[PATCH v5 2/3] rtc: bbnsm: Add the bbnsm rtc support

Jacky Bai
2023-02-15T02:40:10Z

The BBNSM module includes a real time counter with alarm.
Add a RTC driver for this function.

Signed-off-by: Jacky Bai <ping.bai@nxp.com>
Reviewed-by: Peng Fan <peng.fan@nxp.com>
---
- v5 changes: no

- v4 changes:
- update the compatible string to align with binding file

- v3 changes:
- get the regmap directly from parent node
- remove unnecessary dev_err log print

- v2 changes:
- sort the header file alphabetically
- rename the file to add 'nxp' prefix
- refine bbnsm_rtc_irq_handler function, remove the unnecessary
event variable
- add rtc enable check in .read_time, remove rtc enable in probe function
- remove unnecessary dev_err log in probe function
---
drivers/rtc/Kconfig | 12 ++
drivers/rtc/Makefile | 1 +
drivers/rtc/rtc-nxp-bbnsm.c | 226 ++++++++++++++++++++++++++++++++++++
3 files changed, 239 insertions(+)
create mode 100644 drivers/rtc/rtc-nxp-bbnsm.c

diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig
index 2ba72de0fa47..13c9c57aab73 100644
--- a/drivers/rtc/Kconfig
+++ b/drivers/rtc/Kconfig
@@ -1773,6 +1773,18 @@ config RTC_DRV_SNVS
This driver can also be built as a module, if so, the module
will be called "rtc-snvs".

