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authorLinus Torvalds <torvalds@linux-foundation.org>2026-08-23 13:28:57 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2026-08-23 13:28:57 -0700
commit4352b8aee98005853aa63f57d6377282de17a33f (patch)
tree27614d7a9ef05c32d089004e104364ce42324837 /drivers/rtc/rtc-st-lpc.c
downloadlinux-stable-4352b8aee98005853aa63f57d6377282de17a33f.tar.gz
linux-stable-4352b8aee98005853aa63f57d6377282de17a33f.zip
Merge tag 'i3c/for-7.3' of git://git.kernel.org/pub/scm/linux/kernel/git/i3c/linuxgrafted
Pull I3C updates from Alexandre Belloni: "A new driver this cycle, for the AMD AXI I3C controller. There are also new features such as IBI wakeup support, SETAASA device discovery and ACPI support for the the DAA methods, meaning we can now communicate with the SPD devices on DDR5 modules. New driver: - AMD AXI I3C master controller Subsystem: - I3C Common Command Code (CCC) handling improvements, especially around GET CCCs - SETAASA device discovery support - ACPI support for all existing DAA methods like SETDASA, SETNEWDA as well as I2C devices on I3C bus - IBI-based wakeup support Drivers: - dw: SETAASA support - mipi-i3c-hci: advertise IBI wakeup capability, AMD_PT I3C controller support, PIO queue management support for HCI v1.2 - renesas: improve suspend to RAM support, add runtime PM support" * tag 'i3c/for-7.3' of git://git.kernel.org/pub/scm/linux/kernel/git/i3c/linux: (70 commits) i3c: dw: reduce do_daa time if there's no client i3c: mipi-i3c-hci: Add support for AMD_PT I3C controller i3c: mipi-i3c-hci: Add PIO queue management support for HCI v1.2 i3c: mipi-i3c-hci: Fix missing STAT_IBI_STATUS_THLD in PIO mode i3c: dw: rename "pclk" to "apb" to match dt-binding i3c: dw: make struct dw_i3c_cmd smaller i3c: dw: use COMMAND_PORT_TRANSFER_ARG instead of hardcoding i3c: renesas: Don't register devices when ENTDAA times out i3c: master: dw-i3c-master: fix OD timing for first broadcast i3c: mipi-i3c-hci: Advertise IBI wakeup capability i3c: mipi-i3c-hci: Factor out i3c_hci_sysdev() i3c: mipi-i3c-hci-pci: Propagate I3C wakeup requirements to PCI i3c: master: Reject IBI requests from non-IBI-capable devices i3c: master: Add helper to query bus wakeup requirements i3c: master: Report wakeup events for IBIs i3c: master: Support IBI-based wakeup capability i3c: master: Fix potential UAF in i3c_device_match() i3c: master: Fix potential UAF in i3c_device_uevent() i3c: Make dev->desc locking assumptions explicit i3c: master: Fix use-after-free of master->this ...
Diffstat (limited to 'drivers/rtc/rtc-st-lpc.c')
-rw-r--r--drivers/rtc/rtc-st-lpc.c314
1 files changed, 314 insertions, 0 deletions
diff --git a/drivers/rtc/rtc-st-lpc.c b/drivers/rtc/rtc-st-lpc.c
new file mode 100644
index 000000000..c6d452241
--- /dev/null
+++ b/drivers/rtc/rtc-st-lpc.c
@@ -0,0 +1,314 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * rtc-st-lpc.c - ST's LPC RTC, powered by the Low Power Timer
+ *
+ * Copyright (C) 2014 STMicroelectronics Limited
+ *
+ * Author: David Paris <david.paris@st.com> for STMicroelectronics
+ * Lee Jones <lee.jones@linaro.org> for STMicroelectronics
+ *
+ * Based on the original driver written by Stuart Menefy.
