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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-ds1742.c
downloadlinux-stable-f4cdf7ca9a1fdcca413157df19753f388a5a224e.tar.gz
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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-ds1742.c')
-rw-r--r--drivers/rtc/rtc-ds1742.c220
1 files changed, 220 insertions, 0 deletions
diff --git a/drivers/rtc/rtc-ds1742.c b/drivers/rtc/rtc-ds1742.c
new file mode 100644
index 000000000..6ae8b9a29
--- /dev/null
+++ b/drivers/rtc/rtc-ds1742.c
@@ -0,0 +1,220 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * An rtc driver for the Dallas DS1742
+ *
+ * Copyright (C) 2006 Atsushi Nemoto <anemo@mba.ocn.ne.jp>
+ *
+ * Copyright (C) 2006 Torsten Ertbjerg Rasmussen <tr@newtec.dk>
+ * - nvram size determined from resource
+ * - this ds1742 driver now supports ds1743.
+ */
+
+#include <linux/bcd.h>
+#include <linux/kernel.h>
+#include <linux/gfp.h>
+#include <linux/delay.h>
+#include <linux/jiffies.h>
+#include <linux/rtc.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/io.h>
+#include <linux/module.h>
+
+#define RTC_SIZE 8
+
+#define RTC_CONTROL 0
+#define RTC_CENTURY 0
+#define RTC_SECONDS 1
+#define RTC_MINUTES 2
+#define RTC_HOURS 3
+#define RTC_DAY 4
+#define RTC_DATE 5
+#define RTC_MONTH 6
+#define RTC_YEAR 7
+
+#define RTC_CENTURY_MASK 0x3f
+#define RTC_SECONDS_MASK 0x7f
+#define RTC_DAY_MASK 0x07
+
+/* Bits in the Control/Century register */
+#define RTC_WRITE 0x80
+#define RTC_READ 0x40
+
+/* Bits in the Seconds register */
+#define RTC_STOP 0x80
+
+/* Bits in the Day register */
+#define RTC_BATT_FLAG 0x80
+
+struct rtc_plat_data {
+ void __iomem *ioaddr_nvram;
+ void __iomem *ioaddr_rtc;
+ unsigned long last_jiffies;
+};
+
+static int ds1742_rtc_set_time(struct device *dev, struct rtc_time *tm)
+{
+ struct rtc_plat_data *pdata = dev_get_drvdata(dev);
+ void __iomem *ioaddr = pdata->ioaddr_rtc;
+ u8 century;
+
+ century = bin2bcd((tm->tm_year + 1900) / 100);
+
+ writeb(RTC_WRITE, ioaddr + RTC_CONTROL);
+
+ writeb(bin2bcd(tm->tm_year % 100), ioaddr + RTC_YEAR);
+ writeb(bin2bcd(tm->tm_mon + 1), ioaddr + RTC_MONTH);
+ writeb(bin2bcd(tm->tm_wday) & RTC_DAY_MASK, ioaddr + RTC_DAY);
+ writeb(bin2bcd(tm->tm_mday), ioaddr + RTC_DATE);
+ writeb(bin2bcd(tm->tm_hour), ioaddr + RTC_HOURS);
+ writeb(bin2bcd(tm->tm_min), ioaddr + RTC_MINUTES);
+ writeb(bin2bcd(tm->tm_sec) & RTC_SECONDS_MASK, ioaddr + RTC_SECONDS);
+
+ /* RTC_CENTURY and RTC_CONTROL share same register */
+ writeb(RTC_WRITE | (century & RTC_CENTURY_MASK), ioaddr + RTC_CENTURY);
+ writeb(century & RTC_CENTURY_MASK, ioaddr + RTC_CONTROL);
+ return 0;
+}
+
+static int ds1742_rtc_read_time(struct device *dev, struct rtc_time *tm)
+{
+ struct rtc_plat_data *pdata = dev_get_drvdata(dev);
+ void __iomem *ioaddr = pdata->ioaddr_rtc;
+ unsigned int year, month, day, hour, minute, second, week;
+ unsigned int century;
+
+ /* give enough time to update RTC in case of continuous read */
+ if (pdata->last_jiffies == jiffies)
+ msleep(1);
+ pdata->last_jiffies = jiffies;
+ writeb(RTC_READ, ioaddr + RTC_CONTROL);
+ second = readb(ioaddr + RTC_SECONDS) & RTC_SECONDS_MASK;
+ minute = readb(ioaddr + RTC_MINUTES);
+ hour = readb(ioaddr + RTC_HOURS);
+ day = readb(ioaddr + RTC_DATE);
