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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-pcf8583.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-pcf8583.c')
-rw-r--r--drivers/rtc/rtc-pcf8583.c317
1 files changed, 317 insertions, 0 deletions
diff --git a/drivers/rtc/rtc-pcf8583.c b/drivers/rtc/rtc-pcf8583.c
new file mode 100644
index 000000000..df5e20cbc
--- /dev/null
+++ b/drivers/rtc/rtc-pcf8583.c
@@ -0,0 +1,317 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * drivers/rtc/rtc-pcf8583.c
+ *
+ * Copyright (C) 2000 Russell King
+ * Copyright (C) 2008 Wolfram Sang & Juergen Beisert, Pengutronix
+ *
+ * Driver for PCF8583 RTC & RAM chip
+ *
+ * Converted to the generic RTC susbsystem by G. Liakhovetski (2006)
+ */
+#include <linux/module.h>
+#include <linux/i2c.h>
+#include <linux/slab.h>
+#include <linux/rtc.h>
+#include <linux/init.h>
+#include <linux/err.h>
+#include <linux/errno.h>
+#include <linux/bcd.h>
+
+struct rtc_mem {
+ unsigned int loc;
+ unsigned int nr;
+ unsigned char *data;
+};
+
+struct pcf8583 {
+ struct rtc_device *rtc;
+ unsigned char ctrl;
+};
+
+#define CTRL_STOP 0x80
+#define CTRL_HOLD 0x40
+#define CTRL_32KHZ 0x00
+#define CTRL_MASK 0x08
+#define CTRL_ALARMEN 0x04
+#define CTRL_ALARM 0x02
+#define CTRL_TIMER 0x01
+
+
+static struct i2c_driver pcf8583_driver;
+
+#define get_ctrl(x) ((struct pcf8583 *)i2c_get_clientdata(x))->ctrl
+#define set_ctrl(x, v) get_ctrl(x) = v
+
+#define CMOS_YEAR (64 + 128)
+#define CMOS_CHECKSUM (63)
+
+static int pcf8583_get_datetime(struct i2c_client *client, struct rtc_time *dt)
+{
+ unsigned char buf[8], addr[1] = { 1 };
+ struct i2c_msg msgs[2] = {
+ {
+ .addr = client->addr,
+ .flags = 0,
+ .len = 1,
+ .buf = addr,
+ }, {
+ .addr = client->addr,
+ .flags = I2C_M_RD,
+ .len = 6,
+ .buf = buf,
+ }
+ };
+ int ret;
+
+ memset(buf, 0, sizeof(buf));
+
+ ret = i2c_transfer(client->adapter, msgs, 2);
+ if (ret == 2) {
+ dt->tm_year = buf[4] >> 6;
+ dt->tm_wday = buf[5] >> 5;
+
+ buf[4] &= 0x3f;
+ buf[5] &= 0x1f;
+
+ dt->tm_sec = bcd2bin(buf[1]);
+ dt->tm_min = bcd2bin(buf[2]);
+ dt->tm_hour = bcd2bin(buf[3]);
+ dt->tm_mday = bcd2bin(buf[4]);
+ dt->tm_mon = bcd2bin(buf[5]) - 1;
+ }
+
+ return ret == 2 ? 0 : -EIO;
+}
+
+static int pcf8583_set_datetime(struct i2c_client *client, struct rtc_time *dt, int datetoo)
+{
+ unsigned char buf[8];
+ int ret, len = 6;
+
+ buf[0] = 0;
+ buf[1] = get_ctrl(client) | 0x80;
+ buf[2] = 0;
+ buf[3] = bin2bcd(dt->tm_sec);
+ buf[4] = bin2bcd(dt->tm_min);
+ buf[5] = bin2bcd(dt->tm_hour);
+
+ if (datetoo) {
+ len = 8;
+ buf[6] = bin2bcd(dt->tm_mday) | (dt->tm_year << 6);
+ buf[7] = bin2bcd(dt->tm_mon + 1) | (dt->tm_wday << 5);
+ }
+
+ ret = i2c_master_send(client, (char *)buf, len);
+ if (ret != len)
+ return -EIO;
+
+ buf[1] = get_ctrl(client);
+ ret = i2c_master_send(client, (char *)buf, 2);
+
+ return ret == 2 ? 0 : -EIO;
+}
+
+static int pcf8583_get_ctrl(struct i2c_client *client, unsigned char *ctrl)
+{
+ *ctrl = get_ctrl(client);
+ return 0;
+}
+
+static int pcf8583_set_ctrl(struct i2c_client *client, unsigned char *ctrl)
+{
+ unsigned char buf[2];
+
+ buf[0] = 0;
+ buf[1] = *ctrl;
+ set_ctrl(client, *ctrl);
+
+ return i2c_master_send(client, (char *)buf, 2);
+}
+
+static int pcf8583_read_mem(struct i2c_client *client, struct rtc_mem *mem)
+{
+ unsigned char addr[1];
+ struct i2c_msg msgs[2] = {
+ {
+ .addr = client->addr,
+ .flags = 0,
+ .len = 1,
+ .buf = addr,
+ }, {
+ .addr = client->addr,
+ .flags = I2C_M_RD,
+ .len = mem->nr,
+ .buf = mem->data,
+ }
+ };
+
+ if (mem->loc < 8)
+ return -EINVAL;
+
+ addr[0] = mem->loc;
+
+ return i2c_transfer(client->adapter, msgs, 2) == 2 ? 0 : -EIO;
+}
+
+static int pcf8583_write_mem(struct i2c_client *client, struct rtc_mem *mem)
+{
+ unsigned char buf[9];
+ int ret;
+
+ if (mem->loc < 8 || mem->nr > 8)
+ return -EINVAL;
+
+ buf[0] = mem->loc;
+ memcpy(buf + 1, mem->data, mem->nr);
+
+ ret = i2c_master_send(client, buf, mem->nr + 1);
+ return ret == mem->nr + 1 ? 0 : -EIO;
+}
+
+static int pcf8583_rtc_read_time(struct device *dev, struct rtc_time *tm)
+{
+ struct i2c_client *client = to_i2c_client(dev);
+ unsigned char ctrl, year[2];
+ struct rtc_mem mem = {
+ .loc = CMOS_YEAR,
+ .nr = sizeof(year),
+ .data = year
+ };
+ int real_year, year_offset, err;
+
+ /*
+ * Ensure that the RTC is running.
