[PATCH INTERNAL v1 1/3] rtc: tps6594: add driver for TPS6594 PMIC RTC

Esteban Blanc
2023-02-24T13:31:41Z

TPS6594 PMIC is a MFD driver. This add support for the RTC found inside
TPS6594 family of PMIC.

Alarm is also supported.

Signed-off-by: Esteban Blanc <eblanc@baylibre.com>
---
drivers/rtc/Kconfig | 8 +
drivers/rtc/Makefile | 1 +
drivers/rtc/rtc-tps6594.c | 516 ++++++++++++++++++++++++++++++++++++++
3 files changed, 525 insertions(+)
create mode 100644 drivers/rtc/rtc-tps6594.c

diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig
index 677d2601d305..34c63555669d 100644
--- a/drivers/rtc/Kconfig
+++ b/drivers/rtc/Kconfig
@@ -578,6 +578,14 @@ config RTC_DRV_TPS6586X
along with alarm. This driver supports the RTC driver for
the TPS6586X RTC module.

+config RTC_DRV_TPS6594
+ tristate "TI TPS6594 RTC driver"
+ depends on MFD_TPS6594
+ help
+ TI Power Management IC TPS6594 supports RTC functionality
+ along with alarm. This driver supports the RTC driver for
+ the TPS6594 RTC module.
+
config RTC_DRV_TPS65910
tristate "TI TPS65910 RTC driver"
depends on MFD_TPS65910
diff --git a/drivers/rtc/Makefile b/drivers/rtc/Makefile
index d3c042dcbc73..7dbeec711ad5 100644
--- a/drivers/rtc/Makefile
+++ b/drivers/rtc/Makefile
@@ -174,6 +174,7 @@ obj-$(CONFIG_RTC_DRV_TEGRA) += rtc-tegra.o
obj-$(CONFIG_RTC_DRV_TEST) += rtc-test.o
obj-$(CONFIG_RTC_DRV_TI_K3) += rtc-ti-k3.o
obj-$(CONFIG_RTC_DRV_TPS6586X) += rtc-tps6586x.o
+obj-$(CONFIG_RTC_DRV_TPS6594) += rtc-tps6594.o
obj-$(CONFIG_RTC_DRV_TPS65910) += rtc-tps65910.o
obj-$(CONFIG_RTC_DRV_TWL4030) += rtc-twl.o
obj-$(CONFIG_RTC_DRV_V3020) += rtc-v3020.o
diff --git a/drivers/rtc/rtc-tps6594.c b/drivers/rtc/rtc-tps6594.c
new file mode 100644
index 000000000000..f150ef33f65f
--- /dev/null
+++ b/drivers/rtc/rtc-tps6594.c
@@ -0,0 +1,516 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * RTC driver for tps6594 PMIC
+ *
+ * Copyright (C) 2022 BayLibre Incorporated - https://www.baylibre.com/
+ */
+
+#include <linux/bcd.h>
+#include <linux/errno.h>
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/kernel.h>
+#include <linux/math64.h>
+#include <linux/module.h>
+#include <linux/rtc.h>
+#include <linux/types.h>
+#include <linux/platform_device.h>
+#include <linux/property.h>
+
+#include <linux/mfd/tps6594.h>
+
+struct tps6594_rtc {
+ struct rtc_device *rtc;
+};
+
+#define TPS6594_GET_TIME_ON TPS6594_BIT_GET_TIME
+#define TPS6594_GET_TIME_OFF 0
+#define TPS6594_IT_ALARM_ON TPS6594_BIT_IT_ALARM
+#define TPS6594_IT_ALARM_OFF 0
+#define TPS6594_AUTO_COMP_ON TPS6594_BIT_IT_ALARM
+
+/* Total number of RTC registers needed to set time*/
+#define NUM_TIME_REGS (TPS6594_REG_RTC_WEEKS - TPS6594_REG_RTC_SECONDS + 1)
+
+/* Total number of RTC alarm register */
+#define NUM_TIME_ALARM_REGS (NUM_TIME_REGS - 1)
+
+/* Total number of RTC registers needed to set compensation registers */
