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![Alexandre Belloni](/assets/img/avatar_default.png)
The RTC core is always calling rtc_valid_tm after the read_time callback. It is not necessary to call it just before returning from the callback. Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
401 lines
10 KiB
C
401 lines
10 KiB
C
/*
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* Driver for the Epson RTC module RX-6110 SA
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*
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* Copyright(C) 2015 Pengutronix, Steffen Trumtrar <kernel@pengutronix.de>
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* Copyright(C) SEIKO EPSON CORPORATION 2013. All rights reserved.
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*
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* This driver software is distributed as is, without any warranty of any kind,
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* either express or implied as further specified in the GNU Public License.
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* This software may be used and distributed according to the terms of the GNU
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* Public License, version 2 as published by the Free Software Foundation.
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* See the file COPYING in the main directory of this archive for more details.
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*
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* You should have received a copy of the GNU General Public License along with
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* this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include <linux/bcd.h>
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#include <linux/init.h>
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/of_gpio.h>
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#include <linux/regmap.h>
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#include <linux/rtc.h>
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#include <linux/spi/spi.h>
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/* RX-6110 Register definitions */
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#define RX6110_REG_SEC 0x10
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#define RX6110_REG_MIN 0x11
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#define RX6110_REG_HOUR 0x12
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#define RX6110_REG_WDAY 0x13
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#define RX6110_REG_MDAY 0x14
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#define RX6110_REG_MONTH 0x15
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#define RX6110_REG_YEAR 0x16
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#define RX6110_REG_RES1 0x17
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#define RX6110_REG_ALMIN 0x18
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#define RX6110_REG_ALHOUR 0x19
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#define RX6110_REG_ALWDAY 0x1A
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#define RX6110_REG_TCOUNT0 0x1B
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#define RX6110_REG_TCOUNT1 0x1C
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#define RX6110_REG_EXT 0x1D
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#define RX6110_REG_FLAG 0x1E
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#define RX6110_REG_CTRL 0x1F
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#define RX6110_REG_USER0 0x20
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#define RX6110_REG_USER1 0x21
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#define RX6110_REG_USER2 0x22
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#define RX6110_REG_USER3 0x23
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#define RX6110_REG_USER4 0x24
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#define RX6110_REG_USER5 0x25
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#define RX6110_REG_USER6 0x26
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#define RX6110_REG_USER7 0x27
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#define RX6110_REG_USER8 0x28
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#define RX6110_REG_USER9 0x29
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#define RX6110_REG_USERA 0x2A
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#define RX6110_REG_USERB 0x2B
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#define RX6110_REG_USERC 0x2C
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#define RX6110_REG_USERD 0x2D
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#define RX6110_REG_USERE 0x2E
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#define RX6110_REG_USERF 0x2F
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#define RX6110_REG_RES2 0x30
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#define RX6110_REG_RES3 0x31
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#define RX6110_REG_IRQ 0x32
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#define RX6110_BIT_ALARM_EN BIT(7)
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/* Extension Register (1Dh) bit positions */
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#define RX6110_BIT_EXT_TSEL0 BIT(0)
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#define RX6110_BIT_EXT_TSEL1 BIT(1)
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#define RX6110_BIT_EXT_TSEL2 BIT(2)
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#define RX6110_BIT_EXT_WADA BIT(3)
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#define RX6110_BIT_EXT_TE BIT(4)
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#define RX6110_BIT_EXT_USEL BIT(5)
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#define RX6110_BIT_EXT_FSEL0 BIT(6)
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#define RX6110_BIT_EXT_FSEL1 BIT(7)
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/* Flag Register (1Eh) bit positions */
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#define RX6110_BIT_FLAG_VLF BIT(1)
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#define RX6110_BIT_FLAG_AF BIT(3)
