mirror of
https://github.com/torvalds/linux.git
synced 2024-11-14 16:12:02 +00:00
d2912cb15b
Based on 2 normalized pattern(s): this program is free software you can redistribute it and or modify it under the terms of the gnu general public license version 2 as published by the free software foundation this program is free software you can redistribute it and or modify it under the terms of the gnu general public license version 2 as published by the free software foundation # extracted by the scancode license scanner the SPDX license identifier GPL-2.0-only has been chosen to replace the boilerplate/reference in 4122 file(s). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Enrico Weigelt <info@metux.net> Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org> Reviewed-by: Allison Randal <allison@lohutok.net> Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190604081206.933168790@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
293 lines
7.6 KiB
C
293 lines
7.6 KiB
C
// 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;
|
|
struct resource *res;
|
|
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;
|
|
|
|
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
|
|
if (!res)
|
|
return -ENODEV;
|
|
info->index_reg = devm_ioremap_resource(&pdev->dev, res);
|
|
if (IS_ERR(info->index_reg))
|
|
return PTR_ERR(info->index_reg);
|
|
|
|
res = platform_get_resource(pdev, IORESOURCE_MEM, 1);
|
|
if (!res)
|
|
return -ENODEV;
|
|
info->data_reg = devm_ioremap_resource(&pdev->dev, res);
|
|
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;
|
|
info->rtc->nvram_old_abi = true;
|
|
|
|
err = rtc_register_device(info->rtc);
|
|
if (err)
|
|
return err;
|
|
|
|
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");
|