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kernel/drivers/rtc/rtc-rx8581.c
Biju Das 51f896ffd1 rtc: rx8581: Add support for Epson rx8571 RTC 
Add support for Epson rx8571 real-time clock. rx8571 rtc is compatible
with rx8581,except that rx8571 has additional 16 bytes of RAM.

16 bytes of nvmem is supported and exposed in sysfs (# is the instance
number,starting with 0): /sys/bus/nvmem/devices/rx8571-#/nvmem

Signed-off-by: Biju Das <biju.das@bp.renesas.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
2019-03-02 22:20:58 +01:00

340 lines
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/*
* An I2C driver for the Epson RX8581 RTC
*
* Author: Martyn Welch <martyn.welch@ge.com>
* Copyright 2008 GE Intelligent Platforms Embedded Systems, Inc.
*
* 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.
*
* Based on: rtc-pcf8563.c (An I2C driver for the Philips PCF8563 RTC)
* Copyright 2005-06 Tower Technologies
*/
#include <linux/module.h>
#include <linux/i2c.h>
#include <linux/bcd.h>
#include <linux/of.h>
#include <linux/of_device.h>
#include <linux/regmap.h>
#include <linux/rtc.h>
#include <linux/log2.h>
#define RX8581_REG_SC 0x00 /* Second in BCD */
#define RX8581_REG_MN 0x01 /* Minute in BCD */
#define RX8581_REG_HR 0x02 /* Hour in BCD */
#define RX8581_REG_DW 0x03 /* Day of Week */
#define RX8581_REG_DM 0x04 /* Day of Month in BCD */
#define RX8581_REG_MO 0x05 /* Month in BCD */
#define RX8581_REG_YR 0x06 /* Year in BCD */
#define RX8581_REG_RAM 0x07 /* RAM */
#define RX8581_REG_AMN 0x08 /* Alarm Min in BCD*/
#define RX8581_REG_AHR 0x09 /* Alarm Hour in BCD */
#define RX8581_REG_ADM 0x0A
#define RX8581_REG_ADW 0x0A
#define RX8581_REG_TMR0 0x0B
#define RX8581_REG_TMR1 0x0C
#define RX8581_REG_EXT 0x0D /* Extension Register */
#define RX8581_REG_FLAG 0x0E /* Flag Register */
#define RX8581_REG_CTRL 0x0F /* Control Register */
/* Flag Register bit definitions */
#define RX8581_FLAG_UF 0x20 /* Update */
#define RX8581_FLAG_TF 0x10 /* Timer */
#define RX8581_FLAG_AF 0x08 /* Alarm */
#define RX8581_FLAG_VLF 0x02 /* Voltage Low */
/* Control Register bit definitions */
#define RX8581_CTRL_UIE 0x20 /* Update Interrupt Enable */
#define RX8581_CTRL_TIE 0x10 /* Timer Interrupt Enable */
#define RX8581_CTRL_AIE 0x08 /* Alarm Interrupt Enable */
#define RX8581_CTRL_STOP 0x02 /* STOP bit */
#define RX8581_CTRL_RESET 0x01 /* RESET bit */
#define RX8571_USER_RAM 0x10
#define RX8571_NVRAM_SIZE 0x10
struct rx8581 {
struct regmap *regmap;
struct rtc_device *rtc;
};
struct rx85x1_config {
struct regmap_config regmap;
unsigned int num_nvram;
};
/*
* In the routines that deal directly with the rx8581 hardware, we use
* rtc_time -- month 0-11, hour 0-23, yr = calendar year-epoch.
*/
static int rx8581_rtc_read_time(struct device *dev, struct rtc_time *tm)
{
struct i2c_client *client = to_i2c_client(dev);
unsigned char date[7];
unsigned int data;
int err;
struct rx8581 *rx8581 = i2c_get_clientdata(client);
/* First we ensure that the "update flag" is not set, we read the
* time and date then re-read the "update flag". If the update flag
* has been set, we know that the time has changed during the read so
* we repeat the whole process again.