+#define NUM_COMP_REGS (TPS6594_REG_RTC_COMP_MSB - TPS6594_REG_RTC_COMP_LSB + 1)
+
+/* Min and max values supported with 'offset' interface (swapped sign)
+ * After conversion, the values does not exceed the range [-32767, 33767] which COMP_REG must
+ * conform to
+ */
+#define MIN_OFFSET (-277774)
+#define MAX_OFFSET (277774)
+
+/* Number of ticks per hour */
+#define TICKS_PER_HOUR (32768 * 3600)
+
+/* Multiplier for ppb conversions */
+#define PPB_MULT (1000000000LL)
+
+static int tps6594_rtc_alarm_irq_enable(struct device *dev,
+ unsigned int enabled)
+{
+ struct tps6594 *tps = dev_get_drvdata(dev->parent);
+ u8 val = 0;
+ int ret;
+
+ val = enabled ? TPS6594_IT_ALARM_ON : TPS6594_IT_ALARM_OFF;
+
+ ret = regmap_update_bits(tps->regmap, TPS6594_REG_RTC_INTERRUPTS,
+ TPS6594_BIT_IT_ALARM, val);
+
+ return ret;
+}
+
+/* Pulse GET_TIME field of RTC_CTRL_1 to store a timestamp in shadow registers */
+static int tps6594_rtc_shadow_timestamp(struct device *dev, struct tps6594 *tps)
+{
+ int ret;
+
+ /* Set GET_TIME to 0. This way, next time we set GET_TIME to 1 we are sure to store an
+ * up-to-date timestamp
+ */
+ ret = regmap_clear_bits(tps->regmap, TPS6594_REG_RTC_CTRL_1,
+ TPS6594_BIT_GET_TIME);
+ if (ret < 0) {
+ dev_err(dev, "RTC CTRL1 reg update failed with err:%d\n", ret);
+ return ret;
+ }
+
+ /* Copy content of RTC registers to shadow registers or latches to read a coherent
+ * timestamp
+ */
+ ret = regmap_set_bits(tps->regmap, TPS6594_REG_RTC_CTRL_1,
+ TPS6594_BIT_GET_TIME);
+ if (ret < 0) {
+ dev_err(dev, "RTC CTRL1 reg update failed with err:%d\n", ret);
+ return ret;
+ }
+
+ return ret;
+}
+
+/*
+ * Gets current tps6594 RTC time and date parameters.
+ *
+ * The RTC's time/alarm representation is not what gmtime(3) requires
+ * Linux to use:
+ *
+ * - Months are 1..12 vs Linux 0-11
+ * - Years are 0..99 vs Linux 1900..N (we assume 21st century)
+ */
+static int tps6594_rtc_read_time(struct device *dev, struct rtc_time *tm)
+{
+ unsigned char rtc_data[NUM_TIME_REGS];
+ struct tps6594 *tps = dev_get_drvdata(dev->parent);
+ int ret;
+
+ ret = tps6594_rtc_shadow_timestamp(dev, tps);
+ if (ret < 0) {
+ dev_err(dev,
+ "failed to store a timestamp in shadow registers:%d\n",
+ ret);
+ return ret;
+ }
+
+ /* Read shadowed RTC registers */
+ ret = regmap_bulk_read(tps->regmap, TPS6594_REG_RTC_SECONDS, rtc_data,
+ NUM_TIME_REGS);
+ if (ret < 0) {
+ dev_err(dev, "rtc_read_time failed with error :%d\n", ret);
+ return ret;
+ }
+
+ tm->tm_sec = bcd2bin(rtc_data[0]);
+ tm->tm_min = bcd2bin(rtc_data[1]);
+ tm->tm_hour = bcd2bin(rtc_data[2]);
+ tm->tm_mday = bcd2bin(rtc_data[3]);
+ tm->tm_mon = bcd2bin(rtc_data[4]) - 1;
+ tm->tm_year = bcd2bin(rtc_data[5]) + 100;
+ tm->tm_wday = bcd2bin(rtc_data[6]);
+
+ return ret;
+}
+
+/*
+ * Sets current tps6594 RTC time and date parameters.
