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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-max6902.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-max6902.c')
| -rw-r--r-- | drivers/rtc/rtc-max6902.c | 154 |
1 files changed, 154 insertions, 0 deletions
diff --git a/drivers/rtc/rtc-max6902.c b/drivers/rtc/rtc-max6902.c new file mode 100644 index 000000000..daaeb6fb6 --- /dev/null +++ b/drivers/rtc/rtc-max6902.c @@ -0,0 +1,154 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* drivers/rtc/rtc-max6902.c + * + * Copyright (C) 2006 8D Technologies inc. + * Copyright (C) 2004 Compulab Ltd. + * + * Driver for MAX6902 spi RTC + */ + +#include <linux/module.h> +#include <linux/kernel.h> +#include <linux/platform_device.h> +#include <linux/init.h> +#include <linux/rtc.h> +#include <linux/spi/spi.h> +#include <linux/bcd.h> + +#define MAX6902_REG_SECONDS 0x01 +#define MAX6902_REG_MINUTES 0x03 +#define MAX6902_REG_HOURS 0x05 +#define MAX6902_REG_DATE 0x07 +#define MAX6902_REG_MONTH 0x09 +#define MAX6902_REG_DAY 0x0B +#define MAX6902_REG_YEAR 0x0D +#define MAX6902_REG_CONTROL 0x0F +#define MAX6902_REG_CENTURY 0x13 + +static int max6902_set_reg(struct device *dev, unsigned char address, + unsigned char data) +{ + struct spi_device *spi = to_spi_device(dev); + unsigned char buf[2]; + + /* MSB must be '0' to write */ + buf[0] = address & 0x7f; + buf[1] = data; + + return spi_write_then_read(spi, buf, 2, NULL, 0); +} + +static int max6902_get_reg(struct device *dev, unsigned char address, + unsigned char *data) +{ + struct spi_device *spi = to_spi_device(dev); + + /* Set MSB to indicate read */ + *data = address | 0x80; + + return spi_write_then_read(spi, data, 1, data, 1); +} + +static int max6902_read_time(struct device *dev, struct rtc_time *dt) +{ + int err, century; + struct spi_device *spi = to_spi_device(dev); + unsigned char buf[8]; + + buf[0] = 0xbf; /* Burst read */ + + err = spi_write_then_read(spi, buf, 1, buf, 8); + if (err != 0) + return err; + + /* The chip sends data in this order: + * Seconds, Minutes, Hours, Date, Month, Day, Year */ + dt->tm_sec = bcd2bin(buf[0]); + dt->tm_min = bcd2bin(buf[1]); + dt->tm_hour = bcd2bin(buf[2]); + dt->tm_mday = bcd2bin(buf[3]); + dt->tm_mon = bcd2bin(buf[4]) - 1; + dt->tm_wday = bcd2bin(buf[5]); + dt->tm_year = bcd2bin(buf[6]); + + /* Read century */ + err = max6902_get_reg(dev, MAX6902_REG_CENTURY, &buf[0]); + if (err != 0) + return err; + + century = bcd2bin(buf[0]) * 100; + + dt->tm_year += century; + dt->tm_year -= 1900; + + return 0; +} + +static int max6902_set_time(struct device *dev, struct rtc_time *dt) +{ + dt->tm_year = dt->tm_year + 1900; + + /* Remove write protection */ + max6902_set_reg(dev, MAX6902_REG_CONTROL, 0); + + max6902_set_reg(dev, MAX6902_REG_SECONDS, bin2bcd(dt->tm_sec)); + max6902_set_reg(dev, MAX6902_REG_MINUTES, bin2bcd(dt->tm_min)); + max6902_set_reg(dev, MAX6902_REG_HOURS, bin2bcd(dt->tm_hour)); + + max6902_set_reg(dev, MAX6902_REG_DATE, bin2bcd(dt->tm_mday)); + max6902_set_reg(dev, MAX6902_REG_MONTH, bin2bcd(dt->tm_mon + 1)); + max6902_set_reg(dev, MAX6902_REG_DAY, bin2bcd(dt->tm_wday)); + max6902_set_reg(dev, MAX6902_REG_YEAR, bin2bcd(dt->tm_year % 100)); + max6902_set_reg(dev, MAX6902_REG_CENTURY, bin2bcd(dt->tm_year / 100)); + + /* Compulab used a delay here. However, the datasheet + * does not mention a delay being required anywhere... */ + /* delay(2000); */ + + /* Write protect */ + max6902_set_reg(dev, MAX6902_REG_CONTROL, 0x80); + + return 0; +} + +static const struct rtc_class_ops max6902_rtc_ops = { + .read_time = max6902_read_time, + .set_time = max6902_set_time, +}; + +static int max6902_probe(struct spi_device *spi) +{ + struct rtc_device *rtc; + unsigned char tmp; + int res; + + spi->mode = SPI_MODE_3; + spi->bits_per_word = 8; + spi_setup(spi); + + res = max6902_get_reg(&spi->dev, MAX6902_REG_SECONDS, &tmp); + if (res != 0) + return res; + + rtc = devm_rtc_device_register(&spi->dev, "max6902", + &max6902_rtc_ops, THIS_MODULE); + if (IS_ERR(rtc)) + return PTR_ERR(rtc); + + spi_set_drvdata(spi, rtc); + return 0; +} + +static struct spi_driver max6902_driver = { + .driver = { + .name = "rtc-max6902", + }, + .probe = max6902_probe, +}; + +module_spi_driver(max6902_driver); + +MODULE_DESCRIPTION("max6902 spi RTC driver"); +MODULE_AUTHOR("Raphael Assenat"); +MODULE_LICENSE("GPL"); +MODULE_ALIAS("spi:rtc-max6902"); |
