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292 lines
7.6 KiB
292 lines
7.6 KiB
// SPDX-License-Identifier: GPL-2.0-only |
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/* drivers/rtc/rtc-rx4581.c |
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* |
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* written by Torben Hohn <[email protected]> |
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* |
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* Based on: |
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* drivers/rtc/rtc-max6902.c |
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* |
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* Copyright (C) 2006 8D Technologies inc. |
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* Copyright (C) 2004 Compulab Ltd. |
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* |
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* Driver for MAX6902 spi RTC |
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* |
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* and based on: |
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* drivers/rtc/rtc-rx8581.c |
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* |
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* An I2C driver for the Epson RX8581 RTC |
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* |
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* Author: Martyn Welch <[email protected]> |
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* Copyright 2008 GE Intelligent Platforms Embedded Systems, Inc. |
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* |
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* Based on: rtc-pcf8563.c (An I2C driver for the Philips PCF8563 RTC) |
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* Copyright 2005-06 Tower Technologies |
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*/ |
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#include <linux/module.h> |
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#include <linux/kernel.h> |
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#include <linux/platform_device.h> |
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#include <linux/init.h> |
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#include <linux/rtc.h> |
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#include <linux/spi/spi.h> |
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#include <linux/bcd.h> |
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#define RX4581_REG_SC 0x00 /* Second in BCD */ |
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#define RX4581_REG_MN 0x01 /* Minute in BCD */ |
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#define RX4581_REG_HR 0x02 /* Hour in BCD */ |
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#define RX4581_REG_DW 0x03 /* Day of Week */ |
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#define RX4581_REG_DM 0x04 /* Day of Month in BCD */ |
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#define RX4581_REG_MO 0x05 /* Month in BCD */ |
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#define RX4581_REG_YR 0x06 /* Year in BCD */ |
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#define RX4581_REG_RAM 0x07 /* RAM */ |
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#define RX4581_REG_AMN 0x08 /* Alarm Min in BCD*/ |
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#define RX4581_REG_AHR 0x09 /* Alarm Hour in BCD */ |
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#define RX4581_REG_ADM 0x0A |
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#define RX4581_REG_ADW 0x0A |
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#define RX4581_REG_TMR0 0x0B |
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#define RX4581_REG_TMR1 0x0C |
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#define RX4581_REG_EXT 0x0D /* Extension Register */ |
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#define RX4581_REG_FLAG 0x0E /* Flag Register */ |
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#define RX4581_REG_CTRL 0x0F /* Control Register */ |
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/* Flag Register bit definitions */ |
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#define RX4581_FLAG_UF 0x20 /* Update */ |
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#define RX4581_FLAG_TF 0x10 /* Timer */ |
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#define RX4581_FLAG_AF 0x08 /* Alarm */ |
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#define RX4581_FLAG_VLF 0x02 /* Voltage Low */ |
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/* Control Register bit definitions */ |
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#define RX4581_CTRL_UIE 0x20 /* Update Interrupt Enable */ |
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#define RX4581_CTRL_TIE 0x10 /* Timer Interrupt Enable */ |
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#define RX4581_CTRL_AIE 0x08 /* Alarm Interrupt Enable */ |
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#define RX4581_CTRL_STOP 0x02 /* STOP bit */ |
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#define RX4581_CTRL_RESET 0x01 /* RESET bit */ |
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static int rx4581_set_reg(struct device *dev, unsigned char address, |
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unsigned char data) |
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{ |
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struct spi_device *spi = to_spi_device(dev); |
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unsigned char buf[2]; |
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/* high nibble must be '0' to write */ |
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buf[0] = address & 0x0f; |
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buf[1] = data; |
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return spi_write_then_read(spi, buf, 2, NULL, 0); |
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} |
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static int rx4581_get_reg(struct device *dev, unsigned char address, |
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unsigned char *data) |
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{ |
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struct spi_device *spi = to_spi_device(dev); |
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/* Set MSB to indicate read */ |
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*data = address | 0x80; |
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return spi_write_then_read(spi, data, 1, data, 1); |
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} |
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/* |
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* In the routines that deal directly with the rx8581 hardware, we use |