+ *
+ * The RTC's time/alarm representation is not what gmtime(3) requires
+ * Linux to use:
+ *
+ * - Months are 1..12 vs Linux 0-11
+ * - Years are 0..99 vs Linux 1900..N (we assume 21st century)
+ */
+static int tps6594_rtc_set_time(struct device *dev, struct rtc_time *tm)
+{
+ unsigned char rtc_data[NUM_TIME_REGS];
+ struct tps6594 *tps = dev_get_drvdata(dev->parent);
+ int ret;
+
+ rtc_data[0] = bin2bcd(tm->tm_sec);
+ rtc_data[1] = bin2bcd(tm->tm_min);
+ rtc_data[2] = bin2bcd(tm->tm_hour);
+ rtc_data[3] = bin2bcd(tm->tm_mday);
+ rtc_data[4] = bin2bcd(tm->tm_mon + 1);
+ rtc_data[5] = bin2bcd(tm->tm_year - 100);
+ rtc_data[6] = bin2bcd(tm->tm_wday);
+
+ /* Stop RTC while updating the RTC time registers */
+ ret = regmap_clear_bits(tps->regmap, TPS6594_REG_RTC_CTRL_1,
+ TPS6594_BIT_STOP_RTC);
+ if (ret < 0) {
+ dev_err(dev, "RTC stop failed: %d\n", ret);
+ return ret;
+ }
+
+ /* Update all the time registers in one shot */
+ ret = regmap_bulk_write(tps->regmap, TPS6594_REG_RTC_SECONDS, rtc_data,
+ NUM_TIME_REGS);
+ if (ret < 0) {
+ dev_err(dev, "rtc_set_time failed: %d\n", ret);
+ return ret;
+ }
+
+ /* Start back RTC */
+ ret = regmap_set_bits(tps->regmap, TPS6594_REG_RTC_CTRL_1,
+ TPS6594_BIT_STOP_RTC);
+ if (ret < 0)
+ dev_err(dev, "RTC start failed: %d\n", ret);
+
+ return ret;
+}
+
+/*
+ * Gets current tps6594 RTC alarm time.
+ */
+static int tps6594_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alm)
+{
+ unsigned char alarm_data[NUM_TIME_ALARM_REGS];
+ u32 int_val;
+ struct tps6594 *tps = dev_get_drvdata(dev->parent);
+ int ret;
+
+ ret = regmap_bulk_read(tps->regmap, TPS6594_REG_ALARM_SECONDS,
+ alarm_data, NUM_TIME_ALARM_REGS);
+ if (ret < 0) {
+ dev_err(dev, "rtc_read_alarm failed read alarm registers: %d\n",
+ ret);
+ return ret;
+ }
+
+ alm->time.tm_sec = bcd2bin(alarm_data[0]);
+ alm->time.tm_min = bcd2bin(alarm_data[1]);
+ alm->time.tm_hour = bcd2bin(alarm_data[2]);
+ alm->time.tm_mday = bcd2bin(alarm_data[3]);
+ alm->time.tm_mon = bcd2bin(alarm_data[4]) - 1;
+ alm->time.tm_year = bcd2bin(alarm_data[5]) + 100;
+
+ ret = regmap_read(tps->regmap, TPS6594_REG_RTC_INTERRUPTS, &int_val);
+ if (ret < 0) {
+ dev_err(dev, "rtc_read_alarm failed to read alarm status: %d\n",
+ ret);
+ return ret;
+ }
+
+ alm->enabled = int_val & TPS6594_BIT_IT_ALARM ? 1 : 0;
+
+ return ret;
+}
+
+static int tps6594_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alm)
+{
+ unsigned char alarm_data[NUM_TIME_ALARM_REGS];
+ struct tps6594 *tps = dev_get_drvdata(dev->parent);
+ int ret;
+
+ /* Disable alarm irq before changing the alarm timestamp */
+ ret = tps6594_rtc_alarm_irq_enable(dev, 0);
+ if (ret) {
+ dev_err(dev, "rtc_set_alarm failed to disable alarm: %d\n",
+ ret);
+ return ret;
+ }
+
+ alarm_data[0] = bin2bcd(alm->time.tm_sec);
+ alarm_data[1] = bin2bcd(alm->time.tm_min);
+ alarm_data[2] = bin2bcd(alm->time.tm_hour);
+ alarm_data[3] = bin2bcd(alm->time.tm_mday);
+ alarm_data[4] = bin2bcd(alm->time.tm_mon + 1);
+ alarm_data[5] = bin2bcd(alm->time.tm_year - 100);
+
+ /* Update all the alarm registers in one shot */
+ ret = regmap_bulk_write(tps->regmap, TPS6594_REG_ALARM_SECONDS,
+ alarm_data, NUM_TIME_ALARM_REGS);
+ if (ret) {
+ dev_err(dev,
+ "rtc_set_alarm failed to write alarm registers: %d\n",
+ ret);
+ return ret;
+ }
+
+ if (alm->enabled) {
+ ret = tps6594_rtc_alarm_irq_enable(dev, 1);
+ if (ret < 0) {
+ dev_err(dev,
+ "rtc_set_alarm failed to re-enable the alarm: %d\n",
+ ret);
+ return ret;
+ }
+ }
+
+ return ret;
+}
+
+static int tps6594_rtc_set_calibration(struct device *dev, int calibration)
+{
+ unsigned char comp_data[NUM_COMP_REGS];
+ struct tps6594 *tps = dev_get_drvdata(dev->parent);
+ s16 value;
+ int ret;
+
+ /*
+ * TPS6594 uses two's complement 16 bit value for compensation for RTC
+ * crystal inaccuracies. One time every hour when seconds counter
+ * increments from 0 to 1 compensation value will be added to internal
+ * RTC counter value.
