rtc: bbnsm: Add the bbnsm rtc support

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>
Link: https://lore.kernel.org/r/20230215024117.3357341-3-ping.bai@nxp.com
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig
index d2b6d20..d2a7fbc 100644 (file)
--- a/drivers/rtc/Kconfig
+++ b/drivers/rtc/Kconfig
@@ -1786,6 +1786,18 @@ 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 d3c042d..0f11027 100644 (file)
--- 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 (file)
index 0000000..acbfbeb
--- /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");