Adding upstream version 6.1.76.upstream/6.1.76upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 284 insertions, 0 deletions

diff --git a/drivers/rtc/rtc-m48t86.c b/drivers/rtc/rtc-m48t86.c
new file mode 100644
index 000000000..481c9525b
--- /dev/null
+++ b/drivers/rtc/rtc-m48t86.c
@@ -0,0 +1,284 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * ST M48T86 / Dallas DS12887 RTC driver
+ * Copyright (c) 2006 Tower Technologies
+ *
+ * Author: Alessandro Zummo <a.zummo@towertech.it>
+ *
+ * This drivers only supports the clock running in BCD and 24H mode.
+ * If it will be ever adapted to binary and 12H mode, care must be taken
+ * to not introduce bugs.
+ */
+
+#include <linux/module.h>
+#include <linux/rtc.h>
+#include <linux/platform_device.h>
+#include <linux/bcd.h>
+#include <linux/io.h>
+
+#define M48T86_SEC		0x00
+#define M48T86_SECALRM		0x01
+#define M48T86_MIN		0x02
+#define M48T86_MINALRM		0x03
+#define M48T86_HOUR		0x04
+#define M48T86_HOURALRM		0x05
+#define M48T86_DOW		0x06 /* 1 = sunday */
+#define M48T86_DOM		0x07
+#define M48T86_MONTH		0x08 /* 1 - 12 */
+#define M48T86_YEAR		0x09 /* 0 - 99 */
+#define M48T86_A		0x0a
+#define M48T86_B		0x0b
+#define M48T86_B_SET		BIT(7)
+#define M48T86_B_DM		BIT(2)
+#define M48T86_B_H24		BIT(1)
+#define M48T86_C		0x0c
+#define M48T86_D		0x0d
+#define M48T86_D_VRT		BIT(7)
+#define M48T86_NVRAM(x)		(0x0e + (x))
+#define M48T86_NVRAM_LEN	114
+
+struct m48t86_rtc_info {
+	void __iomem *index_reg;
+	void __iomem *data_reg;
+	struct rtc_device *rtc;
+};
+
+static unsigned char m48t86_readb(struct device *dev, unsigned long addr)
+{
+	struct m48t86_rtc_info *info = dev_get_drvdata(dev);
+	unsigned char value;
+
+	writeb(addr, info->index_reg);
+	value = readb(info->data_reg);
+
+	return value;
+}
+
+static void m48t86_writeb(struct device *dev,
+			  unsigned char value, unsigned long addr)
+{
+	struct m48t86_rtc_info *info = dev_get_drvdata(dev);
+
+	writeb(addr, info->index_reg);
+	writeb(value, info->data_reg);
+}
+
+static int m48t86_rtc_read_time(struct device *dev, struct rtc_time *tm)
+{
+	unsigned char reg;
+
+	reg = m48t86_readb(dev, M48T86_B);
+
+	if (reg & M48T86_B_DM) {
+		/* data (binary) mode */
+		tm->tm_sec	= m48t86_readb(dev, M48T86_SEC);
+		tm->tm_min	= m48t86_readb(dev, M48T86_MIN);
+		tm->tm_hour	= m48t86_readb(dev, M48T86_HOUR) & 0x3f;
+		tm->tm_mday	= m48t86_readb(dev, M48T86_DOM);
+		/* tm_mon is 0-11 */
+		tm->tm_mon	= m48t86_readb(dev, M48T86_MONTH) - 1;
+		tm->tm_year	= m48t86_readb(dev, M48T86_YEAR) + 100;
+		tm->tm_wday	= m48t86_readb(dev, M48T86_DOW);
+	} else {
+		/* bcd mode */
+		tm->tm_sec	= bcd2bin(m48t86_readb(dev, M48T86_SEC));
+		tm->tm_min	= bcd2bin(m48t86_readb(dev, M48T86_MIN));
+		tm->tm_hour	= bcd2bin(m48t86_readb(dev, M48T86_HOUR) &
+					  0x3f);
+		tm->tm_mday	= bcd2bin(m48t86_readb(dev, M48T86_DOM));