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* rtc_time -- month 0-11, hour 0-23, yr = calendar year-epoch. |
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*/ |
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static int rx4581_get_datetime(struct device *dev, struct rtc_time *tm) |
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{ |
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struct spi_device *spi = to_spi_device(dev); |
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unsigned char date[7]; |
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unsigned char data; |
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int err; |
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/* First we ensure that the "update flag" is not set, we read the |
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* time and date then re-read the "update flag". If the update flag |
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* has been set, we know that the time has changed during the read so |
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* we repeat the whole process again. |
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*/ |
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err = rx4581_get_reg(dev, RX4581_REG_FLAG, &data); |
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if (err != 0) { |
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dev_err(dev, "Unable to read device flags\n"); |
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return -EIO; |
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} |
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do { |
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/* If update flag set, clear it */ |
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if (data & RX4581_FLAG_UF) { |
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err = rx4581_set_reg(dev, |
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RX4581_REG_FLAG, (data & ~RX4581_FLAG_UF)); |
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if (err != 0) { |
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dev_err(dev, "Unable to write device " |
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"flags\n"); |
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return -EIO; |
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} |
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} |
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/* Now read time and date */ |
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date[0] = 0x80; |
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err = spi_write_then_read(spi, date, 1, date, 7); |
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if (err < 0) { |
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dev_err(dev, "Unable to read date\n"); |
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return -EIO; |
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} |
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/* Check flag register */ |
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err = rx4581_get_reg(dev, RX4581_REG_FLAG, &data); |
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if (err != 0) { |
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dev_err(dev, "Unable to read device flags\n"); |
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return -EIO; |
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} |
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} while (data & RX4581_FLAG_UF); |
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if (data & RX4581_FLAG_VLF) |
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dev_info(dev, |
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"low voltage detected, date/time is not reliable.\n"); |
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dev_dbg(dev, |
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"%s: raw data is sec=%02x, min=%02x, hr=%02x, " |
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"wday=%02x, mday=%02x, mon=%02x, year=%02x\n", |
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__func__, |
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date[0], date[1], date[2], date[3], date[4], date[5], date[6]); |
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tm->tm_sec = bcd2bin(date[RX4581_REG_SC] & 0x7F); |
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tm->tm_min = bcd2bin(date[RX4581_REG_MN] & 0x7F); |
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tm->tm_hour = bcd2bin(date[RX4581_REG_HR] & 0x3F); /* rtc hr 0-23 */ |
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tm->tm_wday = ilog2(date[RX4581_REG_DW] & 0x7F); |
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tm->tm_mday = bcd2bin(date[RX4581_REG_DM] & 0x3F); |
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tm->tm_mon = bcd2bin(date[RX4581_REG_MO] & 0x1F) - 1; /* rtc mn 1-12 */ |
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tm->tm_year = bcd2bin(date[RX4581_REG_YR]); |
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if (tm->tm_year < 70) |
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tm->tm_year += 100; /* assume we are in 1970...2069 */ |
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dev_dbg(dev, "%s: tm is secs=%d, mins=%d, hours=%d, " |
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"mday=%d, mon=%d, year=%d, wday=%d\n", |
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__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, tm->tm_wday); |
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return 0; |
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} |
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static int rx4581_set_datetime(struct device *dev, struct rtc_time *tm) |
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{ |
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struct spi_device *spi = to_spi_device(dev); |
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int err; |
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unsigned char buf[8], data; |
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dev_dbg(dev, "%s: secs=%d, mins=%d, hours=%d, " |
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"mday=%d, mon=%d, year=%d, wday=%d\n", |
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__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, tm->tm_wday); |
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buf[0] = 0x00; |
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/* hours, minutes and seconds */ |
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buf[RX4581_REG_SC+1] = bin2bcd(tm->tm_sec); |
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buf[RX4581_REG_MN+1] = bin2bcd(tm->tm_min); |
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buf[RX4581_REG_HR+1] = bin2bcd(tm->tm_hour); |