+ week = readb(ioaddr + RTC_DAY) & RTC_DAY_MASK;
+ month = readb(ioaddr + RTC_MONTH);
+ year = readb(ioaddr + RTC_YEAR);
+ century = readb(ioaddr + RTC_CENTURY) & RTC_CENTURY_MASK;
+ writeb(0, ioaddr + RTC_CONTROL);
+ tm->tm_sec = bcd2bin(second);
+ tm->tm_min = bcd2bin(minute);
+ tm->tm_hour = bcd2bin(hour);
+ tm->tm_mday = bcd2bin(day);
+ tm->tm_wday = bcd2bin(week);
+ tm->tm_mon = bcd2bin(month) - 1;
+ /* year is 1900 + tm->tm_year */
+ tm->tm_year = bcd2bin(year) + bcd2bin(century) * 100 - 1900;
+
+ return 0;
+}
+
+static const struct rtc_class_ops ds1742_rtc_ops = {
+ .read_time = ds1742_rtc_read_time,
+ .set_time = ds1742_rtc_set_time,
+};
+
+static int ds1742_nvram_read(void *priv, unsigned int pos, void *val,
+ size_t bytes)
+{
+ struct rtc_plat_data *pdata = priv;
+ void __iomem *ioaddr = pdata->ioaddr_nvram;
+ u8 *buf = val;
+
+ for (; bytes; bytes--)
+ *buf++ = readb(ioaddr + pos++);
+ return 0;
+}
+
+static int ds1742_nvram_write(void *priv, unsigned int pos, void *val,
+ size_t bytes)
+{
+ struct rtc_plat_data *pdata = priv;
+ void __iomem *ioaddr = pdata->ioaddr_nvram;
+ u8 *buf = val;
+
+ for (; bytes; bytes--)
+ writeb(*buf++, ioaddr + pos++);
+ return 0;
+}
+
+static int ds1742_rtc_probe(struct platform_device *pdev)
+{
+ struct rtc_device *rtc;
+ struct resource *res;
+ unsigned int cen, sec;
+ struct rtc_plat_data *pdata;
+ void __iomem *ioaddr;
+ int ret = 0;
+ struct nvmem_config nvmem_cfg = {
+ .name = "ds1742_nvram",
+ .reg_read = ds1742_nvram_read,
+ .reg_write = ds1742_nvram_write,
+ };
+
+
+ pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);
+ if (!pdata)
+ return -ENOMEM;
+
+ ioaddr = devm_platform_get_and_ioremap_resource(pdev, 0, &res);
+ if (IS_ERR(ioaddr))
+ return PTR_ERR(ioaddr);
+
+ pdata->ioaddr_nvram = ioaddr;
+ pdata->ioaddr_rtc = ioaddr + resource_size(res) - RTC_SIZE;
+
+ nvmem_cfg.size = resource_size(res) - RTC_SIZE;
+ nvmem_cfg.priv = pdata;
+
+ /* turn RTC on if it was not on */
+ ioaddr = pdata->ioaddr_rtc;
+ sec = readb(ioaddr + RTC_SECONDS);
+ if (sec & RTC_STOP) {
+ sec &= RTC_SECONDS_MASK;
+ cen = readb(ioaddr + RTC_CENTURY) & RTC_CENTURY_MASK;
+ writeb(RTC_WRITE, ioaddr + RTC_CONTROL);
+ writeb(sec, ioaddr + RTC_SECONDS);
+ writeb(cen & RTC_CENTURY_MASK, ioaddr + RTC_CONTROL);
+ }
+ if (!(readb(ioaddr + RTC_DAY) & RTC_BATT_FLAG))
+ dev_warn(&pdev->dev, "voltage-low detected.\n");
+
+ pdata->last_jiffies = jiffies;
+ platform_set_drvdata(pdev, pdata);
+
+ rtc = devm_rtc_allocate_device(&pdev->dev);
+ if (IS_ERR(rtc))
+ return PTR_ERR(rtc);
+
+ rtc->ops = &ds1742_rtc_ops;
+
+ ret = devm_rtc_register_device(rtc);
+ if (ret)
+ return ret;
+
+ devm_rtc_nvmem_register(rtc, &nvmem_cfg);
+
+ return 0;
+}
+
+static const struct of_device_id __maybe_unused ds1742_rtc_of_match[] = {
+ { .compatible = "maxim,ds1742", },
+ { }
+};
+MODULE_DEVICE_TABLE(of, ds1742_rtc_of_match);
+
+static struct platform_driver ds1742_rtc_driver = {
+ .probe = ds1742_rtc_probe,
+ .driver = {
+ .name = "rtc-ds1742",
+ .of_match_table = of_match_ptr(ds1742_rtc_of_match),
+ },
+};
+
+module_platform_driver(ds1742_rtc_driver);
+
+MODULE_AUTHOR("Atsushi Nemoto <anemo@mba.ocn.ne.jp>");
+MODULE_DESCRIPTION("Dallas DS1742 RTC driver");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:rtc-ds1742");