+		/* tm_mon is 0-11 */
+		tm->tm_mon	= bcd2bin(m48t86_readb(dev, M48T86_MONTH)) - 1;
+		tm->tm_year	= bcd2bin(m48t86_readb(dev, M48T86_YEAR)) + 100;
+		tm->tm_wday	= bcd2bin(m48t86_readb(dev, M48T86_DOW));
+	}
+
+	/* correct the hour if the clock is in 12h mode */
+	if (!(reg & M48T86_B_H24))
+		if (m48t86_readb(dev, M48T86_HOUR) & 0x80)
+			tm->tm_hour += 12;
+
+	return 0;
+}
+
+static int m48t86_rtc_set_time(struct device *dev, struct rtc_time *tm)
+{
+	unsigned char reg;
+
+	reg = m48t86_readb(dev, M48T86_B);
+
+	/* update flag and 24h mode */
+	reg |= M48T86_B_SET | M48T86_B_H24;
+	m48t86_writeb(dev, reg, M48T86_B);
+
+	if (reg & M48T86_B_DM) {
+		/* data (binary) mode */
+		m48t86_writeb(dev, tm->tm_sec, M48T86_SEC);
+		m48t86_writeb(dev, tm->tm_min, M48T86_MIN);
+		m48t86_writeb(dev, tm->tm_hour, M48T86_HOUR);
+		m48t86_writeb(dev, tm->tm_mday, M48T86_DOM);
+		m48t86_writeb(dev, tm->tm_mon + 1, M48T86_MONTH);
+		m48t86_writeb(dev, tm->tm_year % 100, M48T86_YEAR);
+		m48t86_writeb(dev, tm->tm_wday, M48T86_DOW);
+	} else {
+		/* bcd mode */
+		m48t86_writeb(dev, bin2bcd(tm->tm_sec), M48T86_SEC);
+		m48t86_writeb(dev, bin2bcd(tm->tm_min), M48T86_MIN);
+		m48t86_writeb(dev, bin2bcd(tm->tm_hour), M48T86_HOUR);
+		m48t86_writeb(dev, bin2bcd(tm->tm_mday), M48T86_DOM);
+		m48t86_writeb(dev, bin2bcd(tm->tm_mon + 1), M48T86_MONTH);
+		m48t86_writeb(dev, bin2bcd(tm->tm_year % 100), M48T86_YEAR);
+		m48t86_writeb(dev, bin2bcd(tm->tm_wday), M48T86_DOW);
+	}
+
+	/* update ended */
+	reg &= ~M48T86_B_SET;
+	m48t86_writeb(dev, reg, M48T86_B);
+
+	return 0;
+}
+
+static int m48t86_rtc_proc(struct device *dev, struct seq_file *seq)
+{
+	unsigned char reg;
+
+	reg = m48t86_readb(dev, M48T86_B);
+
+	seq_printf(seq, "mode\t\t: %s\n",
+		   (reg & M48T86_B_DM) ? "binary" : "bcd");
+
+	reg = m48t86_readb(dev, M48T86_D);
+
+	seq_printf(seq, "battery\t\t: %s\n",
+		   (reg & M48T86_D_VRT) ? "ok" : "exhausted");
+
+	return 0;
+}
+
+static const struct rtc_class_ops m48t86_rtc_ops = {
+	.read_time	= m48t86_rtc_read_time,
+	.set_time	= m48t86_rtc_set_time,
+	.proc		= m48t86_rtc_proc,
+};
+
+static int m48t86_nvram_read(void *priv, unsigned int off, void *buf,
+			     size_t count)
+{
+	struct device *dev = priv;
+	unsigned int i;
+
+	for (i = 0; i < count; i++)
+		((u8 *)buf)[i] = m48t86_readb(dev, M48T86_NVRAM(off + i));
+
+	return 0;
+}
+
+static int m48t86_nvram_write(void *priv, unsigned int off, void *buf,
+			      size_t count)
+{
+	struct device *dev = priv;
+	unsigned int i;
+
+	for (i = 0; i < count; i++)
+		m48t86_writeb(dev, ((u8 *)buf)[i], M48T86_NVRAM(off + i));
+
+	return 0;
+}
+
+/*
+ * The RTC is an optional feature at purchase time on some Technologic Systems
+ * boards. Verify that it actually exists by checking if the last two bytes
+ * of the NVRAM can be changed.