+ */
+ pcf8583_get_ctrl(client, &ctrl);
+ if (ctrl & (CTRL_STOP | CTRL_HOLD)) {
+ unsigned char new_ctrl = ctrl & ~(CTRL_STOP | CTRL_HOLD);
+
+ dev_warn(dev, "resetting control %02x -> %02x\n",
+ ctrl, new_ctrl);
+
+ err = pcf8583_set_ctrl(client, &new_ctrl);
+ if (err < 0)
+ return err;
+ }
+
+ if (pcf8583_get_datetime(client, tm) ||
+ pcf8583_read_mem(client, &mem))
+ return -EIO;
+
+ real_year = year[0];
+
+ /*
+ * The RTC year holds the LSB two bits of the current
+ * year, which should reflect the LSB two bits of the
+ * CMOS copy of the year. Any difference indicates
+ * that we have to correct the CMOS version.
+ */
+ year_offset = tm->tm_year - (real_year & 3);
+ if (year_offset < 0)
+ /*
+ * RTC year wrapped. Adjust it appropriately.
+ */
+ year_offset += 4;
+
+ tm->tm_year = (real_year + year_offset + year[1] * 100) - 1900;
+
+ return 0;
+}
+
+static int pcf8583_rtc_set_time(struct device *dev, struct rtc_time *tm)
+{
+ struct i2c_client *client = to_i2c_client(dev);
+ unsigned char year[2], chk;
+ struct rtc_mem cmos_year = {
+ .loc = CMOS_YEAR,
+ .nr = sizeof(year),
+ .data = year
+ };
+ struct rtc_mem cmos_check = {
+ .loc = CMOS_CHECKSUM,
+ .nr = 1,
+ .data = &chk
+ };
+ unsigned int proper_year = tm->tm_year + 1900;
+ int ret;
+
+ /*
+ * The RTC's own 2-bit year must reflect the least
+ * significant two bits of the CMOS year.
+ */
+
+ ret = pcf8583_set_datetime(client, tm, 1);
+ if (ret)
+ return ret;
+
+ ret = pcf8583_read_mem(client, &cmos_check);
+ if (ret)
+ return ret;
+
+ ret = pcf8583_read_mem(client, &cmos_year);
+ if (ret)
+ return ret;
+
+ chk -= year[1] + year[0];
+
+ year[1] = proper_year / 100;
+ year[0] = proper_year % 100;
+
+ chk += year[1] + year[0];
+
+ ret = pcf8583_write_mem(client, &cmos_year);
+
+ if (ret)
+ return ret;
+
+ ret = pcf8583_write_mem(client, &cmos_check);
+
+ return ret;
+}
+
+static const struct rtc_class_ops pcf8583_rtc_ops = {
+ .read_time = pcf8583_rtc_read_time,
+ .set_time = pcf8583_rtc_set_time,
+};
+
+static int pcf8583_probe(struct i2c_client *client)
+{
+ struct pcf8583 *pcf8583;
+
+ if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
+ return -ENODEV;
+
+ pcf8583 = devm_kzalloc(&client->dev, sizeof(struct pcf8583),
+ GFP_KERNEL);
+ if (!pcf8583)
+ return -ENOMEM;
+
+ i2c_set_clientdata(client, pcf8583);
+
+ pcf8583->rtc = devm_rtc_device_register(&client->dev,
+ pcf8583_driver.driver.name,
+ &pcf8583_rtc_ops, THIS_MODULE);
+
+ return PTR_ERR_OR_ZERO(pcf8583->rtc);
+}
+
+static const struct i2c_device_id pcf8583_id[] = {
+ { .name = "pcf8583" },
+ { }
+};
+MODULE_DEVICE_TABLE(i2c, pcf8583_id);
+
+static struct i2c_driver pcf8583_driver = {
+ .driver = {
+ .name = "pcf8583",
+ },
+ .probe = pcf8583_probe,
+ .id_table = pcf8583_id,
+};
+
+module_i2c_driver(pcf8583_driver);
+
+MODULE_AUTHOR("Russell King");
+MODULE_DESCRIPTION("PCF8583 I2C RTC driver");
+MODULE_LICENSE("GPL");