+config RTC_DRV_BBNSM
+ tristate "NXP BBNSM RTC support"
+ select REGMAP_MMIO
+ depends on ARCH_MXC || COMPILE_TEST
+ depends on HAS_IOMEM
+ depends on OF
+ help
+ If you say yes here you get support for the NXP BBNSM RTC module.
+
+ This driver can also be built as a module, if so, the module
+ will be called "rtc-bbnsm".
+
config RTC_DRV_IMX_SC
depends on IMX_SCU
depends on HAVE_ARM_SMCCC
diff --git a/drivers/rtc/Makefile b/drivers/rtc/Makefile
index 59eb30289335..ea445d1ebb17 100644
--- a/drivers/rtc/Makefile
+++ b/drivers/rtc/Makefile
@@ -33,6 +33,7 @@ obj-$(CONFIG_RTC_DRV_ASPEED) += rtc-aspeed.o
obj-$(CONFIG_RTC_DRV_AT91RM9200)+= rtc-at91rm9200.o
obj-$(CONFIG_RTC_DRV_AT91SAM9) += rtc-at91sam9.o
obj-$(CONFIG_RTC_DRV_AU1XXX) += rtc-au1xxx.o
+obj-$(CONFIG_RTC_DRV_BBNSM) += rtc-nxp-bbnsm.o
obj-$(CONFIG_RTC_DRV_BD70528) += rtc-bd70528.o
obj-$(CONFIG_RTC_DRV_BQ32K) += rtc-bq32k.o
obj-$(CONFIG_RTC_DRV_BQ4802) += rtc-bq4802.o
diff --git a/drivers/rtc/rtc-nxp-bbnsm.c b/drivers/rtc/rtc-nxp-bbnsm.c
new file mode 100644
index 000000000000..1009388b635e
--- /dev/null
+++ b/drivers/rtc/rtc-nxp-bbnsm.c
@@ -0,0 +1,226 @@
+// SPDX-License-Identifier: GPL-2.0+
+//
+// Copyright 2022 NXP.
+
+#include <linux/init.h>
+#include <linux/io.h>
+#include <linux/kernel.h>
+#include <linux/mfd/syscon.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/pm_wakeirq.h>
+#include <linux/regmap.h>
+#include <linux/rtc.h>
+
+#define BBNSM_CTRL 0x8
+#define BBNSM_INT_EN 0x10
+#define BBNSM_EVENTS 0x14
+#define BBNSM_RTC_LS 0x40
+#define BBNSM_RTC_MS 0x44
+#define BBNSM_TA 0x50
+
+#define RTC_EN 0x2
+#define RTC_EN_MSK 0x3
+#define TA_EN (0x2 << 2)
+#define TA_DIS (0x1 << 2)
+#define TA_EN_MSK (0x3 << 2)
+#define RTC_INT_EN 0x2
+#define TA_INT_EN (0x2 << 2)
+
+#define BBNSM_EVENT_TA (0x2 << 2)
+
+#define CNTR_TO_SECS_SH 15
+
+struct bbnsm_rtc {
+ struct rtc_device *rtc;
+ struct regmap *regmap;
+ int irq;
+ struct clk *clk;
+};
+
+static u32 bbnsm_read_counter(struct bbnsm_rtc *bbnsm)
+{
+ u32 rtc_msb, rtc_lsb;
+ unsigned int timeout = 100;
+ u32 time;
+ u32 tmp = 0;
+
+ do {
+ time = tmp;
+ /* read the msb */
+ regmap_read(bbnsm->regmap, BBNSM_RTC_MS, &rtc_msb);
+ /* read the lsb */
+ regmap_read(bbnsm->regmap, BBNSM_RTC_LS, &rtc_lsb);
+ /* convert to seconds */
+ tmp = (rtc_msb << 17) | (rtc_lsb >> 15);
+ } while (tmp != time && --timeout);
+
+ return time;
+}
+
+static int bbnsm_rtc_read_time(struct device *dev, struct rtc_time *tm)
+{
+ struct bbnsm_rtc *bbnsm = dev_get_drvdata(dev);
+ unsigned long time;
+ u32 val;
+
+ regmap_read(bbnsm->regmap, BBNSM_CTRL, &val);
+ if ((val & RTC_EN_MSK) != RTC_EN)
+ return -EINVAL;
+
+ time = bbnsm_read_counter(bbnsm);
+ rtc_time64_to_tm(time, tm);
+
+ return 0;
+}
+
+static int bbnsm_rtc_set_time(struct device *dev, struct rtc_time *tm)
+{
+ struct bbnsm_rtc *bbnsm = dev_get_drvdata(dev);
+ unsigned long time = rtc_tm_to_time64(tm);
+
+ /* disable the RTC first */
+ regmap_update_bits(bbnsm->regmap, BBNSM_CTRL, RTC_EN_MSK, 0);
+
+ /* write the 32bit sec time to 47 bit timer counter, leaving 15 LSBs blank */
+ regmap_write(bbnsm->regmap, BBNSM_RTC_LS, time << CNTR_TO_SECS_SH);
+ regmap_write(bbnsm->regmap, BBNSM_RTC_MS, time >> (32 - CNTR_TO_SECS_SH));
+
+ /* Enable the RTC again */
+ regmap_update_bits(bbnsm->regmap, BBNSM_CTRL, RTC_EN_MSK, RTC_EN);
+
+ return 0;
+}
+
+static int bbnsm_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
+{
+ struct bbnsm_rtc *bbnsm = dev_get_drvdata(dev);
+ u32 bbnsm_events, bbnsm_ta;
