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authorLinus Torvalds <torvalds@linux-foundation.org>2026-08-19 10:09:22 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2026-08-19 10:09:22 -0700
commitf4cdf7ca9a1fdcca413157df19753f388a5a224e (patch)
tree60a31895b2446cd7fa27514e8c2843534a0de0da /drivers/rtc/rtc-max6902.c
downloadlinux-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.c154
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");