+
+static int pcf2131_rtc_lock(struct udevice *dev)
+{
+	int ret = 0;
+	uchar buf[6] = { PCF2131_REG_CTRL1 };
+
+	ret = pcf2131_rtc_read(dev, PCF2131_REG_CTRL1, buf, sizeof(buf));
+	if (ret < 0)
+		return ret;
+
+	buf[PCF2131_REG_CTRL1] |= PCF2131_BIT_CTRL1_STOP;
+	ret = dm_i2c_write(dev, PCF2131_REG_CTRL1, &buf[PCF2131_REG_CTRL1], 1);
+	if (ret < 0)
+		return ret;
+
+	buf[PCF2131_REG_SR_RESET] = PCF2131_SR_VAL_Clr_Pres;
+
+	return dm_i2c_write(dev, PCF2131_REG_SR_RESET, &buf[PCF2131_REG_SR_RESET], 1);
+}
+
+static int pcf2131_rtc_unlock(struct udevice *dev)
+{
+	int ret = 0;
+	uchar buf[6] = { PCF2131_REG_CTRL1 };
+
+	ret = pcf2131_rtc_read(dev, PCF2131_REG_CTRL1, buf, sizeof(buf));
+	if (ret < 0)
+		return ret;
+
+	buf[PCF2131_REG_CTRL1] &= ~PCF2131_BIT_CTRL1_STOP;
+	return dm_i2c_write(dev, PCF2131_REG_CTRL1, &buf[PCF2131_REG_CTRL1], 1);
+}
+
+static int pcf2131_rtc_write(struct udevice *dev, uint offset,
+			     const u8 *buffer, uint len)
+{
+	int ret = 0;
+
+	ret = pcf2131_rtc_lock(dev);
+	if (ret < 0)
+		return ret;
+
+	ret = dm_i2c_write(dev, offset, buffer, len);
+	if (ret < 0)
+		return ret;
+
+	return pcf2131_rtc_unlock(dev);
+}
+
+static int pcf2131_rtc_set(struct udevice *dev, const struct rtc_time *tm)
+{
+	uchar buf[7];
+	int i = 0, ret;
+
+	/* hours, minutes and seconds */
+	buf[i++] = bin2bcd(tm->tm_sec);
+	buf[i++] = bin2bcd(tm->tm_min);
+	buf[i++] = bin2bcd(tm->tm_hour);
+	buf[i++] = bin2bcd(tm->tm_mday);
+	buf[i++] = tm->tm_wday & 0x07;
+
+	/* month, 1 - 12 */
+	buf[i++] = bin2bcd(tm->tm_mon);
+
+	/* year */
+	buf[i++] = bin2bcd(tm->tm_year % 100);
+
+	ret = pcf2131_rtc_lock(dev);
+	if (ret < 0)
+		return ret;
+
+	/* write register's data */
+	ret = dm_i2c_write(dev, PCF2131_REG_SC, buf, i);
+	if (ret < 0)
+		return ret;
+
+	return pcf2131_rtc_unlock(dev);
+}
+
+static int pcf2131_rtc_get(struct udevice *dev, struct rtc_time *tm)
+{
+	int ret = 0;
+	uchar buf[16];
+
+	ret = pcf2131_rtc_read(dev, PCF2131_REG_CTRL1, buf, sizeof(buf));
+	if (ret < 0)
+		return ret;
+
+	if (buf[PCF2131_REG_CTRL3] & 0x04)
+		puts("### Warning: RTC Low Voltage - date/time not reliable\n");
+
+	tm->tm_sec  = bcd2bin(buf[PCF2131_REG_SC] & 0x7F);
+	tm->tm_min  = bcd2bin(buf[PCF2131_REG_MN] & 0x7F);
+	tm->tm_hour = bcd2bin(buf[PCF2131_REG_HR] & 0x3F);
+	tm->tm_mday = bcd2bin(buf[PCF2131_REG_DM] & 0x3F);
+	tm->tm_mon  = bcd2bin(buf[PCF2131_REG_MO] & 0x1F);
+	tm->tm_year = bcd2bin(buf[PCF2131_REG_YR]) + 1900;
+	if (tm->tm_year < 1970)
+		tm->tm_year += 100;	/* assume we are in 1970...2069 */
+	tm->tm_wday = buf[PCF2131_REG_DW] & 0x07;
+	tm->tm_yday = 0;
+	tm->tm_isdst = 0;
+
+	debug("Get DATE: %4d-%02d-%02d (wday=%d)  TIME: %2d:%02d:%02d\n",
+	      tm->tm_year, tm->tm_mon, tm->tm_mday, tm->tm_wday,
+	      tm->tm_hour, tm->tm_min, tm->tm_sec);
+
+	return ret;
+}
+
+static int pcf2131_rtc_reset(struct udevice *dev)
+{
+	/*Doing nothing here*/
+
+	return 0;
+}
+
+static const struct rtc_ops pcf2131_rtc_ops = {
+	.get = pcf2131_rtc_get,
+	.set = pcf2131_rtc_set,
+	.reset = pcf2131_rtc_reset,
+	.read = pcf2131_rtc_read,
+	.write = pcf2131_rtc_write,
+};
+
+static const struct udevice_id pcf2131_rtc_ids[] = {
+	{ .compatible = "nxp,pcf2131" },
+	{ }
+};
+
+U_BOOT_DRIVER(rtc_pcf2131) = {
+	.name	= "rtc-pcf2131",
+	.id	= UCLASS_RTC,
+	.of_match = pcf2131_rtc_ids,
+	.ops	= &pcf2131_rtc_ops,
+};
-- 
2.37.1



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