+ *
+ *
+ * Valid range for compensation value: [-32767 .. 32767]
+ */
+ if (calibration < -32767 || calibration > 32767) {
+ dev_err(dev, "RTC calibration value out of range: %d\n",
+ calibration);
+ return -EINVAL;
+ }
+
+ value = (s16)calibration;
+
+ comp_data[0] = (u16)value & 0xFF;
+ comp_data[1] = ((u16)value >> 8) & 0xFF;
+
+ /* Update all the compensation registers in one shot */
+ ret = regmap_bulk_write(tps->regmap, TPS6594_REG_RTC_COMP_LSB,
+ comp_data, NUM_COMP_REGS);
+ if (ret < 0) {
+ dev_err(dev,
+ "rtc_set_calibration failed to write compensation value: %d\n",
+ ret);
+ return ret;
+ }
+
+ /* Enable automatic compensation */
+ ret = regmap_set_bits(tps->regmap, TPS6594_REG_RTC_CTRL_1,
+ TPS6594_BIT_AUTO_COMP);
+ if (ret < 0)
+ dev_err(dev,
+ "rtc_set_calibration failed to enable auto_comp: %d\n",
+ ret);
+
+ return ret;
+}
+
+static int tps6594_rtc_get_calibration(struct device *dev, int *calibration)
+{
+ unsigned char comp_data[NUM_COMP_REGS];
+ struct tps6594 *tps = dev_get_drvdata(dev->parent);
+ unsigned int ctrl;
+ u16 value;
+ int ret;
+
+ ret = regmap_read(tps->regmap, TPS6594_REG_RTC_CTRL_1, &ctrl);
+ if (ret < 0) {
+ dev_err(dev,
+ "rtc_get_calibration failed to read control register 1: %d\n",
+ ret);
+ return ret;
+ }
+
+ /* If automatic compensation is not enabled report back zero */
+ if (!(ctrl & TPS6594_BIT_AUTO_COMP)) {
+ *calibration = 0;
+ return 0;
+ }
+
+ ret = regmap_bulk_read(tps->regmap, TPS6594_REG_RTC_COMP_LSB, comp_data,
+ NUM_COMP_REGS);
+ if (ret < 0) {
+ dev_err(dev,
+ "rtc_get_calibration failed to read compensation registers: %d\n",
+ ret);
+ return ret;
+ }
+
+ value = (u16)comp_data[0] | ((u16)comp_data[1] << 8);
+
+ *calibration = (s16)value;
+
+ return 0;
+}
+
+static int tps6594_rtc_read_offset(struct device *dev, long *offset)
+{
+ int calibration;
+ s64 tmp;
+ int ret;
+
+ ret = tps6594_rtc_get_calibration(dev, &calibration);
+ if (ret < 0)
+ return ret;
+
+ /* Convert from RTC calibration register format to ppb format */
+ tmp = calibration * (s64)PPB_MULT;
+ if (tmp < 0)
+ tmp -= TICKS_PER_HOUR / 2LL;
+ else
+ tmp += TICKS_PER_HOUR / 2LL;
+ tmp = div_s64(tmp, TICKS_PER_HOUR);
+
+ /* Offset value operates in negative way, so swap sign.