+ *
+ * This is based on the method used in their rtc7800.c example.
+ */
+static bool m48t86_verify_chip(struct platform_device *pdev)
+{
+	unsigned int offset0 = M48T86_NVRAM(M48T86_NVRAM_LEN - 2);
+	unsigned int offset1 = M48T86_NVRAM(M48T86_NVRAM_LEN - 1);
+	unsigned char tmp0, tmp1;
+
+	tmp0 = m48t86_readb(&pdev->dev, offset0);
+	tmp1 = m48t86_readb(&pdev->dev, offset1);
+
+	m48t86_writeb(&pdev->dev, 0x00, offset0);
+	m48t86_writeb(&pdev->dev, 0x55, offset1);
+	if (m48t86_readb(&pdev->dev, offset1) == 0x55) {
+		m48t86_writeb(&pdev->dev, 0xaa, offset1);
+		if (m48t86_readb(&pdev->dev, offset1) == 0xaa &&
+		    m48t86_readb(&pdev->dev, offset0) == 0x00) {
+			m48t86_writeb(&pdev->dev, tmp0, offset0);
+			m48t86_writeb(&pdev->dev, tmp1, offset1);
+
+			return true;
+		}
+	}
+	return false;
+}
+
+static int m48t86_rtc_probe(struct platform_device *pdev)
+{
+	struct m48t86_rtc_info *info;
+	unsigned char reg;
+	int err;
+	struct nvmem_config m48t86_nvmem_cfg = {
+		.name = "m48t86_nvram",
+		.word_size = 1,
+		.stride = 1,
+		.size = M48T86_NVRAM_LEN,
+		.reg_read = m48t86_nvram_read,
+		.reg_write = m48t86_nvram_write,
+		.priv = &pdev->dev,
+	};
+
+	info = devm_kzalloc(&pdev->dev, sizeof(*info), GFP_KERNEL);
+	if (!info)
+		return -ENOMEM;
+
+	info->index_reg = devm_platform_ioremap_resource(pdev, 0);
+	if (IS_ERR(info->index_reg))
+		return PTR_ERR(info->index_reg);
+
+	info->data_reg = devm_platform_ioremap_resource(pdev, 1);
+	if (IS_ERR(info->data_reg))
+		return PTR_ERR(info->data_reg);
+
+	dev_set_drvdata(&pdev->dev, info);
+
+	if (!m48t86_verify_chip(pdev)) {
+		dev_info(&pdev->dev, "RTC not present\n");
+		return -ENODEV;
+	}
+
+	info->rtc = devm_rtc_allocate_device(&pdev->dev);
+	if (IS_ERR(info->rtc))
+		return PTR_ERR(info->rtc);
+
+	info->rtc->ops = &m48t86_rtc_ops;
+
+	err = devm_rtc_register_device(info->rtc);
+	if (err)
+		return err;
+
+	devm_rtc_nvmem_register(info->rtc, &m48t86_nvmem_cfg);
+
+	/* read battery status */
+	reg = m48t86_readb(&pdev->dev, M48T86_D);
+	dev_info(&pdev->dev, "battery %s\n",
+		 (reg & M48T86_D_VRT) ? "ok" : "exhausted");
+
+	return 0;
+}
+
+static struct platform_driver m48t86_rtc_platform_driver = {
+	.driver		= {
+		.name	= "rtc-m48t86",
+	},
+	.probe		= m48t86_rtc_probe,
+};
+
+module_platform_driver(m48t86_rtc_platform_driver);
+
+MODULE_AUTHOR("Alessandro Zummo <a.zummo@towertech.it>");
+MODULE_DESCRIPTION("M48T86 RTC driver");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:rtc-m48t86");