+
+ regmap_read(bbnsm->regmap, BBNSM_TA, &bbnsm_ta);
+ rtc_time64_to_tm(bbnsm_ta, &alrm->time);
+
+ regmap_read(bbnsm->regmap, BBNSM_EVENTS, &bbnsm_events);
+ alrm->pending = (bbnsm_events & BBNSM_EVENT_TA) ? 1 : 0;
+
+ return 0;
+}
+
+static int bbnsm_rtc_alarm_irq_enable(struct device *dev, unsigned int enable)
+{
+ struct bbnsm_rtc *bbnsm = dev_get_drvdata(dev);
+
+ /* enable the alarm event */
+ regmap_update_bits(bbnsm->regmap, BBNSM_CTRL, TA_EN_MSK, enable ? TA_EN : TA_DIS);
+ /* enable the alarm interrupt */
+ regmap_update_bits(bbnsm->regmap, BBNSM_INT_EN, TA_EN_MSK, enable ? TA_EN : TA_DIS);
+
+ return 0;
+}
+
+static int bbnsm_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
+{
+ struct bbnsm_rtc *bbnsm = dev_get_drvdata(dev);
+ unsigned long time = rtc_tm_to_time64(&alrm->time);
+
+ /* disable the alarm */
+ regmap_update_bits(bbnsm->regmap, BBNSM_CTRL, TA_EN, TA_EN);
+
+ /* write the seconds to TA */
+ regmap_write(bbnsm->regmap, BBNSM_TA, time);
+
+ return bbnsm_rtc_alarm_irq_enable(dev, alrm->enabled);
+}
+
+static const struct rtc_class_ops bbnsm_rtc_ops = {
+ .read_time = bbnsm_rtc_read_time,
+ .set_time = bbnsm_rtc_set_time,
+ .read_alarm = bbnsm_rtc_read_alarm,
+ .set_alarm = bbnsm_rtc_set_alarm,
+ .alarm_irq_enable = bbnsm_rtc_alarm_irq_enable,
+};
+
+static irqreturn_t bbnsm_rtc_irq_handler(int irq, void *dev_id)
+{
+ struct device *dev = dev_id;
+ struct bbnsm_rtc *bbnsm = dev_get_drvdata(dev);
+ u32 val;
+
+ regmap_read(bbnsm->regmap, BBNSM_EVENTS, &val);
+ if (val & BBNSM_EVENT_TA) {
+ bbnsm_rtc_alarm_irq_enable(dev, false);
+ /* clear the alarm event */
+ regmap_write_bits(bbnsm->regmap, BBNSM_EVENTS, TA_EN_MSK, BBNSM_EVENT_TA);
+ rtc_update_irq(bbnsm->rtc, 1, RTC_AF | RTC_IRQF);
+
+ return IRQ_HANDLED;
+ }
+
+ return IRQ_NONE;
+}
+
+static int bbnsm_rtc_probe(struct platform_device *pdev)
+{
+ struct device_node *np = pdev->dev.of_node;
+ struct bbnsm_rtc *bbnsm;
+ int ret;
+
+ bbnsm = devm_kzalloc(&pdev->dev, sizeof(*bbnsm), GFP_KERNEL);
+ if (!bbnsm)
+ return -ENOMEM;
+
+ bbnsm->rtc = devm_rtc_allocate_device(&pdev->dev);
+ if (IS_ERR(bbnsm->rtc))
+ return PTR_ERR(bbnsm->rtc);
+
+ bbnsm->regmap = syscon_node_to_regmap(np->parent);
+ if (IS_ERR(bbnsm->regmap)) {
+ dev_dbg(&pdev->dev, "bbnsm get regmap failed\n");
+ return PTR_ERR(bbnsm->regmap);
+ }
+
+ bbnsm->irq = platform_get_irq(pdev, 0);
+ if (bbnsm->irq < 0)
+ return bbnsm->irq;
+
+ platform_set_drvdata(pdev, bbnsm);
+
+ /* clear all the pending events */
+ regmap_write(bbnsm->regmap, BBNSM_EVENTS, 0x7A);
+
+ device_init_wakeup(&pdev->dev, true);
+ dev_pm_set_wake_irq(&pdev->dev, bbnsm->irq);
+
+ ret = devm_request_irq(&pdev->dev, bbnsm->irq, bbnsm_rtc_irq_handler,
+ IRQF_SHARED, "rtc alarm", &pdev->dev);
+ if (ret) {
+ dev_err(&pdev->dev, "failed to request irq %d: %d\n",
+ bbnsm->irq, ret);
+ return ret;
+ }
+
+ bbnsm->rtc->ops = &bbnsm_rtc_ops;
+ bbnsm->rtc->range_max = U32_MAX;
+
+ return devm_rtc_register_device(bbnsm->rtc);
+}
+
+static const struct of_device_id bbnsm_dt_ids[] = {
+ { .compatible = "nxp,imx93-bbnsm-rtc" },
+ { /* sentinel */ },
+};
+MODULE_DEVICE_TABLE(of, bbnsm_dt_ids);
+
+static struct platform_driver bbnsm_rtc_driver = {
+ .driver = {
+ .name = "bbnsm_rtc",
+ .of_match_table = bbnsm_dt_ids,
+ },
+ .probe = bbnsm_rtc_probe,
+};
+module_platform_driver(bbnsm_rtc_driver);
+
+MODULE_AUTHOR("Jacky Bai <ping.bai@nxp.com>");
+MODULE_DESCRIPTION("NXP BBNSM RTC Driver");
+MODULE_LICENSE("GPL");
--
2.34.1