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linux/drivers/rtc/rtc-rx6110.c

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// SPDX-License-Identifier: GPL-2.0-only
/*
* Driver for the Epson RTC module RX-6110 SA
*
* Copyright(C) 2015 Pengutronix, Steffen Trumtrar <kernel@pengutronix.de>
* Copyright(C) SEIKO EPSON CORPORATION 2013. All rights reserved.
*/
#include <linux/bcd.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/of_gpio.h>
#include <linux/regmap.h>
#include <linux/rtc.h>
#include <linux/of.h>
#include <linux/of_device.h>
#include <linux/spi/spi.h>
/* RX-6110 Register definitions */
#define RX6110_REG_SEC 0x10
#define RX6110_REG_MIN 0x11
#define RX6110_REG_HOUR 0x12
#define RX6110_REG_WDAY 0x13
#define RX6110_REG_MDAY 0x14
#define RX6110_REG_MONTH 0x15
#define RX6110_REG_YEAR 0x16
#define RX6110_REG_RES1 0x17
#define RX6110_REG_ALMIN 0x18
#define RX6110_REG_ALHOUR 0x19
#define RX6110_REG_ALWDAY 0x1A
#define RX6110_REG_TCOUNT0 0x1B
#define RX6110_REG_TCOUNT1 0x1C
#define RX6110_REG_EXT 0x1D
#define RX6110_REG_FLAG 0x1E
#define RX6110_REG_CTRL 0x1F
#define RX6110_REG_USER0 0x20
#define RX6110_REG_USER1 0x21
#define RX6110_REG_USER2 0x22
#define RX6110_REG_USER3 0x23
#define RX6110_REG_USER4 0x24
#define RX6110_REG_USER5 0x25
#define RX6110_REG_USER6 0x26
#define RX6110_REG_USER7 0x27
#define RX6110_REG_USER8 0x28
#define RX6110_REG_USER9 0x29
#define RX6110_REG_USERA 0x2A
#define RX6110_REG_USERB 0x2B
#define RX6110_REG_USERC 0x2C
#define RX6110_REG_USERD 0x2D
#define RX6110_REG_USERE 0x2E
#define RX6110_REG_USERF 0x2F
#define RX6110_REG_RES2 0x30
#define RX6110_REG_RES3 0x31
#define RX6110_REG_IRQ 0x32
#define RX6110_BIT_ALARM_EN BIT(7)
/* Extension Register (1Dh) bit positions */
#define RX6110_BIT_EXT_TSEL0 BIT(0)
#define RX6110_BIT_EXT_TSEL1 BIT(1)
#define RX6110_BIT_EXT_TSEL2 BIT(2)
#define RX6110_BIT_EXT_WADA BIT(3)
#define RX6110_BIT_EXT_TE BIT(4)
#define RX6110_BIT_EXT_USEL BIT(5)
#define RX6110_BIT_EXT_FSEL0 BIT(6)
#define RX6110_BIT_EXT_FSEL1 BIT(7)
/* Flag Register (1Eh) bit positions */
#define RX6110_BIT_FLAG_VLF BIT(1)
#define RX6110_BIT_FLAG_AF BIT(3)
#define RX6110_BIT_FLAG_TF BIT(4)
#define RX6110_BIT_FLAG_UF BIT(5)
/* Control Register (1Fh) bit positions */
#define RX6110_BIT_CTRL_TBKE BIT(0)
#define RX6110_BIT_CTRL_TBKON BIT(1)
#define RX6110_BIT_CTRL_TSTP BIT(2)
#define RX6110_BIT_CTRL_AIE BIT(3)
#define RX6110_BIT_CTRL_TIE BIT(4)
#define RX6110_BIT_CTRL_UIE BIT(5)
#define RX6110_BIT_CTRL_STOP BIT(6)
#define RX6110_BIT_CTRL_TEST BIT(7)
enum {
RTC_SEC = 0,
RTC_MIN,
RTC_HOUR,
RTC_WDAY,
RTC_MDAY,
RTC_MONTH,
RTC_YEAR,
RTC_NR_TIME
};
#define RX6110_DRIVER_NAME "rx6110"
struct rx6110_data {
struct rtc_device *rtc;
struct regmap *regmap;
};
/**
* rx6110_rtc_tm_to_data - convert rtc_time to native time encoding
*
* @tm: holds date and time
* @data: holds the encoding in rx6110 native form
*/
static int rx6110_rtc_tm_to_data(struct rtc_time *tm, u8 *data)
{
pr_debug("%s: date %ptRr\n", __func__, tm);
/*
* The year in the RTC is a value between 0 and 99.
* Assume that this represents the current century
* and disregard all other values.