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buf[RX4581_REG_DM+1] = bin2bcd(tm->tm_mday); |
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/* month, 1 - 12 */ |
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buf[RX4581_REG_MO+1] = bin2bcd(tm->tm_mon + 1); |
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/* year and century */ |
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buf[RX4581_REG_YR+1] = bin2bcd(tm->tm_year % 100); |
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buf[RX4581_REG_DW+1] = (0x1 << tm->tm_wday); |
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/* Stop the clock */ |
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err = rx4581_get_reg(dev, RX4581_REG_CTRL, &data); |
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if (err != 0) { |
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dev_err(dev, "Unable to read control register\n"); |
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return -EIO; |
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} |
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err = rx4581_set_reg(dev, RX4581_REG_CTRL, |
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(data | RX4581_CTRL_STOP)); |
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if (err != 0) { |
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dev_err(dev, "Unable to write control register\n"); |
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return -EIO; |
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} |
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/* write register's data */ |
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err = spi_write_then_read(spi, buf, 8, NULL, 0); |
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if (err != 0) { |
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dev_err(dev, "Unable to write to date registers\n"); |
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return -EIO; |
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} |
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/* get VLF and clear it */ |
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err = rx4581_get_reg(dev, RX4581_REG_FLAG, &data); |
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if (err != 0) { |
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dev_err(dev, "Unable to read flag register\n"); |
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return -EIO; |
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} |
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err = rx4581_set_reg(dev, RX4581_REG_FLAG, |
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(data & ~(RX4581_FLAG_VLF))); |
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if (err != 0) { |
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dev_err(dev, "Unable to write flag register\n"); |
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return -EIO; |
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} |
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/* Restart the clock */ |
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err = rx4581_get_reg(dev, RX4581_REG_CTRL, &data); |
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if (err != 0) { |
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dev_err(dev, "Unable to read control register\n"); |
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return -EIO; |
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} |
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err = rx4581_set_reg(dev, RX4581_REG_CTRL, |
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(data & ~(RX4581_CTRL_STOP))); |
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if (err != 0) { |
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dev_err(dev, "Unable to write control register\n"); |
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return -EIO; |
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} |
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return 0; |
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} |
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static const struct rtc_class_ops rx4581_rtc_ops = { |
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.read_time = rx4581_get_datetime, |
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.set_time = rx4581_set_datetime, |
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}; |
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static int rx4581_probe(struct spi_device *spi) |
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{ |
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struct rtc_device *rtc; |
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unsigned char tmp; |
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int res; |
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res = rx4581_get_reg(&spi->dev, RX4581_REG_SC, &tmp); |
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if (res != 0) |
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return res; |
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rtc = devm_rtc_device_register(&spi->dev, "rx4581", |
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&rx4581_rtc_ops, THIS_MODULE); |
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if (IS_ERR(rtc)) |
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return PTR_ERR(rtc); |
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spi_set_drvdata(spi, rtc); |
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return 0; |
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} |
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static const struct spi_device_id rx4581_id[] = { |
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{ "rx4581", 0 }, |
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{ } |
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}; |
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MODULE_DEVICE_TABLE(spi, rx4581_id); |
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static struct spi_driver rx4581_driver = { |
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.driver = { |
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.name = "rtc-rx4581", |
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}, |
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.probe = rx4581_probe, |
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.id_table = rx4581_id, |
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}; |
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module_spi_driver(rx4581_driver); |
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MODULE_DESCRIPTION("rx4581 spi RTC driver"); |
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MODULE_AUTHOR("Torben Hohn"); |
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MODULE_LICENSE("GPL"); |
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MODULE_ALIAS("spi:rtc-rx4581");
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