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#define RX6110_BIT_FLAG_TF BIT(4)
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#define RX6110_BIT_FLAG_UF BIT(5)
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/* Control Register (1Fh) bit positions */
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#define RX6110_BIT_CTRL_TBKE BIT(0)
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#define RX6110_BIT_CTRL_TBKON BIT(1)
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#define RX6110_BIT_CTRL_TSTP BIT(2)
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#define RX6110_BIT_CTRL_AIE BIT(3)
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#define RX6110_BIT_CTRL_TIE BIT(4)
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#define RX6110_BIT_CTRL_UIE BIT(5)
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#define RX6110_BIT_CTRL_STOP BIT(6)
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#define RX6110_BIT_CTRL_TEST BIT(7)
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enum {
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RTC_SEC = 0,
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RTC_MIN,
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RTC_HOUR,
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RTC_WDAY,
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RTC_MDAY,
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RTC_MONTH,
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RTC_YEAR,
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RTC_NR_TIME
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};
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#define RX6110_DRIVER_NAME "rx6110"
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struct rx6110_data {
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struct rtc_device *rtc;
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struct regmap *regmap;
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};
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/**
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* rx6110_rtc_tm_to_data - convert rtc_time to native time encoding
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*
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* @tm: holds date and time
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* @data: holds the encoding in rx6110 native form
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*/
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static int rx6110_rtc_tm_to_data(struct rtc_time *tm, u8 *data)
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{
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pr_debug("%s: date %ds %dm %dh %dmd %dm %dy\n", __func__,
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tm->tm_sec, tm->tm_min, tm->tm_hour,
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tm->tm_mday, tm->tm_mon, tm->tm_year);
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/*
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* The year in the RTC is a value between 0 and 99.
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* Assume that this represents the current century
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* and disregard all other values.
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*/
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if (tm->tm_year < 100 || tm->tm_year >= 200)
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return -EINVAL;
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data[RTC_SEC] = bin2bcd(tm->tm_sec);
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data[RTC_MIN] = bin2bcd(tm->tm_min);
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data[RTC_HOUR] = bin2bcd(tm->tm_hour);
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data[RTC_WDAY] = BIT(bin2bcd(tm->tm_wday));
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data[RTC_MDAY] = bin2bcd(tm->tm_mday);
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data[RTC_MONTH] = bin2bcd(tm->tm_mon + 1);
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data[RTC_YEAR] = bin2bcd(tm->tm_year % 100);
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return 0;
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}
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/**
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* rx6110_data_to_rtc_tm - convert native time encoding to rtc_time
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*
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* @data: holds the encoding in rx6110 native form
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* @tm: holds date and time
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*/
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static int rx6110_data_to_rtc_tm(u8 *data, struct rtc_time *tm)
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{
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tm->tm_sec = bcd2bin(data[RTC_SEC] & 0x7f);
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tm->tm_min = bcd2bin(data[RTC_MIN] & 0x7f);
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/* only 24-hour clock */
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tm->tm_hour = bcd2bin(data[RTC_HOUR] & 0x3f);
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tm->tm_wday = ffs(data[RTC_WDAY] & 0x7f);
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tm->tm_mday = bcd2bin(data[RTC_MDAY] & 0x3f);
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tm->tm_mon = bcd2bin(data[RTC_MONTH] & 0x1f) - 1;
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tm->tm_year = bcd2bin(data[RTC_YEAR]) + 100;
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pr_debug("%s: date %ds %dm %dh %dmd %dm %dy\n", __func__,
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tm->tm_sec, tm->tm_min, tm->tm_hour,
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tm->tm_mday, tm->tm_mon, tm->tm_year);
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/*
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* The year in the RTC is a value between 0 and 99.
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* Assume that this represents the current century
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* and disregard all other values.
