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| author | Linus Torvalds <torvalds@linux-foundation.org> | 2026-08-19 10:09:22 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2026-08-19 10:09:22 -0700 |
| commit | f4cdf7ca9a1fdcca413157df19753f388a5a224e (patch) | |
| tree | 60a31895b2446cd7fa27514e8c2843534a0de0da /drivers/rtc/rtc-ds1302.c | |
| download | linux-stable-f4cdf7ca9a1fdcca413157df19753f388a5a224e.tar.gz linux-stable-f4cdf7ca9a1fdcca413157df19753f388a5a224e.zip | |
Merge tag 'media/v7.3-1' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-mediagrafted
Pull media updates from Mauro Carvalho Chehab:
- v4l2-core: added ISP statistics support and per-block validation
- v4l2-core: Allow unknown HDR10 white point and luminance
- New camera sensors: Sony IMX678 and IMX471m, Himax HM1092 IR sensor
- New codec: Milos: VPU v2.0 codec support
- isp driver: gained support for Dreamchip RPPX1 ISP framework
- vsp1 driver: gained support for RZ/T2H and RZ/N2H
- Novalake driver: gained CVS support for new NVL hardware
- dvb-core: fix feed leak on failed DMX_ADD_PID
- several driver fixes, cleanups and minor improvements
* tag 'media/v7.3-1' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-media: (308 commits)
media: ipu-bridge: check all DMI entries when overriding sensor rotation
media: v4l2-async: avoid deleting unlinked ASC entry on link error
media: rzg2l-cru: Align bytesperline to hardware DMA stride requirement
media: intel/ipu6: fix async notifier cleanup leak on parse error
media: staging/ipu7: fix async notifier UAF on probe error path
media: amd: isp4: fix self-deadlock in isp4sd_pwron_and_init() error path
media: amd: isp4: release partial allocations in isp4if_alloc_fw_gpumem()
media: rcar-isp: Fix VSPX reference leaks
media: rcar-isp: Release ISPCORE resources
media: i2c: imx415: Release runtime PM reference on VBLANK error
media: i2c: imx415: Return test pattern write errors
media: renesas: vsp1: Declare index variables in for loop statement
media: renesas: vsp1: Make reset control optional to support platforms without a reset line
media: dt-bindings: media: renesas,vsp1: Document RZ/T2H and RZ/N2H SoCs
media: dt-bindings: media: renesas,fcp: Document RZ/T2H and RZ/N2H SoCs
media: nxp: imx8-isi: Add additional 32-bit RGB format support
media: nxp: imx8-isi: Add 16-bit raw Bayer format support
media: nxp: imx8-isi: Implement per-stream reference counting for multiplexed streams
media: nxp: imx8-isi: Use BIT_ULL() for 64-bit stream masks
media: nxp: imx8-isi: Correct color map between V4L2 and ISI
...
Diffstat (limited to 'drivers/rtc/rtc-ds1302.c')
| -rw-r--r-- | drivers/rtc/rtc-ds1302.c | 213 |
1 files changed, 213 insertions, 0 deletions
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 <linux/bcd.h> +#include <linux/init.h> +#include <linux/io.h> +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/of.h> +#include <linux/rtc.h> +#include <linux/spi/spi.h> + +#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"); |