*/
if (tm->tm_year < 100 || tm->tm_year >= 200)
return -EINVAL;
data[RTC_SEC] = bin2bcd(tm->tm_sec);
data[RTC_MIN] = bin2bcd(tm->tm_min);
data[RTC_HOUR] = bin2bcd(tm->tm_hour);
data[RTC_WDAY] = BIT(bin2bcd(tm->tm_wday));
data[RTC_MDAY] = bin2bcd(tm->tm_mday);
data[RTC_MONTH] = bin2bcd(tm->tm_mon + 1);
data[RTC_YEAR] = bin2bcd(tm->tm_year % 100);
return 0;
}
/**
* rx6110_data_to_rtc_tm - convert native time encoding to rtc_time
*
* @data: holds the encoding in rx6110 native form
* @tm: holds date and time
*/
static int rx6110_data_to_rtc_tm(u8 *data, struct rtc_time *tm)
{
tm->tm_sec = bcd2bin(data[RTC_SEC] & 0x7f);
tm->tm_min = bcd2bin(data[RTC_MIN] & 0x7f);
/* only 24-hour clock */
tm->tm_hour = bcd2bin(data[RTC_HOUR] & 0x3f);
tm->tm_wday = ffs(data[RTC_WDAY] & 0x7f);
tm->tm_mday = bcd2bin(data[RTC_MDAY] & 0x3f);
tm->tm_mon = bcd2bin(data[RTC_MONTH] & 0x1f) - 1;
tm->tm_year = bcd2bin(data[RTC_YEAR]) + 100;
pr_debug("%s: date %ptRr\n", __func__, tm);
/*
* The year in the RTC is a value between 0 and 99.
* Assume that this represents the current century
* and disregard all other values.
*/
if (tm->tm_year < 100 || tm->tm_year >= 200)
return -EINVAL;
return 0;
}
/**
* rx6110_set_time - set the current time in the rx6110 registers
*
* @dev: the rtc device in use
* @tm: holds date and time
*
* BUG: The HW assumes every year that is a multiple of 4 to be a leap
* year. Next time this is wrong is 2100, which will not be a leap year
*
* Note: If STOP is not set/cleared, the clock will start when the seconds
* register is written
*
*/
static int rx6110_set_time(struct device *dev, struct rtc_time *tm)
{
struct rx6110_data *rx6110 = dev_get_drvdata(dev);
u8 data[RTC_NR_TIME];
int ret;
ret = rx6110_rtc_tm_to_data(tm, data);
if (ret < 0)
return ret;
/* set STOP bit before changing clock/calendar */
ret = regmap_update_bits(rx6110->regmap, RX6110_REG_CTRL,
RX6110_BIT_CTRL_STOP, RX6110_BIT_CTRL_STOP);
if (ret)
return ret;
ret = regmap_bulk_write(rx6110->regmap, RX6110_REG_SEC, data,
RTC_NR_TIME);
if (ret)
return ret;
/* The time in the RTC is valid. Be sure to have VLF cleared. */
ret = regmap_update_bits(rx6110->regmap, RX6110_REG_FLAG,
RX6110_BIT_FLAG_VLF, 0);
if (ret)
return ret;
/* clear STOP bit after changing clock/calendar */
ret = regmap_update_bits(rx6110->regmap, RX6110_REG_CTRL,
RX6110_BIT_CTRL_STOP, 0);
return ret;
}
/**
* rx6110_get_time - get the current time from the rx6110 registers
* @dev: the rtc device in use
* @tm: holds date and time
*/
static int rx6110_get_time(struct device *dev, struct rtc_time *tm)
{
struct rx6110_data *rx6110 = dev_get_drvdata(dev);
u8 data[RTC_NR_TIME];
int flags;
int ret;
ret = regmap_read(rx6110->regmap, RX6110_REG_FLAG, &flags);
if (ret)
return -EINVAL;
/* check for VLF Flag (set at power-on) */
if ((flags & RX6110_BIT_FLAG_VLF)) {
dev_warn(dev, "Voltage low, data is invalid.\n");
return -EINVAL;
}
/* read registers to date */
ret = regmap_bulk_read(rx6110->regmap, RX6110_REG_SEC, data,
RTC_NR_TIME);
if (ret)
return ret;
ret = rx6110_data_to_rtc_tm(data, tm);
if (ret)
return ret;
dev_dbg(dev, "%s: date %ptRr\n", __func__, tm);
return 0;
}
static const struct reg_sequence rx6110_default_regs[] = {
{ RX6110_REG_RES1, 0xB8 },
{ RX6110_REG_RES2, 0x00 },
{ RX6110_REG_RES3, 0x10 },