*/
err = regmap_read(rx8581->regmap, RX8581_REG_FLAG, &data);
if (err < 0)
return err;
if (data & RX8581_FLAG_VLF) {
dev_warn(dev,
"low voltage detected, date/time is not reliable.\n");
return -EINVAL;
}
do {
/* If update flag set, clear it */
if (data & RX8581_FLAG_UF) {
err = regmap_write(rx8581->regmap, RX8581_REG_FLAG,
data & ~RX8581_FLAG_UF);
if (err < 0)
return err;
}
/* Now read time and date */
err = regmap_bulk_read(rx8581->regmap, RX8581_REG_SC, date,
sizeof(date));
if (err < 0)
return err;
/* Check flag register */
err = regmap_read(rx8581->regmap, RX8581_REG_FLAG, &data);
if (err < 0)
return err;
} while (data & RX8581_FLAG_UF);
dev_dbg(dev, "%s: raw data is sec=%02x, min=%02x, hr=%02x, "
"wday=%02x, mday=%02x, mon=%02x, year=%02x\n",
__func__,
date[0], date[1], date[2], date[3], date[4], date[5], date[6]);
tm->tm_sec = bcd2bin(date[RX8581_REG_SC] & 0x7F);
tm->tm_min = bcd2bin(date[RX8581_REG_MN] & 0x7F);
tm->tm_hour = bcd2bin(date[RX8581_REG_HR] & 0x3F); /* rtc hr 0-23 */
tm->tm_wday = ilog2(date[RX8581_REG_DW] & 0x7F);
tm->tm_mday = bcd2bin(date[RX8581_REG_DM] & 0x3F);
tm->tm_mon = bcd2bin(date[RX8581_REG_MO] & 0x1F) - 1; /* rtc mn 1-12 */
tm->tm_year = bcd2bin(date[RX8581_REG_YR]) + 100;
dev_dbg(dev, "%s: tm is secs=%d, mins=%d, hours=%d, "
"mday=%d, mon=%d, year=%d, wday=%d\n",
__func__,
tm->tm_sec, tm->tm_min, tm->tm_hour,
tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);
return 0;
}
static int rx8581_rtc_set_time(struct device *dev, struct rtc_time *tm)
{
struct i2c_client *client = to_i2c_client(dev);
int err;
unsigned char buf[7];
struct rx8581 *rx8581 = i2c_get_clientdata(client);
dev_dbg(dev, "%s: secs=%d, mins=%d, hours=%d, "
"mday=%d, mon=%d, year=%d, wday=%d\n",
__func__,
tm->tm_sec, tm->tm_min, tm->tm_hour,
tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);
/* hours, minutes and seconds */
buf[RX8581_REG_SC] = bin2bcd(tm->tm_sec);
buf[RX8581_REG_MN] = bin2bcd(tm->tm_min);
buf[RX8581_REG_HR] = bin2bcd(tm->tm_hour);
buf[RX8581_REG_DM] = bin2bcd(tm->tm_mday);
/* month, 1 - 12 */
buf[RX8581_REG_MO] = bin2bcd(tm->tm_mon + 1);
/* year and century */
buf[RX8581_REG_YR] = bin2bcd(tm->tm_year - 100);
buf[RX8581_REG_DW] = (0x1 << tm->tm_wday);
/* Stop the clock */
err = regmap_update_bits(rx8581->regmap, RX8581_REG_CTRL,
RX8581_CTRL_STOP, RX8581_CTRL_STOP);
if (err < 0)
return err;
/* write register's data */
err = regmap_bulk_write(rx8581->regmap, RX8581_REG_SC,
buf, sizeof(buf));
if (err < 0)
return err;
/* get VLF and clear it */
err = regmap_update_bits(rx8581->regmap, RX8581_REG_FLAG,
RX8581_FLAG_VLF, 0);
if (err < 0)
return err;
/* Restart the clock */
return regmap_update_bits(rx8581->regmap, RX8581_REG_CTRL,
RX8581_CTRL_STOP, 0);
}
static const struct rtc_class_ops rx8581_rtc_ops = {
.read_time = rx8581_rtc_read_time,
.set_time = rx8581_rtc_set_time,
};
static int rx8571_nvram_read(void *priv, unsigned int offset, void *val,
size_t bytes)
{
struct rx8581 *rx8581 = priv;
return regmap_bulk_read(rx8581->regmap, RX8571_USER_RAM + offset,
val, bytes);
}
