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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-wilco-ec.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-wilco-ec.c')
-rw-r--r--drivers/rtc/rtc-wilco-ec.c194
1 files changed, 194 insertions, 0 deletions
diff --git a/drivers/rtc/rtc-wilco-ec.c b/drivers/rtc/rtc-wilco-ec.c
new file mode 100644
index 000000000..2a205a646
--- /dev/null
+++ b/drivers/rtc/rtc-wilco-ec.c
@@ -0,0 +1,194 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * RTC interface for Wilco Embedded Controller with R/W abilities
+ *
+ * Copyright 2018 Google LLC
+ *
+ * The corresponding platform device is typically registered in
+ * drivers/platform/chrome/wilco_ec/core.c
+ */
+
+#include <linux/bcd.h>
+#include <linux/err.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/platform_data/wilco-ec.h>
+#include <linux/rtc.h>
+#include <linux/timekeeping.h>
+
+#define EC_COMMAND_CMOS 0x7c
+#define EC_CMOS_TOD_WRITE 0x02
+#define EC_CMOS_TOD_READ 0x08
+
+/* Message sent to the EC to request the current time. */
+struct ec_rtc_read_request {
+ u8 command;
+ u8 reserved;
+ u8 param;
+} __packed;
+static struct ec_rtc_read_request read_rq = {
+ .command = EC_COMMAND_CMOS,
+ .param = EC_CMOS_TOD_READ,
+};
+
+/**
+ * struct ec_rtc_read_response - Format of RTC returned by EC.
+ * @reserved: Unused byte
+ * @second: Second value (0..59)
+ * @minute: Minute value (0..59)
+ * @hour: Hour value (0..23)
+ * @day: Day value (1..31)
+ * @month: Month value (1..12)
+ * @year: Year value (full year % 100)
+ * @century: Century value (full year / 100)
+ *
+ * All values are presented in binary (not BCD).
+ */
+struct ec_rtc_read_response {
+ u8 reserved;
+ u8 second;
+ u8 minute;
+ u8 hour;
+ u8 day;
+ u8 month;
+ u8 year;
+ u8 century;
+} __packed;
+
+/**
+ * struct ec_rtc_write_request - Format of RTC sent to the EC.
+ * @command: Always EC_COMMAND_CMOS
+ * @reserved: Unused byte
+ * @param: Always EC_CMOS_TOD_WRITE
+ * @century: Century value (full year / 100)
+ * @year: Year value (full year % 100)
+ * @month: Month value (1..12)
+ * @day: Day value (1..31)
+ * @hour: Hour value (0..23)
+ * @minute: Minute value (0..59)
+ * @second: Second value (0..59)
+ * @weekday: Day of the week (0=Saturday)
+ *
+ * All values are presented in BCD.
+ */
+struct ec_rtc_write_request {
+ u8 command;
+ u8 reserved;
+ u8 param;
+ u8 century;
+ u8 year;
+ u8 month;
+ u8 day;
+ u8 hour;
+ u8 minute;
+ u8 second;
+ u8 weekday;
+} __packed;
+
+static int wilco_ec_rtc_read(struct device *dev, struct rtc_time *tm)
+{
+ struct wilco_ec_device *ec = dev_get_drvdata(dev->parent);
+ struct ec_rtc_read_response rtc;
+ struct wilco_ec_message msg;
+ int ret;
+
+ memset(&msg, 0, sizeof(msg));
+ msg.type = WILCO_EC_MSG_LEGACY;
+ msg.request_data = &read_rq;
+ msg.request_size = sizeof(read_rq);
+ msg.response_data = &rtc;
+ msg.response_size = sizeof(rtc);
+
+ ret = wilco_ec_mailbox(ec, &msg);
+ if (ret < 0)
+ return ret;
+
+ tm->tm_sec = rtc.second;
+ tm->tm_min = rtc.minute;
+ tm->tm_hour = rtc.hour;
+ tm->tm_mday = rtc.day;
+ tm->tm_mon = rtc.month - 1;
+ tm->tm_year = rtc.year + (rtc.century * 100) - 1900;
+ /* Ignore other tm fields, man rtc says userspace shouldn't use them. */
+
+ if (rtc_valid_tm(tm)) {
+ dev_err(dev, "Time from RTC is invalid: %ptRr\n", tm);
+ return -EIO;
+ }
+
+ return 0;
+}
+
+static int wilco_ec_rtc_write(struct device *dev, struct rtc_time *tm)
+{
+ struct wilco_ec_device *ec = dev_get_drvdata(dev->parent);
+ struct ec_rtc_write_request rtc;
+ struct wilco_ec_message msg;
+ int year = tm->tm_year + 1900;
+ /*
+ * Convert from 0=Sunday to 0=Saturday for the EC
+ * We DO need to set weekday because the EC controls battery charging
+ * schedules that depend on the day of the week.
+ */
+ int wday = tm->tm_wday == 6 ? 0 : tm->tm_wday + 1;
+ int ret;
+
+ rtc.command = EC_COMMAND_CMOS;
+ rtc.param = EC_CMOS_TOD_WRITE;
+ rtc.century = bin2bcd(year / 100);
+ rtc.year = bin2bcd(year % 100);
+ rtc.month = bin2bcd(tm->tm_mon + 1);
+ rtc.day = bin2bcd(tm->tm_mday);
+ rtc.hour = bin2bcd(tm->tm_hour);
+ rtc.minute = bin2bcd(tm->tm_min);
+ rtc.second = bin2bcd(tm->tm_sec);
+ rtc.weekday = bin2bcd(wday);
+
+ memset(&msg, 0, sizeof(msg));
+ msg.type = WILCO_EC_MSG_LEGACY;
+ msg.request_data = &rtc;
+ msg.request_size = sizeof(rtc);
+
+ ret = wilco_ec_mailbox(ec, &msg);
+ if (ret < 0)
+ return ret;
+
+ return 0;
+}
+
+static const struct rtc_class_ops wilco_ec_rtc_ops = {
+ .read_time = wilco_ec_rtc_read,
+ .set_time = wilco_ec_rtc_write,
+};
+
+static int wilco_ec_rtc_probe(struct platform_device *pdev)
+{
+ struct rtc_device *rtc;
+
+ rtc = devm_rtc_allocate_device(&pdev->dev);
+ if (IS_ERR(rtc))
+ return PTR_ERR(rtc);
+
+ rtc->ops = &wilco_ec_rtc_ops;
+ /* EC only supports this century */
+ rtc->range_min = RTC_TIMESTAMP_BEGIN_2000;
+ rtc->range_max = RTC_TIMESTAMP_END_2099;
+ rtc->owner = THIS_MODULE;
+
+ return devm_rtc_register_device(rtc);
+}
+
+static struct platform_driver wilco_ec_rtc_driver = {
+ .driver = {
+ .name = "rtc-wilco-ec",
+ },
+ .probe = wilco_ec_rtc_probe,
+};
+
+module_platform_driver(wilco_ec_rtc_driver);
+
+MODULE_ALIAS("platform:rtc-wilco-ec");
+MODULE_AUTHOR("Nick Crews <ncrews@chromium.org>");
+MODULE_LICENSE("GPL v2");
+MODULE_DESCRIPTION("Wilco EC RTC driver");