+ * See 8.3.10.5, (32768 - COMP_REG)
+ */
+ *offset = (long)-tmp;
+
+ return 0;
+}
+
+static int tps6594_rtc_set_offset(struct device *dev, long offset)
+{
+ int calibration;
+ s64 tmp;
+ int ret;
+
+ /* Make sure offset value is within supported range */
+ if (offset < MIN_OFFSET || offset > MAX_OFFSET)
+ return -ERANGE;
+
+ /* Convert from ppb format to RTC calibration register format */
+ tmp = offset * (s64)TICKS_PER_HOUR;
+ if (tmp < 0)
+ tmp -= PPB_MULT / 2LL;
+ else
+ tmp += PPB_MULT / 2LL;
+ tmp = div_s64(tmp, PPB_MULT);
+
+ /* Offset value operates in negative way, so swap sign */
+ calibration = (int)-tmp;
+
+ ret = tps6594_rtc_set_calibration(dev, calibration);
+
+ return ret;
+}
+
+static irqreturn_t tps6594_rtc_interrupt(int irq, void *rtc)
+{
+ struct device *dev = rtc;
+ unsigned long events = 0;
+ struct tps6594 *tps = dev_get_drvdata(dev->parent);
+ struct tps6594_rtc *tps_rtc = dev_get_drvdata(dev);
+ int ret;
+ u32 rtc_reg;
+
+ ret = regmap_read(tps->regmap, TPS6594_REG_RTC_STATUS, &rtc_reg);
+ if (ret)
+ return IRQ_NONE;
+
+ if (rtc_reg & TPS6594_BIT_ALARM)
+ events = RTC_IRQF | RTC_AF;
+
+ /* Notify RTC core on event */
+ rtc_update_irq(tps_rtc->rtc, 1, events);
+
+ return IRQ_HANDLED;
+}
+
+static const struct rtc_class_ops tps6594_rtc_ops = {
+ .read_time = tps6594_rtc_read_time,
+ .set_time = tps6594_rtc_set_time,
+ .read_alarm = tps6594_rtc_read_alarm,
+ .set_alarm = tps6594_rtc_set_alarm,
+ .alarm_irq_enable = tps6594_rtc_alarm_irq_enable,
+ .read_offset = tps6594_rtc_read_offset,
+ .set_offset = tps6594_rtc_set_offset,
+};
+
+static int tps6594_rtc_probe(struct platform_device *pdev)
+{
+ struct tps6594 *tps6594;
+ struct tps6594_rtc *tps_rtc;
+ int irq;
+ int ret;
+
+ tps6594 = dev_get_drvdata(pdev->dev.parent);
+
+ tps_rtc = devm_kzalloc(&pdev->dev, sizeof(struct tps6594_rtc),
+ GFP_KERNEL);
+ if (!tps_rtc)
+ return -ENOMEM;
+
+ tps_rtc->rtc = devm_rtc_allocate_device(&pdev->dev);
+ if (IS_ERR(tps_rtc->rtc))
+ return PTR_ERR(tps_rtc->rtc);
+
+ /* Enable crystal oscillator */
+ ret = regmap_set_bits(tps6594->regmap, TPS6594_REG_RTC_CTRL_2,
+ TPS6594_BIT_XTAL_EN);
+ if (ret < 0)
+ return ret;
+
+ /* Start rtc */
+ ret = regmap_set_bits(tps6594->regmap, TPS6594_REG_RTC_CTRL_1,
+ TPS6594_BIT_STOP_RTC);
+ if (ret < 0)
+ return ret;
+
+ mdelay(100);
+
+ /*
+ * RTC should be running now. Check if this is the case.
+ * If not it might be a missing oscillator.
+ */
+ ret = regmap_test_bits(tps6594->regmap, TPS6594_REG_RTC_STATUS,
+ TPS6594_BIT_RUN);
+ if (ret < 0)
+ return ret;
+ if (ret == 0)
+ return -ENODEV;
+
+ platform_set_drvdata(pdev, tps_rtc);
+
+ irq = platform_get_irq_byname(pdev, TPS6594_IRQ_NAME_ALARM);
+ if (irq < 0) {
+ dev_err(&pdev->dev, "Failed to get irq\n");
+ return irq;
+ }
+
+ ret = devm_request_threaded_irq(&pdev->dev, irq, NULL,
+ tps6594_rtc_interrupt, IRQF_ONESHOT,
+ TPS6594_IRQ_NAME_ALARM, &pdev->dev);
+ if (ret < 0) {
+ dev_err(&pdev->dev, "Failed to request_threaded_irq\n");
+ return ret;
+ }
+
+ tps_rtc->rtc->ops = &tps6594_rtc_ops;
+ tps_rtc->rtc->range_min = RTC_TIMESTAMP_BEGIN_2000;
+ tps_rtc->rtc->range_max = RTC_TIMESTAMP_END_2099;
+
+ return devm_rtc_register_device(tps_rtc->rtc);
+}
+
+static struct platform_driver tps6594_rtc_driver = {
+ .probe = tps6594_rtc_probe,
+ .driver = {
+ .name = "tps6594-rtc",
+ },
+};
+
+module_platform_driver(tps6594_rtc_driver);
+
+MODULE_ALIAS("platform:tps6594-rtc");
+MODULE_AUTHOR("Esteban Blanc <eblanc@baylibre.com>");
+MODULE_DESCRIPTION("TPS6594 RTC driver");
+MODULE_LICENSE("GPL");
--
2.38.1