From 4352b8aee98005853aa63f57d6377282de17a33f Mon Sep 17 00:00:00 2001 From: Linus Torvalds Date: Sun, 23 Aug 2026 13:28:57 -0700 Subject: Merge tag 'i3c/for-7.3' of git://git.kernel.org/pub/scm/linux/kernel/git/i3c/linux 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 ... --- drivers/rtc/rtc-ds1302.c | 213 +++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 213 insertions(+) create mode 100644 drivers/rtc/rtc-ds1302.c (limited to 'drivers/rtc/rtc-ds1302.c') diff --git a/drivers/rtc/rtc-ds1302.c b/drivers/rtc/rtc-ds1302.c new file mode 100644 index 000000000..ecc7d0307 --- /dev/null +++ b/drivers/rtc/rtc-ds1302.c @@ -0,0 +1,213 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Dallas DS1302 RTC Support + * + * Copyright (C) 2002 David McCullough + * Copyright (C) 2003 - 2007 Paul Mundt + */ + +#include +#include +#include +#include +#include +#include +#include +#include + +#define RTC_CMD_READ 0x81 /* Read command */ +#define RTC_CMD_WRITE 0x80 /* Write command */ + +#define RTC_CMD_WRITE_ENABLE 0x00 /* Write enable */ +#define RTC_CMD_WRITE_DISABLE 0x80 /* Write disable */ + +#define RTC_ADDR_RAM0 0x20 /* Address of RAM0 */ +#define RTC_ADDR_TCR 0x08 /* Address of trickle charge register */ +#define RTC_CLCK_BURST 0x1F /* Address of clock burst */ +#define RTC_CLCK_LEN 0x08 /* Size of clock burst */ +#define RTC_ADDR_CTRL 0x07 /* Address of control register */ +#define RTC_ADDR_YEAR 0x06 /* Address of year register */ +#define RTC_ADDR_DAY 0x05 /* Address of day of week register */ +#define RTC_ADDR_MON 0x04 /* Address of month register */ +#define RTC_ADDR_DATE 0x03 /* Address of day of month register */ +#define RTC_ADDR_HOUR 0x02 /* Address of hour register */ +#define RTC_ADDR_MIN 0x01 /* Address of minute register */ +#define RTC_ADDR_SEC 0x00 /* Address of second register */ + +static int ds1302_rtc_set_time(struct device *dev, struct rtc_time *time) +{ + struct spi_device *spi = dev_get_drvdata(dev); + u8 buf[1 + RTC_CLCK_LEN]; + u8 *bp; + int status; + + /* Enable writing */ + bp = buf; + *bp++ = RTC_ADDR_CTRL << 1 | RTC_CMD_WRITE; + *bp++ = RTC_CMD_WRITE_ENABLE; + + status = spi_write_then_read(spi, buf, 2, + NULL, 0); + if (status) + return status; + + /* Write registers starting at the first time/date address. */ + bp = buf; + *bp++ = RTC_CLCK_BURST << 1 | RTC_CMD_WRITE; + + *bp++ = bin2bcd(time->tm_sec); + *bp++ = bin2bcd(time->tm_min); + *bp++ = bin2bcd(time->tm_hour); + *bp++ = bin2bcd(time->tm_mday); + *bp++ = bin2bcd(time->tm_mon + 1); + *bp++ = time->tm_wday + 1; + *bp++ = bin2bcd(time->tm_year % 100); + *bp++ = RTC_CMD_WRITE_DISABLE; + + /* use write-then-read since dma from stack is nonportable */ + return spi_write_then_read(spi, buf, sizeof(buf), + NULL, 0); +} + +static int ds1302_rtc_get_time(struct device *dev, struct rtc_time *time) +{ + struct spi_device *spi = dev_get_drvdata(dev); + u8 addr = RTC_CLCK_BURST << 1 | RTC_CMD_READ; + u8 buf[RTC_CLCK_LEN - 1]; + int status; + + /* Use write-then-read to get all the date/time registers + * since dma from stack is nonportable + */ + status = spi_write_then_read(spi, &addr, sizeof(addr), + buf, sizeof(buf)); + if (status < 0) + return status; + + /* Decode the registers */ + time->tm_sec = bcd2bin(buf[RTC_ADDR_SEC]); + time->tm_min = bcd2bin(buf[RTC_ADDR_MIN]); + time->tm_hour = bcd2bin(buf[RTC_ADDR_HOUR]); + time->tm_wday = buf[RTC_ADDR_DAY] - 1; + time->tm_mday = bcd2bin(buf[RTC_ADDR_DATE]); + time->tm_mon = bcd2bin(buf[RTC_ADDR_MON]) - 1; + time->tm_year = bcd2bin(buf[RTC_ADDR_YEAR]) + 100; + + return 0; +} + +static const struct rtc_class_ops ds1302_rtc_ops = { + .read_time = ds1302_rtc_get_time, + .set_time = ds1302_rtc_set_time, +}; + +static int ds1302_probe(struct spi_device *spi) +{ + struct rtc_device *rtc; + u8 addr; + u8 buf[4]; + u8 *bp; + int status; + + /* Sanity check board setup data. This may be hooked up + * in 3wire mode, but we don't care. Note that unless + * there's an inverter in place, this needs SPI_CS_HIGH! + */ + if (spi->bits_per_word && (spi->bits_per_word != 8)) { + dev_err(&spi->dev, "bad word length\n"); + return -EINVAL; + } else if (spi->max_speed_hz > 2000000) { + dev_err(&spi->dev, "speed is too high\n"); + return -EINVAL; + } else if (spi->mode & SPI_CPHA) { + dev_err(&spi->dev, "bad mode\n"); + return -EINVAL; + } + + addr = RTC_ADDR_CTRL << 1 | RTC_CMD_READ; + status = spi_write_then_read(spi, &addr, sizeof(addr), buf, 1); + if (status < 0) { + dev_err(&spi->dev, "control register read error %d\n", + status); + return status; + } + + if ((buf[0] & ~RTC_CMD_WRITE_DISABLE) != 0) { + status = spi_write_then_read(spi, &addr, sizeof(addr), buf, 1); + if (status < 0) { + dev_err(&spi->dev, "control register read error %d\n", + status); + return status; + } + + if ((buf[0] & ~RTC_CMD_WRITE_DISABLE) != 0) { + dev_err(&spi->dev, "junk in control register\n"); + return -ENODEV; + } + } + if (buf[0] == 0) { + bp = buf; + *bp++ = RTC_ADDR_CTRL << 1 | RTC_CMD_WRITE; + *bp++ = RTC_CMD_WRITE_DISABLE; + + status = spi_write_then_read(spi, buf, 2, NULL, 0); + if (status < 0) { + dev_err(&spi->dev, "control register write error %d\n", + status); + return status; + } + + addr = RTC_ADDR_CTRL << 1 | RTC_CMD_READ; + status = spi_write_then_read(spi, &addr, sizeof(addr), buf, 1); + if (status < 0) { + dev_err(&spi->dev, + "error %d reading control register\n", + status); + return status; + } + + if (buf[0] != RTC_CMD_WRITE_DISABLE) { + dev_err(&spi->dev, "failed to detect chip\n"); + return -ENODEV; + } + } + + spi_set_drvdata(spi, spi); + + rtc = devm_rtc_device_register(&spi->dev, "ds1302", + &ds1302_rtc_ops, THIS_MODULE); + if (IS_ERR(rtc)) { + status = PTR_ERR(rtc); + dev_err(&spi->dev, "error %d registering rtc\n", status); + return status; + } + + return 0; +} + +#ifdef CONFIG_OF +static const struct of_device_id ds1302_dt_ids[] = { + { .compatible = "maxim,ds1302", }, + { /* sentinel */ } +}; +MODULE_DEVICE_TABLE(of, ds1302_dt_ids); +#endif + +static const struct spi_device_id ds1302_spi_ids[] = { + { .name = "ds1302", }, + { /* sentinel */ } +}; +MODULE_DEVICE_TABLE(spi, ds1302_spi_ids); + +static struct spi_driver ds1302_driver = { + .driver.name = "rtc-ds1302", + .driver.of_match_table = of_match_ptr(ds1302_dt_ids), + .probe = ds1302_probe, + .id_table = ds1302_spi_ids, +}; + +module_spi_driver(ds1302_driver); + +MODULE_DESCRIPTION("Dallas DS1302 RTC driver"); +MODULE_AUTHOR("Paul Mundt, David McCullough"); +MODULE_LICENSE("GPL v2"); -- cgit v1.3.1