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*/
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if (tm->tm_year < 100 || tm->tm_year >= 200)
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return -EINVAL;
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return 0;
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}
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/**
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* rx6110_set_time - set the current time in the rx6110 registers
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*
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* @dev: the rtc device in use
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* @tm: holds date and time
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*
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* BUG: The HW assumes every year that is a multiple of 4 to be a leap
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* year. Next time this is wrong is 2100, which will not be a leap year
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*
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* Note: If STOP is not set/cleared, the clock will start when the seconds
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* register is written
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*
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*/
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static int rx6110_set_time(struct device *dev, struct rtc_time *tm)
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{
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struct rx6110_data *rx6110 = dev_get_drvdata(dev);
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u8 data[RTC_NR_TIME];
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int ret;
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ret = rx6110_rtc_tm_to_data(tm, data);
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if (ret < 0)
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return ret;
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/* set STOP bit before changing clock/calendar */
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ret = regmap_update_bits(rx6110->regmap, RX6110_REG_CTRL,
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RX6110_BIT_CTRL_STOP, RX6110_BIT_CTRL_STOP);
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if (ret)
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return ret;
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ret = regmap_bulk_write(rx6110->regmap, RX6110_REG_SEC, data,
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RTC_NR_TIME);
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if (ret)
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return ret;
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/* The time in the RTC is valid. Be sure to have VLF cleared. */
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ret = regmap_update_bits(rx6110->regmap, RX6110_REG_FLAG,
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RX6110_BIT_FLAG_VLF, 0);
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if (ret)
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return ret;
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/* clear STOP bit after changing clock/calendar */
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ret = regmap_update_bits(rx6110->regmap, RX6110_REG_CTRL,
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RX6110_BIT_CTRL_STOP, 0);
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return ret;
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}
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/**
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* rx6110_get_time - get the current time from the rx6110 registers
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* @dev: the rtc device in use
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* @tm: holds date and time
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*/
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static int rx6110_get_time(struct device *dev, struct rtc_time *tm)
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{
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struct rx6110_data *rx6110 = dev_get_drvdata(dev);
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u8 data[RTC_NR_TIME];
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int flags;
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int ret;
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ret = regmap_read(rx6110->regmap, RX6110_REG_FLAG, &flags);
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if (ret)
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return -EINVAL;
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/* check for VLF Flag (set at power-on) */
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if ((flags & RX6110_BIT_FLAG_VLF)) {
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dev_warn(dev, "Voltage low, data is invalid.\n");
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return -EINVAL;
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}
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/* read registers to date */
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ret = regmap_bulk_read(rx6110->regmap, RX6110_REG_SEC, data,
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RTC_NR_TIME);
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if (ret)
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return ret;
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ret = rx6110_data_to_rtc_tm(data, tm);
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if (ret)
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return ret;
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dev_dbg(dev, "%s: date %ds %dm %dh %dmd %dm %dy\n", __func__,
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tm->tm_sec, tm->tm_min, tm->tm_hour,
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tm->tm_mday, tm->tm_mon, tm->tm_year);
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return 0;
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}
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static const struct reg_sequence rx6110_default_regs[] = {
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{ RX6110_REG_RES1, 0xB8 },
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{ RX6110_REG_RES2, 0x00 },
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{ RX6110_REG_RES3, 0x10 },
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{ RX6110_REG_IRQ, 0x00 },
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{ RX6110_REG_ALMIN, 0x00 },
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{ RX6110_REG_ALHOUR, 0x00 },
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{ RX6110_REG_ALWDAY, 0x00 },
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};
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/**
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* rx6110_init - initialize the rx6110 registers
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*
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* @rx6110: pointer to the rx6110 struct in use
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*
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*/
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static int rx6110_init(struct rx6110_data *rx6110)
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{
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struct rtc_device *rtc = rx6110->rtc;
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int flags;
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int ret;
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ret = regmap_update_bits(rx6110->regmap, RX6110_REG_EXT,