static int rx8571_nvram_write(void *priv, unsigned int offset, void *val,
size_t bytes)
{
struct rx8581 *rx8581 = priv;
return regmap_bulk_write(rx8581->regmap, RX8571_USER_RAM + offset,
val, bytes);
}
static int rx85x1_nvram_read(void *priv, unsigned int offset, void *val,
size_t bytes)
{
struct rx8581 *rx8581 = priv;
unsigned int tmp_val;
int ret;
ret = regmap_read(rx8581->regmap, RX8581_REG_RAM, &tmp_val);
(*(unsigned char *)val) = (unsigned char) tmp_val;
return ret;
}
static int rx85x1_nvram_write(void *priv, unsigned int offset, void *val,
size_t bytes)
{
struct rx8581 *rx8581 = priv;
unsigned char tmp_val;
tmp_val = *((unsigned char *)val);
return regmap_write(rx8581->regmap, RX8581_REG_RAM,
(unsigned int)tmp_val);
}
static const struct rx85x1_config rx8581_config = {
.regmap = {
.reg_bits = 8,
.val_bits = 8,
.max_register = 0xf,
},
.num_nvram = 1
};
static const struct rx85x1_config rx8571_config = {
.regmap = {
.reg_bits = 8,
.val_bits = 8,
.max_register = 0x1f,
},
.num_nvram = 2
};
static int rx8581_probe(struct i2c_client *client,
const struct i2c_device_id *id)
{
struct rx8581 *rx8581;
const struct rx85x1_config *config = &rx8581_config;
const void *data = of_device_get_match_data(&client->dev);
static struct nvmem_config nvmem_cfg[] = {
{
.name = "rx85x1-",
.word_size = 1,
.stride = 1,
.size = 1,
.reg_read = rx85x1_nvram_read,
.reg_write = rx85x1_nvram_write,
}, {
.name = "rx8571-",
.word_size = 1,
.stride = 1,
.size = RX8571_NVRAM_SIZE,
.reg_read = rx8571_nvram_read,
.reg_write = rx8571_nvram_write,
},
};
int ret, i;
dev_dbg(&client->dev, "%s\n", __func__);
if (data)
config = data;
rx8581 = devm_kzalloc(&client->dev, sizeof(struct rx8581), GFP_KERNEL);
if (!rx8581)
return -ENOMEM;
i2c_set_clientdata(client, rx8581);
rx8581->regmap = devm_regmap_init_i2c(client, &config->regmap);
if (IS_ERR(rx8581->regmap))
return PTR_ERR(rx8581->regmap);
rx8581->rtc = devm_rtc_allocate_device(&client->dev);
if (IS_ERR(rx8581->rtc))
return PTR_ERR(rx8581->rtc);
rx8581->rtc->ops = &rx8581_rtc_ops;
rx8581->rtc->range_min = RTC_TIMESTAMP_BEGIN_2000;
rx8581->rtc->range_max = RTC_TIMESTAMP_END_2099;
rx8581->rtc->start_secs = 0;
rx8581->rtc->set_start_time = true;
ret = rtc_register_device(rx8581->rtc);
for (i = 0; i < config->num_nvram; i++) {
nvmem_cfg[i].priv = rx8581;
rtc_nvmem_register(rx8581->rtc, &nvmem_cfg[i]);
}
return ret;
}
static const struct i2c_device_id rx8581_id[] = {
{ "rx8581", 0 },
{ }
};
MODULE_DEVICE_TABLE(i2c, rx8581_id);
static const struct of_device_id rx8581_of_match[] = {
{ .compatible = "epson,rx8571", .data = &rx8571_config },
{ .compatible = "epson,rx8581", .data = &rx8581_config },
{ /* sentinel */ }
};
MODULE_DEVICE_TABLE(of, rx8581_of_match);
static struct i2c_driver rx8581_driver = {
.driver = {
.name = "rtc-rx8581",
.of_match_table = of_match_ptr(rx8581_of_match),
},
.probe = rx8581_probe,
.id_table = rx8581_id,
};
module_i2c_driver(rx8581_driver);
MODULE_AUTHOR("Martyn Welch <martyn.welch@ge.com>");
MODULE_DESCRIPTION("Epson RX-8571/RX-8581 RTC driver");
MODULE_LICENSE("GPL");
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