{ RX6110_REG_IRQ, 0x00 },
{ RX6110_REG_ALMIN, 0x00 },
{ RX6110_REG_ALHOUR, 0x00 },
{ RX6110_REG_ALWDAY, 0x00 },
};
/**
* rx6110_init - initialize the rx6110 registers
*
* @rx6110: pointer to the rx6110 struct in use
*
*/
static int rx6110_init(struct rx6110_data *rx6110)
{
struct rtc_device *rtc = rx6110->rtc;
int flags;
int ret;
ret = regmap_update_bits(rx6110->regmap, RX6110_REG_EXT,
RX6110_BIT_EXT_TE, 0);
if (ret)
return ret;
ret = regmap_register_patch(rx6110->regmap, rx6110_default_regs,
ARRAY_SIZE(rx6110_default_regs));
if (ret)
return ret;
ret = regmap_read(rx6110->regmap, RX6110_REG_FLAG, &flags);
if (ret)
return ret;
/* check for VLF Flag (set at power-on) */
if ((flags & RX6110_BIT_FLAG_VLF))
dev_warn(&rtc->dev, "Voltage low, data loss detected.\n");
/* check for Alarm Flag */
if (flags & RX6110_BIT_FLAG_AF)
dev_warn(&rtc->dev, "An alarm may have been missed.\n");
/* check for Periodic Timer Flag */
if (flags & RX6110_BIT_FLAG_TF)
dev_warn(&rtc->dev, "Periodic timer was detected\n");
/* check for Update Timer Flag */
if (flags & RX6110_BIT_FLAG_UF)
dev_warn(&rtc->dev, "Update timer was detected\n");
/* clear all flags BUT VLF */
ret = regmap_update_bits(rx6110->regmap, RX6110_REG_FLAG,
RX6110_BIT_FLAG_AF |
RX6110_BIT_FLAG_UF |
RX6110_BIT_FLAG_TF,
0);
return ret;
}
static const struct rtc_class_ops rx6110_rtc_ops = {
.read_time = rx6110_get_time,
.set_time = rx6110_set_time,
};
static struct regmap_config regmap_spi_config = {
.reg_bits = 8,
.val_bits = 8,
.max_register = RX6110_REG_IRQ,
.read_flag_mask = 0x80,
};
/**
* rx6110_probe - initialize rtc driver
* @spi: pointer to spi device
*/
static int rx6110_probe(struct spi_device *spi)
{
struct rx6110_data *rx6110;
int err;
if ((spi->bits_per_word && spi->bits_per_word != 8) ||
(spi->max_speed_hz > 2000000) ||
(spi->mode != (SPI_CS_HIGH | SPI_CPOL | SPI_CPHA))) {
dev_warn(&spi->dev, "SPI settings: bits_per_word: %d, max_speed_hz: %d, mode: %xh\n",
spi->bits_per_word, spi->max_speed_hz, spi->mode);
dev_warn(&spi->dev, "driving device in an unsupported mode");
}
rx6110 = devm_kzalloc(&spi->dev, sizeof(*rx6110), GFP_KERNEL);
if (!rx6110)
return -ENOMEM;
rx6110->regmap = devm_regmap_init_spi(spi, &regmap_spi_config);
if (IS_ERR(rx6110->regmap)) {
dev_err(&spi->dev, "regmap init failed for rtc rx6110\n");
return PTR_ERR(rx6110->regmap);
}
spi_set_drvdata(spi, rx6110);
rx6110->rtc = devm_rtc_device_register(&spi->dev,
RX6110_DRIVER_NAME,
&rx6110_rtc_ops, THIS_MODULE);
if (IS_ERR(rx6110->rtc))
return PTR_ERR(rx6110->rtc);
err = rx6110_init(rx6110);
if (err)
return err;
rx6110->rtc->max_user_freq = 1;
return 0;
}
static const struct spi_device_id rx6110_id[] = {
{ "rx6110", 0 },
{ }
};
MODULE_DEVICE_TABLE(spi, rx6110_id);
static const struct of_device_id rx6110_spi_of_match[] = {
{ .compatible = "epson,rx6110" },
{ },
};
MODULE_DEVICE_TABLE(of, rx6110_spi_of_match);
static struct spi_driver rx6110_driver = {
.driver = {
.name = RX6110_DRIVER_NAME,
.of_match_table = of_match_ptr(rx6110_spi_of_match),
},
.probe = rx6110_probe,
.id_table = rx6110_id,
};
module_spi_driver(rx6110_driver);
MODULE_AUTHOR("Val Krutov <val.krutov@erd.epson.com>");
MODULE_DESCRIPTION("RX-6110 SA RTC driver");
MODULE_LICENSE("GPL");
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