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RX6110_BIT_EXT_TE, 0);
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if (ret)
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return ret;
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ret = regmap_register_patch(rx6110->regmap, rx6110_default_regs,
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ARRAY_SIZE(rx6110_default_regs));
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if (ret)
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return ret;
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ret = regmap_read(rx6110->regmap, RX6110_REG_FLAG, &flags);
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if (ret)
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return ret;
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/* check for VLF Flag (set at power-on) */
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if ((flags & RX6110_BIT_FLAG_VLF))
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dev_warn(&rtc->dev, "Voltage low, data loss detected.\n");
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/* check for Alarm Flag */
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if (flags & RX6110_BIT_FLAG_AF)
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dev_warn(&rtc->dev, "An alarm may have been missed.\n");
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/* check for Periodic Timer Flag */
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if (flags & RX6110_BIT_FLAG_TF)
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dev_warn(&rtc->dev, "Periodic timer was detected\n");
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/* check for Update Timer Flag */
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if (flags & RX6110_BIT_FLAG_UF)
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dev_warn(&rtc->dev, "Update timer was detected\n");
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/* clear all flags BUT VLF */
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ret = regmap_update_bits(rx6110->regmap, RX6110_REG_FLAG,
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RX6110_BIT_FLAG_AF |
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RX6110_BIT_FLAG_UF |
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RX6110_BIT_FLAG_TF,
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0);
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return ret;
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}
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static const struct rtc_class_ops rx6110_rtc_ops = {
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.read_time = rx6110_get_time,
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.set_time = rx6110_set_time,
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};
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static struct regmap_config regmap_spi_config = {
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.reg_bits = 8,
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.val_bits = 8,
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.max_register = RX6110_REG_IRQ,
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.read_flag_mask = 0x80,
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};
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/**
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* rx6110_probe - initialize rtc driver
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* @spi: pointer to spi device
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*/
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static int rx6110_probe(struct spi_device *spi)
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{
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struct rx6110_data *rx6110;
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int err;
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if ((spi->bits_per_word && spi->bits_per_word != 8) ||
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(spi->max_speed_hz > 2000000) ||
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(spi->mode != (SPI_CS_HIGH | SPI_CPOL | SPI_CPHA))) {
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dev_warn(&spi->dev, "SPI settings: bits_per_word: %d, max_speed_hz: %d, mode: %xh\n",
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spi->bits_per_word, spi->max_speed_hz, spi->mode);
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dev_warn(&spi->dev, "driving device in an unsupported mode");
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}
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rx6110 = devm_kzalloc(&spi->dev, sizeof(*rx6110), GFP_KERNEL);
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if (!rx6110)
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return -ENOMEM;
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rx6110->regmap = devm_regmap_init_spi(spi, ®map_spi_config);
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if (IS_ERR(rx6110->regmap)) {
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dev_err(&spi->dev, "regmap init failed for rtc rx6110\n");
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return PTR_ERR(rx6110->regmap);
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}
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spi_set_drvdata(spi, rx6110);
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rx6110->rtc = devm_rtc_device_register(&spi->dev,
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RX6110_DRIVER_NAME,
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&rx6110_rtc_ops, THIS_MODULE);
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if (IS_ERR(rx6110->rtc))
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return PTR_ERR(rx6110->rtc);
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err = rx6110_init(rx6110);
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if (err)
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return err;
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rx6110->rtc->max_user_freq = 1;
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return 0;
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}
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static int rx6110_remove(struct spi_device *spi)
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{
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return 0;
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}
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static const struct spi_device_id rx6110_id[] = {
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{ "rx6110", 0 },
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{ }
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};
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MODULE_DEVICE_TABLE(spi, rx6110_id);
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static struct spi_driver rx6110_driver = {
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.driver = {
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.name = RX6110_DRIVER_NAME,
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},
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.probe = rx6110_probe,
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.remove = rx6110_remove,
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.id_table = rx6110_id,
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};
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module_spi_driver(rx6110_driver);
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MODULE_AUTHOR("Val Krutov <val.krutov@erd.epson.com>");
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MODULE_DESCRIPTION("RX-6110 SA RTC driver");
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MODULE_LICENSE("GPL");
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