+ */
+
+#include <linux/clk.h>
+#include <linux/delay.h>
+#include <linux/init.h>
+#include <linux/io.h>
+#include <linux/irq.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_irq.h>
+#include <linux/platform_device.h>
+#include <linux/rtc.h>
+
+#include <dt-bindings/mfd/st-lpc.h>
+
+/* Low Power Timer */
+#define LPC_LPT_LSB_OFF 0x400
+#define LPC_LPT_MSB_OFF 0x404
+#define LPC_LPT_START_OFF 0x408
+
+/* Low Power Alarm */
+#define LPC_LPA_LSB_OFF 0x410
+#define LPC_LPA_MSB_OFF 0x414
+#define LPC_LPA_START_OFF 0x418
+
+/* LPC as WDT */
+#define LPC_WDT_OFF 0x510
+#define LPC_WDT_FLAG_OFF 0x514
+
+struct st_rtc {
+ struct rtc_device *rtc_dev;
+ struct rtc_wkalrm alarm;
+ struct clk *clk;
+ unsigned long clkrate;
+ void __iomem *ioaddr;
+ bool irq_enabled:1;
+ spinlock_t lock;
+ short irq;
+};
+
+static void st_rtc_set_hw_alarm(struct st_rtc *rtc,
+ unsigned long msb, unsigned long lsb)
+{
+ unsigned long flags;
+
+ spin_lock_irqsave(&rtc->lock, flags);
+
+ writel_relaxed(1, rtc->ioaddr + LPC_WDT_OFF);
+
+ writel_relaxed(msb, rtc->ioaddr + LPC_LPA_MSB_OFF);
+ writel_relaxed(lsb, rtc->ioaddr + LPC_LPA_LSB_OFF);
+ writel_relaxed(1, rtc->ioaddr + LPC_LPA_START_OFF);
+
+ writel_relaxed(0, rtc->ioaddr + LPC_WDT_OFF);
+
+ spin_unlock_irqrestore(&rtc->lock, flags);
+}
+
+static irqreturn_t st_rtc_handler(int this_irq, void *data)
+{
+ struct st_rtc *rtc = (struct st_rtc *)data;
+
+ rtc_update_irq(rtc->rtc_dev, 1, RTC_AF);
+
+ return IRQ_HANDLED;
+}
+
+static int st_rtc_read_time(struct device *dev, struct rtc_time *tm)
+{
+ struct st_rtc *rtc = dev_get_drvdata(dev);
+ unsigned long lpt_lsb, lpt_msb;
+ unsigned long long lpt;
+ unsigned long flags;
+
+ spin_lock_irqsave(&rtc->lock, flags);
+
+ do {
+ lpt_msb = readl_relaxed(rtc->ioaddr + LPC_LPT_MSB_OFF);
+ lpt_lsb = readl_relaxed(rtc->ioaddr + LPC_LPT_LSB_OFF);
+ } while (readl_relaxed(rtc->ioaddr + LPC_LPT_MSB_OFF) != lpt_msb);
+
+ spin_unlock_irqrestore(&rtc->lock, flags);
+
+ lpt = ((unsigned long long)lpt_msb << 32) | lpt_lsb;
+ do_div(lpt, rtc->clkrate);
+ rtc_time64_to_tm(lpt, tm);
+
+ return 0;
+}
+
+static int st_rtc_set_time(struct device *dev, struct rtc_time *tm)
+{
+ struct st_rtc *rtc = dev_get_drvdata(dev);
+ unsigned long long lpt, secs;
+ unsigned long flags;
+
+ secs = rtc_tm_to_time64(tm);
+
+ lpt = (unsigned long long)secs * rtc->clkrate;
+
+ spin_lock_irqsave(&rtc->lock, flags);
+
+ writel_relaxed(lpt >> 32, rtc->ioaddr + LPC_LPT_MSB_OFF);
+ writel_relaxed(lpt, rtc->ioaddr + LPC_LPT_LSB_OFF);
+ writel_relaxed(1, rtc->ioaddr + LPC_LPT_START_OFF);
+
+ spin_unlock_irqrestore(&rtc->lock, flags);
+
+ return 0;
+}
+
+static int st_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *wkalrm)
+{
+ struct st_rtc *rtc = dev_get_drvdata(dev);
+ unsigned long flags;
+
+ spin_lock_irqsave(&rtc->lock, flags);
+
+ memcpy(wkalrm, &rtc->alarm, sizeof(struct rtc_wkalrm));
+
+ spin_unlock_irqrestore(&rtc->lock, flags);
+
+ return 0;
+}
+
+static int st_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
+{
+ struct st_rtc *rtc = dev_get_drvdata(dev);
+
+ if (enabled && !rtc->irq_enabled) {
+ enable_irq(rtc->irq);
+ rtc->irq_enabled = true;
+ } else if (!enabled && rtc->irq_enabled) {
+ disable_irq(rtc->irq);
+ rtc->irq_enabled = false;
+ }
+
+ return 0;
+}
+
+static int st_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *t)
+{
+ struct st_rtc *rtc = dev_get_drvdata(dev);
+ struct rtc_time now;
+ unsigned long long now_secs;
+ unsigned long long alarm_secs;
+ unsigned long long lpa;
+
+ st_rtc_read_time(dev, &now);
+ now_secs = rtc_tm_to_time64(&now);
+ alarm_secs = rtc_tm_to_time64(&t->time);
+
+ memcpy(&rtc->alarm, t, sizeof(struct rtc_wkalrm));
+
+ /* Now many secs to fire */
+ alarm_secs -= now_secs;
+ lpa = (unsigned long long)alarm_secs * rtc->clkrate;
+
+ st_rtc_set_hw_alarm(rtc, lpa >> 32, lpa);
+ st_rtc_alarm_irq_enable(dev, t->enabled);
+
+ return 0;
+}
+
+static const struct rtc_class_ops st_rtc_ops = {
+ .read_time = st_rtc_read_time,
+ .set_time = st_rtc_set_time,
+ .read_alarm = st_rtc_read_alarm,
+ .set_alarm = st_rtc_set_alarm,
+ .alarm_irq_enable = st_rtc_alarm_irq_enable,
+};
+
+static int st_rtc_probe(struct platform_device *pdev)
+{
+ struct device_node *np = pdev->dev.of_node;
+ struct st_rtc *rtc;
+ uint32_t mode;
+ int ret = 0;
+
+ ret = of_property_read_u32(np, "st,lpc-mode", &mode);
+ if (ret) {
+ dev_err(&pdev->dev, "An LPC mode must be provided\n");
+ return -EINVAL;
+ }
+
+ /* LPC can either run as a Clocksource or in RTC or WDT mode */
+ if (mode != ST_LPC_MODE_RTC)
+ return -ENODEV;
+
+ rtc = devm_kzalloc(&pdev->dev, sizeof(struct st_rtc), GFP_KERNEL);
+ if (!rtc)
+ return -ENOMEM;
+
+ rtc->rtc_dev = devm_rtc_allocate_device(&pdev->dev);
+ if (IS_ERR(rtc->rtc_dev))
+ return PTR_ERR(rtc->rtc_dev);
+
+ spin_lock_init(&rtc->lock);
+
+ rtc->ioaddr = devm_platform_ioremap_resource(pdev, 0);
+ if (IS_ERR(rtc->ioaddr))
+ return PTR_ERR(rtc->ioaddr);
+
+ rtc->irq = irq_of_parse_and_map(np, 0);
+ if (!rtc->irq) {
+ dev_err(&pdev->dev, "IRQ missing or invalid\n");
+ return -EINVAL;
+ }
+
+ ret = devm_request_irq(&pdev->dev, rtc->irq, st_rtc_handler,
+ IRQF_NO_AUTOEN, pdev->name, rtc);
+ if (ret) {
+ dev_err(&pdev->dev, "Failed to request irq %i\n", rtc->irq);
+ return ret;
+ }
+
+ enable_irq_wake(rtc->irq);
+
+ rtc->clk = devm_clk_get_enabled(&pdev->dev, NULL);
+ if (IS_ERR(rtc->clk))
+ return dev_err_probe(&pdev->dev, PTR_ERR(rtc->clk),
+ "Unable to request clock\n");
+
+ rtc->clkrate = clk_get_rate(rtc->clk);
+ if (!rtc->clkrate) {
+ dev_err(&pdev->dev, "Unable to fetch clock rate\n");
+ return -EINVAL;
+ }
+
+ device_set_wakeup_capable(&pdev->dev, 1);
+
+ platform_set_drvdata(pdev, rtc);
+
+ rtc->rtc_dev->ops = &st_rtc_ops;
+ rtc->rtc_dev->range_max = U64_MAX;
+ do_div(rtc->rtc_dev->range_max, rtc->clkrate);
+
+ ret = devm_rtc_register_device(rtc->rtc_dev);
+ if (ret)
+ return ret;
+
+ return 0;
+}
+
+#ifdef CONFIG_PM_SLEEP
+static int st_rtc_suspend(struct device *dev)
+{
+ struct st_rtc *rtc = dev_get_drvdata(dev);
+
+ if (device_may_wakeup(dev))
+ return 0;
+
+ writel_relaxed(1, rtc->ioaddr + LPC_WDT_OFF);
+ writel_relaxed(0, rtc->ioaddr + LPC_LPA_START_OFF);
+ writel_relaxed(0, rtc->ioaddr + LPC_WDT_OFF);
+
+ return 0;
+}
+
+static int st_rtc_resume(struct device *dev)
+{
+ struct st_rtc *rtc = dev_get_drvdata(dev);
+
+ rtc_alarm_irq_enable(rtc->rtc_dev, 0);
+
+ /*
+ * clean 'rtc->alarm' to allow a new
+ * .set_alarm to the upper RTC layer
+ */
+ memset(&rtc->alarm, 0, sizeof(struct rtc_wkalrm));
+
+ writel_relaxed(0, rtc->ioaddr + LPC_LPA_MSB_OFF);
+ writel_relaxed(0, rtc->ioaddr + LPC_LPA_LSB_OFF);
+ writel_relaxed(1, rtc->ioaddr + LPC_WDT_OFF);
+ writel_relaxed(1, rtc->ioaddr + LPC_LPA_START_OFF);
+ writel_relaxed(0, rtc->ioaddr + LPC_WDT_OFF);
+
+ return 0;
+}
+#endif
+
+static SIMPLE_DEV_PM_OPS(st_rtc_pm_ops, st_rtc_suspend, st_rtc_resume);
+
+static const struct of_device_id st_rtc_match[] = {
+ { .compatible = "st,stih407-lpc" },
+ {}
+};
+MODULE_DEVICE_TABLE(of, st_rtc_match);
+
+static struct platform_driver st_rtc_platform_driver = {
+ .driver = {
+ .name = "st-lpc-rtc",
+ .pm = &st_rtc_pm_ops,
+ .of_match_table = st_rtc_match,
+ },
+ .probe = st_rtc_probe,
+};
+
+module_platform_driver(st_rtc_platform_driver);
+
+MODULE_DESCRIPTION("STMicroelectronics LPC RTC driver");
+MODULE_AUTHOR("David Paris <david.paris@st.com>");
+MODULE_LICENSE("GPL");